88 results about "Acid proteinase" patented technology

The invention relates to the field of gene engineering and enzyme engineering, in particular to an acid protease mutant with improved stability and a product and application thereof. In particular to an acid protease mutant IAIC6M with improved heat resistance and a coding gene thereof. A mutant IAIC6M is obtained by performing D86I, G168A, Q185I and Q339C mutation on an iaic6 sequence as shown in an amino acid sequence SEQ ID NO.1, and compared with IAIC, the mutant can still maintain more than 60% of enzyme activity at 75 DEG C for 3 minutes, while the IAIC can only maintain 20% of enzyme activity at 75 DEG C for 3 minutes; the acid protease mutant IAIC6M disclosed by the invention has the following properties: the optimum pH is 3.0, and the acid protease mutant IAIC6M still has higher enzyme activity under a high-temperature condition and has wide application value in the aspects of industry, food, medicine and the like.

The invention belongs to the technical field of gene engineering, and discloses an acid protease mutant as well as a coding gene and application thereof. Compared with parent acid protease with an amino acid sequence as shown in SEQ ID NO: 1, the acid protease mutant comprises mutant S60V; the acid protease mutant has at least 98% and less than 100% sequence identity with the parent acid protease. Compared with parent acid protease, the thermal stability of the acid protease mutant provided by the invention is remarkably improved, and the enzyme activity retention rate is greater than 63% after the acid protease mutant is treated at 75 DEG C for 3 minutes and can reach 90.6% to the maximum. The acid protease mutant provided by the invention is beneficial to the application of protease in industrial production.

OF THE INVENTION Provided herein is a method of preparing an extracellular matrix (ECM) material, including incubating vaginal tissue in a protease, incubating the vaginal tissue in a solution including at least one detergent, incubating the vaginal tissue in a composition including at least one disinfecting agent, thereby producing a decellularized ECM material, lyophilizing the decellularized ECM material, thereby producing a lyophilized ECM material, comminuting the lyophilized ECM material, partially or completely solubilizing the comminuted, lyophilized ECM material with an acid protease to produce solubilized ECM, lyophilizing the solubilized ECM to produce lyophilized, solubilized ECM.

The invention discloses an aspergillus niger recombinant bacterium AnCT-XynB-K-agdA and application thereof, and belongs to the technical field of microbiology and bioengineering. According to the invention, Aspergillus niger AnCat is taken as an expression host, firstly, an acid protease regulatory factor prtT is knocked out to obtain a defective strain, and then different chaperonins are subjected to fusion expression by optimizing integration sites of a laccase lcc9 expression cassette, so that the high-expression laccase chaperonin is obtained. According to the method, an expression vector pC3-5 'agdA-PcitA-XynB-L-lcc9-hph-3' agdA is constructed, a recombinant bacterium AnCT-XynB-K-agdA is further obtained, the enzyme activity of the extracellular laccase subjected to shake flask fermentation reaches 1821.2 U / L, and finally, the recombinant efficient expression of the laccase Lcc9 in aspergillus niger is realized.

The invention relates to the technical field of deep processing of paeonia ostii, in particular to paeonia ostii peptide capable of whitening, moisturizing, tightening and promoting collagen synthesis as well as a preparation method and application of the paeonia ostii peptide. The paeonia ostii flower peptide capable of whitening, moisturizing, tightening and promoting collagen synthesis is prepared through water bath, homogenization, alkali extraction and acid precipitation pretreatment, three times of enzymolysis through compound enzyme of acid protease, cellulase and pectinase and alkaline protease and solid-liquid separation, operation is easy, the requirement for equipment is low, and the paeonia ostii flower peptide is suitable for industrial large-scale production. The prepared paeonia ostii flower peptide has good inhibition capability on tyrosinase, hyaluronidase and elastinase, and also has excellent anti-saccharification and anti-inflammatory effects. Besides, five paeonia ostii active peptide fragments are screened out, are high in activity and non-toxic, can be combined with tyrosinase, hyaluronidase, MMP-1, MMP-3 and COX-2 receptor protein, and have the effects of whitening, moisturizing, tightening and promoting collagen synthesis.

The invention belongs to the technical field of gene engineering, and particularly relates to an acid protease mutant as well as a coding gene, a preparation method and application thereof. The amino acid sequence of the acid protease mutant is as shown in SEQ ID NO. 2. The acid protease mutant provided by the invention has the advantages of high enzyme activity, strong pH and temperature adaptability, good high temperature resistance and the like, can react in a wide pH value (pH 2.0-6.0) and temperature range (30-70 DEG C), is beneficial for improving the flexibility of a production process, particularly can adapt to industrial production at a relatively high temperature and can meet a relatively long-time high-temperature catalytic environment, and the acid protease mutant has a wide application prospect. The enzyme prepared by the method is high in enzyme activity, not easy to inactivate in a high-temperature environment, can maintain 70% or more of enzyme activity for 1 h at 50 DEG C, can maintain 55% or more of enzyme activity for 1 h at 55 DEG C, and shows good market prospects and industrial application values in the fields of wine brewing, feed processing, leather softening and the like.

The invention relates to aspergillus oryzae sourced protease and application thereof in traditional bean fermentation products, and belongs to the technical field of enzyme engineering and microbial engineering. The amino acid sequence provided by the invention comprises an acid protease, two neutral proteases and an alkaline protease, wherein the proteases have higher degradation degree on globulin and albumin; the enzyme activity is the highest at 45-50 DEG C, and the salt tolerance is good. When the soybean sauce is prepared, the physicochemical indexes, free amino acids, organic acids and flavor substances of the soybean sauce are remarkably improved; wherein the quantity and the content of flavor substances are remarkably increased, and the content of free amino acid is increased by 20-25%; and the flavor sensory evaluation is more pleasant. In the early stage to the middle stage of fermentation, the content of amino acid nitrogen in the soy sauce is remarkably increased, the production cycle of the soy sauce can be shortened, and the method has wide application prospects in the food industry.

The invention relates to the field of biochemistry, and provides a method for preparing hydrolyzed conchiolin protein, which comprises the following steps: 1) adding pearl powder into a weak acid-containing aqueous solution, and stirring the obtained suspension for more than 6 hours; 2) adjusting the pH value of the suspension to 2.5-3.5, adding acid protease, and treating for more than 2 hours; and (3) heating to inactivate the acid protease, centrifuging, adjusting the obtained supernate to be neutral, and passing through a 20kD filter membrane to obtain the filtrate, namely the hydrolyzed conchiolin protein solution. The invention also provides application of the hydrolyzed conchiolin protein in preparation of cosmetics.

The present invention relates to the technical field of bacterial enzyme fermentation, and provides a bacterial enzyme synergistic fermentation method for removing antinutritional factors in soybean meal, the method comprises the following steps: S1, soybean meal pretreatment: soybean meal, water and an auxiliary agent are mixed and then subjected to steam explosion treatment, and the auxiliary agent comprises citric acid, a hydrogen peroxide solution and polyphenol; s2, bacterial enzyme fermentation: mixing the pretreated soybean meal with molasses and water to obtain a raw material, adding a complex microbial inoculant and a complex enzyme, uniformly stirring, and fermenting; the complex microbial inoculants comprise saccharomycetes, bacillus subtilis, lactobacillus rhamnosus and pediococcus pentosaceus; the compound enzyme comprises acid protease, pectinase, phytase, glucanase, alpha-galactosidase and keratinase; and S3, after fermentation is finished, drying the materials to obtain the fermented soybean meal. According to the fermentation method, the glycinin degradation rate can reach 79% or above, the acid soluble protein content is increased to 26% or above, the anti-nutritional factor content is remarkably reduced, and the nutritional value is greatly increased.

The invention relates to the technical field of animal feed, in particular to a high-efficiency growth-promoting pig compound additive and a preparation method thereof. The high-efficiency growth-promoting pig compound additive is prepared from the following raw materials in parts by weight: 5-8 parts of bacillus subtilis; 3 to 5 parts of bacillus licheniformis; 4 to 6 parts of fructo-oligosaccharide; 3 to 5 parts of galactooligosaccharide; 8 to 12 parts of yeast extract; 2-4 parts of a yucca extract; 1 to 2 parts of cellulase; 1-2 parts of acid protease; 0.5 to 1.5 parts of curcumin; 0.3 to 0.8 part of tea polyphenol; 1-3 parts of taurine; and 2 to 4 parts of glycine chelated zinc. According to the efficient growth-promoting pig compound additive and the preparation method thereof, multi-dimensional collaborative optimization is adopted, probiotics and prebiotics are combined, colonization of beneficial bacteria in intestinal tracts is promoted, metabolic active substances are generated, antibiotic dependence is replaced, organic microelements are used for replacing high-dose inorganic zinc, and the risk of environment residues is reduced; the natural anti-inflammatory component and the light stabilizer reduce oxidative stress and photosensitive toxicity, are significantly superior to the traditional scheme, and have both environmental friendliness and cost effectiveness.

The invention discloses an acid protease mutant PepA4 with improved heat resistance and application thereof, and relates to the technical field of gene engineering and enzyme engineering. The amino acid sequence of the acid protease mutant PepA4 is obtained by carrying out D67A, E103D, E304K and S368L point mutation on an amino acid sequence as shown in SEQ ID NO: 1, and the amino acid sequence of the acid protease mutant PepA4 is as shown in SEQ ID NO: 2. The high-temperature-resistant acid protease disclosed by the invention can still maintain the enzyme activity of 80% or above at 75 DEG C for 5 minutes. The acid protease provided by the invention has better acid resistance, and can be widely applied to food processing, leather processing and feed processing industries.

The invention discloses camellia seed meal oligopeptide as well as a preparation method and application thereof. The method comprises the following steps: S1, pretreating camellia seed meal to obtain a pretreated substance; s2, performing enzymolysis and wall breaking to obtain first enzymatic hydrolysate; wherein the enzymolysis wall breaking adopts a mixed enzyme, and the mixed enzyme comprises amylase and cellulase; s3, extracting crude protein to obtain crude protein; s4, carrying out crude protein enzymolysis on the crude protein to obtain a second enzymatic hydrolysate; wherein the crude proteolysis adopts mixed protease, and the mixed protease comprises first protease and second protease; wherein the first protease is one or more of alkaline protease, neutral protease and acid protease; the second protease is papain; and S5, purifying the second enzymatic hydrolysate to obtain the camellia seed meal oligopeptide. The average molecular weight of the obtained product is smaller than 1000 Daltons, and the product has biological activity and high application value in the fields of cosmetics and functional food.

The invention relates to a stabilized fertilizer containing antibacterial peptide and a preparation method thereof, the stabilized fertilizer containing antibacterial peptide is characterized by containing jerusalem artichoke antibacterial peptide; the jerusalem artichoke antibacterial peptide is a product obtained after jerusalem artichoke residues are subjected to enzymolysis. The enzymolysis is protease enzymolysis; the protease is acid protease or alkaline protease. The antibacterial peptide-containing fertilizer prepared by the invention can meet the requirement of a stable fertilizer without additionally adding a nitrification inhibitor or a urease inhibitor.

The invention discloses a method for preparing sunflower seed meal fermented feed. The method comprises the following steps: step 1, crushing sunflower seed meal with shells, and carrying out steam explosion treatment; step 2, carrying out enzymolysis by adopting a compound enzyme; step 3, fermenting by adopting saccharomycetes, lactic acid bacteria and acid protease; and 4, performing low-temperature drying, crushing, packaging and warehousing. The fiber degradation rate can reach 80% and the reducing sugar content can reach 10% (under 8% of moisture) after steam explosion treatment and cellulose compound enzyme treatment, so that the influence of the fiber on the application proportion is solved, and the energy value is also improved; through synergistic fermentation of saccharomycetes, lactic acid bacteria and acid protease, the protein content of the product is increased, the protein is degraded into small peptides, the digestibility of the sunflower seed meal is increased, in addition, lactic acid generated by the lactic acid bacteria and the fragrance of the yeast can improve the palatability of the fermented sunflower seed meal, and the application of the sunflower seed meal in livestock and poultry breeding is promoted.

This invention discloses a low-temperature enzymatic hydrolysis compound beverage made from edible and medicinal plants, and its preparation method. Using jujube powder as a base, at least two kinds of dried powders from medicinal and edible plants are compounded. Enzymatic hydrolysis is performed using a compound enzyme containing cellulase, pectinase, and acidic protease at 45-50℃ and pH 4.0-5.0. The product is then subjected to enzyme inactivation and solid-liquid separation (filtration / centrifugation or a combination thereof). Amylase can be added for high-starch / polysaccharide raw materials. The product contains no added flavorings, colorings, sweeteners, or preservatives. After 12 months of storage at room temperature, the sedimentation rate is ≤0.5%, and the retention rate of active ingredients is 26%-31% higher than that of traditional high-temperature processes. The process is highly versatile and can be adapted to different separation methods, enabling the industrial production of clean-label, highly stable plant-based beverages.

The present application belongs to the technical field of fermented feed, and particularly relates to a fermented feed taking rice bran as main material and a preparation method thereof. High-quality protein and other nutritional components in rice bran are usually combined with substances such as phytic acid in rice bran, and are not easy to be digested and absorbed by the gastrointestinal tract of animals. In view of the above problems, the present application provides a fermented feed taking rice bran as main material, which comprises fermentation raw materials, fermentation seed liquid, phytase and acid protease. Research shows that, for the degradation of phytate in rice bran, in addition to the phytase in the fermented feed playing a role, the type and combination of strains in the fermented feed also promote the degradation of phytic acid (salt) in rice bran. The bacillus licheniformis, lactobacillus plantarum and saccharomyces cerevisiae preferred by the present application can further improve the degradation rate of phytic acid (salt) and protein in rice bran, improve the release amount of inorganic phosphorus and polypeptide in the fermented feed, and then improve the utilization rate of nutritional components in rice bran.

The invention relates to the technical field of biological waste treatment, in particular to a preparation method and application of a silkworm sand feed additive. The invention provides a technical scheme for preparing a silkworm and mulberry sand feed additive rich in acid protease, pectinase and cellulase by taking silkworm sand as a core matrix and performing directional pretreatment, adaptive strain fermentation and standardized post-treatment. According to the invention, silkworm sand-corncob powder is used as a composite substrate, and the silkworm sand and the corncob powder complement each other in function, so that the problems of unbalanced nutrition and poor air permeability of a single substrate are solved. Specific aspergillus niger is used for segmented solid-state fermentation, parameters are set in a differentiated mode, and full-amount utilization of the silkworm sand is achieved; the product quality and enzyme activity are improved by optimizing the process, and the resource value is improved from the low-added-value field to the high-added-value enzyme preparation industry.

The invention relates to the technical field of preparation of deep-sea longevity fish precise active peptides, in particular to a deep-sea longevity fish precise active peptide with uric acid reducing and anti-inflammatory effects as well as a preparation method and application of the deep-sea longevity fish precise active peptide. The preparation method comprises the following steps: carrying out medium-temperature pretreatment, carrying out step-by-step enzymolysis with alkaline protease and acid protease, centrifuging, filtering, carrying out ultrafiltration interception and the like, and screening out 10 non-reported non-toxic active peptide fragments. The active peptide has a multi-target synergistic effect, inhibits the activity of xanthine oxidase, regulates and controls the expression of uric acid resorption protein, regulates and controls the expression of uric acid transporter protein, realizes bidirectional regulation of uric acid metabolism, efficiently removes hydroxyl radicals, activates superoxide dismutase and reduces the content of inflammation-related factors. The technology is simple and easy to control, low in equipment requirement and suitable for large-scale production, the active ingredients are natural, safety is high, the active ingredients can serve as functional factors to be applied to functional food, health care products and the like, and safe and diversified intervention schemes are provided for hyperuricemia and related inflammation problems.

The invention discloses a fattening feed additive composition for old cattle and a fattening method, and belongs to the technical field of feed. The additive composition comprises the following components in parts by weight: 13-20 parts of a rumen function regulator, 4-10 parts of an intestinal repair agent, 10-20 parts of a rumen bypass compound enzyme preparation, 5-10 parts of a muscle-increasing growth-promoting composition, 5.5-7.3 parts of a functional trace element composition and 32.7-62.5 parts of a carrier. Wherein the rumen function regulator is compounded by a coated saccharomyces cerevisiae culture and bacillus subtilis; the rumen bypass compound enzyme preparation comprises acid protease, neutral protease and cellulase; the muscle-building and growth-promoting combination is coated guanidinoacetic acid. Through regulation and control of a rumen-intestinal tract-tissue three-level linkage network, the rumen fermentation function of the old cattle is remarkably improved, the feed conversion rate is increased, and meanwhile muscle hyperplasia and meat tenderization are achieved. By means of the fattening method, the average daily gain of the old cattle is increased by 22.8% or above, the muscle shear force is reduced by 29.6% or above, the feed conversion ratio is reduced by 17.1% or above, and green and efficient fattening is achieved.

This invention discloses an antioxidant active peptide derived from Litsea cubeba, its preparation method, and its application, relating to the field of biotechnology. The amino acid sequence of this Litsea cubeba-derived antioxidant active peptide is NPYYFWDLSF. The preparation method of this Litsea cubeba-derived antioxidant active peptide includes the following steps: S1, extracting Litsea cubeba protein from Litsea cubeba seed cake; S2, enzymatically hydrolyzing the Litsea cubeba protein using acidic protease to obtain the enzymatic hydrolysis product; S3, separating the enzymatic hydrolysis product by ultrafiltration and collecting the ultrafiltration fraction; S4, screening candidate peptides with high antioxidant activity from the peptide fragments of the ultrafiltration fraction; the application of the Litsea cubeba-derived antioxidant active peptide in the preparation of drugs or functional foods for the prevention or treatment of oxidative stress-related diseases; the NPYYFWDLSF peptide obtained by the preparation method of this application can alleviate oxidative stress damage through the PI3K-AKT signaling pathway; this application provides a theoretical basis for the high-value utilization and potential application of Litsea cubeba by-products.

The invention relates to the technical field of health-care food, and discloses a composition and method for improving storage stability of donkey-hide gelatin peptide tablets, and the method comprises the following steps: firstly, treating donkey-hide gelatin by using acid protease and neutral protease in sequence through a sequential enzymolysis method to prepare composite donkey-hide gelatin peptide composed of grabbing peptide and stable peptide; then, the composite donkey-hide gelatin peptide and metal salt are subjected to a synergistic chelation reaction, and a donkey-hide gelatin peptide metal complex is obtained; and finally, adding sodium alginate into the complex solution, constructing a three-dimensional gel network in situ by using metal ions in the complex as a cross-linking agent, and drying, granulating and tabletting to obtain the final tablet. According to the method, the bifunctional peptide system prepared by sequential enzymolysis obviously improves the complexing rate of metal ions and inhibits oxidation reaction caused by free ions; meanwhile, the in-situ constructed gel network structure is used as a physical skeleton, so that the friability and hygroscopicity of the tablet are effectively reduced.

The invention provides an extraction method for increasing the oleuropein conversion rate and the hydroxytyrosol content in olive pomace, and belongs to the technical field of natural product extraction. Based on the analysis of the characteristics of the olive pomace material, firstly, the compact structure of the olive pomace is destroyed through steam explosion pretreatment, and pores are loosened; then carrying out compound enzyme enzymolysis, cooperatively hydrolyzing wrapped binding protein by adopting acid protease and hemicellulase in a combined manner, destroying a polysaccharide wrapping barrier in the pomace, and promoting rapid release of oleuropein; finally, high static pressure extraction is adopted, ultrahigh pressure is used for accelerating solvent permeation, the conversion rate of oleuropein is increased, and the content of hydroxytyrosol is comprehensively increased. The method is green and efficient, the oleuropein conversion rate can be increased to the maximum extent, and the content of hydroxytyrosol is increased; the degradation loss of hydroxytyrosol in the extraction process is reduced, and the economic benefits of the olive pomace are comprehensively improved.

The invention belongs to the technical field of enzyme preparations and biological fermentation, and relates to a composite saccharifying enzyme for producing alcohol from thick mash corn and a use method of the composite saccharifying enzyme, and the composite saccharifying enzyme contains 70-90% of glucoamylase, 5-10% of pullulanase, 5-8% of acid protease and 3-5% of xylanase according to the enzyme activity unit ratio. The use method of the composite saccharifying enzyme in production of alcohol from thick mash corn comprises the following steps: S1, sieving corn flour, adding water, uniformly mixing, then adding alpha-amylase, heating, and liquefying to obtain liquefied mash; and S2, cooling the liquefied mash, adjusting the pH to be acidic, adding a compound saccharifying enzyme and saccharomyces cerevisiae, synchronously performing saccharification and fermentation treatment, and distilling after the treatment is completed to obtain the alcohol. The composite saccharifying enzyme disclosed by the invention can solve the problems of low starch utilization rate, high mash viscosity, more residual sugar and the like in the alcohol fermentation of the thick mash corn.

Provided are an acid protease mutant, an encoding gene therefor, and a use thereof, relating to the technical field of genetic engineering. Compared with a parent acid protease having an amino acid sequence as shown in SEQ ID NO: 1, the acid protease mutant comprises mutant S60V; and the acid protease mutant has at least 98% and less than 100% sequence identity with the parent acid protease. Compared with the parent acid protease, the provided acid protease mutant exhibits significantly improved thermal stability, and has an enzyme activity retention rate greater than 63% after being treated at 75°C for 3 minutes, with a maximum retention rate of up to 90.6%. The provided acid protease mutant facilitates a use of a protease in industrial production.

An organic solid-state fermentation enzyme formulation and an organic plant protease hydrolysate, and preparation methods therefor. The organic solid-state fermentation enzyme formulation is prepared by solid-state fermentation of protease-producing microorganisms, wherein the organic solid-state fermentation enzyme formulation comprises neutral protease, acidic protease, alkaline protease, glucoamylase, and cellulase. By means of using the protease-producing microorganisms to perform solid-state fermentation on organic plant raw materials, the organic solid-state fermentation enzyme formulation rich in the acidic protease, the neutral protease, the alkaline protease, the cellulase, and the glucoamylase is obtained, and then a small amount of additional enzyme is added in the organic solid-state fermentation enzyme formulation, thereby improving the plant proteolysis efficiency by means of an enzyme system synergistic complementary effect.

The present application relates to a kind of acid protease-producing thermomyces lanuginosus and its application, the acid protease-producing thermomyces lanuginosus is thermomyces lanuginosus (Thermomyces lanuginosus) TL-S5 strain, the preservation number is CCTCC NO: M 20241912, and the preservation date is September 4, 2024.The strain has excellent acid protease-producing capacity, has good flavor-producing capacity, can produce a variety of ester, alcohol, ketone and other flavoring substances, has great application prospect in related fermentation processes such as baijiu and koji making.

The present application belongs to the technical field of processing eucommia ulmoides, and particularly relates to a method for resolving and pulverizing residual hard-to-degrade plant tissues on eucommia ulmoides glue by using biological enzymes. The present application uses eucommia ulmoides shell crude glue as raw material, and resolves the raw material by using three biological enzymes in the following order: acid protease, alkaline xylanase and acid xylanase. Then, trace colored tissue debris and plant pigments attached to the G glue filament are removed by ultrasonic cleaning with a surfactant to obtain original flocculent eucommia ulmoides pure white fine glue. The acid protease enzymolysis conditions are as follows: pH 3.0, 55 DEG C oscillation for 48 h. The alkaline xylanase enzymolysis conditions are as follows: pH 7.2, 50 DEG C oscillation for 48 h. The acid xylanase enzymolysis conditions are as follows: pH 4.8, 50 DEG C oscillation for 72 h. The present application successfully separates and pulverizes the brown hard shell in the inner layer of eucommia ulmoides from the eucommia ulmoides glue filament, removes all non-glue plant tissues such as the outer epidermis and the hard shell in the inner layer of eucommia ulmoides shell, and obtains high-purity eucommia ulmoides glue after ultrasonic cleaning with a surfactant, with a purity as high as 98.94%.

The present invention provides a novel proteolytic enzyme composition more particularly an orally administered pro¬teolytic enzyme composition comprising of one or more acid proteases, one or more alkaline protease and one or more plant proteases. More particularly, the composition comprises of microbial (fungal, bacterial or other microbes) protease enzymes, proteases from plant and animals proteases thereof.

The invention relates to the technical field of microorganisms, in particular to lactobacillus brevis X4-4 and application of the lactobacillus brevis X4-4 in fermentation. The preservation number of the lactobacillus brevis X4-4 provided by the invention is CGMCC (China General Microbiological Culture Collection Center) No. 31284. The activity of pyruvate dehydrogenase, malic acid-lactase, N-acetyltransferase and acid protease of the strain is remarkably higher than that of existing common lactobacillus, malic acid and protein in food raw materials can be efficiently utilized, and beneficial products can be generated. The lactobacillus brevis X4-4 has the specific advantages that 1) the lactobacillus brevis X4-4 can survive in a large quantity in an environment with relatively low pH (Potential of Hydrogen); (2) malic acid is converted into lactic acid which participates in pyruvic acid metabolism and arginine synthesis, so that the irritative sour feeling of the raw materials is reduced; (3) protein can be hydrolyzed into small molecule peptide under an acidic condition, so that the utilization rate of the protein is increased; and 4) the method can be used for single fruit raw materials or high-protein raw materials, and can also be used for fruit and protein composite raw materials.

The invention discloses a fermented feed additive for replacing soybean meal as well as a preparation method and application of the fermented feed additive. The fermented feed additive disclosed by the invention is prepared by performing acid protease enzymolysis on a mixed fermentation raw material and fermenting the mixed fermentation raw material with a complex microbial inoculant, wherein the mixed fermentation raw materials comprise the following components in parts by weight: 40-80 parts of corn protein powder, 30-60 parts of corn steep liquor, 7-12 parts of corn germ meal, 4-15 parts of molasses and 2-5 parts of extruded soybeans; the complex microbial inoculant is composed of pediococcus acidilactici, candida utilis and bacillus subtilis according to the viable count ratio of (1-3): (1-3): (0.1-1). The fermented feed additive can effectively replace soybean meal in animal daily ration, the utilization rate of nutrients by animals is increased, the health level of the animals is improved, and the production performance of the animals is improved.