Insight into Biodegradation of Triclosan by a Newly Isolated Strain Bacillus Sp. Dl4: Performance Evaluation, Rsm Analysis and Metagenomics Analysis

Abstract

The overuse of triclosan (TCS) due to its broad spectrum is detrimental to ecological safety and human health. An aerobic bacterium, Bacillus sp. DL4, was isolated with the capability of TCS biodegradation, and the TCS biodegradation efficiency reached nearly 100% at 96 h under the optimized conditions obtained by RSM analysis (35°C, 138.73rpm, initial pH 7.31, and 5% strain DL4). TCS biodegradation kinetics and characteristic of strain DL4 determined the factors that affect TCS biodegradation. TCS was used as the sole carbon source for DL4 growth, but the growth rate decreased when the TCS concentration exceeded 20mg/L, it may be due to the toxic effects of TCS. Functional annotations of GO and KEGG indicated that a large number of functional genes were involved in and facilitated TCS degradation by DL4. Three metabolite products were detected and identified during the biodegradation process by LC-MS, and a possible degradation pathway was tentatively hypothesized. This study demonstrated that Bacillus sp. DL4 can be used for the efficient treatment of TCS polluted water.

Keywords: Bacillus sp., Triclosan, RSM analysis, Biodegradation, Metabolites