Method for producing grease based on open type fermentation of bacteriostatic traditional Chinese medicine residues

Abstract

The invention is applicable to the technical field of resource utilization and biological refinery of plant-derived traditional Chinese medicine residues, and provides an open type fermentation grease production method based on bacteriostatic traditional Chinese medicine residues, which comprises the following steps: firstly, mixing the bacteriostatic traditional Chinese medicine residues and traditional Chinese medicine residues rich in polysaccharide, and then carrying out dilute acid pretreatment; then cellulase is added for hydrolysis to prepare traditional Chinese medicine residue hydrolysate as a fermentation culture medium, the fermentation culture medium does not need to be sterilized, the oleaginous yeast is directly inoculated for open fermentation, bacteriostatic components in the mixed medicine residues can avoid infectious microbe pollution, and fermentable sugar can be efficiently converted into microbial oil by the oleaginous yeast. The method is simple and efficient to operate, adopts an open fermentation mode, avoids sugar loss caused by high-temperature and high-pressure sterilization, remarkably reduces the process and equipment cost, improves the grease yield and the grease production efficiency, and has obvious comprehensive technical advantages. The fatty acid composition of the prepared microbial oil is similar to that of vegetable oil, and the microbial oil is suitable for being used as a biodiesel raw material.

Description

Technical Field

[0001] The invention belongs to the technical field of resource utilization of traditional Chinese medicine residues and biorefining, and in particular relates to a method for producing oil through open fermentation of antibacterial traditional Chinese medicine residues. Background Art

[0002] Some oleaginous yeasts in nature can use various cheap carbon sources as energy sources to synthesize and store large amounts of oil under certain conditions. Yeasts that can accumulate oil in their cells and exceed 20% (w / w) of their cell dry weight are called oleaginous yeasts. Some oleaginous yeasts can even accumulate more than 80% of their cell dry weight in their cells. The main component of the oil produced by oleaginous yeast is triglycerides, and its fatty acid composition is similar to that of commercial animal and vegetable oils, mainly C 16 -C 18 Long-chain fatty acid composition. Compared with animal and vegetable oils, bio-oil production has the characteristics of short production cycle, no seasonal and climate restrictions, wide sources of raw materials, and easy implementation of large-scale production. It is a new type of oil resource with great potential. Bio-oil can not only be used as a substitute for edible oil or other functional oils, but also provide raw materials for the sustainable development of the biodiesel industry.

[0003] As a by-product generated during the production and processing of traditional Chinese medicine, Chinese medicine residues include mixed solid wastes such as plant roots, stems, leaves, animal residues, and minerals. They are not only underutilized biomass resources, but also a potential source of environmental pollution. Its composition is complex, including medicinal residues, extract residues, etc. However, most Chinese medicine residues are treated as waste, resulting in waste of resources and environmental pollution. Due to the lack of effective management and utilization mechanisms, the random stacking or dumping of Chinese medicine residues has a serious impact on the surrounding environment. Plant-based Chinese medicine residues contain rich cellulose, hemicellulose, polysaccharides, proteins, fats and trace elements, which can provide sufficient nutrient sources for microorganisms. However, due to the low bioavailability of cellulose and lignin structures, the pretreatment step and saccharolysis process become particularly critical in the process of lignocellulose biorefining. Biomass conversion is a complex process, which mainly includes five core steps: selecting suitable biomass, effective pretreatment of raw materials, enzymatic saccharification, microbial fermentation, and downstream processing. After processing, the plant-based medicinal residue releases nutrients and is converted into renewable energy sources such as ethanol, methane, and biodiesel through microbial fermentation, demonstrating great potential in energy conversion and resource recycling.

[0004] Chinese herbal medicine is an important source of natural compounds. Many drugs used clinically are extracted from Chinese herbal medicine. Antibacterial drug residue metabolites are mainly divided into two categories: primary and secondary. Among them, carbohydrates and lipids are the basic substances produced by plants through primary metabolic pathways. Secondary metabolites include phenolic compounds, carotenoids, alkaloids, saponins and terpenoids. These secondary metabolites play an important role in plants, and many of them have significant pharmacological properties, such as anti-inflammatory, anti-tumor, antioxidant and antibacterial activities. Antibacterial Chinese herbal medicine residues, which are regarded as waste, may have a negative impact on the environment and ecosystem if not properly treated. Through fermentation treatment, these wastes can be converted into valuable products, thereby reducing waste emissions. The fermentation process can convert organic matter in antibacterial drug residues into biofertilizers, biofeeds, etc., realizing the recycling of resources. This not only helps to reduce environmental pollution, but also provides a sustainable source of nutrients for agriculture and animal husbandry.

[0005] Open fermentation systems that do not require sterilization have shown great advantages in biochemical production, especially by eliminating high-temperature and high-pressure sterilization operations, which significantly saves energy and thus reduces production costs. Studies have shown that for a plant that can produce 10,000 tons of microbial lipids per year, the cost of sterilization accounts for 1.4% of the total utility cost and 4% of the installation cost of the fermentation process. For two-stage microbial lipid production with a working volume of 24,000L, the non-sterile process significantly reduces the total utility cost. Non-sterile fermentation technology can significantly reduce energy consumption and equipment costs, improve production efficiency, and achieve effective fermentation of microorganisms. Secondly, these technologies are generally more environmentally friendly and reduce the emission of wastewater and exhaust gas. However, this open system also faces the potential risk of contamination by infectious microorganisms. It is quite challenging to ferment under non-sterile conditions without affecting the performance of the bioreactor. This difficulty limits the widespread application of non-sterile fermentation.

[0006] Since Chinese medicine residue itself is a carbon source waste, by hydrolyzing Chinese medicine residue into fermentable sugar as fermentation raw material, it can achieve effective utilization of resources, reduce waste emissions, and conform to the concept of green and sustainable production. The antibacterial Chinese medicine residue itself has a certain antibacterial effect. If the hydrolyzed sugar solution can still maintain a certain selective antibacterial property, it will help improve the adaptability and fermentation efficiency of microorganisms, inhibit the growth of miscellaneous bacteria to a certain extent, reduce pollution problems in the fermentation process, and reduce the need for additional antibacterial agents. Therefore, using antibacterial Chinese medicine residue as a raw material for non-sterile fermentation not only achieves effective utilization of resources and waste reduction, but also may help improve fermentation efficiency and product quality and reduce production costs. Summary of the invention

[0007] In view of the above problems, the purpose of the present invention is to provide a method for producing oil based on open fermentation of antibacterial Chinese medicine residues, aiming to solve the problems of complex process flow, high fermentation cost and low oil yield in the existing preparation of microbial oils from Chinese medicine residues.

[0008] The method for producing oil by open fermentation based on antibacterial Chinese medicine residues comprises the following steps:

[0009] Step S1: Select selective antibacterial Chinese medicine residues, mix the Chinese medicine residues with other polysaccharide-rich Chinese medicine residues, and perform dilute acid pretreatment;

[0010] Step S2: adjusting the antibacterial Chinese medicine residue after acid pretreatment in S1 to a suitable pH, adding a certain amount of cellulase, performing enzymatic hydrolysis at a certain temperature for a period of time, and directly using the enzymatic hydrolyzate obtained by solid-liquid separation as a fermentation medium without sterilization;

[0011] Step S3: culturing the oil-producing yeast in a seed culture medium to obtain an oil-producing microbial seed liquid;

[0012] Step S4: inoculate the oil-producing microbial seed liquid obtained in step S3 into the fermentation medium obtained in step S2, and culture it with ventilation for a period of time under a non-sterile environment and a certain temperature and pH. When the total concentration of the carbon source in the culture medium is lower than the set threshold, the fermentation is terminated.

[0013] Step S5: collecting the solid phase containing the oleaginous yeast by solid-liquid separation, and then extracting the intracellular lipids from the collected solid phase.

[0014] Specifically, in step S1, the antibacterial Chinese medicine residue is a plant-derived antibacterial Chinese medicine residue mainly composed of cellulose, hemicellulose, lignin and protein, and containing a small amount of trace elements and effective medicinal ingredients. Its enzymatic hydrolyzate can selectively inhibit Gram-negative bacteria and Gram-positive bacteria, but has no inhibitory effect on some oil-producing yeasts. The antibacterial Chinese medicine residue includes one or more of the residues of Rehmannia glutinosa, Platycodon grandiflorum, Scrophularia ningpoensis, Pulsatilla striata, Bletilla striata, Codonopsis pilosula, and Galla chinensis. The polysaccharide-rich Chinese medicine residue is a Chinese medicine residue with a high polysaccharide content in the residue components, and after acid hydrolysis and enzyme hydrolysis, the polysaccharide can be hydrolyzed into fermentable sugars. Including one or more of the residues of Poria cocos, Paeonia suffruticosa, Licorice, Codonopsis pilosula, Ginkgo biloba, White Peony Root, Pueraria lobata, Curcuma longa, and Radix Isatidis. The mixed residue is a mixed residue after the residues with strong antibacterial effect are mixed with the residues with high polysaccharide content in any proportion.

[0015] Specifically, in step S1, the acid is sulfuric acid, hydrochloric acid or nitric acid, the acid concentration range is 1g / L to 10g / L, the pretreatment temperature is 120°C to 190°C, and the pretreatment time is 5min to 2h. The mixed Chinese medicine residue is evenly mixed with dilute acid according to a solid-liquid ratio of 8% to 15% (w / v), and pretreated at high temperature, where w / v is a mass volume ratio.

[0016] Specifically, in step S2, the acid pretreatment of the Chinese medicinal residue is adjusted to a pH value of 4.5 to 5.5. Cellulase is added at an enzyme loading of 5 to 20 FPU / g, and enzymolysis is performed in a water bath shaker at a temperature of 45°C to 55°C for 24 to 96 hours. After the enzymolysis is completed, the solid-liquid separation is performed to obtain an enzyme hydrolyzate, and the sugar-containing hydrolyzate is adjusted to a pH value of 5 to 7, and is used as a fermentation medium without sterilization.

[0017] Specifically, in step S3, the oleaginous yeast is Trichosporon oleaginosus, Trichosporon dermatophyte, Trichosporon fermentative, Rhodotorula toruloides, Yarrowia lipolytica, Cryptococcus curvatus or Rhodotorula glutinosus, including wild-type strains and natural or artificial mutants thereof.

[0018] Specifically, in step S4, the inoculation amount of the oleaginous yeast seed solution inoculated into the fermentation medium is 5% to 15% (v / v), and the culture is carried out at 25° C. to 35° C. with aeration, and the fermentation is terminated when the sugar concentration in the fermentation medium is lower than 5 g / L. Here, v / v is a volume ratio.

[0019] Specifically, in step S5, the oil obtained by extraction is an oil containing one or more long-chain fatty acids and their derivatives, which is suitable as a raw material for biodiesel.

[0020] The beneficial effects of the present invention are:

[0021] 1. In the present invention, the selective antibacterial properties of the antibacterial Chinese medicine residues reduce the use of exogenous antibacterial drugs in the enzymatic hydrolysis stage of the residues, and the hydrolyzate after enzymatic hydrolysis can be directly used for oil fermentation without high temperature and high pressure sterilization, which significantly reduces the loss of fermentable sugars;

[0022] 2. In the present invention, the antibacterial Chinese medicine residue itself has certain selective antibacterial properties, so the goal of using the antibacterial Chinese medicine residue for non-sterile fermentation to prepare microbial oils is achieved. The antibacterial Chinese medicine residue can stabilize the growth ability of microorganisms during the fermentation process, and can obtain biomass and oil yields equivalent to or even higher than those of sterilized fermentation. Compared with the sterilized fermentation of Chinese medicine residue, the open fermentation of Chinese medicine residue significantly reduces the process cost and equipment cost, and improves the production output of microbial oils;

[0023] 3. In the present invention, the mixed drug residues after polysaccharide-rich Chinese drug residues and antibacterial Chinese drug residues are mixed in any proportions and subjected to non-sterile fermentation to prepare microbial oils. The polysaccharide-rich Chinese drug residues make up for the shortcomings of low fermentable sugar concentration and poor fermentation effect of single antibacterial drug residue enzymatic hydrolyzate; and the antibacterial drug residues make up for the shortcomings of polysaccharide-rich Chinese drug residues that are easily contaminated by miscellaneous bacteria during the fermentation process, affecting oil production. The use of mixed drug residues for non-sterile fermentation to prepare microbial oils significantly simplifies the process flow, reduces equipment costs, improves oil production efficiency, oil output and oil yield, and enhances the technical and economic benefits of microbial oil production, and has broad application prospects.

[0024] 4. By mixing antibacterial Chinese medicine residues with polysaccharide-rich Chinese medicine residues, the application scope of the non-sterile fermentation can be greatly expanded, completely solving the outstanding problem that the total amount of Chinese medicine residues is abundant but the output of a single Chinese medicine residue is low.

[0025] The oil obtained by the present invention is an oil of one or more long-chain fatty acids and derivatives thereof, which can be used to prepare biodiesel or other high value-added products and has very good application value. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 The present invention provides a process flow chart of a method for producing oil through open fermentation based on antibacterial Chinese medicine residues. DETAILED DESCRIPTION

[0027] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0028] The present invention provides a method for producing oil by open fermentation based on antibacterial Chinese medicine residues, which specifically comprises the following steps:

[0029] Step S1: Select selective antibacterial Chinese medicine residues, mix the Chinese medicine residues with other polysaccharide-rich Chinese medicine residues, and perform dilute acid pretreatment;

[0030] In this step, the antibacterial Chinese medicine residue is a plant-derived antibacterial Chinese medicine residue mainly composed of cellulose, hemicellulose, starch, lignin and protein, and containing a small amount of trace elements and effective medicinal ingredients. Its enzymatic hydrolyzate can selectively inhibit Gram-negative bacteria and Gram-positive bacteria, but has no inhibitory effect on some oleaginous yeasts. The antibacterial Chinese medicine residue includes one or more of Rehmannia glutinosa, Platycodon grandiflorum, Scrophularia ningpoensis, Pulsatilla striata, Bletilla striata, Kezi, and Galla chinensis residues. The polysaccharide-rich drug residue is a drug residue component with a high polysaccharide content, and after acid hydrolysis and enzyme hydrolysis, the polysaccharide can be hydrolyzed into fermentable sugars. Including one or more of Poria cocos, Paeonia suffruticosa, Licorice, Codonopsis pilosula, Ginkgo biloba, White Peony Root, Pueraria lobata, Curcuma longa, and Radix Isatidis drug residues. The mixed drug residue is a mixed drug residue after the drug residue with strong antibacterial effect and the drug residue with high polysaccharide content are mixed in any proportion. The acid is sulfuric acid, hydrochloric acid or nitric acid, the acid concentration range is 1g / L to 10g / L, the pretreatment temperature is 120°C to 190°C, and the pretreatment time is 5min to 2h. The mixed Chinese medicine residue is evenly mixed with the dilute acid according to a solid-liquid ratio of 8% to 15% (w / v), and pretreated at high temperature, where w / v is a mass volume ratio.

[0031] Step S2: adjusting the antibacterial Chinese medicine residue after acid pretreatment in S1 to a suitable pH, adding a certain amount of cellulase, performing enzymatic hydrolysis at a certain temperature for a period of time, and directly using the enzymatic hydrolyzate obtained by solid-liquid separation as a fermentation medium without sterilization;

[0032] In this step, the acid pretreatment of the Chinese medicinal residue is adjusted to a pH value of 4.5 to 5.5. Cellulase is added at an enzyme loading of 5 to 20 FPU / g, and enzymolysis is carried out in a water bath shaker at a temperature of 45°C to 55°C for 24 to 96 hours. After the enzymolysis is completed, the solid-liquid separation is performed to obtain an enzyme hydrolyzate, and the sugar-containing hydrolyzate is adjusted to a pH value of 5 to 7, and is used as a fermentation medium without sterilization.

[0033] Step S3: culturing the oil-producing yeast in a seed culture medium to obtain an oil-producing microbial seed liquid;

[0034] In this step, the oleaginous yeast is a yeast that accumulates oil content exceeding 20% ​​of the cell dry weight after fermentation culture. The oleaginous yeast is an oleaginous yeast and its mutants that can metabolize glucose, xylose and soluble oligosaccharides, including Cutaneotrichosporon oleaginosum, Cryptococcus curvatus, Lipomyces starkeyi, Trichosporon cutaneum, Trichosporonfermentans, Rhodosporidium toruloides, Yarrowia lipolytica or Rhodotorula glutinis. These strains can be purchased directly from strain collections such as the China General Microbiology Culture Collection (CGMCC), the China Industrial Microbiology Culture Collection (CICC), the American Type Culture Collection (ATCC), the U.S. Agricultural Research Culture Collection (NRRL), the UK National Strain Collection (UKNCC), the Netherlands Microbiology Collection (CBS), or the German Microbiology Collection (DSMZ), or isolated from nature. Artificial or natural mutant strains with different characteristics from the original strains can also be used.

[0035] Step S4: inoculate the oil-producing microbial seed liquid obtained in step S3 into the fermentation medium obtained in step S2, and culture it with ventilation for a period of time under a non-sterile environment and a certain temperature and pH. When the total concentration of the carbon source in the culture medium is lower than the set threshold, the fermentation is terminated.

[0036] In this step, the inoculation amount of the oleaginous yeast seed solution inoculated into the fermentation medium is 5% to 15% (v / v), and the culture is carried out at 25° C. to 35° C. with aeration, and the fermentation is terminated when the sugar concentration in the fermentation medium is lower than 5 g / L. Here, v / v is the volume ratio.

[0037] Step S5: collecting the solid phase containing the oleaginous yeast by solid-liquid separation, and then extracting the intracellular lipids from the collected solid phase.

[0038] In this step, solid-liquid separation can be carried out by centrifugation or filtration, and oil is extracted from the solid phase obtained after separation, and the oil yield of the microorganism is calculated. The microbial oil is mainly glycerol esters of long-chain fatty acids and their derivatives, which can be made into biodiesel after transesterification, such as preparing biodiesel by transesterification under acid catalysis (this process is a conventional preparation process and will not be repeated here). In addition, the unsaturated fatty acids contained in the microbial oil can also be used to prepare other high value-added products.

[0039] The present invention is described below by means of specific examples. The following examples select typical examples of culturing typical oil-producing microorganisms with typical Chinese medicine residue materials, which is helpful for understanding the present invention, but does not limit the application of the present invention to other materials or oil-producing strains in any form.

[0040] Embodiment 1:

[0041] 1. Prepare sugar solution by acid hydrolysis and enzymolysis of mixed dregs containing kelp residues: Mix the kelp residues and ginkgo residues after wet crushing in a 1L reactor at a ratio of 1:3 (w / w), add 10g / L H2SO4 to a solid-liquid ratio of 8% (w / v), stir the mixture until it is uniform, and react at 120°C for 60min. After the mixture obtained above is cooled, adjust the pH to 4.5 with solid NaOH, and add 5FPU / g cellulase. Stir the reactor well and put it into a water bath shaker with a speed of 200rpm and a temperature of 50°C to start enzymatic hydrolysis, adjust the pH to 4.5 after 1h and 3h, and hydrolyze for 24h. The total reducing sugar content in the hydrolyzate is 62.2g / L.

[0042] 2. After 24 hours of enzymatic hydrolysis, filter or centrifuge to obtain the supernatant, mix the supernatant and adjust the pH to 6.0. It can be used as a fermentation medium without high temperature and high pressure sterilization.

[0043] 3. Open fermentation of mixed medicinal residues containing koji medicinal residues to produce microbial oil: Use YEPD medium (glucose 20g / L, yeast powder 10g / L, peptone 10g / L), adjust the pH to 6.0, and sterilize at 121°C for 20min. Pick a ring of Lipomyces starkeyi AS2.1560 to inoculate the seed culture medium, 30°C, 200rpm shaking culture for 36h, and obtain oil-producing microbial seed liquid; inoculate the seed liquid into the mixed medicinal residue sugar liquid culture medium obtained in step 2, with an inoculation amount of 10% (v / v), and terminate the fermentation after aeration culture at 30°C for 96h.

[0044] 4. Through optical microscopic examination of the open fermentation endpoint samples of mixed medicinal residues containing kelp residues, it was found that there was almost no contamination by foreign bacteria, and a large amount of oil accumulated in the oleaginous yeast cells. Specifically, the biomass, oil amount and oil content were 19.0g / L, 11.9g / L and 62.6% respectively.

[0045] Embodiment 2:

[0046] 1. Preparation of sugar solution by acid hydrolysis and enzymolysis of mixed drug residues containing Platycodon grandiflorum drug residues: Platycodon grandiflorum drug residues and Paeonia suffruticosa drug residues after wet crushing are mixed in a 1L reactor at a ratio of 1:1 (w / w, mass ratio, the same below), 10g / L H2SO4 is added to a solid-liquid ratio of 15% (w / v, mass volume ratio, the same below), the mixture is fully stirred until uniform, and reacted at 120°C for 60min. After the mixture obtained above is cooled, the pH is adjusted to 4.8 with solid NaOH, and 15FPU / g cellulase is added. After full stirring, the reactor is placed in a water bath shaker with a speed of 200rpm and a temperature of 50°C to start enzymatic hydrolysis, and the pH is adjusted to 4.8 after 1h and 3h, and the hydrolysis is performed for 72h. The total reducing sugar content in the hydrolyzate is 115.4g / L.

[0047] 2. After 72 hours of enzymatic hydrolysis, filter or centrifuge to obtain the supernatant, mix the supernatant and adjust the pH to 6.0. It can be used directly as a fermentation medium without high temperature and high pressure sterilization.

[0048] 3. Open fermentation of mixed medicinal residues containing Platycodon grandiflorum dregs to produce microbial oil: Use YEPD medium (glucose 20g / L, yeast powder 10g / L, peptone 10g / L), adjust the pH to 6.0, and sterilize at 121°C for 20min. Pick a ring of Cryptococcus curvatus ATCC 20509 to access the seed culture medium, 30°C, 200rpm shaking culture for 24h, and obtain oil-producing microbial seed liquid; inoculate the seed liquid into the mixed medicinal residue sugar liquid culture medium obtained in step 2, with an inoculation amount of 10% (v / v, volume ratio, the same below), and terminate the fermentation after aeration culture at 30°C for 120h.

[0049] 4. The open fermentation end point samples of mixed medicinal residues containing Platycodon grandiflorum medicinal residues were examined by optical microscope, and it was found that there was no contamination by foreign bacteria, and a large amount of oil accumulated in the oleaginous yeast cells. Specifically, the biomass, oil amount and oil content were 33.2g / L, 23.1g / L and 69.6% respectively.

[0050] Embodiment 3:

[0051] 1. Prepare sugar solution by acid hydrolysis and enzymolysis of mixed dregs containing raw Rehmannia glutinosa dregs: Mix the wet-crushed raw Rehmannia glutinosa dregs and Poria glutinosa dregs in a 1L reactor at a ratio of 1:2 (w / w), add 5g / L HCl to a solid-liquid ratio of 12% (w / v), stir the mixture until it is uniform, and react at 120°C for 60min. After the mixture obtained above is cooled, adjust the pH to 4.8 with solid NaOH, and add 15FPU / g cellulase. Stir the reactor thoroughly and place it in a water bath shaker with a speed of 200rpm and a temperature of 50°C to start enzymatic hydrolysis, adjust the pH to 4.8 after 1h and 3h, and hydrolyze for 72h. The total reducing sugar content in the hydrolyzate is 90.1g / L.

[0052] 2. After 72 hours of enzymatic hydrolysis, filter or centrifuge to obtain the supernatant, mix the supernatant and adjust the pH to 6.0. It can be used as a fermentation medium without high temperature and high pressure sterilization.

[0053] 3. Open fermentation of mixed dregs containing raw Rehmannia root dregs to produce microbial oil: Use YEPD medium (glucose 20g / L, yeast powder 10g / L, peptone 10g / L), adjust the pH to 6.0, and sterilize at 121°C for 20min. Pick an evolved strain of Cutaneotrichosporon oleaginosum ATCC 20509 and inoculate it into the seed culture medium, shake and culture at 30°C, 200rpm for 24h to obtain oil-producing microbial seed liquid; inoculate the seed liquid into the mixed dregs sugar liquid culture medium obtained in step 2, with an inoculation amount of 10% (v / v), and terminate the fermentation after aeration culture at 35°C for 120h.

[0054] 4. The solid phase containing oleaginous yeast was collected by solid-liquid separation to obtain a total of 28.1 g / L of dry bacteria. The conventional method was used to extract oil, and the yield of the obtained oil was 19.7 g / L, and the oil content was 70.1%. The open fermentation end point sample of the mixed drug residue containing raw Rehmannia root residue was examined by optical microscopy, and it was found that there was no contamination by miscellaneous bacteria, and a large amount of oil accumulated in the oleaginous yeast cells.

[0055] Embodiment 4:

[0056] 1. Prepare sugar solution by acid hydrolysis and enzymolysis of mixed dregs containing raw Rehmannia glutinosa dregs: Mix the wet-crushed raw Rehmannia glutinosa dregs, turmeric dregs and Poria glutinosa dregs in a 1L reactor at a ratio of 1:2:2 (w / w), add 1g / L H2SO4 to a solid-liquid ratio of 12% (w / v), stir the mixture until it is uniform, and react at 190°C for 5min. After the mixture obtained above is cooled, adjust the pH to 5.5 with solid NaOH, and add 25FPU / g cellulase. Stir the reactor thoroughly and put it into a water bath shaker with a speed of 200rpm and a temperature of 50°C to start enzymatic hydrolysis, adjust the pH to 4.8 after 1h and 3h, and hydrolyze for 72h. The total reducing sugar content in the hydrolyzate is 92.5g / L.

[0057] 2. After 72 hours of enzymatic hydrolysis, filter or centrifuge to obtain the supernatant, mix the supernatant and adjust the pH to 6.0. It can be used as a fermentation medium without high temperature and high pressure sterilization.

[0058] 3. Open fermentation of raw Rehmannia root residue and Poria root residue to produce microbial oil: Use YEPD medium (glucose 20g / L, yeast powder 10g / L, peptone 10g / L), adjust the pH to 6.0, and sterilize at 121°C for 20min. Pick a ring of Yarrowia lipolytica Po1g to inoculate the seed culture medium, shake and culture at 25°C, 200rpm for 24h to obtain oil-producing microbial seed liquid; inoculate the seed liquid into the mixed drug residue sugar liquid culture medium obtained in step 2, with an inoculation amount of 10% (v / v), and terminate the fermentation after aeration culture at 25°C for 96h.

[0059] 4. The solid phase containing oleaginous yeast was collected by solid-liquid separation to obtain a total of 27.6 g / L of dry bacteria. The conventional method was used to extract oil, and the yield of the obtained oil was 18.2 g / L, and the oil content was 65.9%. The open fermentation end point sample of the mixed drug residue containing raw Rehmannia root residue was examined by optical microscopy, and it was found that there was no contamination by miscellaneous bacteria, and a large amount of oil accumulated in the oleaginous yeast cells.

[0060] Embodiment 5:

[0061] 1. Preparation of sugar solution by acid hydrolysis and enzymolysis of mixed dregs containing gallnut dregs: Mix the gallnut dregs and licorice dregs crushed by wet method in a 1L reactor at a ratio of 1:4 (w / w), add 10g / L HNO3 to a solid-liquid ratio of 10% (w / v), stir the mixture until it is uniform, and react at 120°C for 120min. After the mixture obtained above is cooled, adjust the pH to 5.0 with solid NaOH, and add 15FPU / g cellulase. Stir the reactor well and put it into a water bath shaker with a speed of 200rpm and a temperature of 50°C to start enzymatic hydrolysis, adjust the pH to 5.0 after 1h and 3h, and hydrolyze for 72h. The total reducing sugar content in the hydrolyzate is 70.4g / L.

[0062] 2. After 72 hours of enzymatic hydrolysis, filter or centrifuge to obtain the supernatant, mix the supernatant and adjust the pH to 6.0. It can be used as a fermentation medium without high temperature and high pressure sterilization.

[0063] 3. Open fermentation of mixed medicinal residues containing gallnut medicinal residues to produce microbial oil: Use YEPD medium (glucose 20g / L, yeast powder 10g / L, peptone 10g / L), adjust the pH to 6.0, and sterilize at 121°C for 20min. Pick a ring-shaped Trichosporon cutaneum GIM 2.67 to inoculate the seed culture medium, 30°C, 200rpm shaking culture for 24h, and obtain the oil-producing microbial seed liquid; inoculate the seed liquid into the mixed medicinal residue sugar liquid culture medium obtained in step 2, with an inoculation amount of 5% (v / v), and terminate the fermentation after aeration culture at 30°C for 96h.

[0064] 4. Through optical microscopic examination of the open fermentation endpoint samples of mixed medicinal residues containing gallnut medicinal residues, it was found that there was no contamination by foreign bacteria, and a large amount of oil accumulated in the oleaginous yeast cells. Specifically, the biomass, oil amount and oil content were 20.0g / L, 12.1g / L and 60.5% respectively.

[0065] Embodiment 6:

[0066] 1. Prepare sugar solution by acid hydrolysis and enzymolysis of mixed dregs containing Scrophularia ningpoensis dregs: Mix the wet-crushed Scrophularia ningpoensis dregs and Pueraria lobata dregs in a 1L reactor at a ratio of 1:3 (w / w), add 10g / L H2SO4 to a solid-liquid ratio of 12% (w / v), stir the mixture until it is uniform, and react at 120°C for 30min. After the mixture obtained above is cooled, adjust the pH to 4.8 with solid NaOH, and add 15FPU / g cellulase. Stir the reactor evenly and put it into a water bath shaker with a speed of 200rpm and a temperature of 50°C to start enzymatic hydrolysis, adjust the pH to 4.8 after 1h and 3h, and hydrolyze for 72h. The total reducing sugar content in the hydrolyzate is 90.2g / L.

[0067] 2. After 72 hours of enzymatic hydrolysis, filter or centrifuge to obtain the supernatant, mix the supernatant and adjust the pH to 6.0. It can be used as a fermentation medium without high temperature and high pressure sterilization.

[0068] 3. Open fermentation of mixed medicinal residues containing raw Rehmannia root residues to produce microbial oil: Use YEPD medium (glucose 20g / L, yeast powder 10g / L, peptone 10g / L), adjust the pH to 6.0, and sterilize at 121°C for 20min. Pick a ring of Rhodosporidium toruloides CGMCC 2.1389 to inoculate the seed culture medium, 30°C, 200rpm shaking culture for 24h, and obtain oil-producing microbial seed liquid; inoculate the seed liquid into the mixed medicinal residue sugar liquid culture medium obtained in step 2, with an inoculation amount of 15% (v / v), and terminate the fermentation after aeration culture at 30°C for 96h.

[0069] 4. The open fermentation end point samples of mixed medicinal residues containing Scrophularia ningpoensis medicinal residues were examined by optical microscope, and it was found that there was no contamination by foreign bacteria, and a large amount of oil accumulated in the oleaginous yeast cells. Specifically, the biomass, oil amount and oil content were 28.0g / L, 18.5g / L and 66.1% respectively.

[0070] Embodiment 7:

[0071] 1. Preparation of sugar solution by acid hydrolysis and enzymolysis of mixed drug residues containing Bletilla striata residues: Weigh 50g of Bletilla striata residues after wet crushing, weigh 20g of Bletilla striata residues in a 1L reactor, add 10g / L H2SO4 to a solid-liquid ratio of 14% (w / v), stir the mixture until it is uniform, and react at 120°C for 60min. After the mixture obtained above is cooled, adjust the pH to 4.8 with solid NaOH, and add 15FPU / g cellulase. Stir the reactor evenly and put it into a water bath shaker with a speed of 200rpm and a temperature of 50°C to start enzymatic hydrolysis, adjust the pH to 4.8 after 1h and 3h, and hydrolyze for 72h. The total reducing sugar content in the hydrolyzate is 97.2g / L.

[0072] 2. After 72 hours of enzymatic hydrolysis, filter or centrifuge to obtain the supernatant, mix the supernatant and adjust the pH to 6.0. It can be used as a fermentation medium without high temperature and high pressure sterilization.

[0073] 3. Open fermentation of mixed medicinal residues containing Bletilla striata residues to produce microbial oil: Use YEPD medium (glucose 20g / L, yeast powder 10g / L, peptone 10g / L), adjust the pH to 6.0, and sterilize at 121°C for 20min. Pick a ring of fermentative Trichosporonfermentans CICC 1368 to inoculate the seed culture medium, 30°C, 200rpm shaking culture for 24h, and obtain oil-producing microbial seed liquid; inoculate the seed liquid into the mixed medicinal residue sugar liquid culture medium obtained in step 2, with an inoculation amount of 10% (v / v), and terminate the fermentation after aeration culture at 30°C for 96h.

[0074] 4. The solid phase containing oleaginous yeast was collected by solid-liquid separation to obtain a total of 28.8 g / L of dry bacteria. The conventional method was used to extract oil, and the yield of the obtained oil was 19.1 g / L. The oil content was 66.3%. The open fermentation end point sample of the mixed medicinal residue containing Bletilla striata medicinal residue was examined by optical microscopy, and it was found that there was no contamination by foreign bacteria, and a large amount of oil accumulated in the oleaginous yeast cells.

[0075] Embodiment 8:

[0076] 1. Preparation of sugar solution by acid hydrolysis and enzymolysis of mixed dregs containing Pulsatilla striata dregs: Weigh 50g of Pulsatilla striata dregs after wet crushing and 20g of Paeonia lactiflora dregs in a 1L reactor, add 10g / L H2SO4 to a solid-liquid ratio of 14% (w / v), stir the mixture until it is uniform, and react at 120°C for 60min. After the mixture obtained above is cooled, adjust the pH to 4.8 with solid NaOH, and add 15FPU / g cellulase. Stir the reactor evenly and put it into a water bath shaker with a speed of 200rpm and a temperature of 50°C to start enzymatic hydrolysis, adjust the pH to 4.8 after 1h and 3h, and hydrolyze for 96h. The total reducing sugar content in the hydrolyzate is 87.4g / L.

[0077] 2. After 96h enzymatic hydrolysis, filter or centrifuge to obtain the supernatant, mix the supernatant and adjust the pH to 5.0. It can be used as a fermentation medium without high temperature and high pressure sterilization.

[0078] 3. Open fermentation of mixed medicinal residues containing Bletilla striata residues to produce microbial oil: Use YEPD medium (glucose 20g / L, yeast powder 10g / L, peptone 10g / L), adjust the pH to 6.0, and sterilize at 121°C for 20min. Pick a ring of Rhodotorula glutinis CGMCC 2258 to inoculate the seed culture medium, shake and culture at 25°C, 200rpm for 24h to obtain oil-producing microbial seed liquid; inoculate the seed liquid into the mixed medicinal residue sugar liquid culture medium obtained in step 2, with an inoculation amount of 10% (v / v), and terminate the fermentation after aeration culture at 25°C for 120h.

[0079] 4. The solid phase containing oleaginous yeast was collected by solid-liquid separation to obtain a total of 24.5 g / L of dry bacteria. The conventional method was used to extract oil, and the yield of the obtained oil was 15.1 g / L. The oil content was 61.6%. The open fermentation endpoint sample of the mixed drug residue containing Pulsatilla striata drug residue was examined by optical microscopy, and it was found that there was no contamination by miscellaneous bacteria, and a large amount of oil accumulated in the oleaginous yeast cells.

[0080] Embodiment 9:

[0081] 1. Preparation of sugar solution by acid hydrolysis and enzymolysis of mixed dregs containing raw Rehmannia root dregs: Weigh 50g of wet-crushed Pulsatilla truncatula dregs and 20g of turmeric dregs in a 1L reactor, add 10g / L H2SO4 to a solid-liquid ratio of 14% (w / v), stir the mixture until it is uniform, and react at 120°C for 60min. After the mixture obtained above is cooled, adjust the pH to 4.8 with solid NaOH, and add 15FPU / g cellulase. Stir the reactor thoroughly and put it into a water bath shaker with a speed of 200rpm and a temperature of 50°C to start enzymatic hydrolysis, adjust the pH to 4.8 after 1h and 3h, and hydrolyze for 96h. The total reducing sugar content in the hydrolyzate is 87.1g / L.

[0082] 2. After 96h enzymatic hydrolysis, filter or centrifuge to obtain the supernatant, mix the supernatant and adjust the pH to 5.0. It can be used as a fermentation medium without high temperature and high pressure sterilization.

[0083] 3. Open fermentation of mixed medicinal residues containing raw Rehmannia root residues to produce microbial oil: Use YEPD medium (glucose 20g / L, yeast powder 10g / L, peptone 10g / L), adjust the pH to 6.0, and sterilize at 121°C for 20min. Pick a ring of Rhodotorula glutinis CGMCC 2258 to inoculate the seed culture medium, shake and culture at 25°C, 200rpm for 24h to obtain oil-producing microbial seed liquid; inoculate the seed liquid into the mixed medicinal residue sugar liquid culture medium obtained in step 2, with an inoculation amount of 10% (v / v), and terminate the fermentation after aeration culture at 25°C for 120h.

[0084] 4. The solid phase containing oleaginous yeast was collected by solid-liquid separation to obtain a total of 26.7 g / L of dry bacteria. The conventional method was used to extract oil, and the yield of the obtained oil was 19.5 g / L. The oil content was 73.0%. The open fermentation end point sample of the mixed drug residue containing raw Rehmannia root residue was examined by optical microscopy, and it was found that there was no contamination by miscellaneous bacteria, and a large amount of oil accumulated in the oleaginous yeast cells.

[0085] Embodiment 10:

[0086] 1. Preparation of sugar solution by acid hydrolysis and enzymolysis of mixed dregs containing dregs of Herba Codonopsis pilosulae: Weigh 50g of wet-crushed dregs of Herba Pulsatillae and 20g of Radix Isatidis dregs in a 1L reactor, add 10g / L H2SO4 to a solid-liquid ratio of 13% (w / v), stir the mixture until it is uniform, and react at 120°C for 60min. After the mixture obtained above is cooled, adjust the pH to 4.8 with solid NaOH, and add 15FPU / g cellulase. Stir the reactor thoroughly and evenly, put it into a water bath shaker with a speed of 200rpm and a temperature of 50°C to start enzymatic hydrolysis, adjust the pH to 4.8 after 1h and 3h, and hydrolyze for 96h. The total reducing sugar content in the hydrolyzate is 80.6g / L.

[0087] 2. After 96h enzymatic hydrolysis, filter or centrifuge to obtain the supernatant, mix the supernatant and adjust the pH to 5.0. It can be used as a fermentation medium without high temperature and high pressure sterilization.

[0088] 3. Open fermentation of mixed medicinal residues containing koji medicinal residues to produce microbial oil: Use YEPD medium (glucose 20g / L, yeast powder 10g / L, peptone 10g / L), adjust the pH to 6.0, and sterilize at 121°C for 20min. Pick a ring of Lipomyces starkeyi AS2.1560 to inoculate the seed culture medium, 30°C, 200rpm shaking culture for 24h, and obtain the oil-producing microbial seed liquid; inoculate the seed liquid into the mixed medicinal residue sugar liquid culture medium obtained in step 2, with an inoculation amount of 10% (v / v), and terminate the fermentation after aeration culture at 30°C for 120h.

[0089] 4. The solid phase containing oleaginous yeast was collected by solid-liquid separation to obtain a total of 23.6 g / L of dry bacteria. The conventional method was used to extract oil, and the yield of the obtained oil was 14.9 g / L. The oil content was 63.1%. The open fermentation end point sample of the mixed drug residue containing the drug residue of the kelp was examined by optical microscopy, and it was found that there was no contamination by miscellaneous bacteria, and a large amount of oil accumulated in the oleaginous yeast cells.

[0090] Comparative Example 1:

[0091] 1. Prepare sugar solution by acid hydrolysis and enzymolysis of mixed dregs containing kelp residues: Mix the kelp residues and ginkgo residues after wet crushing in a 1L reactor at a ratio of 1:3 (w / w), add 10g / L H2SO4 to a solid-liquid ratio of 8% (w / v), stir the mixture until it is uniform, and react at 120°C for 60min. After the mixture obtained above is cooled, adjust the pH to 4.5 with solid NaOH, and add 5FPU / g cellulase. Stir the reactor well and put it into a water bath shaker with a speed of 200rpm and a temperature of 50°C to start enzymatic hydrolysis, adjust the pH to 4.5 after 1h and 3h, and hydrolyze for 24h. The total reducing sugar content in the hydrolyzate is 62.2g / L.

[0092] 2. After 24 hours of enzymatic hydrolysis, filter or centrifuge to obtain the supernatant, mix the supernatant and adjust the pH to 6.0. Sterilize the hydrolyzate in an autoclave at 121°C for 20 minutes and use it as a fermentation medium. At this time, the total reducing sugar concentration drops to 58.7 g / L.

[0093] 3. Conventional fermentation of mixed medicinal residues containing koji medicinal residues to produce microbial oil: Use YEPD medium (glucose 20g / L, yeast powder 10g / L, peptone 10g / L), adjust the pH to 6.0, and sterilize at 121°C for 20min. Pick a ring of Lipomyces starkeyi AS2.1560 to access the seed culture medium, 30°C, 200rpm shaking culture for 36h, and obtain oil-producing microbial seed liquid; inoculate the seed liquid into the mixed medicinal residue sugar liquid culture medium obtained in step 2, with an inoculation amount of 10% (v / v), and terminate the fermentation after aeration culture at 30°C for 96h.

[0094] 4. Through optical microscopic examination of the open fermentation endpoint samples of mixed medicinal residues containing kelp residues, it was found that there was almost no contamination by foreign bacteria, and a large amount of oil accumulated in the oleaginous yeast cells. Specifically, the biomass, oil amount and oil content were 18.8g / L, 10.5g / L and 55.9% respectively.

[0095] Comparative Example 2:

[0096] 1. Preparation of sugar solution by acid hydrolysis and enzymatic hydrolysis of Poria residue: Weigh 50g of wet-crushed Poria residue in a 1L reactor, add 10g / L H2SO4 to a solid-liquid ratio of 10% (w / v), stir the mixture until uniform, and react at 120°C for 60min. After the mixture obtained above is cooled, adjust the pH to 4.8 with solid NaOH, and add 15FPU / g cellulase. Stir the reactor well and put it into a water bath shaker with a speed of 200rpm and a temperature of 50°C to start enzymatic hydrolysis, adjust the pH to 4.8 after 1h and 3h, and hydrolyze for 72h. The glucose concentration of Poria residue after acid hydrolysis is 40.7g / L, and the xylose concentration is 7.9g / L. After enzymatic hydrolysis of Poria residue, the cumulative glucose concentration is 46.0g / L, the xylose concentration is 9.1g / L, and the total reducing sugar content is 69.7g / L.

[0097] 2. After 72 hours of enzymatic hydrolysis, filter or centrifuge to obtain the supernatant, mix the supernatant and adjust the pH to 6.0. Use it directly as a fermentation medium without high temperature and high pressure sterilization.

[0098] 3. Open fermentation of Poria residue to produce microbial oil: Use YEPD medium (glucose 20g / L, yeast powder 10g / L, peptone 10g / L), adjust the pH to 6.0, and sterilize at 121°C for 20min. Pick a ring of Cryptococcus curvatus ATCC 20509 to access the seed culture medium, 30°C, 200rpm shaking culture for 24h, and obtain the oil-producing microbial seed liquid; inoculate the seed liquid into the Poria residue sugar liquid culture medium obtained in step 2, with an inoculation amount of 10% (v / v), and terminate the fermentation after aeration culture at 30°C for 96h.

[0099] 4. Through optical microscopy, the end-point samples of the open fermentation of Poria residue were found to be contaminated by a large number of bacteria, and the intracellular lipid accumulation of oleaginous yeast was relatively small. The final biomass, lipid amount and lipid content were only 17.7g / L, 7.8g / L and 44.1%, respectively.

[0100] The results of the above examples and comparative examples are shown in the following table:

[0101]

[0102]

[0103] It can be seen from the examples and comparative examples that high-temperature sterilization will cause a certain amount of sugar loss when conventional fermentation is used to produce microbial oils. In addition, although the open fermentation mode using Poria cocos residue to produce microbial oils reduces process costs and equipment costs, the antibacterial properties of Poria cocos residue are poor and are easily contaminated by foreign bacteria during the fermentation process. Compared with sterilized fermentation, the oil-producing yeast accumulates less intracellular oil and the oil yield is significantly reduced.

[0104] By adding traditional Chinese medicine residues with strong antibacterial properties to produce microbial oils in an open fermentation mode, the sugar loss caused by the sterilization process is avoided, and the residue hydrolyzate has a good inhibitory effect on Gram-negative and Gram-positive bacteria, so that compared with sterilization fermentation, the dry bacteria and oil production are slightly increased. The open fermentation of traditional Chinese medicine residues rich in polysaccharides and good oil production performance with antibacterial traditional Chinese medicine residues not only significantly reduces the production cost of microbial oils, but also increases the oil production and oil yield.

[0105] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for producing oil by open fermentation based on antibacterial Chinese medicine residues, characterized in that: The method comprises the following steps: Step S1: Select selective antibacterial Chinese medicine residues, mix the Chinese medicine residues with other polysaccharide-rich Chinese medicine residues, and perform dilute acid pretreatment; Step S2: adjusting the antibacterial Chinese medicine residue after acid pretreatment in S1 to a suitable pH, adding a certain amount of cellulase, performing enzymatic hydrolysis at a certain temperature for a period of time, and directly using the enzymatic hydrolyzate obtained by solid-liquid separation as a fermentation medium without sterilization; Step S3: culturing the oil-producing yeast in a seed culture medium to obtain an oil-producing microbial seed liquid; Step S4: inoculate the oil-producing microbial seed liquid obtained in step S3 into the fermentation medium obtained in step S2, and culture it with ventilation for a period of time under a non-sterile environment and a certain temperature and pH. When the total concentration of the carbon source in the culture medium is lower than the set threshold, the fermentation is terminated. Step S5: collecting the solid phase containing the oleaginous yeast by solid-liquid separation, and then extracting the intracellular lipids from the collected solid phase.

2. The method for producing oil by open fermentation based on antibacterial Chinese medicine residues as claimed in claim 1, characterized in that: In step S1, the antibacterial Chinese medicine residue is a plant-derived antibacterial Chinese medicine residue mainly composed of cellulose, starch, hemicellulose, lignin and protein, and containing a small amount of trace elements and effective medicinal ingredients. Its enzymatic hydrolyzate can selectively inhibit Gram-negative bacteria and Gram-positive bacteria, but has no inhibitory effect on some oil-producing yeasts, and the antibacterial Chinese medicine residue includes one or more of the residues of Rehmannia glutinosa, Platycodon grandiflorum, Scrophularia ningpoensis, Pulsatilla striata, Bletilla striata, Codonopsis pilosula, and Galla chinensis.

3. The method for producing oil by open fermentation based on antibacterial Chinese medicine residues as claimed in claim 1, characterized in that: In step S1, the polysaccharide-rich Chinese medicine residues are Chinese medicine residues with high polysaccharide content, and polysaccharides can be hydrolyzed into fermentable sugars after acid hydrolysis and enzyme hydrolysis, including one or more of the residues of Poria cocos, Paeonia suffruticosa, Licorice, Codonopsis pilosula, Ginkgo biloba, White Peony Root, Pueraria lobata, Curcuma longa, and Isatis indigotica.

4. The method for producing oil by open fermentation based on antibacterial Chinese medicine residues as claimed in claim 1, characterized in that: In step S1, the mixed medicinal residue is a mixture of medicinal residue with strong selective antibacterial effect and medicinal residue with high polysaccharide content in any proportion.

5. The method for producing oil by open fermentation based on antibacterial Chinese medicine residues as claimed in claim 1, characterized in that: In step S1, the acid is sulfuric acid, hydrochloric acid or nitric acid, the acid concentration range is 1 g / L to 10 g / L, the pretreatment temperature is 120° C. to 190° C., and the pretreatment time is 5 min to 2 h.

6. The method for producing oil by open fermentation based on antibacterial Chinese medicine residues as claimed in claim 1, characterized in that: In step S1, the mixed Chinese medicinal residue is evenly mixed with dilute acid at a solid-liquid ratio of 8% to 15% (w / v), and pretreated at high temperature, where w / v is a mass-to-volume ratio.

7. The method for producing oil by open fermentation based on antibacterial Chinese medicine residues as claimed in claim 1, characterized in that: In step S2, the acid pretreatment of the Chinese medicinal residue is adjusted to a pH value of 4.5 to 5.

5. Cellulase is added at an enzyme loading of 5 to 20 FPU / g, and enzymolysis is performed in a water bath shaker at a temperature of 45°C to 55°C for 24 to 96 hours. After the enzymolysis is completed, solid-liquid separation is performed to obtain an enzyme hydrolyzate, and the sugar-containing hydrolyzate is adjusted to a pH value of 5 to 7, and is used as a fermentation medium without sterilization.

8. The method for producing oil by open fermentation based on antibacterial Chinese medicine residues as claimed in claim 1, characterized in that: In step S3, the oleaginous yeast is Trichosporon oleaginosus, Trichosporon dermatophyte, Trichosporon fermentative, Rhodotorula toruloides, Yarrowia lipolytica, Cryptococcus curvatus or Rhodotorula glutinosus, including wild-type strains and natural or artificial mutants thereof.

9. The method for producing oil by open fermentation based on antibacterial Chinese medicine residues as claimed in claim 1, characterized in that: In step S4, the inoculation amount of the oleaginous yeast seed solution inoculated into the fermentation medium is 5% to 15% (v / v), and the culture is carried out at 25° C. to 35° C. with aeration, and the fermentation is terminated when the sugar concentration in the fermentation medium is lower than 5 g / L. Here, v / v is the volume ratio.

10. The method for producing oil by open fermentation based on antibacterial Chinese medicine residues as claimed in claim 1, characterized in that: In step S5, the extracted oil is an oil containing one or more long-chain fatty acids and their derivatives, which is suitable as a raw material for biodiesel.

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