一株磺胺喹噁啉降解菌株Aspergillus sp.S-3的分离、鉴定及其降解代谢途径  

Isolation and characterization of a sulfaquinoxaline-degrading strain Aspergillus sp.S-3 and its degradation pathway

作　　者：陈雪婷 张玉平 刘菁华 CHEN Xueting;ZHANG Yuping;LIU Jinghua(Shanghai Fisheries Research Institute(Shanghai Fisheries Technical Promotion Station),Shanghai 200433,China)

机构地区：[1]上海市水产研究所(上海市水产技术推广站),上海200433

出　　处：《应用与环境生物学报》2024年第5期1022-1030,共9页Chinese Journal of Applied and Environmental Biology

基　　金：上海市科技兴农重点攻关项目(2020-02-08-00-07-F01483);国家自然科学基金项目(31900097);上海市自然科学基金面上项目(20ZR1450800)资助。

摘　　要：磺胺喹噁啉(SQX)在集约化的养殖业中应用广泛,其残留威胁生态系统和人体健康,目前关于微生物纯培养物降解SQX的研究较少.从养殖池塘底泥样品中分离到一株SQX降解菌株S-3,通过形态学特征和ITS序列系统发育分析将其鉴定为曲霉属(Aspergillus sp.).单因素实验表明,菌株S-3的最佳生长和降解温度及pH分别为30℃和7.0,降解最佳接种量为1%-5%.在此条件下,菌株S-3对初始浓度为0.8-24mg/L的SQX具有较高的降解率(72h降解率均在83.0%以上).菌株S-3还可以降解磺胺邻二甲氧嘧啶和磺胺异恶唑,降解率分别为78.5%和65.5%.通过超高效液相色谱串联高分辨率电喷雾电离质谱仪鉴定了菌株S-3降解SQX生成的6种代谢产物,并据此推测菌株S-3分别采用分子内SO2的脱除、脱氨羟基化以及喹噁啉基的羟基化策略开启SQX的降解.采用Toxicity Estimation Software Tool(T.E.S.T.)软件评估了降解产物的毒性,结果表明其急性毒性、发育毒性和致突变性的毒性分级区间整体上呈现减毒趋势.斑马鱼攻毒试验初步表明菌株S-3对水生生物的安全性较高.本研究获得一株高效安全的SQX降解菌株Aspergillus sp.S-3,为环境污染的微生物修复提供菌株资源和理论依据.(图8表4参34)Sulfaquinoxaline(SQX)is widely used in intensive livestock and poultry farming;however,its residues pose a threat to ecosystems and human health.Microbial degradation of SQX in pure culture has not been widely examined.In this study,a fungus capable of degrading SQX was isolated from pond sediment using traditional methods.The isolate,designated S-3,was identified as a member of the genus Aspergillus through morphological observations and internal transcribed spacer sequence analysis.The optimal conditions for growth and degradation of SQX by strain S-3 were 30℃ and pH 7.0.The optimal inoculation amount for degradation was 1%-5%.Under these conditions,strain S-3 degraded large amounts of SQX,with over 83.0% degradation observed at 72 h at initial concentrations of 0.8-24 mg/L.Additionally,strain S-3 degraded sulfadoxine and sulfisoxazole at degradation rates of 78.5% and 65.5%,respectively.Six possible SQX degradation products were identified using ultra-high-performance liquid chromatography-tandem highresolution electrospray ionization mass spectrometry.Accordingly,three distinct metabolic pathways were tentatively proposed,which may be initiated by SO2 extrusion,hydroxylation deamination,or hydroxylation of the quinoxaline moiety.The Toxicity Estimation Software Tool predicted a reduction in the acute toxicity,developmental toxicity,and mutagenicity of the metabolites.Additionally,a zebrafish challenge test showed that strain S-3 was safe for aquatic organisms.Aspergillus sp.S-3 was isolated as an efficient and safe degrader of SQX,providing a valuable resource and theoretical basis for bioremediation of SQX residues in the environment.

关 键 词：磺胺喹噁啉 微生物降解 曲霉菌属 降解特性 代谢产物 

分 类 号：X172[环境科学与工程—环境科学]