Bacillus pumilus B12 Degrades Polylactic Acid and Degradation Is Affected by Changing Nutrient Conditions
Bacillus pumilus B12 Degrades Polylactic Acid and Degradation Is Affected by Changing Nutrient Conditions
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DOI：
10.3389/fmicb.2019.02548
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发表时间：
2019-11-22
影响因子：
5.2
通讯作者：
Reynolds, Todd B.
中科院分区：
文献类型：
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作者：
Bonifer, Kyle S.;Wen, Xianfang;Reynolds, Todd B.
聚乳酸（PLA）越来越多地用作传统石油基塑料的可生物降解替代品。在这项研究中，我们确定了一种新的农业土壤分离的短小芽孢杆菌（B12），能够降解高分子量聚乳酸薄膜。这种降解可以在短时间内检测到，通过释放L-乳酸单体在48小时内检测到显著降解，从而允许快速鉴定，非常适合实验变化。使用L-乳酸作为PLA膜降解的代理的有效性通过PLA膜中的刚性损失和断裂外观得到证实，分别通过原子力显微镜和扫描电子显微镜（SEM）测量。此外，我们已经观察到PLA降解响应于主要由核苷酸碱基腺嘌呤驱动的氨基酸/核苷酸补充剂混合物的剂量依赖性降低。此外，特定碳源的培养基的修正案提高PLA的降解速率，而磷酸盐和钾的添加降低PLA的降解速率由B。pumilus B12.这些结果表明B. pumilus B12根据环境条件调整其酶表达，这些条件可用于研究该过程的调节。总之，这项工作为研究生物降解塑料的细菌降解奠定了基础。
Poly-lactic acid (PLA) is increasingly used as a biodegradable alternative to traditional petroleum-based plastics. In this study, we identify a novel agricultural soil isolate of Bacillus pumilus (B12) that is capable of degrading high molecular weight PLA films. This degradation can be detected on a short timescale, with significant degradation detected within 48-h by the release of L-lactate monomers, allowing for a rapid identification ideal for experimental variation. The validity of using L-lactate as a proxy for degradation of PLA films is corroborated by loss of rigidity and appearance of fractures in PLA films, as measured by atomic force microscopy and scanning electron microscopy (SEM), respectively. Furthermore, we have observed a dose-dependent decrease in PLA degradation in response to an amino acid/nucleotide supplement mix that is driven mainly by the nucleotide base adenine. In addition, amendments of the media with specific carbon sources increase the rate of PLA degradation, while phosphate and potassium additions decrease the rate of PLA degradation by B. pumilus B12. These results suggest B. pumilus B12 is adapting its enzymatic expression based on environmental conditions and that these conditions can be used to study the regulation of this process. Together, this work lays a foundation for studying the bacterial degradation of biodegradable plastics.