灭线磷降解菌DS-1的分离鉴定及其降解特性

【目的】筛选能降解灭线磷的微生物,解决土壤环境中存在的灭线磷残留问题。【方法】从长期施用灭线磷的土壤中采集土样,通过富集培养方法分离能降解灭线磷的微生物。用紫外分光光度法测定灭线磷的含量。【结果】获得一株能以灭线磷为唯一碳源生长的细菌DS-1,结合生理生化特性及16SrDNA序列相似性分析将其鉴定为蜡状芽孢杆菌(Bacilluscereus)。生长特性和灭线磷降解试验结果表明,灭线磷浓度为10mg·L-1时降解率最高为77.1%,50mg·L-1的相对降解量最高为26.8mg·L-1;DS-1在温度为30℃时对灭线磷的降解率为51.6%,显著高于4℃、25℃以及40℃的降解率。【结论】DS-1降解灭线磷的最适温度为30℃,最适pH为7.0,最佳碳源和氮源分别为蔗糖和硫酸铵,最佳碳氮摩尔比为4:1。

Identification and Characterization of an Ethoprophos-Degrading Bacteria DS-1 and Its Degradation Characteristics

Objective] Biodegradation is an effective and economic method to treat the soil environment that has been polluted by ethoprophos.The study focused on the isolating and characterizing bacteria with abilities to degrade ethoprophos.Method] The enrichment method was used to find the bacteria which can degrade the ethoprophos from the soil samples of long-term application of ethoprophos. The content of ethoprophos was determined by using UV. Result] A bacterial strain DS-1 capable of utilizing ethoprophos as sole carbon source was isolated. It was preliminarily identified as Bacillus cereus according to its physiological-biochemical characteristics and the similarity analysis of its 16S Rdna sequence (GenBank Accession No. GQ149481). The growth and degrading characteristics of this strain were tested. The highest degradation rate of ethoprophos was up to 77.1% when ethoprophos concentration was 10 mg·L~(-1), and the relative degradation amount of 50 mg·L~(-1) was 26.8 mg·L~(-1) which is the highest. The degradation rate of ethoprophos was 51.6% at 30℃, significantly higher than that at 4℃,25℃ and 40℃ Conclusion] The optimal temperature and Ph for the ethoprophos degradation under the action of DS-1 were 30℃ and 7.0, respectively. The optimal carbon and nitrogen sources were sucrose, ammonium sulfate, and the optimum molar ratio of carbon to nitrogen was 4:1.