摘要
软骨藻酸(domoicacid,DA)是由拟菱形藻有害藻华产生的一种强烈的海洋神经毒素,严重威胁人类健康和生态安全.DA通常随着海洋雪快速沉降到底栖厌氧环境,但目前关于DA厌氧生物转化行为知之甚少.考察了海洋富集菌群BH1对DA的厌氧共代谢生物转化.结果表明,菌群BH1对1mg/LDA厌氧生物转化率可达80%,降解符合准一级动力学反应,DA生物转化速率常数为0.0992d^(-1).通过高效液相色谱串联高分辨质谱法(HPLC-HRMS/MS)鉴定DA产物,并推测了DA厌氧生物转化途径,包括生物异构化、脯氨酸环脱氢以及脱羧途径,表明厌氧生物转化是DA的重要脱毒过程.16SrRNA扩增子测序分析结果表明,DA的加入导致微生物菌群物种组成发生明显变化.优势菌属瘤胃解蛋白质菌属和脱硫弧菌属对DA具有良好的耐受性,可能是潜在的DA厌氧降解菌.研究可为全面了解DA在厌氧环境中的行为和归趋提供理论依据.
Domoic acid(DA) is a powerful marine neurotoxin generated by harmful algal blooms of Pseudo-nitzschia diatoms and severely threatens human health and ecosystem safety. Commonly, DA packaged in marine snow rapidly transfers to the benthic anaerobic environment, and current knowledge on anaerobic biotransformation behavior of DA is very limited. Anaerobic cometabolic biotransformation of DA by a newly enriched marine consortium BH1 is investigated. The results show that more than 80% of DA with concentration of 1 mg/L is biotransformed with pseudo-first-order kinetic reaction under anaerobic conditions, and biotransformation rate constant for DA is 0.099 2 d^(-1). Furthermore, based on DA metabolites identified by high performance liquid chromatography-high-resolution orbitrap mass spectrometry(HPLC-HRMS/MS), DA anaerobic biotransformation pathways are proposed, including bioisomerization, proline ring dehydrogenation and decarboxylation pathways, indicating anaerobic biotransformation is an important detoxification process for DA. 16 S rRNA amplicon sequencing analysis reveals that microbial community composition has significant difference after DA addition. The genera Proteiniclasticum and Desulfovibrio are dominant during DA anaerobic biotransformation, which may jointly contribute to the elevated bacterial community resistance and biotransformation to DA. The study could provide a theoretical basis for comprehensive understanding of behavior and fate for DA in anaerobic environments.
作者
杜苗苗
金媛
昝帅君
顾晨
张宇晴
王竞
DU Miaomiao;JIN Yuan;ZAN Shuaijun;GU Chen;ZHANG Yuqing;WANG Jing(School of Environmental Science and Technology,Dalian University of Technology,Dalian 116024,China;National Marine Environmental Monitoring Center,Dalian 116023,China)
出处
《大连理工大学学报》
CAS
CSCD
北大核心
2022年第6期551-558,共8页
Journal of Dalian University of Technology
基金
国家自然科学基金资助项目(42177375)。
关键词
软骨藻酸
厌氧生物转化
降解途径
微生物群落
domoic acid
anaerobic biotransformation
degradation pathway
microbial community
