典型短链烯烃的微生物降解转化机制研究进展

Research progress in the microbial degradation and transformation mechanisms of typical short-chain alkenes

摘要:

烯烃是一类含有碳-碳双键的不饱和烃类物质，广泛存在于自然过程和人为活动中。结构的差异导致不同烯烃具有不同的功能和特点。例如，乙烯是植物生长发育的基本调节物质；丙烯是工业制造聚丙烯和丙烯腈的关键原料；1,3-丁二烯主要用于合成橡胶和塑料，是一级致癌物；而异戊二烯是排放产量最大的非甲烷生物源挥发性有机物，对全球气候变化具有重要影响。微生物在烯烃的降解与转化中起着关键作用，研究这些微生物的作用有助于更好地理解烯烃在环境中的寿命、归趋及影响，这对于地球化学循环的研究及污染场地的修复具有重要意义。本文首先总结了5种典型短链烯烃(乙烯、丙烯、丁烯、1,3-丁二烯、异戊二烯)的微生物好氧与厌氧的降解和转化的机制，发现烯烃降解菌株的分布十分广泛，涵盖多个微生物分类，但微生物对不同烯烃的降解具有一定的共性。例如，在有氧条件下，短链烯烃通常首先被烯烃单加氧酶氧化，生成的产物随后与辅酶M或谷胱甘肽结合后，经过一系列酶促转化后最终进入微生物的中心代谢途径。而在无氧条件下，短链烯烃则可被产乙酸菌、产甲烷菌等微生物通过加氢反应进行转化。通过总结微生物对常见短链烯烃的降解和转化机制，旨在强调微生物在烯烃污染场地生物修复中的重要作用，并加深对微生物在地球化学循环和全球气候变化中贡献的理解，以此推动可持续发展和资源的有效利用。

关键词:微生物降解;短链烯烃;乙烯;异戊二烯;1,3-丁二烯;厌氧微生物

Abstract:

Alkenes, unsaturated hydrocarbons with carbon-carbon double bonds, are emitted in large quantities through both natural and anthropogenic processes. These compounds exhibit diverse functions and characteristics due to variations in their structures. Ethylene, for instance, is a crucial regulator of plant growth, while propylene serves as the primary raw material for the industrial production of polypropylene and acrylonitrile. However, some alkenes pose environmental and health risks. 1,3-butadiene, used in the manufacturing of synthetic rubber and plastics, is a known carcinogen. Isoprene, the most abundant non-methane biogenic volatile organic compound, significantly impacts global climate change. Microorganisms play a critical role in the environmental fate of alkenes by mediating their degradation and transformation. Understanding these microbial processes is essential for elucidating the flow of alkenes in the environment and their impacts on geochemical cycles. Furthermore, this knowledge holds great promise for the bioremediation of alkene-contaminated sites. This paper comprehensively reviews the aerobic and anaerobic microbial degradation and transformation mechanisms of five prevalent short-chain alkenes: ethylene, propylene, butene, 1,3-butadiene, and isoprene. Alkene-degrading strains are widely distributed across multiple phyla. Despite the structural differences among alkenes, their microbial degradation pathways share common features. For example, under oxic conditions, short-chain alkenes are typically oxidized by alkene monooxygenases, the products of which are then conjugated with coenzyme M or glutathione. After a series of enzymatic transformations, they ultimately enter the central metabolic pathways of microorganisms. Under anoxic conditions, short-chain alkenes can be transformed by acetogens, methanogens, and other microorganisms via hydrogenation reactions. By elucidating the mechanisms of microbial degradation and transformation of common short-chain alkenes, this study emphasizes the crucial role of microorganisms in bioremediation efforts at alkene-contaminated sites. Moreover, it contributes to a deeper understanding of microbial influences on geochemical cycles and global climate change, ultimately promoting sustainable development and efficient resource utilization.

Key words:microbial degradation;short-chain alkenes;ethylene;isoprene;1,3-butadiene;anaerobic microorganisms