Abstract:

p-cresol is a typical aromatic phenolic pollutant found in wastewater from the coal chemical, petrochemical, pharmaceutical, and pesticide industries. It is essential to understand the microbial metabolic pathways of p-cresol for the design and optimization of microbial wastewater treatment systems. Despite the microbial degradation pathways of p-cresol have been reported, the metabolic diversity within a single strain remains unknown. This study focused on the diverse metabolic pathways for p-cresol biodegradation in a p-cresol degrading bacterium Acinetobacter sp. L1. A total of nineteen p-cresol metabolic intermediates were detected and identified in the culture of strain L1, and three possible degradation pathways of p-cresol were proposed on the basis of LC-MS analysis. The methyl oxidation, the aromatic ring hydroxylation and the phosphorylation of the hydroxyl group were possible together involved in p-cresol biodegradation by strain L1. Moreover, under optimal degradation conditions at 35 ℃ and pH=7.0, strain L1 could metabolize 22.5% of 8 mg/L p-cresol in minimal medium within 14 d, and could degrade 90% of 10 mg/L p-cresol in wastewater containing cresol within 5 d.

Key words: p-cresol, Acinetobacter sp., biodegradation, metabolites, metabolic pathway

摘要：

对甲酚是煤化工、石油化工、制药和农药工业废水中的一种典型芳香族酚类污染物，深入了解对甲酚微生物代谢途径对于微生物废水处理系统的设计和优化至关重要。目前，对甲酚的微生物降解途径已有报道，但单个菌株内对甲酚代谢途径的多样性却知之甚少。以分离鉴定的一株对甲酚降解菌Acinetobacter sp. L1为研究对象，采用液质联用技术检测并鉴定了19种对甲酚的代谢产物，这些代谢产物支持菌株L1可能同时通过甲基氧化、芳环羟化和芳环羟基磷酸化途径降解对甲酚；在35 ℃和pH=7.0的最适降解条件下，菌株L1在14 d内对无机盐培养液中8 mg/L对甲酚的降解率为22.5%，在5 d内对实际废水中10 mg/L的对甲酚实现了90%的降解率。

关键词: 对甲酚, 不动杆菌属, 降解, 代谢产物, 降解途径

CLC Number: 

• X703

• X52