Bacillus subtilis（Bacillus subtilis）, YesBacillusCAS 68038-70-0.The single cell is 0.7~0.8 × 2~3 μ m in diameter and evenly stained.nothingCapsule, Zhou ShengFlagellum, can move.Gram positive bacteriaIt can form endogenous stress resistant spores, 0.6~0.9 × 1.0~1.5micron, elliptical to columnar, located atThallusIn the center or slightly off center, the cell does not expand after the formation of spore.Rapid growth and reproduction,colony of bacteriaThe surface is rough and opaque, dirty white or yellowishLiquid mediumWhen it grows in the medium, it often forms wrinkled film, which is an aerobic bacterium.[1]
It can utilize protein, various sugars and starch to decomposeTryptophanformationindole。It is widely used in genetic researchPurine nucleotideThe synthesis pathway and its regulation mechanism were clearly studied.Widely distributed in soil and putrid organic matter, easy toWithered grassIt is named because it breeds in juice.[2]
Some strains areAlpha amylaseandneutral proteaseImportant production bacteria;Some strains have an enzyme system that strongly degrades nucleotides, so they are often used as parent strains for breeding or preparation of nucleoside producing strains5'-NucleotidaseOf bacteria.[3]
Bacillus subtilisyesBacillusIt is widely distributed in soil and decaying organic matter, and is easy to reproduce in dry grass juice.The single cell of the bacterium is (07 ～ 0. 8) μ m × (2-3) μ m, evenly colored.No capsule, flagellum, active, Gram positive, spore (06 ～ 0. 9)μm ×( 1. 0～ 1. 5) μ m, located in the center or slightly off the center of the cell, and the cell does not expand after the formation of spores.The surface of the colony is rough and opaque, dirty white or yellowish, and it often forms wrinkled walls when growing in the liquid medium, which is aerobic bacteria.It can utilize protein and various sugars to decompose tryptophan.Among them, B. subtilis has great potential in biological control. Under suitable conditions such as temperature and ventilation, a large number of young cells form spores.In addition, Bacillus subtilis grows fast, has low nutritional requirements, can efficiently secrete many proteins and metabolites, and does not produce toxins. It is a non pathogenic safe microorganism.It is widely used in medicine, hygiene and food.In microbiological experiments, the culture medium formula of Bacillus subtilis commonly used for detection and observation: 1 L distilled water+20 g glucose+15 g peptone+5 g sodium chloride+05 g beef paste+20 g agar.[4]
Bacillus subtilis has two growth periods: spore dormancy period and reproductive growth period. Bacillus subtilis will enter the spore dormancy period in the unfavorable environment such as poor growth environment and lack of nutrients, and form spores that have strong resistance and can survive in high temperature, acid and alkali and other polar environments, so as to adapt to the environment and survive.Once the environment becomes suitable for growth and nutrition is sufficient, the spores will enter automaticallyreproductive growthThe spores grow back into Bacillus subtilis.[1]
Main role
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Bacillus subtilis under 100 times oil lens stained with methylene blue
2. Bacillus subtilis rapidly consumes free oxygen in the intestinal tract, causing intestinal hypoxia and promoting beneficial effectsAnaerobic bacteriaGrowth, indirectly inhibiting the growth of other pathogenic bacteria.[4]
3. Irritating animals (human body)immune organ To activate T and B lymphocytes, improve immunoglobulin and antibody levelscellular immunityAnd humoral immune function, improveGroup immunity。[4]
4. Self synthesis of Bacillus subtilisAlpha amylase、protease、lipase、cellulaseAnd other enzymes, which play a role together with the digestive enzymes in animal body (human body) in the digestive tract.[4]
6. Bacillus subtilis carries out spore promoting and microencapsulation treatment on special bacteria, which has good stability and oxidation resistance in the spore state;Extrusion resistance;High temperature resistance, long-term resistance to 60 ° C high temperature, and 20 minutes of survival at 120 ° C;It is acid and alkali resistant, can maintain activity in the acidic stomach environment, can resist the attack of saliva and bile, and is a living bacterium that can reach the large and small intestines 100% directly in microorganisms.[5]
bioscience
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When entering the human body, it can reach the large and small intestine 100%, inhibit pathogenic bacteria, promote the growth of beneficial anaerobic bacteria, and produce organic acids such as lactic acid, reduce the intestinal PH value, and indirectly inhibit the growth of other pathogenic bacteria.Improve the level of immunoglobulin and antibody, enhance cellular immunity and humoral immunity, and improve group immunity.Synthesize α - amylase, protease, lipase, cellulase and other enzymes, and play a role in the digestive tract together with digestive enzymes in animals (human body).
Action mechanism
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Competitive role
The competition of Bacillus subtilis mainly includes two aspects: nutrition competition and spatial site competition.Bacillus subtilis has more advantages in spatial site competition, that is, it can reproduce and colonize rapidly and massively on the surface of animal tissues or in plants and in the soil where plants grow, effectively prevent the propagation of pathogenic microorganisms, interfere with the infection of plant pathogenic microorganisms on plants, and destroy the colonization of pathogenic microorganisms on plants, so as to achieve the effect of bacteriostasis and disease control.[1]
Bacteriolysis
Bacillus subtilis can be adsorbed on the hyphae of pathogenic fungi, and grow together with the hyphae. During the growth process, it will produce bacteriolytic substances, which will digest the hyphae.Generally, it will cause mycelium breakage, disintegration or cytoplasmic degradation;OrSecondary metabolitesIt can dissolve the cell wall of pathogen spores, resulting in cell wall perforation and deformity.[1]
Produce antibacterial substances
Produce antibiotic substances that can inhibit the growth of bacteria, viruses, fungi and pathogens. These antibiotic substances are mainly phospholipids, amino sugars, peptides and lipopeptides.Among them, lipopeptide antibiotics are the most important antibacterial substances of Bacillus subtilis.[1]
Biological oxygen capture
Bacillus subtilis isgram-positiveAerobic bacteria can rapidly consume free oxygen in the intestines of animals, thus effectively improving the utilization efficiency of nutrients.Bacillus subtilis can also secrete amylase, lipase, protease, cellulase and other endogenous enzymes, providing a large number of endogenous enzymes for animals, to a certain extent, it can make up for the lack of endogenous enzymes in animals.[1]
stayBacillus subtilisIn a rich water body, the surface tension of water is relatively small, and a film can be formed on the small circle of blown bubbles.[6]
Scope of application
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Aquaculture
Bacillus subtilis has a strong inhibitory effect on harmful microorganisms such as vibrio, Escherichia coli and baculovirus in aquaculture. It can secrete a large amount of chitinase, decompose toxic and harmful substances in aquaculture ponds, purify water quality, and decompose residual bait, feces, organics, etc. in the ponds. It has a strong role in cleaning up small particles of garbage in water.Bacillus subtilis is also widely used in feed. It has strong protease, lipase and amylase activities, which can promote the degradation of nutrients in feed and make aquatic animals more fully absorb and utilize feed.[7]
Bacillus subtilis can reduceShrimp diseaseThe occurrence of harm can greatly increase the yield of prawn, thus improving economic benefits, biological environmental protection, stimulating the development of immune organs of aquatic animals, and enhancing the immunity of the body;Reduce the occurrence of shrimp diseases, significantly increase the yield of shrimp, thereby improving economic efficiency, purifying water quality, no pollution, no residue.[8]
Plant disease resistance
Bacillus subtilis successfully colonizes to the plant rhizosphere, surface or body, competes with pathogens for nutrition around the plant, secretes antibacterial substances to inhibit the growth of pathogens, and induces the plant defense system to resist the invasion of pathogens, so as to achieve the purpose of biological control.Bacillus subtilis can mainly inhibit many plant diseases caused by plant pathogens such as filamentous fungi.Bacillus subtilis strains isolated from rhizosphere soil, root surface, plants and leaves of crops have antagonistic effects on many fungal and bacterial diseases of different crops.asgrain cropsInRice sheath blight, rice blast,wheat sharp eyespot , bean root rot.Among vegetable diseases, tomato leaf disease, fusarium wilt, cucumber fusarium wilt, downy mildew, eggplant gray mold and powdery mildew,phytophthora capsici Etc.Bacillus subtilis can also control a variety of diseases of postharvest fruits, such as apple mold heart disease,penicillium italicum , nectarine brown rot, strawberry grey mold and powdery mildew,Banana wilt, crown rot, anthracnose, apple pear green mold, black spot, canker, Jinhua pear fruit rot.In addition, Bacillus subtilisdothiorella gregaria , canker, black spot and anthracnose of trees, tea leaf spot, tobacco anthracnose, black shank, brown spot, root rot,Cotton damping off, Fusarium wilt, etc. also have good control effect.[9]
Animal feed production
Bacillus subtilis is a kind of probiotic bacteria often added to animal feed. It is added to animal feed in the form of spore.Spores are living cells in a dormant state, which can tolerate the adverse environment during feed processing. They are stable and easy to store after being prepared as bacterial agents, and can quickly recover and reproduce after entering the animal intestine.Bacillus subtilis can play its prebiotic properties after it recovers and proliferates in the intestinal tract of animals, including improving the intestinal flora of animals, enhancing the immunity of the body, and providing enzymes needed by many animals. It can make up for the lack of enzymes in the body of animals, promote the growth and development of animals, and has a significant prebiotic effect.[10]
Medical field
A variety of extracellular enzymes secreted by Bacillus subtilis have been applied in many different fields, including lipase and serineFibrinolytic protease(i.enatto kinase）It is widely used in the pharmaceutical industry.Lipase has a variety of catalytic capabilities. It works together with the original digestive enzymes in the digestive tract of animals or humans to keep the digestive tract in a healthy balance.Nattokinase is a serine protease secreted by Bacillus subtilis natto, which has the functions of dissolving thrombus, improving blood circulation, softening blood vessels and increasing vascular elasticity.[10]
Water purification
Bacillus subtilis can be used as a microbial regulator to improve water quality, inhibit harmful microorganisms, and create excellent aquatic organisms
State environment.Due to long-term high-density breeding of animals, there is a large amount of food residue, animal debris, feces deposition and other pollutants accumulated in the aquaculture water body, which is easy to cause water quality deterioration and endanger the health of the breeding animals, and even reduce production to cause losses, which is a huge hazard to the sustainable development of the aquaculture industry.Bacillus subtilis can colonize in water bodies and form dominant flora through nutrition competition or spatial site competition to inhibit the growth and reproduction of harmful pathogenic bacteria (such as vibrio, Escherichia coli) and other harmful microorganisms in water bodies, thus changing the number and structure of microorganisms in water bodies and sediment, and effectively preventing diseases of aquatic animals caused by water quality deterioration.At the same time, Bacillus subtilis, as a strain that can secrete extracellular enzymes, secretes a variety of enzymes that can effectively decompose organic matters in water and improve water quality.For example, the active substances produced by Bacillus subtilis, such as chitinase, protease and lipase, can decompose the organic matter in water and degrade the nutrients in animal feed, which not only enables animals to fully absorb and use the nutrients in feed, but also can greatly improve the water quality;Bacillus subtilis can also adjust the pH value of aquaculture water.[10]
other
Bacillus subtilis in sewage treatment andBiological fertilizerFermentation or fermentation bed production is also widely used as a multifunctional microorganism.
1. Municipal and industrial sewage treatment, industrial circulating water treatment, treatment of septic tank, septic tank, etc., livestock and breeding animal waste, odor treatment, manure treatment system, garbage, cesspit, cesspool, etc;[11]
2. Animal husbandry, poultry, special animals and pet breeding;[11]
3. It can be mixed with a variety of strains and plays an important role in agricultural production.[11]
