Isolation and Identification of Microorganisms in Bio-organic Fertilizers and Construction of a Liquid Microbial Agent

【Objective】 The study was conducted to understand the species of microorganisms in bio-organic fertilizer and the relationship among various microorganisms and to construct an efficient and convenient liquid microbial agent. 【Method】 Bacteria were isolated from fertilizer by streak plate method, and identified by colony observation, Gram Staining Method and 16SrDNA homologous gene sequence comparison method. At the same time, the antagonistic effects and culture conditions of bacteria were studied by using the hypha cake method and the spread-plate method. 【Result】 Four bacterial colonies, namely, Lactobacillus plantarum, Bacillus subtilis, Bacillus licheniformis and Bacillus megaterium, were isolated and showed no antagonistic effect. When adding B. licheniformis, B. subtilis, B. megaterium, L. plantarum at the ratio of 1∶1∶1∶1 into beef extract-peptone liquid medium of different pH for cultivation the number of living bacteria was determined by spread-coat plate method and the optimuml pH was 7.0. 【Conclusion】 There was no antagonistic effect among the four species of bacteria that isolated from bio-organic fertilizer. When the bacterial colonies were prepared at equal ratio and added into the beef extract-peptone liquid medium with pH of 7.0, the strains could grow well and a kind of efficient liquid microbial agent was obtained.