Identification and characterization of novel poly(<Emphasis Type="SmallCaps">dl</Emphasis>-lactic acid) depolymerases from metagenome |
| |
Authors: | Daisuke Mayumi Yukie Akutsu-Shigeno Hiroo Uchiyama Nobuhiko Nomura Toshiaki Nakajima-Kambe |
| |
Institution: | Graduate School of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Ibaraki, Japan. |
| |
Abstract: | Many poly(lactic acid) (PLA)-degrading microorganisms have been isolated from the natural environment by culture-based methods, but there is no study about unculturable PLA-degrading microorganisms. In this study, we constructed a metagenomic library consisting of the DNA extracted from PLA disks buried in compost. We identified three PLA-degrading genes encoding lipase or hydrolase. The purified enzymes degraded not only PLA, but also various aliphatic polyesters, tributyrin, and p-nitrophenyl esters. From their substrate specificities, the PLA depolymerases were classified into an esterase rather than a lipase. Among the PLA depolymerases, PlaM4 exhibited thermophilic properties; that is, it showed the highest activity at 70 degrees C and was stable even after incubation for 1 h at 50 degrees C. PlaM4 had absorption and degradation activities for solid PLA at 60 degrees C, which indicates that the enzyme can effectively degrade PLA in a high-temperature environment. On the other hand, the enzyme classification based on amino acid sequences showed that the other PLA depolymerases, PlaM7 and PlaM9, were not classified into known lipases or esterases. This is the first report on the identification and characterization of PLA depolymerase from a metagenome. |
| |
Keywords: | Metagenome Depolymerase Esterase Biodegradable plastic Polylactide Lipase |
本文献已被 PubMed SpringerLink 等数据库收录! |
|