Saccharomyces cerevisiae and application thereof in preparation of vinasse feed

Abstract

The invention provides a strain of saccharomyces cerevisiae, the strain of saccharomyces cerevisiae is named as Saccharomyces cerevisiae LDGJ4, the strain of saccharomyces cerevisiae is preserved in China Center for Type Culture Collection on March 19, 2025, and the preservation number is CCTCC NO: M 2025529. The Saccharomyces cerevisiae provided by the invention is used for fermenting Luzhou-flavor distiller's grains, the Saccharomyces cerevisiae provided by the invention shows good adaptability in the fermentation process, and distiller's grain fermented feed with rich nutritional value and good palatability can be prepared. The problems of waste materials, pollution and the like in the white spirit brewing industry are solved; meanwhile, the additional economic value is increased.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of microbial fermentation, and particularly relates to a Saccharomyces cerevisiae and application thereof in preparation of distiller's grain feed. BACKGROUND

[0002] In recent years, with the rapid development of animal husbandry, the resources of animal feed are increasingly scarce, and the preparation of animal feed from agricultural by-products has become one of the effective ways to alleviate the shortage of feed. As a main by-product in the process of making Luzhou-flavor liquor, distiller's grain is rich in nutrients such as protein, crude fat, crude fiber, and nitrogen-free extract, and also contains natural immune activators and active factors such as β-glucan and mannose oligosaccharide, which has high utilization value of feed resources. However, the fiber content in distiller's grain is high, which is difficult for animals to digest and absorb, and the moisture content and acidity are high, which is easy to ferment, spoil, and rot, and a large amount of leachate will be produced during storage, causing environmental pollution.

[0003] At present, the main way to improve the utilization value of distiller's grain is to use microbial fermentation technology for pretreatment and modification. In the prior art, the fermentation of strains such as Saccharomyces cerevisiae, Candida utilis, and Candida tropicalis can increase the protein content of distiller's grain and improve the palatability of the distiller's grain product. However, due to the low content of sugars and the presence of phenols, aldehydes, esters, organic acids and other substances that inhibit the growth of Saccharomyces cerevisiae in Luzhou-flavor distiller's grain, the use of conventional commercial Saccharomyces cerevisiae for fermentation of Luzhou-flavor distiller's grain has the problems of poor adaptability of the strain to the environment of Luzhou-flavor distiller's grain, difficulty in rapid proliferation to form dominant flora, easy breeding of mold, unstable fermentation quality, and the need to add more raw and auxiliary materials, which cannot meet the demand of Luzhou-flavor distiller's grain for the preparation of biological fermented feed.

[0004] Therefore, it is urgent to screen a more suitable strain for preparing feed from distiller's grain waste to further improve the economic value. SUMMARY

[0005] In view of this, the present application provides a Saccharomyces cerevisiae strain which can better adapt to the environment of Luzhou-flavor distiller's grain, and the crude protein and crude fat after fermentation preparation are greatly improved, which can meet the requirements of feed.

[0006] To achieve the above purpose, the technical scheme adopted by the present application is as follows: A Saccharomyces cerevisiae strain, which is named Saccharomyces cerevisiae LDGJ4, was preserved in China Typical Culture Collection Center on March 19, 2025, and the preservation number is CCTCC NO: M 2025529.

[0007] A method for preparing distiller's grain feed from distiller's grain, comprising the following steps: S1, the above Saccharomyces cerevisiae is inoculated in a culture medium for activation, and an activated culture medium is obtained; S2, the activated culture medium is inoculated in a liquid culture medium for culture, and a seed liquid is obtained; S3, taking distiller's grains, adjusting pH, adding fermentation accessories and inoculating the seed liquid, and after fermentation, drying is performed to obtain a distiller's grain feed product.

[0008] Further, the culture medium component in step S1 is as follows: 1% of yeast powder, 2% of proteose peptone, 2% of glucose, 1000 mL of distilled water, and pH=6.0; The activation condition is: temperature 30±2℃, and time 36±2h.

[0009] Further, the liquid culture medium in step S2 is YPD liquid culture medium; The culture condition is: temperature 30±2℃, and time 12h~24h.

[0010] Further, the distiller's grains in step S3 are Luzhou-flavor liquor grains, and the water content is 50wt%~55wt%; The pH value is 4.3; The fermentation accessories are sugarcane molasses and puffed corn flour; The viable cell count of Saccharomyces cerevisiae in the seed liquid is (6.0~10.0)×10 8 CFU / mL; The fermentation condition is: temperature 30±2℃, and time 36±2h.

[0011] In some specific embodiments, preferably, the fermentation accessories account for 10% of the mass of the Luzhou-flavor liquor grains, wherein the addition amount of sugarcane molasses is 0.8~1.2%, and the addition amount of puffed corn flour is 8.8~9.2%; The inoculation amount of the seed liquid is 14~16 mL per 1 kg of the Luzhou-flavor liquor grains.

[0012] In some specific embodiments, preferably, the drying temperature in step S3 is 63~67℃, and the water content of the distiller's grain feed product is 8wt%~12wt%.

[0013] In some specific embodiments, preferably, the pH is adjusted by using quicklime in step S3.

[0014] The above Saccharomyces cerevisiae is applied to the preparation of a distiller's grain feed.

[0015] Compared with the prior art, the present application has the following beneficial effects: (1) The Saccharomyces cerevisiae screened and obtained in the present application can be well applied to the preparation of Luzhou-flavor liquor grain feed (the dry basis viable yeast number after fermentation for 48h reaches 23.02×108 The CFU / g count was significantly higher than that of commercially available yeast, while the dry-based live yeast count after 48 hours of fermentation was only 3.44 × 10⁻⁶. 8 The prepared distillers' grains feed (CFU / g) exhibits high protein (16.98%), high fat (4.59%), and is rich in overall nutrition; at the same time, it is low in crude fiber (8.17%), which can improve the palatability of the feed. Attached Figure Description

[0016] Figure 1 This is a colony morphology diagram of the *Saccharomyces cerevisiae* strain obtained by screening in this invention. Detailed Implementation

[0017] The present invention will be further described in detail below with reference to specific embodiments, so that those skilled in the art can more clearly understand the present invention. Unless otherwise specified, the technical means used in the following embodiments are all conventional means well known to those skilled in the art, and all reagents and consumables are commercially available products.

[0018] Example 1 This embodiment provides a brewer's yeast ( Saccharomyces cerevisiae The screening and identification process for LDGJ4 is as follows: 1.1. Isolation of strains tolerant to the fermentation lees environment from the fermentation lees A bacterial strain capable of tolerating the environment of strong-aroma baijiu (Chinese liquor) lees was isolated from the lees storage yard of Lude Bio-Environmental Technology Co., Ltd. The isolation method is as follows: Accurately weigh 10g of the distiller's grains sample and place it in 90mL of sterile water containing glass beads. Place the sample in a shaker at a constant temperature (30℃) for 30 minutes to disperse it. Then, serially dilute with sterile water to a final concentration of 10g. -1 ~10 -4 For each concentration gradient, 100 μL was spread onto Bengal Red agar plates, with 3 plates for each concentration gradient. The plates were incubated at 30°C for 3 days. Colonies were picked daily and transferred to Bengal Red agar plates for purification. Microscopic examination was performed to select strains with yeast morphology.

[0019] 1.2 Culture characteristics of yeast strains The yeast strain isolated in step 1.1 was inoculated onto Bengal red agar medium and cultured at 30°C for 2 days. Colony morphology was then observed. Figure 1 As shown, the colonies are milky white, dull, and the bacterial cells are raised, moist, and easily picked up.

[0020] 1.3 Identification of strains A small amount of bacterial culture from the strain isolated in step 1.1 was taken, and genomic DNA was extracted using a column chromatography method. The 18S rDNA of the strain was then amplified using a PCR instrument, resulting in a 300bp fragment. The conserved 18S rDNA sequence of the strain was obtained using a cloning sequencing method with a 3730XL sequencer (SEQ ID No. 1).

[0021] The specific details of SEQ ID No. 1 are as follows:

[0022] A comparison was made with the NCBI (National Center for Biotechnology Information) nucleic acid database. Saccharomyces cerevisiae The consistency of the *Saccharomyces cerevisiae* strain reached over 99%, confirming that this strain is indeed a *Saccharomyces cerevisiae* strain. Saccharomyces cerevisiae ), and named it LDGJ4.

[0023] Example 2 This embodiment provides a method for preparing distiller's grains feed using the *Saccharomyces cerevisiae* strain screened and obtained in Example 1. The specific process is as follows: S1. Under aseptic conditions, pick a loopful of Saccharomyces cerevisiae LDGJ4 from Bengal red agar medium (same as step 1.2 in Example 1) and transfer it to a sterile activation medium (composition as follows: 1% yeast extract, 2% peptone, 2% glucose, 1000mL distilled water, pH=6.0, autoclaved at 121℃ for 15 minutes), and incubate at 30±2℃ for 36±2h to obtain the activation culture solution.

[0024] S2. Under aseptic conditions, the activated culture medium obtained in step S1 is inoculated into sterile YPD liquid culture medium (composition as follows: 1% yeast extract, 2% peptone, 2% glucose, 1000mL distilled water, pH=6.0, autoclaved at 121℃ for 15 minutes), and cultured in a constant temperature shaker at 30±2℃ for 12h~24h to obtain the seed culture of Saccharomyces cerevisiae LDGJ4.

[0025] S3. Preparation of Distillers' Grains Feed: The moisture content of the strong-aroma baijiu lees is dried to 50wt%~55wt%, and the pH is adjusted to 4.3 using quicklime. 1000g of the treated lees is weighed into a fermentation box, and 10% of the dry weight of the lees is added as fermentation aid (in this example, the fermentation aid is 1% sugarcane molasses and 9% puffed corn flour). 15mL of the brewing yeast seed liquid obtained in step S2 is inoculated into each container (the yeast viable count is (6.0~10.0)×10⁻¹⁰). 8 The yeast was fermented at 30℃ for 36 hours (CFU / mL). Samples were taken at 12h, 24h, 30h, and 36h of fermentation, diluted and spread to detect the viable yeast count and the total yeast count under a microscope. After fermentation, the distiller's grains were dried at 65℃ with forced air to a moisture content of 8wt%~12wt% to obtain the distiller's grains feed product.

[0026] Comparative Example 1 This comparative example provides a method for preparing fermented feed using strong-aroma baijiu lees. The steps and processes are basically the same as in Example 1, except that in step S3, 15 mL of commercially available brewer's yeast seed solution (commercially available brewer's yeast active dry powder, activated with a 2% sucrose solution before inoculation) is used. After activation, the number of viable yeast cells in the seed solution is (6.0~10.0) × 10⁻¹⁰. 8 Fermentation was carried out using CFU / mL, while all other parameters remained unchanged.

[0027] Comparative Example 2 This comparative example provides a method for preparing fermented feed using strong-aroma baijiu lees. The steps and process are basically the same as in Example 1, except that no bacteria are inoculated and the material is directly dried to make feed.

[0028] Furthermore, in order to understand the adaptability of the strains screened in this invention and conventional commercially available strains in the fermentation of distiller's grains, the number of yeast cells at different times was statistically analyzed, and the results are shown in Table 1 below.

[0029] Table 1. Yeast counts at each stage of distiller's grains fermentation

[0030] Table 1 shows that the brewing yeast LDGJ4 can adapt better to the environment of strong-aroma fermentation mash and grow rapidly, reaching a dry basis live yeast count of 23.02 × 10⁻⁶ at 48 hours of fermentation. 8 CFU / g, total yeast count on dry basis reached 35.97 × 10⁻⁶. 8 The adaptability of commercially available yeast initially increases and then decreases with fermentation time, but the highest dry-based live yeast count is only 3.44 × 10⁶. 8 The CFU / g is far lower than that of the strains screened and obtained in this invention.

[0031] Furthermore, in order to understand the nutritional status of the final prepared distillers' grains feed, the nutritional content of each prepared distillers' grains feed was measured, and the results are shown in Table 2 below.

[0032] Table 2. Results of nutritional indicators of various distillers' grains (12% moisture meter)

[0033] As shown in Table 4, Saccharomyces cerevisiae LDGJ4 can increase the protein content (16.98%, compared to 15.63% after fermentation with conventional commercially available yeast) and fat content (4.59%, compared to 3.34% after fermentation with conventional commercially available yeast), thus increasing the nutritional value of the distillers' grains. It also has the characteristic of low crude fiber (8.17%, compared to 8.47% after fermentation with conventional commercially available yeast), which can improve the palatability of the feed.

[0034] Unless otherwise specified, all raw materials used in this invention are existing substances that can be purchased directly from the market.

[0035] The above are merely preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A strain of brewer's yeast, characterized in that, The brewer's yeast is named Saccharomyces cerevisiae LDGJ4 was deposited at the China Center for Type Culture Collection on March 19, 2025, with accession number CCTCC NO: M2025529.

2. A method for preparing distillers' grains feed using distillers' grains, characterized in that, Includes the following steps: S1. The *Saccharomyces cerevisiae* as described in claim 1 is inoculated into a culture medium for activation to obtain an activated culture medium; S2. Inoculate the activated culture medium into the liquid culture medium and culture to obtain the seed culture; S3. Take the distiller's grains, adjust the pH, add fermentation aids and inoculate with the above seed liquid. After fermentation, dry and crush to obtain the distiller's grains feed product.

3. The method according to claim 2, characterized in that, The culture medium components in step S1 are as follows: 1% yeast extract, 2% peptone, 2% glucose, 1000 mL distilled water, pH=6.0; The activation conditions are: temperature 30±2℃, time 36±2h.

4. The method according to claim 2, characterized in that, The liquid culture medium in step S2 is YPD liquid culture medium; The culture conditions were: temperature 30±2℃, time 12h~24h.

5. The method according to claim 2, characterized in that, The lees used in step S3 are strong-aroma baijiu lees with a water content of 50wt%~55wt%. The pH value is 4.3; The fermentation adjuvants are sugarcane molasses and puffed corn flour; The viable count of *Saccharomyces cerevisiae* in the seed culture was (6.0~10.0) × 10⁻¹⁰. 8 CFU / mL; The fermentation conditions were: temperature 30±2℃, time 36±2h.

6. The method according to claim 5, characterized in that, The fermentation auxiliary materials account for 10% of the mass of the strong-aroma baijiu lees, of which sugarcane molasses accounts for 0.8-1.2% and puffed corn flour accounts for 8.8-9.2%. The seed liquid inoculation amount is calculated based on the mass of strong-aroma baijiu lees: 14-16 mL per 1 kg.

7. The method according to any one of claims 2-6, characterized in that, In step S3, the drying temperature is 63~67℃, and the moisture content of the distillers' grains feed product is 8wt%~12wt%.

8. The method according to any one of claims 2-6, characterized in that, In step S3, the pH is adjusted using quicklime.

9. The application of the brewing yeast of claim 1 in the preparation of distiller's grains feed.

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