降解1,3-二甲基-2-咪唑烷酮细菌的分离及功能评价

背景] 1，3-二甲基-2-咪唑烷酮（1，3-Dimethyl-2-Imidazolidinone，DMI）作为一种强极性非质子溶剂，在生产和应用过程的环境中有稳定残留问题，存在安全隐患。目的] 分离筛选具有降解DMI能力的微生物菌株，为清除环境中残留的DMI提供优良的微生物菌种资源。方法] 从DMI生产区域土壤采集样品分离DMI抗性微生物，采用形态学及分子生物学鉴定确定其分类地位，并对DMI降解能力进行测定。结果] 分离到最高能够耐受5%（体积分数） DMI的微生物菌株，形态学及分子生物学鉴定初步表明获得的菌株DT-1和DT-2为贝莱斯芽孢杆菌（Bacillus velezensis）；全细胞及细胞提取液均具有降解DMI的能力；其中菌株DT-1及其细胞提取液对1%（体积分数） DMI的降解率分别达到48%和68%。结论] 从DMI生产区域土壤中分离到具有DMI降解能力的芽孢杆菌，不但可为DMI污染的微生物治理提供优良微生物资源，而且扩展了人们对芽孢杆菌生物学功能的认识。

Isolation of 1,3-dimethyl-2-imidazolidinone degrading bacteria and evaluation of its function

Background] 1,3-Dimethyl-2-imidazolidinone (DMI) is a nonproton solvent with strong polarity, which remains steadily in waste water from production and application processes and causes potential hazard to people''s health. Objective] Acquisition of DMI degrading microbial strains. Methods] Isolation and screen of DMI degrading microbial strains from the soil of manufacture plant by DMI tolerance assay. The strains were identified by morphological features and 16S rRNA gene sequence analysis. Results] Two putative Bacillus velezensis strains tolerant to 5% (V/V) DMI were isolated from the soil samples, which were designated as DT-1 and DT-2 respectively. Both the whole cells and the cell-free extracts could reduce the DMI levels in the reaction systems. The degrading rates of whole cells and cell-free extract of strain DT-1 reached 48% and 68% respectively at 1% (V/V) DMI concentration. Conclusion] DMI degrading Bacillus strains were obtained, which provided a basis for microbial degradation of DMI in the polluted environments. Moreover, the results in this study expand our knowledge of the biological function of Bacillus.