Studies On Optimization Of Fermentation Conditions And Biocontrol Effects Against Fusarium Solar Of Bacillus Amyloliguefaciens15-1-1

The Bacillus amyloliguefaciens strain15-1-1was isolated from pepper rhizosphere in Heilongjiang by Pesticide Laboratory of Northeast Agricultural University. In this paper, the strain Bacillus amyloliquefaciens15-1-1fermentation medium composition and culture conditions were optimized, also, the spectrum antibacterial on the15-1-1strain, sterile broth pepper stability and control root rot indoor pot experiment were measured. The main conclusions are as follows.1. The Nutrition facts and ratios of liquid fermentation medium of Bacillus amyloliquefaciens15-1-1was optimized by us. The results showed that optimum medium contains2.0%glucose,0.5%peptone,1.0%radix scutellariate and0.5%NaCl. The favorable fermentation condition was: fermentation time36h, fermentation temperature32℃, rotation speed150rpm, original pH7.0, inoculum of0.5%which cultured in250mL flask with40mL culture.2.Studies on the stability of strain15-1-1shows:15-1-1fermented liquid was stable under60℃. When in the condition of80℃, it has a relatively good thermostability, with the stability of its active substance decreased when time increased. The inhibition activity of sterile fermented liquid remained stable during natural and mild acid condition, showing that the sterile fermented liquid has high storage stability.3.The results of the Sterile broth inhibitory spectrum showed that the sterile broth of Bacillus amyloliquefaciens15-1-1had effective inhibition on Sclerotinia sclerotinorum, Fusarium oxysporum, Rhizoctonia solani, Verticilliun dahliae, Bipolaris sorokiniana and Phytophthora sojae. The inhibition provides a theoretical basis for its application for biocontrol agents.4.Pot experments in greenhouse showed that the cell-free filtrate of15-1-1fermentation had a good control efficacy to the hot pepper root rot in seedings after inoculated with pathogen. The strain15-1-1cell-free filtrate was used at48h,24h and Oh before the hot pepper root rot was inoculated. The biocontrol efficacy were95.4%,85.3%,and75.9%respectively after inoculated for7d.The biocontrol efficacy were91.7%,64.7%,57.4%respectively after inoculated14d, and75.8%,53.6%,43.7%respectively after inoculated21d. The result showed that strain15-1-1was a potential biocontrol agent in hot pepper root rot control.