Biodegradation of flonicamid by Ensifer adhaerens CGMCC 6315 and enzymatic characterization of the nitrile hydratases involved

Microbial Cell Factories

Neng-Dang Jiang¹  Yi-Jun Dai¹  Yun-Xiu Zhao¹  Ke-Xin Chen¹  Li Wang¹  Feng Ge²  Shi-Lei Sun³ 

[1] Jiangsu Key Laboratory for Microbes and Functional Genomics, Jiangsu Engineering and Technology Research Center for Industrialization of Microbial Resources, College of Life Science, Nanjing Normal University, 210023, Nanjing, People’s Republic of China;Nanjing Institute of Environmental Sciences, Ministry of Environmental Protection, 210042, Nanjing, People’s Republic of China;The Key Laboratory of Biotechnology for Medicinal Plants of Jiangsu Province and School of Life Science, Jiangsu Normal University, 221116, Xuzhou, People’s Republic of China;

关键词: Biodegradation;    Cell immobilization;    Ensifer adhaerens;    Enzymatic degradation;    Flonicamid;   

DOI  :  10.1186/s12934-021-01620-4

来源: Springer

【 摘 要 】

BackgroundFlonicamid (N-cyanomethyl-4-trifluoromethylnicotinamide, FLO) is a new type of pyridinamide insecticide that regulates insect growth. Because of its wide application in agricultural production and high solubility in water, it poses potential risks to aquatic environments and food chain.ResultsIn the present study, Ensifer adhaerens CGMCC 6315 was shown to efficiently transform FLO into N-(4-trifluoromethylnicotinoyl) glycinamide (TFNG-AM) via a hydration pathway mediated by two nitrile hydratases, PnhA and CnhA. In pure culture, resting cells of E. adhaerens CGMCC 6315 degraded 92% of 0.87 mmol/L FLO within 24 h at 30 °C (half-life 7.4 h). Both free and immobilized (by gel beads, using calcium alginate as a carrier) E. adhaerens CGMCC 6315 cells effectively degraded FLO in surface water. PnhA has, to our knowledge, the highest reported degradation activity toward FLO, Vmax = 88.7 U/mg (Km = 2.96 mmol/L). Addition of copper ions could increase the enzyme activity of CnhA toward FLO by 4.2-fold. Structural homology modeling indicated that residue β-Glu56 may be important for the observed significant difference in enzyme activity between PnhA and CnhA.ConclusionsApplication of E. adhaerens may be a good strategy for bioremediation of FLO in surface water. This work furthers our understanding of the enzymatic mechanisms of biodegradation of nitrile-containing insecticides and provides effective transformation strategies for microbial remediation of FLO contamination.

【 授权许可】

CC BY