Isolation, screening and quantification of Poly-β-hydroxybutyrate (PHB) from extreme halophilic Archaea

Abstract

The Archaea remain the most enigmatic of life’s three domains and halophiles constitute a very heterogeneous group of extremophiles in this domain. Due to their special characteristics, they have been suggested to hold potential for a variety of biotechnological applications such as production of enzymes, compatible solutes, degradation of toxic compounds and polymer production. The study aimed at efficient production and screening of thirteen haloarchael strains isolated from saltpans at Newport and Nari for their ability to produce PHB. The production by these strains was determined by the spectrophotometric method and results suggest that all the thirteen haloarchaeal isolates exhibited the ability to produce PHB, though to a varying extent. It was found that PHB yield ranged from 0.01-1.17%. All the thirteen isolates were then subjected to secondary screening for examining DCW, PHB production and yield as a function of incubation time. The maximum PHB production was by four haloarchaeal isolates viz., Haloarcula sp. 1 (3.77%), Halorubrum sp. 2 (2.07%), Halobaculum sp. (2.02%) and Halobacterium salinarum (0.75%). The growth almost became constant after its optimum period whereas, PHB yield declined.