Osamu HIRUTA
   Department   Kumamoto Health Science University  ,
   Kumamoto Health Science University Graduate School  Division of Health Sciences, Graduate School of Health Sciences
   Position  
Language English
Publication Date 1998
Type
Peer Review Peer reviewed
Title Enzymatic degradation of poly(hydroxyalkanoate) by Corynebacterium aquaticum IM-1 isolated from activated sludge
Contribution Type
Journal Polymer Degradation and Stability
Journal TypeAnother Country
Volume, Issue, Page 61(2)
Author and coauthor Masako Ito, Yuji Saito, Toshio Matsunobu, Osamu Hiruta, Hidehi Takebe
Details Poly(4-hydroxybutyric acid)-degrading bacteria were isolated from activated sludge. One strain was selected, which was identified as Corynebacterium aquaticum. The strain C. aquaticum IM-1 excreted an extracellular poly(hydroxyalkanoate) [PHA]depolymerase and grew on 4-hydroxybutyric acid as the sole carbon source. The molecular weight of the purified PHA depolymerase was determined as approximately 33000 Da by SDS-PAGE. The optimum activity of the depolymerase was observed at pH 6.5 and 40 °C. and N-terminal sequences of the depolymerase were not applicable to the well-known enzymes. The enzymatic degradation of polyesters was studied by the erosion rate of solution-cast films of poly(3-hydroxybutyrate-co-4-hydroxybutyrate) and poly(ω-hydroxyalkanoate) of different chain lengths (C3–C6). The water-soluble products of poly(3-hydroxybutyrateco-97mol%4-hydroxybutyrate) film were revealed by 1H NMR and FAB-MS analysis, and the main product was the dimer of 4-hydroxybutyric acid.