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CN-122004353-A - Straw protein feed based on fungus fermentation and preparation method thereof

CN122004353ACN 122004353 ACN122004353 ACN 122004353ACN-122004353-A

Abstract

The invention relates to the technical field of feed biology, and discloses a straw protein feed based on fungus fermentation and a preparation method thereof. The feed takes a modified straw substrate as a main raw material, improves accessibility of cellulose by carrying out structural modification on natural straw, introduces an organic micromolecular metabolism inducer into a fungus fermentation system, and is prepared by fermenting under controlled conditions by matching with a nitrogen source, minerals and a fermentation regulation auxiliary agent. The organic micromolecular metabolism inducer is not used as a main carbon source in the fermentation process, can regulate and control fungal nitrogen metabolism and protein synthesis pathways, and promotes the efficient conversion of nitrogen sources to microbial proteins. Compared with the prior art, the method can obviously improve the crude protein content, the protein digestibility and the nitrogen source utilization efficiency of the straw fermented feed, realize the high-value utilization of the agricultural straw, and is suitable for popularization and application of the feed industry.

Inventors

  • WANG YUQIONG
  • CHEN LIMING
  • GOU CHANGLONG
  • LUO LILONG
  • YANG WENXI
  • ZHANG LIANG

Assignees

  • 内蒙古民族大学

Dates

Publication Date
20260512
Application Date
20260115

Claims (10)

  1. 1. A straw protein feed based on fungus fermentation is characterized by comprising, by weight, 60-85 parts of a modified straw substrate, 0.05-2 parts of an organic micromolecular metabolism inducer, 1-5 parts of a fungus strain, 2-10 parts of a nitrogen source, 0.5-3 parts of mineral and trace element auxiliary agents and 0.1-2 parts of a fermentation regulation auxiliary agent, wherein the modified straw substrate is obtained by physically crushing natural straw, and then forming chemical combination and intermolecular force on the surface of straw cellulose/hemicellulose through the action of the modified substance, so as to reduce the coating degree of lignin on cellulose and improve the accessibility of cellulose, the organic micromolecular metabolism inducer is selected from at least one of polyalcohol low-molecular organic compounds, the polyalcohol low-molecular organic compounds are not used as main carbon sources in the fungus fermentation process and participate in an energy metabolism system, and the fungus nitrogen metabolism and protein synthesis related metabolic pathway can enter into the fungus metabolism system, so that the high-efficiency conversion of the external nitrogen source to microbial protein is promoted, the obtained straw protein feed is improved, and the obtained straw protein feed has the crude protein content of the fungus strain and the capability of degrading the fungus protein.
  2. 2. The straw protein feed based on fungal fermentation according to claim 1, wherein said polyol low molecular weight organic compound is selected from one or more of glycerol, ethylene glycol, glycerol, sorbitol.
  3. 3. The straw protein feed based on fungus fermentation, which is characterized by comprising, by weight, 80-95 parts of natural straw, 1-5 parts of a modifier, 2-10 parts of a polyhydroxy organic modifier and 1-5 parts of a weakly alkaline structure regulator, wherein the modifier is chitosan, the polyhydroxy organic modifier is glycerol, and the weakly alkaline structure regulator is sodium carbonate.
  4. 4. A fungal fermentation-based straw protein feed according to any one of claims 1 to 3, wherein the preparation method of the modified straw substrate comprises the following steps: (1) Crushing natural straw to obtain the particle size of 1-3 mm, then adding water for soaking, removing surface impurities and fully wetting the straw to obtain pretreated straw; (2) Adding sodium carbonate aqueous solution into the pretreated straw, treating under stirring to loosen and break part of lignin structure in the straw, and then carrying out solid-liquid separation to obtain straw with structure regulated; (3) Adding glycerol into the straw with the structure regulated, and mixing and reacting at a certain temperature to enable the glycerol and straw cellulose and/or hemicellulose to form intermolecular acting force so as to obtain polyhydroxy modified straw; (4) Adding chitosan into the polyhydroxy modified straw, and reacting under the condition of water phase to enable the modifier to react with hydroxyl on the surface of the straw to form a product with a stable combination structure; (5) And drying, crushing and shaping the product to obtain the modified straw substrate.
  5. 5. The straw protein feed based on fungus fermentation according to claim 3, wherein the reaction condition of the step (2) is that the mass fraction of the sodium carbonate aqueous solution is 0.5-3wt%, the treatment temperature is 40-80 ℃, the treatment time is 0.5-3 h, and stirring is continuously carried out in the reaction process.
  6. 6. The straw protein feed based on fungal fermentation according to claim 3, wherein the reaction condition of the step (3) is that the addition amount of glycerol is 1-10% of the mass of straw, the reaction temperature is 50-90 ℃, and the reaction time is 1-4 hours.
  7. 7. The straw protein feed based on fungus fermentation according to claim 3, wherein the reaction condition of the step (4) is that the addition amount of chitosan is 0.5-5% of the mass of straw, the reaction temperature is 25-70 ℃, the reaction time is 0.5-3 h, and the reaction system is an aqueous phase condition.
  8. 8. The straw protein feed based on fungus fermentation, which is disclosed in claim 1, is characterized in that the nitrogen source is formed by mixing urea and ammonium sulfate according to the mass ratio of (1-3): 1-2, the mineral and trace element auxiliary agent is formed by mixing monocalcium phosphate, magnesium sulfate, zinc sulfate and ferrous sulfate according to the mass ratio of (2-5): 1-3): 0.1-0.5, and the fermentation regulation auxiliary agent is formed by mixing monopotassium phosphate and citric acid according to the mass ratio of (1-3): 0.5-2.
  9. 9. The preparation method of the straw protein feed based on fungal fermentation is characterized by comprising the following steps of: s1, mixing a modified straw substrate, a nitrogen source, minerals, trace element auxiliary agents and fermentation regulation auxiliary agents, adding an organic micromolecular metabolism inducer, and fully and uniformly mixing to obtain a fermentation substrate; S2, adding water into the fermentation substrate to adjust the water content to 55-70%, then sterilizing the fermentation substrate, and cooling for later use; S3, inoculating fungus strains into the cooled fermentation substrate under the aseptic condition, wherein the inoculation amount is 1-5% of the mass of the fermentation substrate, and uniformly mixing; s4, placing the inoculated fermentation substrate in a fermentation environment for fermentation, and controlling fermentation temperature, humidity and pH conditions to ensure that fungi degrade the modified straw substrate and synthesize microbial protein under the action of an organic micromolecular metabolism inducer to obtain a fermentation product; S5, after fermentation, drying, crushing and screening the fermentation product to obtain a straw protein feed finished product based on fungus fermentation.
  10. 10. The preparation method of the straw protein feed based on fungus fermentation according to claim 9, wherein the reaction condition of the step S2 is that the water content of a fermentation substrate is 55-70%, the sterilization temperature is 100-121 ℃, the sterilization time is 15-40 min, the reaction condition of the step S3 is that the inoculation amount of fungus strains is 1-5% of the mass of the fermentation substrate, the inoculation process is carried out under the aseptic condition, the reaction condition of the step S4 is that the fermentation temperature is 20-30 ℃, the fermentation humidity is 60-70%, the fermentation time is 10-20 d, and the pH of a fermentation system in the fermentation process is 4.5-6.5.

Description

Straw protein feed based on fungus fermentation and preparation method thereof Technical Field The invention belongs to the field of feed biotechnology and biological fermentation engineering, and particularly relates to a straw protein feed based on fungus fermentation and a preparation method thereof. Background With the rapid development of animal husbandry and aquaculture, the demand for protein materials in animal feeds continues to grow. The traditional feed protein sources mainly depend on plant or animal protein raw materials such as bean pulp, fish meal and the like, so that the cost is high, the influence of international market fluctuation is large, and grain resource competition and ecological environment pressure are increased to a certain extent. Therefore, the development of the protein feed raw material is widely available, low in cost and sustainable, and the protein feed raw material has become an important research direction in the fields of feed industry and agricultural resource comprehensive utilization. The straw agricultural wastes such as corn straw, wheat straw, rice straw and the like have huge annual output, and the main components are cellulose, hemicellulose and lignin, so the straw agricultural wastes have potential resource utilization value. However, because the lignin content in the straw is high and the structure is compact, the cellulose is tightly coated by the lignin, so that the cellulose has low digestibility and limited nutritive value when being directly used as feed, and even can cause burden to the digestive system of animals. At present, the straw forage is mostly utilized by adopting modes of physical crushing, chemical alkali treatment or simple microbial fermentation, and the like, but the problems of insufficient lignin degradation, limited nutrition lifting range, low protein content and the like still exist generally. The fungus fermentation technology is considered as an effective way for improving the nutritional value of the straw feed because of the strong cellulose and lignin degradation capability. In the prior art, white rot fungi, aspergillus and other microorganisms are often selected for fermenting the straw, and the crude protein content is increased to a certain extent and the palatability is improved through the growth and metabolism of the microorganisms. However, the existing fungus fermentation straw feed technology focuses on strain screening and conventional fermentation condition optimization, directional modification on straw structure is insufficient, and regulation and control means on fungus protein anabolic pathway are limited, so that nitrogen source utilization efficiency is low, and improvement effect of protein and amino acid is still limited. The additives for fermentation regulation in the prior art are mostly conventional nutritional supplements or inorganic salts, mainly act on the stability of fermentation environment, have weak induction effect on fungus metabolism direction, and are difficult to realize remarkable improvement of the protein content of the straw under the premise of not remarkably increasing the cost of raw materials. Therefore, a new technical scheme is needed, and a new metabolism regulation means is introduced in the fungus fermentation process through effectively modifying the straw substrate structure, so that the efficient conversion of carbon sources in straw to microbial proteins is realized, and the straw protein feed with high protein, high digestibility and suitability for industrial application is prepared. Disclosure of Invention The invention aims to solve the problems of compact straw structure, serious cellulose coating caused by lignin, low accessibility of carbon sources, low nitrogen source utilization efficiency and limited microbial protein synthesis capability in the fungal fermentation process in the prior art, and provides a straw protein feed based on fungal fermentation and a preparation method thereof. According to the invention, the straw substrate is subjected to composite structural modification to improve accessibility of cellulose, and a specific polyalcohol low-molecular organic compound is introduced into a fungus fermentation system to serve as a metabolism inducer, so that a fungus nitrogen metabolism and protein synthesis related metabolism channel is regulated and controlled on the premise of not serving as a main carbon source to participate in energy metabolism, thereby promoting efficient conversion of an external nitrogen source into microbial protein, and realizing remarkable improvement of protein content and digestion utilization rate of straw feed. The aim of the invention can be achieved by the following technical scheme: The straw protein feed based on fungus fermentation comprises, by weight, 60-85 parts of a modified straw substrate, 0.05-2 parts of an organic micromolecular metabolism inducer, 1-5 parts of a fungus strain, 2-10 parts of a nitrogen source, 0