Penicillium oxalicum G6 and application thereof

Abstract

The invention relates to the field of microorganisms, in particular to penicillium oxalicum G6 and application thereof. The preservation number of the penicillium oxalicum G6 provided by the invention is CGMCC (China General Microbiological Culture Collection Center) No.41386. The Penicillium oxalicum G6 provided by the invention can quickly start a compost heating process in a low-temperature environment, the high-temperature period is prolonged, the high-temperature peak value of compost is improved, and the generated compost product is highly harmless and non-toxic. Meanwhile, the strain has a relatively strong cellulose degradation function and also has a growth promoting effect, and compared with a commercial fertilizer, the dry weight of the overground part and the underground part of the plant can be effectively increased. Therefore, the strain provided by the invention has multiple functions and is a probiotic with excellent properties.

Description

Technical Field

[0001] The invention relates to the field of microorganisms, in particular to a strain of Penicillium oxalicum G6 and application thereof. Background Art

[0002] In recent years, the agricultural economy has developed rapidly, and solid waste has accumulated seriously. The straw produced by farmland planting and the livestock manure produced by the breeding industry are important components of China's agricultural solid waste. The annual output of livestock and poultry manure can reach about 3.8 billion tons, and the annual output of straw can reach about 700 million tons. Therefore, the resource treatment of agricultural solid waste is a problem that needs to be solved at present.

[0003] Aerobic composting is a common method for treating solid waste such as livestock and poultry manure, agricultural straw, and domestic garbage. Under the conditions of sufficient oxygen, suitable water content, C / N, and temperature, a series of biochemical reactions are carried out by the metabolism of microorganisms such as bacteria, fungi, and actinomycetes in livestock and poultry manure to decompose the macromolecular organic matter in the raw materials into small molecular organic matter, and finally convert it into humus, so that agricultural waste can be reduced and harmless. Composting technology has become one of the most important agricultural waste resource utilization technologies due to its low cost, high safety and applicability and suitability for agricultural applications. However, the Xinjiang Uygur Autonomous Region is located in the northwestern border area of ​​my country, with low temperatures in autumn and winter, making it difficult to start the composting process and difficult to meet the standard composting temperature. In addition, the high content of difficult-to-degrade cellulose in agricultural straw leads to a prolonged composting maturity period and incomplete degradation of the material, which greatly reduces the efficiency of composting and limits the application and promotion of composting technology.

[0004] Using microorganisms to degrade cellulose has the advantages of environmental protection, high efficiency and low cost. Although researchers at home and abroad have conducted a series of studies on the aerobic composting process and the role of bacterial agents, the current research on microorganisms used to promote cellulose degradation in composting under low temperature environments is still immature. Therefore, screening out cold-resistant bacteria with cellulose degradation capabilities and preparing mature bacterial agents are of great significance to accelerate the aerobic composting process in low temperature environments. Summary of the invention

[0005] The purpose of the present invention is to provide a strain of Penicillium oxalicum G6 and its application to solve the problems existing in the above-mentioned prior art. The Penicillium oxalicum G6 provided by the present invention can quickly start the composting heating process in a low temperature environment, prolong the high temperature cycle, and increase the high temperature peak of the composting. At the same time, the strain also has the ability to degrade cellulose.

[0006] To achieve the above object, the present invention provides the following solutions:

[0007] The invention provides a strain of Penicillium oxalicum G6, the deposit number of which is CGMCC No. 41386. During the composting temperature rising period, the strain can rapidly increase the composting temperature, and the strain has high biological activity and adaptability at this stage.

[0008] The present invention provides a method for culturing the above-mentioned Penicillium oxalicum G6, comprising the following steps:

[0009] The activated Penicillium oxalate G6 is inoculated into a fermentation medium for fermentation culture to obtain a fermentation liquid containing Penicillium oxalate G6.

[0010] Preferably, the fermentation medium comprises components in the following concentrations: CMC-Na 5.0 g / L, peptone 5.0 g / L, yeast extract 1.0 g / L, KH2PO4 0.5 g / L and MgSO4 0.25 g / L.

[0011] Preferably, the initial pH of the fermentation culture is 6.5-7.0, the temperature is 0°C-25°C, the rotation speed is 150r / min, and the time is 48h.

[0012] The present invention provides the use of the above-mentioned Penicillium oxalicum G6 in preparing a low-temperature composting fermentation agent.

[0013] The invention provides a low-temperature composting fermentation agent, wherein the effective ingredients of the low-temperature composting fermentation agent include the above-mentioned Penicillium oxalicum G6.

[0014] Further preferably, the effective viable bacteria count of the low-temperature composting fermentation agent is ≥ 1×10 8 CFU / mL.

[0015] The invention provides application of the low-temperature composting fermentation agent in preparing compost.

[0016] Preferably, the method comprises the following steps:

[0017] The low-temperature composting fermentation agent is inoculated into the fertilizer to be fermented, and then aerobic fermentation is performed to obtain compost.

[0018] Further preferably, the effective viable bacteria count of the low-temperature composting fermentation agent is ≥ 1×10 8 CFU / mL, the inoculation amount is 1% of the mass of the fertilizer to be fermented.

[0019] Further preferably, the aerobic fermentation is low-temperature aerobic fermentation; and the initial temperature of the aerobic fermentation is 20°C.

[0020] Further preferably, the present invention provides the use of the above-mentioned Penicillium oxalicum G6 or the above-mentioned low-temperature composting fermentation agent in promoting compost maturity.

[0021] Further preferably, the compost is cow dung and cotton stalk low-temperature aerobic compost.

[0022] Further preferably, the present invention provides the use of the above-mentioned Penicillium oxalicum G6 in the degradation of agricultural straw.

[0023] Further preferably, the present invention provides the use of the above-mentioned Penicillium oxalicum G6 in producing cellulase.

[0024] The present invention provides the use of the above-mentioned Penicillium oxalicum G6 in the preparation of a bacterial agent or a microbial fertilizer for promoting plant growth.

[0025] Further preferably, the plant is cotton.

[0026] The present invention provides a bacterial agent or microbial fertilizer for promoting plant growth, wherein the active ingredients of the bacterial agent or microbial fertilizer include the above-mentioned Penicillium oxalicum G6.

[0027] Further preferably, the plant is cotton.

[0028] Further preferably, the present invention also provides the use of the above-mentioned plant growth promoting bacterial agent or microbial fertilizer in promoting plant growth.

[0029] Further preferably, the plant is cotton.

[0030] Further preferably, the present invention also provides a method for promoting plant growth, comprising the following steps:

[0031] The above-mentioned bacterial agents or microbial fertilizers for promoting plant growth are applied during the seedling stage of the plants.

[0032] Further preferably, the plant is cotton.

[0033] The present invention discloses the following technical effects:

[0034] 1. The Penicillium oxalicum G6 provided by the present invention can quickly start the composting heating process under low temperature environment, prolong the high temperature period of composting, increase the high temperature peak of composting, and the resulting composting product is highly harmless and non-toxic. Chinese patent document CN117660252 (application number: 202311683194.5) discloses the invention of a low-temperature composite bacterial agent, including: 3 parts of low-temperature cellulose degrading bacteria, 1 part of low-temperature starch degrading bacteria, and 1 part of low-temperature sugar degrading bacteria. Relative to the invention, the advantages and differences of the strains involved in the present invention are: the bacterial agent provided by the present invention only contains one kind of microorganism. In comparison, the preparation process is easier and the same degree of starting composting heating and extending the high temperature cycle effect can be produced under low temperature environment. Moreover, the preparation of the bacterial agent containing this strain is simple and convenient.

[0035] 2. The Penicillium oxalicum G6 provided by the present invention has a strong cellulose degradation function. Chinese patent document CN111909852A (application number: 202010698524.8) discloses a cellulose degrading bacterium, the strain is named Talaromyces amestolkiae, strain number P5, and the strain has a good degradation effect on crop straw. Relative to the invention, the advantages and differences of the strain provided by the present invention are: Penicillium oxalicum G6 can survive under conditions of 0°C-25°C, and the wheat straw degradation rate measured after one week of cultivation at 15°C is 73.3%, which is 3 times higher than the wheat straw degradation rate of Talaromyces amestolkiae P5 measured at 25°C on the 25th day.

[0036] 3. By inoculating a fermentation liquid containing Penicillium oxalate G6 in the compost, the degradation of materials can be accelerated, and the compost can be made highly harmless and non-toxic. Chinese patent document CN115725447A (application number: 202211001055.5) discloses a Bacillus velezensis SSF6, which can reduce the biological toxicity of straw compost. Relative to the invention, the advantages and differences of the strains provided by the present invention are: the compost extract of Penicillium oxalate G6 added to the present invention can make the seed germination index reach 225%, while the germination index of the straw compost extract after adding Bacillus velezensis SSF6 to the invention is 108%. It can be seen that the compost of the present invention is more non-toxic.

[0037] 4. The Penicillium oxalicum G6 provided by the present invention also has a growth-promoting effect and can effectively increase the dry weight of the above-ground and underground parts of plants compared to commercial fertilizers.

[0038] In summary, the Penicillium oxalicum G6 provided by the present invention has multiple functions and is a probiotic with excellent performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0040] Figure 1 This is the growth colony image of strain G6;

[0041] Figure 2 The cellulose degradation circles of strain G6 at 25℃(A), 15℃(B), 10℃(C) and 0℃(D);

[0042] Figure 3is the phylogenetic tree of 16S rDNA of G6 strain;

[0043] Figure 4 is the curve of temperature change with composting time; where Environment is the ambient temperature; CK is the blank group; T is the experimental group;

[0044] Figure 5 The curve of pH changing with composting time; CK is the blank group; T is the experimental group;

[0045] Figure 6 is the curve of EC changing with composting time; CK is the blank group; T is the experimental group;

[0046] Figure 7 is the curve of GI changing with composting time; CK is the blank group; T is the experimental group;

[0047] Figure 8 The curve of the percentage change of cellulose with composting time; CK is the blank group; T is the experimental group;

[0048] Fig. 9 The changes of EC values ​​at different depths of soils treated with different methods; CK is 100% chemical fertilizer; M1 is 100% T; M2 is 100% commercial organic fertilizer;

[0049] Fig.10 The changes in the accumulation of above-ground and underground dry matter at the seedling stage of cotton under different treatments; CK is 100% chemical fertilizer; M1 is 100% T; M2 is 100% commercial organic fertilizer.

[0050] Biomaterial Deposit Information

[0051] Penicillium oxalicum G6 is deposited in the General Microbiology Center (CGMCC) of the China Microbiological Culture Collection Administration, and the deposit address is the Institute of Microbiology, Chinese Academy of Sciences, No. 3, Yard 1, Beichen West Road, Chaoyang District, Beijing. The deposit date is June 27, 2024, and its deposit number is CGMCC No.41386. DETAILED DESCRIPTION

[0052] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as limiting the present invention, but should be understood as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0053] It should be understood that the terms described in the present invention are only for describing a particular embodiment and are not intended to limit the present invention. In addition, for the numerical range in the present invention, it should be understood that each intermediate value between the upper and lower limits of the scope is also specifically disclosed. The intermediate value in any stated value or stated range, and each smaller range between any other stated value or intermediate value in the described range is also included in the present invention. The upper and lower limits of these smaller ranges can be independently included or excluded in the scope.

[0054] Unless otherwise indicated, all technical and scientific terms used herein have the same meanings as those generally understood by those skilled in the art. Although the present invention describes only preferred methods and materials, any methods and materials similar or equivalent to those described herein may also be used in the implementation or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials associated with the documents. In the event of a conflict with any incorporated document, the content of this specification shall prevail.

[0055] It will be apparent to those skilled in the art that various modifications and variations may be made to the specific embodiments of the present invention description without departing from the scope or spirit of the present invention. Other embodiments derived from the present invention description will be apparent to those skilled in the art. The present invention description and examples are exemplary only.

[0056] The words “include,” “including,” “have,” “contain,” etc. used in this document are open-ended terms, meaning including but not limited to.

[0057] Materials preparation:

[0058] 1. Experimental reagents and equipment: The main experimental reagents are shown in Table 1, and the equipment is shown in Table 2.

[0059] Table 1 Main reagents

[0060] Reagents Product Specifications Reagents Product Specifications NaCl Analytical grade Zinc chloride Analytical grade Sodium Carboxymethyl Cellulose Analytical grade Congo Red Indicator Dipotassium hydrogen phosphate Analytical grade Magnesium sulfate heptahydrate Analytical grade Potassium dihydrogen phosphate Analytical grade Manganese sulfate Analytical grade Sodium phosphate Analytical grade Ammonium sulfate Analytical grade Ferrous Sulfate Heptahydrate Analytical grade Potassium Sodium Tartrate Chemically pure Potassium Nitrate Analytical grade 3,5-Dinitrosalicylic acid Chemically pure

[0061] Table 2 Main equipment and instruments

[0062] Instrument Name model Origin Instrument Name model Origin Clean bench ZHJH-C1112B China pH Meter PHSJ-4F China Autoclave MJ-54A USA Electronic balance SQP Germany Ultrapure water instrument MILL-QBIOCCEL USA Pipette Eppendorf Germany Refrigerated high speed centrifuge Frcsco17 USA UV spectrophotometer Evolution201 USA Electric constant temperature water bath DK-80 China -80℃ Refrigerator DW-86L388J China Constant temperature incubator HWS-80 China -20℃ Refrigerator BCD-271TMCM China Constant temperature shaking table HZQ-F160A China Flow cytometry CytoFLEX USA Blast drying oven DHG-9030A China

[0063] 2. Prepare the culture medium:

[0064] (1) PDA medium: 1 L potato extract, 16.0 g agar, 20.0 g glucose, sterilize at 115°C for 15 min.

[0065] (2) LB solid medium: 5.0 g yeast extract, 10.0 g tryptone, 10.0 g NaCl, 14.0 g agar, dilute to 1 L with water, pH 7.0, sterilize at 121°C for 15 min.

[0066] (3) Beef extract peptone medium: 5.0 g beef extract, 10.0 g peptone, 10.0 g NaCl, 20.0 g agar, dilute to 1 L with water, pH 7.2-7.4, sterilize at 121°C for 15 min.

[0067] (4) Sodium carboxymethyl cellulose culture medium: CMC-Na 10.0 g, KH2PO4 1.5 g, NaH2PO4·7H2O 2.5 g, MgSO4·7H2O 0.3 g, FeSO4·7H2O 0.005 g, ZnCl2 0.0017 g, MnSO4 0.0016 g, (NH4)2SO4 1.5 g, make up to 1 L with water, pH 7.0, sterilize at 121°C for 15 min.

[0068] (5) Liquid fermentation medium: CMC-Na 5.0 g, peptone 5.0 g, yeast extract 1.0 g, KH2PO4 0.5 g, MgSO4 0.25 g, dilute to 1 L with water, pH 6.5-7.0, sterilize at 121°C for 15 min.

[0069] Example 1 Screening of strains

[0070] 1. Sampling: Take samples of livestock and poultry manure and straw compost during the warming period in Xinjiang Uygur Autonomous Region, store them in sterile sealed bags, and place them in a 4°C refrigerator after sealing.

[0071] 2. Screening of cellulose-degrading bacteria

[0072] Soak the sample in sterile water and shake it on a shaker for 6 hours to obtain the sample extract. Take the sample extract and dilute it with sterile water to a dilution concentration of 10 -4 , 10 -5 , 10 -6 , 10 -7 The dilution was spread on PDA medium and LB solid medium, and placed in incubators at 0℃, 10℃, 15℃ and 25℃ for 48h. The bacteria that can grow at the four temperatures at the same time were separated and the strain type was preliminarily determined.

[0073] The obtained fungi were inoculated into PDA medium, and the bacteria were inoculated into LB solid medium. After inverted culture at 25°C for 48 hours, the strains with better growth were selected for plate streaking screening to obtain a large number of single colonies of the strains. The streaking culture was continued until the pure culture of each strain was obtained. The purified strains were inoculated into beef extract peptone medium for 2 days, and their colony morphology was observed. Finally, the strains were inoculated on the slant and stored in a refrigerator at 4°C for use.

[0074] The individual colonies of the strain with good growth were transferred to sodium carboxymethyl cellulose agar plates, and inverted in constant temperature incubators at 0℃, 10℃, 15℃ and 25℃ for 10d, 8d, 6d and 4d respectively. Slowly pour Congo red dye solution on the plate, stain for 30 minutes, and then decolorize with 0.9% (W / V) sodium chloride solution for 25 minutes. Observe the transparent circles that appear on the plate, and select the strain with higher clarity of transparent circles and larger ratio of transparent circle diameter to colony diameter (D / d). It is named G6 strain, and the other strains are named X1 and X3 strains. The measurement results of each strain are shown in Table 3. The photo of the growing colony of G6 strain after inverted culture at 25℃ for 48h is shown in Figure 1 The degradation circle photos of G6 strain at 25℃(A), 15℃(B), 10℃(C), and 0℃(D) are shown in the figure. Figure 2 shown.

[0075] Table 3 Determination results of degradation zone diameter D / d of strain G6 on sodium carboxymethyl cellulose medium

[0076]

[0077] Depend on Figure 1 It can be seen that the colonies of strain G6 have a fluffy or cotton-like texture, are light green in color, and are round or oval in shape. Figure 2 According to the records, the degradation zone diameter of the G6 strain ranges from 2.11 to 5.52 cm, and the degradation zone diameter is the largest under the 15°C culture condition. The G6 colony diameter ranges from 0.71 to 4.15 cm, and the colony diameter is also the largest under the 15°C culture condition. Compared with the X1 and X3 strains, the D / d value of the G6 strain under 25°C and 10°C culture is the largest. It can be seen that the growth and metabolic activities of the G6 strain are relatively active at these two temperatures, showing a strong adaptability.

[0078] The G6 strain was streaked and purified for three generations and stored in a -80°C refrigerator with glycerol until use.

[0079] Example 2 Construction of phylogenetic evolutionary tree

[0080] Figure 3 The sequences in GenBank that have high homology to the obtained sequence are all from the genus Penicillium.

[0081] Example 3 Degradation of filter paper strips

[0082] Filter paper treatment: Soak the filter paper in 1% (V / V) dilute acetic acid for 24 hours, test with iodine solution to confirm that there is no starch, then wash with 2% (W / V) soda water until neutral, and dry for later use.

[0083] Filter paper culture medium: filter paper strip 1×6cm, KH2PO4 1.0g, NaCl 0.1g, MgSO47H2O 0.3g, NaNO3 2.5g, FeCl3 0.01g, CaCl2 0.1g, make up to 1L with water, sterilize at 121℃ for 15min.

[0084] The G6 strain was inoculated into PD medium and cultured at 25°C and 150 r / min for 48 h. 5 mL of inoculum was inoculated into a 250 mL Erlenmeyer flask containing 50 mL of filter paper medium, and 5 ml of sterile water was set as a control. The culture was shaken at 15°C and 150 r / min for 5 days, and the filter paper rot was observed and the filter paper weight loss rate (degradation rate) was calculated as shown in Table 4.

[0085] Table 4 Filter paper strip degradation results

[0086]

[0087]

[0088] Note: "+" indicates that the edge of the filter paper is expanded, "++" indicates that the filter paper is neatly expanded and bent, "+++" indicates that the filter paper is amorphous and basically becomes a paste, and "++++" indicates that the filter paper is a paste

[0089] As shown in Table 4, the degradation rate of strain G6 was the highest at 15°C, which was 72.67%, and the filter paper was in a paste state.

[0090] It can be seen from Examples 1-3 that strain G6 belongs to the genus Penicillium, so the inventor named it Penicillium oxalicum G6, and deposited it in the General Microbiology Center (CGMCC) of the China Microbiological Culture Collection Administration, the deposit address is the Institute of Microbiology, Chinese Academy of Sciences, No. 3, Yard 1, Beichen West Road, Chaoyang District, Beijing, the deposit date is June 27, 2024, and its deposit number is CGMCC No.41386.

[0091] Example 4 Degradation of wheat straw by Penicillium oxalicum G6

[0092] The wheat straw was cut into 2cm×3cm small pieces, dried and crushed into 80 mesh.

[0093] Penicillium oxalicum G6 was inoculated into liquid fermentation medium and cultured at 25°C and 150 r / min for 48 h to obtain a bacterial solution with an effective viable count of 1×10 8 CFU / mL. The obtained bacterial liquid was inoculated into 100mL of liquid fermentation medium containing 2% (W / V) straw cellulose at a ratio of 10% inoculation, and cultured at 0℃, 10℃, 15℃ and 25℃, 150r / min constant temperature shaking. After one week of culture, the fermentation liquid was filtered with filter paper, rinsed with distilled water, and dried in a drying oven at 85℃ to constant weight. The residue was weighed and the straw degradation rate was calculated by weight loss method. The calculation formula of straw degradation rate is: straw degradation rate = (initial weight of straw (g) - weight of straw after degradation (g)) / initial weight (g) × 100%. The straw degradation rate of the strain is shown in Table 5.

[0094] Table 5 Results of wheat straw degradation

[0095]

[0096] As shown in Table 5, the straw degradation rate of Penicillium oxalicum G6 ranged from 12.45% to 73.65%, and the straw degradation rate at a temperature of 15°C was the highest, which was 73.65%.

[0097] Example 5 Determination of the enzyme activity of Penicillium oxalicum G6 during wheat straw degradation

[0098] The enzyme activity of Penicillium oxalicum G6 during the straw degradation process at 0°C, 10°C, 15°C and 25°C was measured, and the fermentation liquid from the 1st to 7th day of the straw degradation process in Example 4 was selected to measure the enzyme activity.

[0099] Definition of enzyme activity: Using the dinitrosalicylic acid colorimetric method, the amount of enzyme that decomposes the substrate to produce 1 μL of glucose per minute is defined as one enzyme activity unit U. The calculation formula is:

[0100]

[0101] Where ρ is OD 540 The corresponding glucose concentration (mg / mL) under the absorbance value, N is the solution dilution multiple, and T is the reaction time.

[0102] Determination of CMC enzyme activity: The straw degradation fermentation broth samples cultured at different time points were centrifuged at 4°C and 8000r / min for 15min, 1.0mL of the supernatant (crude enzyme solution) was taken, 1.0mL of the reaction substrate 0.2% (W / V) sodium carboxymethyl cellulose (CMC-Na) solution was added, and the mixture was kept warm in a 50°C water bath for 1h. Subsequently, 2.0mL of DNS solution was added, and the reaction was stopped by heating at 100°C in a water bath for 10min. After cooling to room temperature, the light absorption value was measured at 540nm.

[0103] FPA enzyme activity assay: Cut Xinhua filter paper into strips of 1.0 cm × 6.0 cm, put them into a test tube, take 1.0 mL of the crude enzyme solution prepared during the CMC enzyme activity assay, add 2.0 mL of acetate buffer, place it in a 50°C water bath at a constant temperature for 50 min, then take it out, add 2.0 mL of the termination reaction solution (DNS solution), mix and shake well, then color it in a 100°C water bath for 5 min, take it out and place it at room temperature to cool naturally, and measure the light absorption value at 540 nm according to the DNS method.

[0104] The results of the determination of enzyme activity of the strains at 0℃, 10℃, 15℃ and 25℃ during straw degradation are shown in Table 6.

[0105] Table 6 Results of enzyme activity determination of Penicillium oxalicum G6 at different temperatures and time

[0106]

[0107] As shown in Table 6, from the perspective of time, as time goes on, the CMC enzyme activity and FPA enzyme activity of the strain at 10℃, 15℃, and 25℃ show a trend of first increasing and then decreasing, and the enzyme activity reaches a peak value from the 4th to the 6th day; while at 0℃, the enzyme activity shows a downward trend as a whole, and the peak value appears on the 2nd day. From the perspective of temperature, although 0℃ is an extremely low temperature, in the early stage of the experiment, the CMC enzyme activity and FPA enzyme activity produced by the strain are significantly higher than those of other treatments. This may be because the metabolic activity of the strain slows down at low temperature, and the enzymes accumulated in the early stage are retained at a higher concentration, resulting in higher enzyme activity in a short time.

[0108] Example 6 Application of Penicillium oxalicum G6 in aerobic composting

[0109] Preparation of the fermentation broth of Penicillium oxalate G6: inoculate Penicillium oxalate G6 into a liquid fermentation medium for fermentation culture, the inoculation amount is 5% (V / V), the initial pH is 6.5-7.0, the fermentation culture condition parameters are: 0°C-25°C, 150r / min culture for 48h, and obtain Penicillium oxalate G6 fermentation broth; dilute the fermentation broth to obtain an effective viable count of 1×10 8 CFU / mL of Penicillium oxalicum G6 fermentation broth.

[0110] The composting experiment was conducted at the open-air test site of Xi'an University of Technology. The outdoor ambient temperature was around 20°C, and the ventilation quality was good. The total dry weight of the compost mixture was 15 kg, and the dry weight ratio of cow dung and cotton stalks was 3:1. The cow dung and cotton stalks were mixed evenly, and 1% (inoculant weight / compost substrate weight) of the fermentation liquid of Penicillium oxalicum G6 was added (the effective viable bacteria count of the fermentation liquid was 1×10 8 CFU / mL) were fully mixed, the carbon-nitrogen ratio was 25:1, and the moisture content was maintained at about 60wt.%, which was recorded as the experimental group (T); the natural fermentation composting experiment was set as the blank group (CK), and the compost was turned at irregular intervals to prevent insufficient oxygen from affecting the quality of the compost.

[0111] The composting process includes: initial stage, heating period, high temperature period, cooling period and mature period. The composting process lasts for 23 days. Samples are taken at 0, 2, 5, 9 and 23 days respectively, and parameters such as temperature, pH, EC and seed germination index GI are measured at the same time. Temperature, pH and EC are measured by thermometer, pH meter and conductivity meter respectively. Seed germination index (GI): Weigh 5.0g of the sample, mix the sample with deionized water in a ratio of 1:10, and shake on a shaker at 180r / min for 20min, take it out and let it stand for 10min. Pipette 5ml of the above extract into a culture dish with filter paper, evenly place 25 cabbage seeds, incubate at a constant temperature in an incubator for 48h, use distilled water as the blank group (CK), and calculate the seed germination index (GI). The calculation formula is as follows:

[0112]

[0113] Where M1 is the average germination rate of treated seeds, R1 is the average root length of treated seeds, M2 is the average germination rate of control seeds, and R2 is the average root length of control seeds.

[0114] Temperature changes of different composting treatments Figure 4 As shown. During the composting process, the ambient temperature was low, maintained at around 20°C. The compost temperature of the T treatment inoculated with Penicillium oxalate G6 reached above 50°C after the second day, and reached a peak of 65.1°C on the fourth day, and the temperature was above 50°C for 9 days. The CK treatment was maintained above 50°C for 7 days, with the highest temperature less than 60°C, which was 7.9°C lower than the highest temperature of the T treatment. In a low temperature environment, the addition of Penicillium oxalate G6 can accelerate the start of the compost temperature rise process, increase the peak temperature of the compost, and promote the maturity of the compost.

[0115] Changes in pH value of compost under different treatments Figure 5As shown. In the early stage of composting, oxygen and nutrients are sufficient, microbial activity is improved, a large amount of ammonium nitrogen is produced, and the pH value of the T treatment rises faster than that of the CK treatment. In the later stage, microorganisms continue to metabolize, release ammonia, and the pH value decreases. Finally, the pH values ​​of the CK treatment and the T treatment dropped to 8.09 and 8.12, respectively. It can be seen that the strain provided by the present invention has obvious advantages in regulating the pH value during the composting process. This shows that the strain performs well in promoting rapid initial fermentation and optimizing the final pH value, and can effectively improve the quality of compost.

[0116] The EC value changes of different treatments in composting are as follows Figure 6 As shown in the figure, in the early stage of composting, the EC value increases due to the mineralization process, but in the later stage, small molecules are continuously converted into large molecules of humus, and the EC value decreases. Figure 6 It can be seen that the strain provided by the present invention can effectively promote the mineralization process and effectively transform small molecules into humus in the later stage of fermentation, thereby optimizing the conductivity of the compost.

[0117] Seed germination index survey results are as follows Figure 7 As shown. The GI of the T treatment reached more than 80% on the second day, and reached the maturity standard earlier than the CK treatment. The final GI value of the T treatment was as high as 255%, while that of the CK treatment was only 99%. It can be seen that the strain provided by the present invention can significantly improve the seed germination index of plants.

[0118] The cellulose content in compost is Figure 8 As shown in the figure. In the initial composting process, the cellulose content accounted for 29.2%. At the end of composting maturity, the cellulose content of CK and T treatments dropped to 28.5% and 23.4%, respectively, and the degradation rates were 2.4% and 19.9%, respectively. It can be seen that T treatment is more conducive to the degradation of cellulose in compost and improves the quality of compost.

[0119] Example 7 Changes in EC values ​​at different depths in different treatments of soil

[0120] Preparation of the fermentation broth of Penicillium oxalate G6: inoculate Penicillium oxalate G6 into a liquid fermentation medium for fermentation culture, the inoculation amount is 5% (V / V), the initial pH is 6.5-7.0, the fermentation culture condition parameters are: 0°C-25°C, 150r / min culture for 48h, and obtain Penicillium oxalate G6 fermentation broth; dilute the fermentation broth to obtain an effective viable count of 1×10 8 CFU / mL of Penicillium oxalicum G6 fermentation broth.

[0121] Before cotton sowing, different base fertilizers were applied to the soil at a depth of 0-60cm. The base fertilizers all provided a nitrogen content of 375kg / hectare. Other management measures remained consistent and in line with local actual conditions. According to the different base fertilizers, there are three treatment methods: CK-100% chemical fertilizer treatment, M1-100% T treatment and M2-100% commercial organic fertilizer treatment. Among them, the CK treatment is specifically: applying inorganic fertilizers with a nitrogen content of 46% at different depths, with a total application amount of 815.2kg / hectare, once every 10 days, and a total of 3 applications; the M1 treatment is specifically: applying finished compost fermented with oxalic acid Penicillium G6 fermentation liquid with a nitrogen content of 2% at different depths, with a total application amount of 18750kg / hectare, once every 10 days, and a total of 3 applications; the M2 treatment is specifically: applying agricultural commercial organic fertilizers with a nitrogen content of 10% at different depths, with a total application amount of 3750kg / hectare, once every 10 days, and a total of 3 applications.

[0122] Seven days after the application of base fertilizer, cotton was sown. Thirty days after sowing, cotton entered the seedling stage. The EC values ​​of cotton seedling soil at different depths of 0-5cm, 5-10cm, 10-20cm, 20-30cm, 30-40cm and 40-60cm are as follows: Fig. 9 As soil depth increased, the CK treatment increased the soil EC value, while the M1 and M2 treatments decreased the soil EC value. The EC value of the M1 treatment was as low as 0.12 mS·cm at a soil depth of 40-60 cm. -1 It can be seen that the finished decomposed fertilizer containing the Penicillium oxalicum G6 agent provided by the present invention has the advantage of significantly reducing the electrical conductivity of the soil, and can effectively improve the salt accumulation of the soil and improve the soil quality.

[0123] Example 8 Changes in the accumulation of aboveground and underground dry matter in cotton seedlings under different treatments

[0124] Preparation of the fermentation broth of Penicillium oxalate G6: inoculate Penicillium oxalate G6 into a liquid fermentation medium for fermentation culture, the inoculation amount is 5% (V / V), the initial pH is 6.5-7.0, the fermentation culture condition parameters are: 0°C-25°C, 150r / min culture for 48h, and obtain Penicillium oxalate G6 fermentation broth; dilute the fermentation broth to obtain an effective viable count of 1×10 8 CFU / mL of Penicillium oxalicum G6 fermentation broth.

[0125] Before cotton sowing, different base fertilizers were applied to the soil at a depth of 0-60cm. The base fertilizers all provided a nitrogen content of 375kg / hectare. Other management measures remained consistent and in line with local actual conditions. According to the different base fertilizers, there are three treatment methods: CK-100% chemical fertilizer treatment, M1-100% T treatment and M2-100% commercial organic fertilizer treatment. Among them, the CK treatment is specifically: applying inorganic fertilizers with a nitrogen content of 46% at different depths, with a total application amount of 815.2kg / hectare, once every 10 days, and a total of 3 applications; the M1 treatment is specifically: applying finished compost fermented with oxalic acid Penicillium G6 fermentation liquid with a nitrogen content of 2% at different depths, with a total application amount of 18750kg / hectare, once every 10 days, and a total of 3 applications; the M2 treatment is specifically: applying agricultural commercial organic fertilizers with a nitrogen content of 10% at different depths, with a total application amount of 3750kg / hectare, once every 10 days, and a total of 3 applications.

[0126] Seven days after the application of base fertilizer, cotton was sown. Thirty days after sowing, cotton entered the seedling stage. The dry matter accumulation (aboveground and underground) of cotton seedlings was investigated. The results are as follows: Fig.10 As shown. Under the M1 and M2 treatments, the cumulative amount of dry matter in the cotton seedling stage was higher than that in CK. The cumulative amount of the underground part and the aboveground part of the cotton seedling stage treated with M1 exceeded that of the M2 treatment by 0.16g and 0.64g, respectively. It can be seen that the finished decomposed fertilizer containing the oxalic acid Penicillium G6 bacterial agent provided by the present invention can effectively promote plant growth.

[0127] The embodiments described above are only descriptions of the preferred modes of the present invention, and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should all fall within the protection scope determined by the claims of the present invention.

Claims

1. A Penicillium oxalicum G6, characterized in that: The deposit number of the Penicillium oxalicum G6 is CGMCC No.41386.

2. The method for culturing Penicillium oxalicum G6 according to claim 1, characterized in that: The following steps are involved: The activated Penicillium oxalate G6 is inoculated into a fermentation medium for fermentation culture to obtain a fermentation liquid containing Penicillium oxalate G6.

3. The culture method according to claim 2, characterized in that The fermentation medium includes components with the following concentrations: CMC-Na 5.0 g / L, peptone 5.0 g / L, yeast extract 1.0 g / L, KH2PO4 0.5 g / L and MgSO4 0.25 g / L.

4. The culture method according to claim 2, characterized in that The initial pH of the fermentation culture is 6.5-7.0, the temperature is 0°C-25°C, the rotation speed is 150r / min, and the time is 48h.

5. Use of the Penicillium oxalicum G6 according to claim 1 in preparing a low-temperature composting starter.

6. A low-temperature composting fermentation agent, characterized in that: The active ingredients of the low-temperature composting fermentation agent include the Penicillium oxalicum G6 described in claim 1.

7. Use of the low-temperature composting fermentation agent according to claim 6 in preparing compost.

8. The use according to claim 7, characterized in that: The following steps are involved: The low-temperature composting fermentation agent according to claim 6 is inoculated into the fertilizer to be fermented, and then aerobic fermentation is performed to obtain compost.

9. Use of the Penicillium oxalicum G6 according to claim 1 in the preparation of a bacterial agent or microbial fertilizer for promoting plant growth.

10. A bacterial agent or microbial fertilizer for promoting plant growth, characterized in that: The active ingredient of the bacterial agent or microbial fertilizer includes the Penicillium oxalicum G6 described in claim 1.

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