Microbial fertilizers are more expensive than organic fertilizers because of the addition of biologically active bacteria! Therefore, the role of strains is the most important for microbial fertilizers. At present, the main microbial strains on the market are mainly Bacillus subtilis, so understanding the role of Bacillus subtilis is very important.
Today we will take a look:
The antibiotic effect means that antibacterial microorganisms can inhibit the growth and metabolism of pathogenic microorganisms by producing metabolites at low concentrations, thereby affecting the survival and activity of pathogenic microorganisms. For nearly half a century, many effective antibacterial substances have been isolated and purified from the metabolites of different Bacillus subtilis strains.
The bacteriolytic action of Bacillus subtilis is mainly manifested by adsorption on the mycelium of pathogenic bacteria, and it grows with the growth of mycelium, and then it produces lysogenous substances that cause the protoplasm leakage to cause the mycelium to break; or it can produce antibacterial substances by dissolving pathogen spores. The cell wall or cell membrane, resulting in cell wall perforation, deformity and other phenomena to inhibit spore germination.
Inducing plant resistance and promoting plant growth
Inducing plant-producing resistance means that Bacillus subtilis not only inhibits plant pathogens, but also induces the plant’s own resistance mechanism to enhance the plant’s resistance to diseases. What is PGPR? Internationally, the rhizosphere-promoting bacteria that can promote plant growth in the soil are generally called Plant growth promoting rhizobaceria (abbreviated as PGPR).
Among them, Bacillus subtilis has the strongest resistance, the most functions, the widest adaptability, and the most stable effect. Bacillus subtilis can produce substances like cell division factors and plant growth hormones, and promote the growth of plants so that plants can resist pathogenic bacteria.
Protect the environment
Bacillus subtilis is widely used in biological fertilizers. When used as a crop or soil, it can colonize the rhizosphere or in the body of the crop and act as a specific fertilizer. At present, microbiological fertilizers are used to fertilize fertility, increase the utilization of chemical fertilizers, and inhibit the absorption, purification and repair of nitrates, heavy metals, and pesticides by crops.
Reuse soil to reduce the occurrence of crop diseases and promote the decomposing use of crop straws and urban garbage. The improvement of crop product quality and food safety has played an irreplaceable role.
Biosorption and biodegradation of phenanthrene and pyrene in soil by Bacillus subtilis
The soil to which the soil is attached is called a soil-water environment system, in which there are a large number of soil-indigenous microorganisms, and biofilms exist on the surface because the biofilm forms a barrier, and the organic pollutants come into contact with the solid substrate supporting the biofilm. Before that, it must first reach and pass through the isolation layer. This strongly changes the adsorption behavior of the mineral particles or the substrate and has an important influence on the adsorption.
Effect of Bacillus subtilis on Respiration of Soil Microorganisms
Soil respiration intensity, as one of the indicators of soil biological activity, can reflect the transformation and supply capacity of soil nutrients to a certain extent. The change of the respiration rate and the change direction also reflect the sensitivity and response mode of the ecosystem to stress, and it is the environmental safety. An important indicator of the evaluation is that when the soil is contaminated with foreign pollutants, the microorganism may need more energy to maintain its survival, and the metabolic activity of soil microorganisms will respond to different degrees. Studies have shown that Bacillus subtilis treated with various mass fractions showed a stimulatory effect on soil respiration, and the greater the mass fraction of Bacillus subtilis in soil, the greater the stimulatory effect on soil respiration intensity, ie, stimulation intensity and application quality score. Positive correlation.
Effect of Bacillus subtilis on soil urease activity
Using soil enzymes as monitoring indicators to evaluate the ecotoxicological effects of pesticides has become one of the research hotspots in the field of environmental science. Urease is a type of hydrolase that has been studied in depth in the soil. It is the only enzyme that has a major impact on the conversion of urea into soil and the utilization of urea.
After the urea is applied to the soil, it is quickly decomposed into carbon dioxide and ammonia under the catalytic action of urease, so the reduction of soil urease activity not only can slow down the hydrolysis of urea, but also make the hydrolysis product more adsorbed by the soil and effectively reduce the urea hydrolysate. Ammonia volatilization losses may also reduce the potential of the hydrolysate NH nitrification.
Improvement of saline-alkali land by Bacillus subtilis
The hazards of soil salt accumulation in soil are poor in soil structure, poor air permeability, high bulk density, increased soil temperature, poor aerobic microbial activity, slow nutrient release, low permeability coefficient, and strong capillary action, leading to further intensification of surface soil salinization. Soil cold, hard, board phenomenon. In general, when the water-soluble salt accumulation in the surface or subsurface layer exceeds 0.1%, or the alkalinity of the soil alkalized layer exceeds 5%, it belongs to saline soil.
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