Preparation Of Agricultural Agent With Streptomyces Silaceus And Its Application Effect

Streptomyces is a kind of microbial group with wide application value and economic value.It is widely distributed and diverse in different natural ecological environment and has different metabolic functions.Microbial agents can alleviate the problem of environmental pollution,and can promote crop growth,improve product quality,so the production and application of microbial fertilizer in China is rising.Today,the continuous development of new formulations,the innovation of process equipment and the increasing of application promotion area make the production of microbial fertilizer of China to enter a new era of development.A strain of SN16 was screened by our laboratory.It was found that the strain had good antagonistic effect on Fusarium proliferatum and Fusarium moniliforme.Through the morphological,physiological and biochemical identification and 16 S rDNA sequence analysis,it was identified as Streptomyces silaceus.In this study,the fermentation conditions of Streptomyces SN16 were screened nitrogen source,carbon source and pH by making a single factor optimization.And then use RSM to optimize its fermentation medium and culture conditions,Streptomyces SN16 dry weight as the response value.The optimal liquid fermentation conditions were 1.05 g of yeast powder,19.83 g of soluble starch and 6.96 of pH.After the fermentation of the strain in this liquid fermentation medium,the dry weight of the strain reached 0.704 ± 0.022 g of dry weight of SN16,which was small with the predicted value.In order to prepare Streptomyces SN16 bacteria,the best solid state fermentation process was determined.Among them,the solid fermentation medium is 80% of the rice flour and 20% of the wheat bran,the fermentation conditions for the initial water content of 50%,inoculation amount of 10%,pH natural,culture 7d.After the optimization of solid-state fermentation conditions,the number of viable bacteria in SN16 strain reached 9.43×108 cfu/g.In order to improve the biological stability of Streptomyces silaceus SN16 agent,through the carrier,protective agent dispersing agent and other additives were optimized to determine the best formula Streptomyces SN16.The pot experiment of wheat,Chinese cabbage and tobacco seedlings was used to verify the effect of the agent.The results showed that the best formula of Streptomyces silaceus SN16 agent was 20% bacterial powder,24% 1 mg / m L sodium alginate solution,24% 10 mg / mL sodium carboxymethyl cellulose(CMC)solution,32% diatomaceous earth.In this formula,the biomass of microbial inoculum was 2.45 ×108cfu/g at 4?after 60 d,and it could reach 0.94×108 cfu/g after 60 d storage at room temperature.The fermentation broth of Streptomyces silaceus SN16 has a promoting effect on the germination of wheat seeds.Compared with the control,the germination rate,germination potential and germination index were increased by 2.76%,8.67% and 14.83% respectively.Similarly,the cabbage seeds were treated with the fermentation broth.Results compared with the control,the germination rate,germination potential and germination index were increased by 1.00%,1.66% and 4.94%.Pot experiment showed that 2% Streptomyces SN16 could promote the growth of wheat seedlings.It could significantly improve the root length,fresh weight and dry weight of wheat seedling,which was 15.77%,68.42% and 101.90% higher than that of the CK,respectively.After treatment with 0.5% agent,the plant height and fresh weight of Chinese cabbage seedlings were increased by 90.05% and 297.37% respectively compared with the control group.After treatment with 1%,the maximum leaf length and maximum leaf width of tobacco seedlings were increased by 127.23% and 129.65% respectively compared with the control group.