土壤中高环多环芳烃微生物降解的研究进展

Recent Advances in Biodegradation of High-molecular Weight PAHs in Soil

摘要:

微生物修复是去除土壤中多环芳烃(PAHs)的主要措施。本文以微生物修复PAHs污染土壤的理论基础及其难点为主线, 全面综述了土壤中高环PAHs的微生物降解机理。近年来, 富集分离得到的以高环PAHs为唯一碳源和能源的优势降解菌逐渐增多, 其中, 主要是代谢降解四环PAHs的单株降解菌, 一些降解菌还能以共代谢方式利用五环PAHs。高环PAHs污染土壤修复的一个难点是其低生物可利用性, 微生物通过释放生物表面活性剂、形成生物膜以及分泌胞外多糖提高高环PAHs的生物可利用性, 从而加速其降解。真菌和细菌联合作用能增强污染土壤实地修复的效果。因此, 通过微生物修复技术来去除土壤中PAHs具有环境友好性、经济适用性以及可持续应用性。

Abstract:

Bioremediation is a promising technique for eliminating polycyclic aromatic hydrocarbons (PAHs) from contaminated soil. The microbial biodegradation mechanisms of high-molecular weight polycyclic aromatic hydrocarbons (HMW)-PAHs in soils were reviewed with special emphasis on the principles and difficulties of bioremediation of PAH-contaminated soil. Some genera of microorganisms able to utilize HMW-PAHs as the sole carbon and energy source have been isolated. Most of them are mainly single strains which can metabolically degrade four-ring PAHs, and some of them can co-metabolize five-ring PAHs. Low bioaccessibility of HMW-PAHs is a difficulty in the bioremediation of contaminated soil. Release of surfactants, formation of biofilms and production of extracellular polymeric substances by some of the PAH-degrading bacteria can enhance the bioaccessibility of PAHs and therefore accelerate the biodegradation. Combination of bacteria and fungi can increase their in situ bioremediation efficiency. Therefore, bioremediation is an environmentally friendly, economic suitable and sustainable technique for eliminating PAHs from soil.