Enzymatic characterization of a depolymerase from the isolated bacterium Variovorax sp C34 that degrades poly(enriched lactate-co-3-hydroxybutyrate)
Enzymatic characterization of a depolymerase from the isolated bacterium Variovorax sp C34 that degrades poly(enriched lactate-co-3-hydroxybutyrate)
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DOI：
10.1016/j.polymdegradstab.2014.08.013
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发表时间：
2014-12-01
影响因子：
5.9
通讯作者：
Taguchi, Seiichi
中科院分区：
文献类型：
--
作者：
Sun, Jian;Matsumoto, Ken'ichiro;Taguchi, Seiichi
聚[（R）-乳酸-co-（R）-3-羟基丁酸酯][P（LA-co-3 HB）]是一种生物基聚酯，具有透明和柔性特性，由携带LA聚合酶的工程菌产生。在这项研究中，我们试图从土壤样品中分离P（富集LA-co-3 HB）降解细菌，以确定具有降解这种新型聚合物的能力的酶。在约500个样品中，基于补充有乳化P（67摩尔% LA-co-3 HB）的培养基的浊度的降低，分离出表现出有效P（富集LA-co-3 HB）降解活性的革兰氏阴性菌04。根据16 S rDNA序列分析，该菌株属于Variovorax sp.。接下来，我们尝试从菌株C34的培养上清液中分离和纯化有助于聚合物降解的解聚酶。纯化的酶具有42 kDa的分子量，并表现出对P（67 mol% LA-co-3 HB）以及3 HB均聚物[P（3 HB）]的降解活性，但对LA均聚物（PDLA和PLLA）没有降解活性。另一方面，来自粪产碱菌T1的P（3 HB）的充分表征的解聚酶不降解P（67摩尔% LA-co-3 HB）、PDLA或PLLA。这一结果表明，新分离的解聚酶不同于A.粪便的(C)2014爱思唯尔有限公司版权所有。
Poly[(R)-lactate-co-(R)-3-hydroxybutyratel [P(LA-co-3HB)] is a biobased polyester with semitransparent and flexible properties produced in engineered bacteria carrying an LA-polymerizing enzyme. In this study, we attempted to isolate the P(enriched LA-co-3HB)-degrading bacteria from soil samples in order to identify enzymes with the capacity to degrade this new type of polymer. Among approximately 500 samples, the Gram-negative bacterium 04, which exhibited potent P(enriched LA-co-3HB)-degrading activity, was isolated based on the decrease in the turbidity of culture medium supplemented with emulsified P(67 mol% LA-co-3HB). Based on its 16S rDNA sequence, this isolated bacterium was identified as a member of Variovorax sp.. Next, we attempted to isolate and purify the depolymerase that contributes to the polymer degradation from the culture supernatant of strain C34. The purified enzyme had a molecular mass of 42 kDa and exhibited degradation activity towards the P(67 mol% LA-co-3HB) as well as 3HB homopolymer [P(3HB)], but not LA homopolymers (PDLA and PLLA). On the other hand, a well-characterized depolymerase of P(3HB) derived from Alcaligenes faecalis T1 did not degrade P(67 mol% LA-co-3HB), PDLA or PLLA. This result suggests that the newly isolated depolymerase differs from the P(3HB) depolymerase from A. faecalis. (C) 2014 Elsevier Ltd. All rights reserved.