聚乳酸(PLA)生物降解的研究进展

Progress on biodegradation of polylactic acid—A Review

聚乳酸(Polylactic Acid,PLA)是一种新兴的,由可再生资源——乳酸聚合而成的高分子聚酯。因为其具有优良的物理化学性能、生物相容性及生物可降解性,且对环境及人体无毒害作用,而被认为是一种最具潜力的绿色生物塑料。作为环境友好材料,聚乳酸日益受到人们的重视。基于可循环利用的考虑,其生物降解的研究也成为当前研究的一个重要方面。本文综述了PLA生物降解领域的相关进展,包括降解的微生物学、相关酶学及分子生物学,系统阐述了PLA可能的生物降解机制,并对生物系统处理PLA废弃物的可行性进行了探讨。

Polylactic acid is a high molecular-weight polyester made from renewable resources such as corn or starch. It is a promising biodegradable plastic due to its mechanical properties, biocompatibility and biodegradability. To achieve natural recycling of polylactic acid, relative microorganisms and the underlying mechanisms in the biodegradation has become an important issue in biodegradable materials. Up to date, most isolated microbes capable of degrading polylactic acid belong to actinomycetes. Proteases secreted by these microorganisms are responsible for the degradation. However, subtle differences exist between these polylactic acid degrading enzymes and typical proteases with respect to substrate binding and catalysis. Amino acids relative to catalysis are postulated to be highly plastic allowing their catalytic hydrolysis of polylactic acid. In this paper we reviewed current studies on biodegradation of polylactic acid concerning its microbial, enzymatic reactions and the possible mechanisms. We also discussed the probability of biologically recycling PLA by applying highly efficient strains and enzymes.