Methylobacterium sp. YAL-2对乙酰甲胺磷的降解特性

Degradation Characteristics of Acephate by Methylobacterium sp. YAL-2

从有机磷生产厂家的下水道污泥中分离出一株对高浓度和低浓度乙酰甲胺磷都具有高效降解能力的寡营养菌YAL-2,根据形态、生理生化和16S rRNA基因系统发育分析,将菌株YAL-2鉴定为Methylobacterium sp.降解特性实验表明,菌株YAL-2能利用乙酰甲胺磷为唯一碳源生长和降解;在添加了甲醇的无机盐培养基中,84 h可完全降解300mg L-1乙酰甲胺磷,24 h将50 mg L-1和10 mg L-1乙酰甲胺磷降至非检测水平;4 d能完全去除100 mg L-1甲胺磷,5 d分别降解58.4%和40.6%的100 mg L-1乐果、敌敌畏.小青菜农药残留去除实验显示,菌株YAL-2可在7 d内将乙酰甲胺磷和甲胺磷将至限量水平.结果表明,将菌株YAL-2应用于保证果蔬等食品的食用安全是可行的.

It is very urgent to remove acephate residues in fruits,vegetables and other foods.A oligotrophic bacteria YAL2,capable of high efficiently degrading acephate both at high concentration and low concentration,was isolated from the wastewater sludge of a pesticide factory which has produced organophosphorus pesticides for many years.Strain YAL-2 was identified preliminarily as Methylobacterium sp.according to its morphological observation,physiological and biochemical test,and phylogenetic analysis based on 16S rRNA gene sequence.The degradation experiments indicated that the strain YAL2 could utilize acephate as its sole carbon source for growth.In medium MSM-2 added methanol,the strain YAL-2 could completely remove 300 mg L-1acephate after 84 h under optimal conditions,and degraded low concentration of acephate（from 10 mg L-1 to 50 mg L-1） to an non-detectable level after 24 h.Moreover,YAL-2 also showed the ability of degrading 100% of 100 mg L-1methamidophos in 4 days,58.4% of 100 mg L-1dimethoate and 40.6% of 100 mg L-1dichlorvos in 5 days.Spraying the strain YAL-2 could degrade acephate or methamidophos in pakchoi leaves to below the detectable level in safety interval of 7 days.These results suggested that it was feasible for applying the strain YAL-2 to ensure the edible safety of the fruits,vegetables and other foods.