聚乳酸材料在不同土壤环境中生物降解的菌群结构分析

Microbial diversity and community structure in biodegradation of poly(lactic) acid(PLA) in different soil environments

【目的】评价聚乳酸(Polylactic acid,PLA)材料在不同土壤环境中自然降解的效果,通过对3种不同土壤菌群结构的分析,找到能够对聚乳酸材料有降解作用的优势菌群。【方法】通过扫描电镜、断裂拉伸强度和CO2释放量测定来评价3种土壤对PLA材料的降解效果,并运用高通量测序技术,对3种土壤细菌群落进行基因组测序分析,检测3个样本细菌群落的差异性。【结果】PLA材料在沼泽地、芒果林地和稻田中的生物降解率分别为13.7%、10.6%和4.5%。3种土壤的样品分别获得11 110、11 236和8 848个OTU,共涉及细菌域的9个主要门和16个主要科。其中沼泽地土壤的微生物群落丰富度和多样性最高,稻田土壤最低。【结论】结合土壤的降解效果,土壤中生物群落丰富度和多样性越高,对PLA材料的降解作用越好。同时变形菌门(Proteobacteria)和拟杆菌门(Bacteroidetes)是降解聚乳酸材料的优势菌群。在科水平上,黄杆菌科(Flavobacteriaceae)、丛毛单胞菌科(Comamonadaceae)和噬纤维菌科(Cytophagaceae)的微生物对聚乳酸材料的降解最有潜力。这一研究成果为能有效降解聚乳酸材料的微生物资源的开发提供了理论依据。

Objective] To evaluate microbial biodegradation, three kinds of soil, swamp, orchard and farmland were selected. And to find dominant microbe that can degrade the PLA, we characterize the different of abundance, diversity and community structure of the three microbial strain. [Methods] The residual degraded PLA were analyzed by SEM, the tensile strength, elongation at break and CO2 generation analysis. And characterize the different of abundance, diversity and community structure of the three kinds of soil by using pyro-sequencing. [Results] The PLA biodegradation in swamp, orchard, and farmland were 13.7%, 10.6%, 4.5%, respectively. The taxonomic analysis of the pyro-sequencing data was grouped into 9 different phyla and 16 different class. [Conclusion] By comparing the microbial community of three kinds of soil, Proteobacteria and Bacteroidetes were the two most dominant phylato degrade the PLA. Flavobacteriaceae, Comamonadaceae and Cytophagaceae were the three most dominant class to degrade the PLA. The result provides scientific basis for the study of microbial diversity and community structure in biodegradation of PLA.