利用甘薯淀粉废水生产有机磷农药降解菌剂条件的初探

Study on Fermentation Condition of Organophosphorus Pesticide-degrading Bacterium Using Sweet Potato Starch

为生产低成本且具有高效降解有机磷农药残留效用的菌制剂,利用甘薯淀粉废水进行菌剂的发酵,同时降低废水的化学需氧量(COD),减轻环境污染。通过形态学和分子生物学的方法,对从油菜叶面分离出的有机磷降解菌株N20的菌体形态进行扫描电镜观察,对其16SrDNA基因序列进行同源性比较和系统发育分析,将其鉴定为蜡样芽孢杆菌Bacilluscereus。同时,以甘薯淀粉废水为培养基发酵该有机磷农药降解菌,考察不同培养条件对其在甘薯淀粉废水中的生长状况的影响。研究结果表明,甘薯淀粉废水生产有机磷农药降解菌剂的最佳摇瓶培养条件为:种子液的种龄10h,接种量5%,初始pH7.0～7.5,摇床转速200r/min,发酵温度35℃,发酵时间24h。研究结果可为有机磷农药的生物降解制剂的工业化生产提供实用参数。

In order to obtain the best organophosphorus pesticide-degrading bacterium at low cost,the author used sweet potato starch wastewater to ferment inocula,which could decrease the COD of wastewater and lessen environment pollution.In this study,the organophosphorus pesticide-degrading bacterium strain N20 was isolated from Brassica napus leaf.The strain N20 was preliminarily identified as Bacillus cereus using scanning electron microscopic observations,16S rDNA sequence homology comparison and phylogenetic analysis.Furthermore,the potato starch wastewater was used as the culture media to explore the influence of growth status in different culture conditions.The results of research showed that the optimum culture condition determined with shaking flask cultures was at the bacterium spawn age of 10 h,inoculation capacity 5%,initial pH 7.0-7.5,shaking speed 200 r/min,temperature 35℃,and fermentation time 24 h.These results were the available parameters for the industrial production of this organophosphorus pesticide-degrading agent.