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为分离筛选具有毒死蜱降解特性的植物内生菌,从农药厂废液池旁采集小飞蓬植物样本,经表面消毒后研磨提取植物汁液,通过以毒死蜱作为单一碳源的无机盐培养基(MSM)进行连续5代培养筛选,获得一株植物内生细菌XFP-gy,经生理生化试验及16Sr DNA同源性比对分析,初步鉴定该菌属阪崎克罗诺杆菌属(Cronobacter sp.)。将菌株XFP-gy在以毒死蜱(初始质量浓度为20 mg/L)为单一碳源的MSM中培养,至第6天时达生长高峰,第9天时毒死蜱的降解率为77.28%。在M SM培养基中补充牛肉膏和蛋白胨(加富培养基)可以促进菌株XFP-gy的生长,并将其对毒死蜱第5天的降解率由69.59%提高到98.0%。菌株XFP-gy降解毒死蜱的最佳培养条件为30℃和p H 7.0,在此条件下,增加培养液中原始接菌量,降低底物毒死蜱的初始质量浓度,可明显提高XFP-gy对毒死蜱的降解效率,当毒死蜱初始质量浓度为10 mg/L,原始接菌量为2%时,至第9天时在培养液中未检出毒死蜱残留。
In order to isolate and screen endophytic fungi with chlorpyrifos degradability, plant samples of Spearmint were collected from the waste liquid pool of pesticide plant. After surface disinfection, plant juice was milled and extracted. Through inorganic salt medium (MSM) with chlorpyrifos as sole carbon source, The strain XFP-gy of endophytic bacteria was obtained from five generations of continuous culture. The physiological and biochemical tests and 16Sr DNA homology analysis were used to identify the strain Cronobacter sp. The strain XFP-gy was cultured in MSM with single carbon source of chlorpyrifos (initial concentration of 20 mg / L) and reached the peak of growth on the 6th day. On the 9th day, the degradation rate of chlorpyrifos was 77.28%. Supplementation of beef extract and peptone (enriched media) in M SM medium promoted the growth of strain XFP-gy and increased the degradation rate of chlorpyrifos from 69.59% to 98.0% on day 5. The optimal culture conditions for XFP-gy degradation of chlorpyrifos were 30 ℃ and p H 7.0. Under this condition, increasing the initial amount of inoculum in the culture medium and decreasing the initial concentration of chlorpyrifos substrate could significantly increase the toxicity of chlorpyrifos When the initial concentration of chlorpyrifos was 10 mg / L and the original amount of inoculation was 2%, no chlorpyrifos residue was detected in the culture solution by the 9th day.