β-ketothiolase in production of poly β-hydroxybutyrate [PHB] by extremely Halophilic archaea Haloarcula sp., its optimization and purification

Abstract

One of the eye catching subjects in the scientific community is environmental friendly and economic production of bioplastics [poly β-hydroxybutyrate (PHB)]. Most of the research on PHB using microbes has been directed towards the processes which are costly. However, PHB production from Halophilic archaea which are extremophiles have been completely overlooked. Halophilic archaea offer certain advantages as requiring non sterile conditions for growth which makes the process completely cost effective. The present work aims at PHB production by Halophilic archaea with optimization of the enzyme β-ketothiolase as a primary precursor for PHB production and its purification. Amongst the three key enzymes for PHB biosynthesis, β-ketothiolase is a primary enzyme required for PHB synthesis. The information on β-ketothiolase from the archaeal domain, especially from Haloarchaea, is very sparse. Hence the present study is directed towards detection of β-ketothiolase from Haloarcula sp., its optimization and purification. Optimization had been carried out by using fifteen different parameters. As a result of optimization, maximum enzyme activity (0.047 Eu/ml) was exhibited by Haloarcula sp. which is also the maximum PHB producer