Purification and Properties of an Extracellular Polyhydroxybutyrate Depolymerase from Pseudomonas mendocina DSWY0601

作     者：WANG Yan LI Fan WANG Zhan-yong LIU Dong-bo XIA Hong-mei LIU Ling-fei CHEN Shan 

作者机构：School of Life SciencesNortheast Normal UniversityChangchun 130024P.R.China School of Environmental and Biological EngineeringLiaoning Shihua UniversityFushun 113001P.R.China 

出 版 物：《Chemical Research in Chinese Universities》 (高等学校化学研究（英文版）)

年 卷 期：2012年第28卷第3期

页      面：459-464页

核心收录：

学科分类：081704[工学-应用化学] 07[理学] 08[工学] 070305[理学-高分子化学与物理] 071005[理学-微生物学] 0710[理学-生物学] 1007[医学-药学(可授医学、理学学位)] 100705[医学-微生物与生化药学] 0817[工学-化学工程与技术] 080501[工学-材料物理与化学] 0805[工学-材料科学与工程（可授工学、理学学位）] 0703[理学-化学] 10[医学] 

基　　金：Supported by the National Natural Science Foundation of China (Nos.31100046 31100099) 

主　　题：Polyhydroxybutyrate(PHB) PHB depolymerase Pseudomonas mendocina Polyhydroxyalkanoate(PHA) 

摘      要：An extracellular polyhydroxybutyrate（PHB） depolymerase was purified to homogeneity from the culture supernatant of a PHB-degrading bacterium, Pseudomonas mendocina DSWY0601, which was isolated from brewery sewage for the ability to form clear zones on the PHB mineral agar plates. The molecular weight of the purified PHB depolymerase as determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis（SDS-PAGE） was ap- proximately 59800 at the optimal temperature and pH value being 50 ℃ and 8.5, respectively. PHB depolymerase was stable in a temperature range of 20--50 ℃ and sensitive to pH value within a pH range of 8.0-9.5. PHB depo- lymerase degraded poly-3-hydroxybutyrate-co-4-hydroxybutyrate（P3/4HB） and poly-3-hydroxybutyrate-co-3- hydroxyvalerate（PHBV） but did not degrade poly（lactic acid）（PLA）, poly（butylene succinate）（PBS） or poly- （caprolactone）（PCL）. PHB depolymerase was sensitive to phenylmethylsulfonyl fluoride（PMSF）, H202 and SDS. The main product after enzymatic degradation of PHB was indentified as 3-hydroxbutyrate monomer（3HB） by mass spectrometric analysis, suggesting that PHB depolymerase acted as an exo-type hydrolase. Analysis ofphaZpm gene reveals that PHB depolymerase is a typical denatured short-chain-length PHA（dPHAscL, PHA=polyhydroxyalkanoate） depolymerase containing catalytic domain, linker and substrate-binding domain.