Purification and Properties of Poly(3-hydroxybutyrate-co-hydroxyvalerate) Depolymerase from Streptomyces sp.

YASHCHUK O; MIYAZAKI SS

Congreso; XLII Reunión Anual de la Sociedad Argentina de Investigación en Bioquímica y Biología Molecular; 2006

A bacterial strain capable of degrading poly(3-hydroxybutyrate-co-hydroxyvalerate) (PHBV) was isolated from a soil simple. This organism, which was identified as Streptomyces sp., secreted PHBV depolymerase into the culture fluid when it was cultivated on PHBV. The culture supernatant containing extracellular PHBV depolymerase was concentrated 95-fold by high pressure ultrafiltration (Stirred Ultrafiltration Cells Modes 8200 Device, Milllipore) through a YM 10 membrane then was purified to electrophoretic homogeneity by ion exchange column chromatography on DEAE-Sephadex A-50 and gel filtration on Sephadex G-150. The molecular mass of the PHBV depolymerase was estimated to be 24.0 kDa by SDS-PAGE  technique on 12% gel. The maximum activity was observed near pH 7.0 and 32ºC. The enzyme retained full activity between pH 4 and 6, and lost activity at temperatures above 45ºC. The activity of the enzyme treated with various metal ions and chemical reagent were assayed. Inhibition by these compounds showed dependence on metal ions and both sulfhydril and disulfide bonds. It was significantly inactivated by 1 mM Tween-80 and not inhibited by ethylenediaminetetraacetic acid.