Purification of β-ketothiolase from halophilic archaea haloarcula sp.1 isolated from Bhavnagar coast, Gujarat, India.

Abstract

Members of the Archaeal family have been determined to accumulate Poly (3-hydroxybutyrate) (PHB) during their growth. A total of 13 extremely Halophilic Archaeal isolates designated as NPW-1 to NPW-13 were capable of accumulating large amounts of PHB. Out of which best four isolates were selected from enzyme assay. Since measurements of enzyme activities related to Archaeal PHB biosynthesis have never been achieved, we investigated the first enzyme of PHB biosynthesis in Haloarcula sp.1 i.e., β-ketothiolase. Crude extracts of strain cultivated under accumulating conditions showed maximum β-ketothiolase activity. β ketothiolase was partially purified by ammonium sulfate fractionation and highest activity was obtained in 60% saturation fraction. This is the first description of an archaebacterial β-ketothiolase . Silver staining of the purified enzyme (fraction 8) with SDS – PAGE showed that enzyme subunited molecular weight putatively identified was 45 kDa.