New Insights into Lincomycin Biodegradation by Conexibacter Sp. Ld01 : Genomics Characterization, Biodegradation Kinetics and Pathways

An aerobic lincomycin-degrading bacterial strain Conexibacter sp. LD01, belonging to the phylum of Actinobacteria, was isolated from activated sludge. Both second-generation and third-generation sequencing technologies were applied to uncover the genomics characterization and high-quality genome with 99.2% of completeness and 2.2% of contamination was obtained. The biodegradation kinetics of lincomycin fits well with modified Gompertz model (R 2 ≥ 0.97). Conexibacter sp. LD01 could subsist lincomycin as the sole carbon, nitrogen and energy sources. When 500 mg/L of glucose was added as co-substrate, the biodegradation rate was improved significantly, while the addition of 500 mg/L sodium pyruvate showed slightly inhibition. Ammonia nitrogen was the best nitrogen source for Conexibacter sp. LD01 to grow and degrade lincomycin. Totally, 17 metabolic products consisting of 9 novel products were detected and five biodegradation pathways, including N-demethylation, breakage of amido bond, sulfoxidation, oxidation of pyrrolidine ring and propylamino chain were proposed. ermE , amiA2 and amiB2 were potentially functional genes relating to N-demethylation and breakage of amido bond, respectively. This study significantly expands our understanding on the functional microorganisms for lincomycin biodegradation at phylum level and provides comprehensive insights into biodegradation mechanism of lincomycin