Application of metabolites of Bacillus in feed and fermentation

Bacillus: Generally defined as a class of aerobic or facultative anaerobic gram-positive rod or globular bacteria that can form spores (endospores). They include Bacillus, Lactobacillus, Clostridium, desulphurize enterobacter and Spore Occidentum. The latest list of feed additives includes seven organisms that produce spores, including Bacillus licheniformis, Bacillus subtilis, Bacillus retinosus, Bacillus pumilus, Bacillus coagulans, Bacillus cereus lateralis, and Clostridium clostridium clostridium.

Bacillus is widely used as probiotics in feed and is an ideal feed additive. It has the following advantages: (1) Beneficial bacillus has a good probiotic effect, which can help animals digest and absorb, improve their immune ability, and improve the microecological environment in animals. (2) Stable bacillus has spore-producing performance and can withstand high temperature processing, long-term storage, granulation extrusion and other environments. Generally, bacillus powder stored for 1 year can maintain more than 90% of its activity, showing good stability; (3) Bacillus with high tolerance is generally added to feed in the form of spores. Spores have good acid resistance and adapt to a wide pH range, and can reach the intestine through gastric acid to play its role; (4) Rapid increment: Bacillus has the characteristic of rapid growth. After the spores enter the intestine, they can germinate quickly, produce nutrients and have probiotics. Bacillus is also a kind of microorganism bacteria mainly used in raw material fermentation at present. Its fermentation advantage lies in its ability to secrete a variety of metabolites, including a variety of enzymes, volatile fatty acids, vitamins, antibacterial substances and other metabolites. It can not only improve the nutritional value of raw materials, but also increase the functional substances in raw materials.

Bacillus can produce amylase, protease and a small amount of lipase, cellulase, phytase, glycosylase and pectinase during its growth and reproduction. The addition of this bacillus preparation in animal feed will produce the above digestive enzymes in the intestinal tract, promote the digestion and absorption of nutrients in animals and improve the feed conversion rate. As is known to all, bacillus subtilis enzyme is the main body of the industrial mold market. The protease and amylase produced by bacillus subtilis are the most widely used enzymes in the industrial enzyme market, and these two enzymes alone account for 50% of the whole industrial enzyme market. Bacillus subtilis and bacillus licheniformis has a strong capacity of protease, amylase and lipase, at the same time also has the degradation of xylan, pectin, galacturonic acid polymer, carboxymethyl cellulose, lichen glycan substances such as ability, in the raw material in the fermentation process can effectively decompose the macromolecule nutrients and antinutritional factors in plant material. Reportedly bacillus in animal intestines, also can produce h2s decomposition of enzymes, amino oxidase and indoles can be oxidized to nontoxic and harmless substance, thus reduce animal house within the concentration of harmful gases such as ammonia, hydrogen sulfide, odor, reduce environmental pollution, the enzymes in mycotoxin biodegradable metabolites are widely used, in with aflatoxin B1 degradation strains screening test found that 1 strain of bacillus subtilis of AFB1 has good degradation rate, degradation rate can reach 90.28%, the toxicity tests showed that the degradation of the active material is a kind of extracellular protease.

Volatile fatty acids such as acetic acid, propionic acid and butyric acid produced by Bacillus during its growth and reproduction can reduce the pH value of animal intestines, effectively inhibit the growth of harmful bacteria, and create an acidic environment for the growth of lactic acid bacteria. In addition propionic acid can also participate in the tricarboxylic acid cycle, providing energy for animals. It was reported that the contents of acetic acid, propionic acid and butyric acid in the fermentation broth of Bacillus subtilis could reach 0.225g/L, 2.59 g/L and 3.49 g/L, respectively. Some bacillus also has unique functions in acid production. For example, Bacillus coagulans is the only bacillus capable of producing L-lactic acid and belongs to the same type of lactic acid fermentation bacteria. It can also produce coagulins to inhibit the growth of harmful bacteria. Clostridium butyrate is an obligate anaerobic Gram-positive bacillus. The final metabolites of starch and sugar are butyric acid, acetic acid and lactic acid. The main metabolite of Clostridium butyrate is the main nutrient for regeneration and repair of intestinal epithelial cells.

Bacillus can synthesize VC, VB1, VB2, VB6 and other vitamins by itself during its growth and reproduction. Provide nutrients to animals to promote their growth and improve their performance. The results showed that VC, VB1, VB2 and VB6 contents in bacillus subtilis fermentation broth were up to 0.878mg/L, 21.33mg/L, 9.31mg/L and 0.204mg/L respectively.

Bacillus can produce inhibitory mold material, bacillus produced by different mold material is different, the main antibacterial substances from bacillus subtilis for fat peptide antibacterial substances, such as hay rhzomorph, bacitracin and polymyxin b and nystatin, antimicrobial substance produced by the bacillus licheniformis as mitogen, benzene acetic acid bacteria and antimicrobial proteins, such as setting for L - lactic acid bacillus and coagulation factor, bacteriocin, etc., short and bacillus mainly for antimicrobial proteins, lateral spore bacillus of lysozyme, bacteriocin, polypeptide antibiotic, etc. Study reported bacillus subtilis CG can secrete aminoglycoside compounds of sea cucumber "rotten skin disease pathogenic bright arc Yin (Vibrio splendidus) has significant inhibitory effect, produced by the bacillus bacteriostat epicuticular fungus also has better inhibition effect, bacillus subtilis is considered to be an effective inhibition of strains of aspergillus flavus and degradation of the toxin, was isolated from bacillus subtilis bacillus drug D belongs to the one of hay rhzomorph family, is currently the strongest inhibition of aspergillus flavus and only a kind of antibiotics.

Bacillus has good stress resistance and abundant metabolites, so it has a very broad prospect in feed and raw material fermentation. However, due to various types of bacillus, different types of metabolites, different feeding animals, different demands for fermentation products, certain differences in fermentation time, and great differences in application effect. Therefore, how to make full use of the abundant valuable metabolites of Bacillus should be further explored