Gordonia sp. H52对合成孕激素左炔诺孕酮的降解特性

Degradation characteristics of levonorgestrel by Gordonia sp. H52

摘要:

【背景】合成孕激素左炔诺孕酮因其具有内分泌干扰效应而受到广泛关注，微生物在污染物降解和环境修复方面具有广泛的应用潜力，但目前对左炔诺孕酮在微生物降解中的特性和机理认识仍然有限。【目的】加速左炔诺孕酮污染的治理，亟须分离获取左炔诺孕酮的高效降解菌并探究其降解机制。【方法】以养殖场的废水为接种物，选育出对左炔诺孕酮具有高效降解功能的菌株；基于菌株形态特征、生理生化特征及16S rRNA基因序列分析，确定菌株所属的分类层级；进而通过对左炔诺孕酮的降解动力学进行探究，同时结合菌株全基因组分析及降解产物谱图，确定菌株对左炔诺孕酮的降解特性。【结果】分离获得与Gordonia cholesterolivorans Chol-3的16S rRNA基因序列相似性达99.0%的Gordonia sp. H52，该菌株在18 h内可以实现对0.5 mg/L左炔诺孕酮的100%去除。液相色谱与串联质谱联用分析结果发现，菌株H52降解左炔诺孕酮后产生5种代谢产物，侧链炔基的裂解及脱羟基是该菌降解左炔诺孕酮的主要途径。该菌株还可以同时促进水体中多种合成孕激素的去除，使左炔诺孕酮的去除率由0%提高到91.06%、醋酸炔诺酮的去除率由37%提高到100%、孕二烯酮的去除率由0%提高到88.87%。【结论】Gordonia sp. H52对合成孕激素左炔诺孕酮表现出高效的降解特性，为合成孕激素污染水体的治理与修复提供了宝贵的菌种资源和理论参考。

关键词:合成孕激素;左炔诺孕酮;Gordonia sp. H52;降解特性

Abstract:

[Background] The synthetic progestin levonorgestrel has attracted wide attention due to its endocrine-disrupting effects. Microorganisms demonstrate extensive potential in pollutant degradation and environmental remediation. However, the characteristics and mechanisms of levonorgestrel degradation by microorganisms remain poorly understood. [Objective] To isolate an efficient levonorgestrel-degrading strain and explore its degradation mechanism for the remediation of levonorgestrel pollution. [Methods] We isolated a strain capable of efficiently degrading levonorgestrel from aquaculture wastewater and identified the strain based on its morphological, physiological, and biochemical characteristics and the 16S rRNA gene sequence. The degradation characteristics of the strain for levonorgestrel were investigated by whole genome analysis, degradation kinetics, and analysis of the degradation product spectrum. [Results] Gordonia sp. H52 was isolated, which had 99.0% homology of the 16S rRNA gene sequence compared with Gordonia cholesterolivorans Chol-3. This strain completely removed 0.5 mg/L levonorgestrel within 18 h. Liquid chromatography-tandem mass spectrometry revealed that Gordonia sp. H52 produced five metabolites during the degradation process of levonorgestrel, primarily through the cleavage of the side chain and hydroxy group. Furthermore, the strain facilitated the removal of various synthetic progestins in water, increasing the removal rates of levonorgestrel from 0% to 91.06%, acetylene norethindrone from 37% to 100%, and gestodene from 0% to 88.87%. [Conclusion] Gordonia sp. H52 demonstrates high degradation efficiency for levonorgestrel. This study provides valuable microbial resources and theoretical references for the treatment and remediation of water contamination caused by synthetic progestins.

Key words:synthetic progestin;levonorgestrel;Gordonia sp. H52;degradation characteristics