College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing, 210095, China.
College of Geographic and Biologic Information Nanjing University of Posts and Telecommunications, Nanjing, 210023, China.
Sci Rep. 2017 Jul 28;7(1):6795. doi: 10.1038/s41598-017-06338-1.
2-hydroxy-1,4 naphthoquinone (lawsone) is widely used and induces environmental pollutions during its production and application. In the present study, a lawsone-degrading bacterium strain, LH-3 was successfully isolated from the activated sludge. Based on the 16S rRNA gene analysis, the strain LH-3 phylogenetically belonged to the Pseudomonas taiwanensis. It could degrade 200 mg L lawsone completely in 9 h with an inoculum quantity of 1% (v/v). The effects of environmental conditions on the degradation process and the degradation pathway were systematically investigated. LH-3 could maintain its high degradation efficiency under high salt condition. The identified intermediates of salicylic acid, 2-hydroxy-4-oxo-chroman-2-carboxylic acid, and catechol elucidated the potential degradation pathway. Furthermore, the immobilized LH-3 strain cells prepared with alginate gel and biochar performed excellent stability in nine successive degradation runs. It could sucessfully survive in laboratory scale sequencing batch reactor and become to be the dominant species. This study clearly revealed that LH-3 could serve as an attractive candidate for the microbial remediation of lawsone-containing wastewater.
2-羟基-1,4 萘醌（龙葵素）在生产和应用过程中广泛使用，并造成环境污染。本研究从活性污泥中成功分离出一株龙葵素降解菌 LH-3。基于 16S rRNA 基因分析，菌株 LH-3 系统发育上属于台湾假单胞菌。在接种量为 1%（v/v）的条件下，9 小时内可完全降解 200mg/L 的龙葵素。系统研究了环境条件对降解过程和降解途径的影响。LH-3 能够在高盐条件下保持较高的降解效率。鉴定出的水杨酸、2-羟基-4-氧代色原-2-羧酸和儿茶酚中间产物阐明了潜在的降解途径。此外，用海藻酸钠凝胶和生物炭制备的固定化 LH-3 菌株细胞在九次连续降解运行中表现出优异的稳定性。它可以在实验室规模的序批式反应器中成功存活并成为优势物种。这项研究清楚地表明，LH-3 可以作为一种有吸引力的候选微生物修复含龙葵素废水的方法。
