Complex microbial inoculant, saccharification leavening agent and application thereof

Abstract

The invention relates to the technical field of bioengineering, in particular to a complex microbial inoculant, a saccharification leavening agent and application of the saccharification leavening agent. The aspergillus oryzae YBF1201 and the rhizopus oryzae YBF1202 are separated from white spirit yeast, the metabolic enzyme production characteristics of the strains and enzyme protein function annotation information are combined to determine that the strains have the capability of producing alpha-amylase and glucamylase through metabolism respectively, and the strains are important microorganisms responsible for the saccharification function; starch can be decomposed to generate fermentable sugars such as glucose for other fermentation microorganisms to use. The saccharification leavening agent prepared by using the composition has relatively strong saccharification capability of decomposing starch, promotes the growth of saccharomycetes, can greatly improve the yield of ethanol, has an effect of increasing the content of key flavor substances of white spirit, and has a wide application prospect.

Description

Technical Field

[0001] The present invention relates to the field of bioengineering technology, and in particular to a composite bacterial agent, a saccharification and fermentation agent and applications thereof. Background Art

[0002] Fermented food is a type of food that humans process and manufacture using natural food as raw materials and beneficial microbial flora. It has unique flavor and nutritional components. The production of fermented food requires the participation of multiple microorganisms. The complex metabolic mechanisms and interspecies interactions of these microorganisms jointly affect and determine the quality of fermented food. For the production of most fermented foods, two important processes, saccharification and fermentation, are required. Molds are the main species responsible for saccharification, including Aspergillus, Rhizopus, Mucor, etc. They metabolize to produce amylase to degrade the starch in the raw materials into monosaccharides or oligosaccharides such as glucose and maltose. The fermentation process is mainly participated by yeast and some bacteria. They use the small molecule fermentable sugars produced in the saccharification process as energy substances for metabolic activities. The metabolites are transformed and accumulated through complex processes to eventually form the unique flavor of fermented food. Therefore, the saccharification process is the driving force of fermentation. The saccharification power directly affects the growth rate of the fermentation flora and the metabolism of key flavor substances. At present, in the production process of typical fermented foods, such as liquor, vinegar, and soy sauce, the extensive and uncontrollable nature of solid-state fermentation often affects the bacterial saccharification process, resulting in low saccharification power and thus affecting the fermentation quality. This is particularly prominent in the production process of liquor. Insufficient saccharification power leads to the inability to fully decompose the starch in the raw materials, resulting in the "tender box" problem, that is, the fermentable sugar content of the fermentation system is too low, affecting the proliferation and metabolism of yeast, resulting in too low ethanol content in liquor, and bland flavor. Therefore, artificially domesticating pure functional bacteria to improve the saccharification power of the starter has become an important research direction for improving the quality of fermented foods and improving the flavor. Summary of the invention

[0003] In order to achieve the purpose of improving the saccharifying power of the starter and thus promoting food fermentation, the present invention separates an Aspergillus oryzae and a Rhizopus oryzae from Baijiu Daqu. The saccharifying power can be significantly improved by compounding them, so the following invention content is proposed.

[0004] In a first aspect, the present invention provides a strain of Aspergillus oryzae ( Aspergillus oryzae ), the Aspergillus oryzae is Aspergillus oryzae YBF1201, and the deposit number is CGMCC No. 41605.

[0005] At the same time, the present invention provides a strain of Rhizopus oryzae ( Rhizopus oryzae ), the Rhizopus oryzae is Rhizopus oryzae YBF1202, and its deposit number is CGMCC No. 41714.

[0006] Aspergillus oryzae YBF1201, isolated from Baijiu Daqu, has been deposited in the General Microbiology Center of China Microbiological Culture Collection Administration on October 31, 2024. Address of the depository unit: Institute of Microbiology, Chinese Academy of Sciences, No. 3, Yard 1, Beichen West Road, Chaoyang District, Beijing; Postal Code: 100101, Classification Name: Aspergillus oryzae Aspergillus oryzae , the deposit number is CGMCC No. 41605.

[0007] Rhizopus oryzae YBF1202, isolated from Baijiu Daqu, was deposited in the General Microbiology Center of China Microbiological Culture Collection Administration on December 11, 2024. Address of the depository: Institute of Microbiology, Chinese Academy of Sciences, No. 3, Yard 1, Beichen West Road, Chaoyang District, Beijing; Postal Code: 100101, Classification Name: Rhizopus oryzae Rhizopus oryzae , the deposit number is CGMCC No. 41714.

[0008] The present invention finds that after the two molds are compounded, they metabolize in the wheat bran culture medium to produce a large amount of α-amylase and glucoamylase. The two amylases have a synergistic effect on starch degradation, and the saccharification capacity of degrading starch in the raw materials into small molecular fermentable sugars such as glucose and maltose is significantly improved.

[0009] In a second aspect, the present invention provides a composite bacterial agent containing the above-mentioned Aspergillus oryzae YBF1201 and Rhizopus oryzae YBF1202.

[0010] Preferably, in the composite bacterial agent, the volume ratio of the Aspergillus oryzae YBF1201 spore suspension to the Rhizopus oryzae YBF1202 spore suspension is (1-100): (1-100).

[0011] More preferably, in the composite bacterial agent, the volume ratio of the Aspergillus oryzae YBF1201 spore suspension to the Rhizopus oryzae YBF1202 spore suspension is 1:(10-50).

[0012] Most preferably, in the composite bacterial agent, the volume ratio of the Aspergillus oryzae YBF1201 spore suspension to the Rhizopus oryzae YBF1202 spore suspension is 1:10.

[0013] Under the above ratio, the prepared composite bacterial agent or saccharification and fermentation agent has the highest saccharification activity. Applying it to liquor fermentation can obtain a higher ethanol yield and increase the yield of key flavor substances in the liquor.

[0014] In the specific implementation process, the composite bacterial agent is in the form of any one of the following: living cells, dry bacteria, immobilized cells, liquid bacterial agent or solid bacterial agent.

[0015] In a third aspect, the present invention provides a saccharification and fermentation agent containing the above-mentioned composite bacterial agent.

[0016] Preferably, the method for preparing the saccharification and fermentation agent comprises: inoculating the composite bacterial agent into a wheat bran culture medium to obtain the saccharification and fermentation agent (culture).

[0017] Preferably, the preparation method of the saccharification and fermentation agent comprises: inoculating the composite bacterial agent into a wheat bran culture medium, culturing at 28-32°C (preferably for more than 60 h, most preferably for 70-75 h), and then drying the culture (preferably at 40-50°C) to obtain the saccharification and fermentation agent.

[0018] In a fourth aspect, the present invention provides the use of the Aspergillus oryzae YBF1201, the Rhizopus oryzae YBF1202, the composite bacterial agent or the saccharification and fermentation agent in food production; preferably in liquor fermentation.

[0019] In the specific implementation process, the food production includes the production of food fermentation agents (such as white wine Daqu, white wine bran qu, soy sauce qujing, etc.).

[0020] After the composite bacterial agent or the saccharification and fermentation agent is applied as described above, the saccharification power of the fermentation system can be effectively enhanced, the utilization rate of raw materials can be improved, the growth of fermentation flora can be promoted, the fermentation time can be shortened, the food flavor can be enriched and strengthened, and the yield and quality of fermented food can be improved.

[0021] In a fifth aspect, the present invention provides the use of the Aspergillus oryzae YBF1201, the Rhizopus oryzae YBF1202, the composite bacterial agent or the saccharification and fermentation agent in starch deep processing (eg, papermaking, pharmaceutical fields).

[0022] In a sixth aspect, the present invention provides a method for fermenting liquor, comprising: inoculating the composite bacterial agent or the saccharification fermentation agent into a grain solid fermentation medium for fermentation; preferably, the grain is sorghum; preferably, the fermentation temperature is 28~32°C.

[0023] Preferably, the inoculation amount is 10% or more, more preferably 12% or more.

[0024] Preferably, the mass of the cereal solid-state fermentation medium is greater than 100 g.

[0025] Preferably, the fermentation time is more than 5 days, more preferably more than 7 days.

[0026] Compared with the prior art, the present invention has the following beneficial effects: The present invention separates an Aspergillus oryzae and a Rhizopus oryzae from liquor Daqu, and determines that they have the ability to metabolize and produce α-amylase and glucoamylase respectively by combining the metabolic enzyme production characteristics of the strains and the enzyme protein function annotation information, and are important microorganisms responsible for saccharification functions, which can decompose starch to produce glucose and other fermentable sugars for use by other fermentation microorganisms. The saccharification fermentation agent prepared by the combination has a strong saccharification ability to decompose starch and promote yeast growth, which can greatly increase ethanol production, and at the same time has a gain effect on the content of key flavor substances in liquor, and has broad application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a statistical chart of the flavor substances of liquor produced by saccharification and fermentation agents in each experimental group and the control group.

[0028] Figure 2 It is a comprehensive statistical chart of the flavor substance content and ethanol production in each experimental group and the control group. DETAILED DESCRIPTION

[0029] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be described clearly and completely below. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0030] If no specific techniques or conditions are specified in the examples, all are carried out according to conventional methods or the techniques or conditions described in the literature in the field, or according to the product instructions. If no manufacturer is specified for the reagents and instruments used, all are conventional products that can be purchased through regular channels.

[0031] Example 1 This embodiment provides a composite bacterial agent, and the preparation method is as follows: Two fungi were screened from Baijiu Daqu, namely YBF1201 and YBF1202. The physiological and biochemical characteristics of these two fungi were detected. After ITS sequencing and analysis, the fungi YBF1201 and YBF1202 were identified. Aspergillus oryzae The homology was as high as 99.82%. Combined with physiological and biochemical characteristics, YBF1201 was identified as Aspergillus oryzae; YBF1202 was identified as Rhizopus oryzae The homology was as high as 98.74%. Combined with the physiological and biochemical characteristics, YBF1202 was identified as Rhizopus oryzae.

[0032] Aspergillus oryzae YBF1201 and Rhizopus oryzae YBF1202 were inoculated into PDA medium, cultured at 30°C for 48 hours, and then the mature mycelium was inoculated into PDA medium again. The above operation was repeated three times to obtain purified culture of Aspergillus oryzae and Rhizopus oryzae.

[0033] Take a solid plate culture medium inoculated with pure Aspergillus oryzae and Rhizopus oryzae for 72 hours, add 10 sterile glass beads to the plate under sterile conditions, then add 3 ml of sterile saline containing 0.01% Tween-80 to soak the surface of the mold colony, slowly and evenly rotate the culture medium to allow the eluent to fully soak the spores on the surface of the mold colony and elute the spores, and aspirate the eluent into a centrifuge tube to obtain a crude spore suspension.

[0034] The crude spore suspension was mixed with an equal volume of 1% oxalic acid solution and heated at 70°C for 10 min, then quickly cooled to room temperature and centrifuged at 3600 r / min for 10 min to remove impurities and the influence of other microorganisms on the spore suspension.

[0035] The concentration of the spore suspension after centrifugation was measured using a microscopic counting plate, and the spore concentration in the suspension was calculated. After that, the spores were diluted with sterile saline to adjust the concentrations of the Rhizopus oryzae spore suspension and the Aspergillus oryzae spore suspension to 1×10 5 CFU / mL, and compounded according to different volume ratios to prepare a composite bacterial agent.

[0036] Example 2 This embodiment provides a saccharification fermentation agent, which is to inoculate the composite bacterial agent prepared in Example 1 into a wheat bran culture medium for fermentation culture, obtain a culture colonized with molds having saccharification function and enriched with amylase as a saccharification fermentation agent, and measure its saccharification ability, as follows: Preparation of wheat bran culture medium: Take 400 g of crushed wheat grains and pass them through a 40-mesh sieve, mix them with 600 g of wheat bran, add 1.5% ammonium sulfate, add 1 L of deionized water, stir and mix thoroughly, and heat at 121°C for 15 minutes.

[0037] Inoculation of compound microbial agent: Control the total number of mold spores in the fermentation system to 3×10 3 CFU / g, calculate the addition amount of Aspergillus oryzae YBF1201 and Rhizopus oryzae YBF1202 spore suspension at different proportions and add them into wheat bran medium under sterile conditions, fully stir the inoculated wheat bran medium and compact it, culture it at 30℃ and 70% relative humidity, invert it after 12h, start timing from inoculation, take samples every 12h and measure the saccharification power, determine the proportion of composite bacterial agent with the strongest saccharification power and fermentation time.

[0038] Preparation of saccharification and fermentation agent: Take 20g of solid bran culture medium inoculated with composite bacterial agent after a certain culture time. The texture of the culture medium is required to be compact, without loose or broken particles and uneven agglomeration. The surface of the culture medium is evenly covered with mold hyphae. Samples are taken from the center of the culture medium, and the top 0.3-0.5cm thick part is removed. The collected culture is placed in a constant temperature dryer and dried at 45℃ for 24h, then taken out and crushed, and the crushing particle size is controlled to be less than 0.6mm (through a 30-mesh sieve).

[0039] Determination of saccharification power: Saccharification power is defined as the number of milligrams of glucose produced by 1g saccharification fermentation agent saccharifying starch for 1h at 40℃ and pH4.6, in units of U. The amount of glucose produced is detected by the DNS method. Take 10g of dried and crushed culture, add 20ml of citric acid buffer and shake and extract for 30min, centrifuge the extract at 7200r / min for 15min, and take the supernatant to prepare saccharification enzyme extract. Take 5ml of saccharification enzyme extract and mix it with 5ml of 2% (w / v) starch solution, react at 55℃ for 1h and accurately time it, add 5ml of 20% NaOH (w / v) solution to terminate the reaction, take 2ml of the above reaction solution, add 3ml of DNS dye solution, heat it in a boiling water bath for 5min, take it out and place it in an ice water bath to cool, dilute it to 10ml with distilled water, measure the absorbance at 540nm, and compare it with the standard curve prepared after the same treatment with standard glucose solution to determine the amount of glucose produced.

[0040] Subjects: Experimental group 1: Aspergillus oryzae YBF1201 and YBF1202 were inoculated into wheat bran medium at a ratio of 100:1 and fermented for 108 h. Samples were taken every 12 h and the saccharification capacity was measured.

[0041] Experimental group 2: Aspergillus oryzae YBF1201 and YBF1202 were inoculated into wheat bran medium at a ratio of 50:1 and fermented for 108 h. Samples were taken every 12 h and the saccharification capacity was measured.

[0042] Experimental group 3: Aspergillus oryzae YBF1201 and YBF1202 were inoculated into wheat bran medium at a ratio of 10:1 and fermented for 108 h. Samples were taken every 12 h and the saccharification capacity was measured.

[0043] Experimental group 4: Aspergillus oryzae YBF1201 and YBF1202 were inoculated into wheat bran medium at a ratio of 1:1 and fermented for 108 h. Samples were taken every 12 h and the saccharification capacity was measured.

[0044] Experimental group 5: Aspergillus oryzae YBF1201 and YBF1202 were inoculated into wheat bran medium at a ratio of 1:100 and fermented for 108 h. Samples were taken every 12 h and the saccharification capacity was measured.

[0045] Experimental group 6: Aspergillus oryzae YBF1201 and YBF1202 were inoculated into wheat bran medium at a ratio of 1:50 and fermented for 108 h. Samples were taken every 12 h and the saccharification capacity was measured.

[0046] Experimental group 7: Aspergillus oryzae YBF1201 and YBF1202 were inoculated into wheat bran medium at a ratio of 1:10 and fermented for 108 h. Samples were taken every 12 h and the saccharification capacity was measured.

[0047] Control group 1: Pure strain of Aspergillus oryzae YBF1201 was fermented in wheat bran medium for 108 h, and samples were taken every 12 h to measure the saccharification capacity.

[0048] Control group 2: Pure strain of Rhizopus oryzae YBF1202 was fermented in wheat bran medium for 108 h, and samples were taken every 12 h to measure the saccharification capacity.

[0049] The saccharification capacity of experimental groups 1 to experimental groups 7 and control groups 1 and 2 was measured at 9 time points within 12h-108h of culture after inoculation. The results are shown in Table 1. The saccharification fermentation agent prepared by the composite bacterial agent in experimental group 7 (Aspergillus oryzae YBF1201 and Rhizopus oryzae YBF1202 inoculated at 1:10) had the highest saccharification capacity at 72h, reaching 395U, which was significantly higher than that of the control group cultured with a single strain. Compared with the pure saccharification fermentation agents of Aspergillus oryzae and Rhizopus oryzae, the saccharification capacity was increased by 55.51% and 15.16%, respectively, which proved that the composite bacterial agent of the present invention can effectively improve the saccharification capacity of the fermentation agent and enhance the fermentation performance.

[0050] Table 1 Saccharification test results

[0051] Further, in this example, based on experimental group 7, Aspergillus oryzae YBF1201 of the present invention and commercially available Rhizopus oryzae (purchased from Shandong Hezhong Kangyuan Biotechnology Co., Ltd.) were compounded at a ratio of 1:10 (Comparative Example 1), and commercially available Aspergillus oryzae (purchased from Jining Yuyuan Biotechnology Co., Ltd.) and Rhizopus oryzae YBF1202 of the present invention were compounded at a ratio of 1:10 (Comparative Example 2) to detect saccharification capacity. The results are shown in Table 2.

[0052] Table 2

[0053] It can be seen that the composite bacterial agent of the present invention selects a specific combination of Aspergillus oryzae YBF1201 and Rhizopus oryzae YBF1202, which can greatly improve the saccharification capacity of the fermentation agent compared with other composite bacterial agents prepared by combining Aspergillus oryzae and Rhizopus oryzae.

[0054] Example 3 This example is aimed at the saccharification fermentation agents in each experimental group and the control group under the 72h culture time in Example 2, and applies them to sorghum solid-state fermentation and measures the yield of ethanol and key flavor substances to verify the effect of the high saccharification fermentation agent prepared by the composite bacterial agent on the fermentation of liquor. The specific process is as follows: Sorghum solid fermentation test: Take an appropriate amount of fresh whole sorghum grains and crush them. The proportion of sorghum after crushing that passes through a 30-mesh sieve must be higher than 30%. Then mix them at a weight ratio of sorghum: water = 1:1.1, and add fresh rice husks that are 10% of the mass of sorghum. Steam them in a steamer for 1.5 hours and stir them evenly. Dispense them in special stainless steel fermentation tanks, 100g per tank. Take the saccharification fermentation agent made of the composite bacterial agent in Example 2, sprinkle it into the sorghum at a ratio of 10% and stir it evenly. Fully compact the sorghum in the stainless steel tank and seal it. Ferment it at 30°C for 7 days.

[0055] Determination of ethanol content: 5 g of fermented sorghum was placed in a 20 ml headspace bottle, and the ethanol and key flavor substances were determined by headspace solid phase microextraction combined with gas chromatography-mass spectrometry. The conditions of headspace solid phase microextraction combined with gas chromatography-mass spectrometry are as follows: Sample extraction conditions: temperature 45°C, rotation speed 450r / min, time 30min, oscillation time 30min, extraction depth 22mm, injection depth 35mm, desorption time 300s.

[0056] GC-MS analysis conditions: chromatographic column: DB-Wax (60m×250μm×0.25μm); injection port temperature 250℃; heating program 40℃, hold for 4min, then increase to 150℃ at a rate of 5℃ / min, hold for 4min, then increase to 230℃ at a rate of 4℃ / min, hold for 8min, injection volume 1μL, split ratio 20:1, detector temperature 230℃, tail flow 30mL / min, hydrogen flow rate 40MmL / min, air flow rate 400mL / min.

[0057] Mass spectrometry conditions: electron energy 70 eV, ion source EI, temperature 230 °C, mass scanning range 28-500 amu, full scan, quantification using selected ion scanning mode (SIM) combined with 4-octanol internal standard method.

[0058] Subjects: Experimental group: There were seven groups in total, with the mold ratio consistent with that set in the experimental group in Example 2, and the culture time after inoculation into the bran culture medium was 72 hours.

[0059] Control group: There were two groups in total, with the mold ratio being consistent with that set for the control group in Example 2, and the culture time after inoculation into the bran culture medium was 72 hours.

[0060] The results are shown in Table 3. When the high saccharifying power fermentation agent prepared by the composite bacterial agent of the present invention is applied to ethanol fermentation, the ethanol yield can be significantly improved. Among them, the high saccharifying power fermentation agent in experimental group 6 and experimental group 7 significantly promoted the ethanol yield in the fermentation process of liquor, reaching 80.48 mg / g and 67.28 mg / g, respectively. Compared with the saccharifying fermentation agent of Rhizopus oryzae in the control group, the ethanol yield of the composite mold fermentation agent increased by 290% and 226%, respectively. Compared with the saccharifying fermentation agent of Aspergillus oryzae in the control group, the ethanol yield of the saccharifying fermentation agent prepared by the composite bacterial agent increased by 60% and 33.8%, respectively, which proves that the composite bacterial agent of the present invention can greatly improve the saccharifying power and thus promote the good performance of ethanol fermentation.

[0061] Table 3 Comparison of ethanol production

[0062] The contents of flavor substances in liquor produced by saccharification and fermentation agents in each experimental group and the control group were compared. Figure 1 As shown in Table 4. Compared with pure mold preparations, the composite bacterial agent of the present invention is used as a saccharification fermentation agent for liquor fermentation. The content of main flavor substances such as esters, alcohols, and acids in the product is significantly improved. In particular, the composite bacterial agent in experimental group 7 not only enables the saccharification fermentation agent to obtain the highest saccharification power, but also significantly improves its flavor content. Compared with pure mold preparations of Aspergillus oryzae and Rhizopus oryzae, the ester content is increased by 8.6% and 20.7%, respectively, and the organic acid flavor substances are increased by 28.1% and 36.6%. Among the ester components, the increase in the content of ethyl acetate, ethyl lactate, ethyl octanoate, isopentyl caproate, and ethyl butyrate is the most obvious. These esters usually have a sweet smell similar to fruits and cream, are important flavor substances in liquor, participate in the formation of the unique body flavor of liquor, and have a vital impact on the quality of liquor. Among them, ethyl lactate has an important influence on the richness and coordination between the flavor levels of liquor. When its content is too low, it will cause the body to produce a dull fragrance, resulting in a single aroma and a unique style of losing the body. In addition, the content of acidic substances such as acetic acid, butyric acid, and dimethylbutyric acid also increased significantly. The rich acidic substances reacted with ethanol to undergo esterification, further promoting the production of ester aroma substances during the fermentation process of liquor.

[0063] Table 4 Significantly increased flavor substances in liquor saccharified and fermented by composite bacterial agents

[0064] Comprehensive changes in flavor substance content and ethanol content in each experimental group and control group ( Figure 2 ), the composite bacterial agent of the present invention (especially experimental group 7) can significantly improve the saccharification power of the saccharification fermentation agent, promote the rate of conversion of starchy raw materials into glucose, and when applied to liquor fermentation, can provide sufficient energy substances for the fermentation bacteria in the liquor fermentation system and promote its growth and metabolism, thereby increasing the yield of ethanol and key flavor substances, enriching and enhancing the flavor of liquor. Therefore, the present invention is conducive to improving the raw material utilization rate and production efficiency in the liquor production process, while ensuring the flavor quality of liquor, and contributing to the industrialization and standardization of liquor production.

[0065] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A strain of Aspergillus oryzae ( Aspergillus oryzae ), characterized in that, The Aspergillus oryzae is Aspergillus oryzae YBF1201, and its deposit number is CGMCC No.41605.

2. A strain of Rhizopus oryzae ( Rhizopus oryzae ), characterized in that, The Rhizopus oryzae is Rhizopus oryzae YBF1202, and its deposit number is CGMCC No.41714.

3. A composite bacterial agent, characterized in that: The composite bacterial agent comprises the Aspergillus oryzae YBF1201 described in claim 1 and the Rhizopus oryzae YBF1202 described in claim 2.

4. The composite bacterial agent according to claim 3, characterized in that: In the composite bacterial agent, the volume ratio of the Aspergillus oryzae YBF1201 spore suspension to the Rhizopus oryzae YBF1202 spore suspension is (1-100): (1-100).

5. The composite bacterial agent according to claim 4, characterized in that: In the composite bacterial agent, the volume ratio of the Aspergillus oryzae YBF1201 spore suspension to the Rhizopus oryzae YBF1202 spore suspension is 1:(10-50); more preferably 1:

10.

6. The composite bacterial agent according to claim 3, characterized in that: The composite bacterial agent is in the form of any one of the following: living cells, dry bacteria, immobilized cells, liquid bacterial agent or solid bacterial agent.

7. A saccharification and fermentation agent, characterized in that: It contains the composite bacterial agent according to any one of claims 3 to 6.

8. Use of the Aspergillus oryzae YBF1201 according to claim 1, the Rhizopus oryzae YBF1202 according to claim 2, the composite bacterial agent according to any one of claims 3 to 6, or the saccharification and fermentation agent according to claim 7 in food production; preferably in liquor fermentation.

9. Use of the Aspergillus oryzae YBF1201 described in claim 1, the Rhizopus oryzae YBF1202 described in claim 2, the composite bacterial agent described in any one of claims 3 to 6, or the saccharification and fermentation agent described in claim 7 in deep processing of starch.

10. A liquor fermentation method, characterized in that: include: The composite bacterial agent according to any one of claims 3 to 6 or the saccharification and fermentation agent according to claim 7 is inoculated into a grain solid fermentation medium for fermentation; preferably, the grain is sorghum; preferably, the fermentation temperature is 28 to 32°C.

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