除草剂二甲戊灵的真菌降解及其特性研究

Biodegradation of herbicide pendimethalin by fungi and its characteristics

富集分离了除草剂二甲戊灵降解真菌 ,并研究了其降解特性 .结果表明 ,真菌可以降解二甲戊灵 ,利用富集培养的方法从环境中分离到 16株能降解二甲戊灵的真菌 ,其中 10株真菌 5d内对 10 0mg·L-1二甲戊灵的降解率大于 6 0 % .以其中 3株生理耐受能力强、降解能力高的真菌为例 ,研究了外加碳源浓度、初始pH值、二甲戊灵浓度和培养温度对真菌生长量和降解能力的影响 .此 3株真菌经鉴定分别属于土生曲霉组 (Aspergillusterreus)、长梗串孢霉属 (Monilochaetes)和烟色曲霉组 (Aspergillusfurnigatus) .在外加碳源浓度为 0 .5 %～ 1.0 %的范围内 ,真菌生长量和降解率达到最大 ;在中性培养液中 ,3株真菌的生长量大 ,降解能力强 ;在浓度为 10 0mg·L-1时降解率和生长量都比较大 ,而绝对去除量随二甲戊灵浓度的提高而增加 ,在 5 0 0mg·L-1时达到最大 ;真菌的生长和降解需要适宜的温度 ,2 0～ 30℃培养时 ,降解率和生长量最大 .本研究提出了 3株真菌生长和降解二甲戊灵的最佳培养条件 ,可为农药污染治理及生产污水处理提供理论依据 .

Fungi, which can grow on and degrade pendimethalin ,were isolated from activated sludge and soil .The biodegradation characterization in vitro was studied. The results showed that pendimethalin could be degraded by fungi, 16 fungi were isolated by enrichment culture,among which ,10 fungi could degrade more than 60% pendimethalin in 5 days in culture fluid. According to the physiological resistance and the capacity to degrade pendimethalin ,three fungi were considered as efficiently degrading strains identified as Aspergillus terreus, Monilochaetes and Aspergillus furnigatus. The efficiency of degradation was affected by culture conditions such as pH ,temperature, and concentration of cane sugar and pendimethanlin. The results showed that when the additional carbon source was 0.5%～1.0%, pH value was 6～8 ,and cultivated temperature was 20～30℃, the growth amount of fungi and the degradation rate were enhanced. The fungi grew quickly , and the biodegradation rate was high under pendimethalin concentration being 100 mg·L -1 . The removed amount of pendimethalin increased with increasing pendimethalin concentration . The optimal conditions were proposed ,which could provide theoretic basis for prevention and control of pesticides pollution.