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[目的]富营养化湖泊蓝藻暴发已成突出的环境问题,打捞蓝藻的处理和利用是目前的技术难题,探究蓝藻的农药化利用可行性。[方法]以新鲜蓝藻为基质自然厌氧发酵不同时间得到蓝藻沼液,并以4种培养基(LB、新鲜蓝藻、蓝藻发酵2个月沼液、蓝藻发酵6个月沼液)为原料,接种苏云金芽孢杆菌(B.thuringiensis GIM1.32),对比菌种在不同培养基中生长代谢特征、杀虫晶体蛋白产量,并以3龄小菜蛾为测试对象测定毒力效价。[结果]蓝藻自然厌氧发酵是一个产酸过程,自然状况下(20~25℃)直接打捞富集的蓝藻藻泥产气潜力为27.27 mL/g。随蓝藻自然厌氧发酵时间的增加,沼液中TS、VS、pH值、粗脂肪、蛋白质含量均呈现下降趋势,多糖含量呈现上升趋势,灰分变化不明显。当含固率3%、pH值为7、接种物种龄10 h、接种量2%、培养温度30℃时,不同阶段蓝藻沼液制备B.t.的晶体蛋白含量、LC50值、Tx均低于新鲜蓝藻培养基。[结论]新鲜蓝藻是B.t.GIM 1.32菌种的生长代谢良好的培养基,能够使其正常完成芽孢和伴孢晶体的合成,为蓝藻资源化利用提供了一条新的、高值处理利用途径,既将蓝藻变废为宝,又可有效降低苏云金芽孢杆菌生物农药生产成本。
[Objective] The outbreak of blue-green algae in eutrophic lakes has become a prominent environmental problem. The treatment and utilization of cyanobacteria is the current technical challenge to explore the feasibility of pesticide utilization of cyanobacteria. [Method] Cyanobacterial biogas slurry was obtained from natural cyanobacteria by natural anaerobic fermentation at different times. Four kinds of culture medium (LB, fresh cyanobacteria, cyanobacteria fermenting two months biogas slurry and cyanobacteria fermenting six months biogas slurry) The B. thuringiensis GIM1.32 was inoculated to compare the growth and metabolic characteristics of the strains in different media and the production of insecticidal crystal protein. The virulence titer of the diamondback moth Plutella xylostella was determined at the 3rd instar larvae. [Result] The natural anaerobic fermentation of cyanobacteria was an acidogenic process. The natural gas potential of cyanobacteria directly recovered by enrichment was 27.27 mL / g under natural conditions (20-25 ℃). With the increase of natural anaerobic fermentation time of cyanobacteria, the content of TS, VS, pH, crude fat and protein in biogas slurry showed a downward trend, the content of polysaccharide showed an upward trend, and the change of ash did not change obviously. The crystal protein content, LC50 value and Tx of Bt prepared by cyanobacteria biogas slurry at different stages were lower than those of fresh cyanobacteria at 3% solid content, pH value 7, inoculum size 10 h, inoculum size 2% and culture temperature 30 ℃. Medium. [Conclusion] The fresh cyanobacteria was a good medium for growth and metabolism of BtGIM 1.32 strain, which could make the synthesis of spore and spore crystal normally. It provided a new way of high-value treatment and utilization for the utilization of cyanobacteria. Blue algae turning waste into treasure, but also can effectively reduce the production costs of Bacillus thuringiensis bio-pesticides.