The Isolation, Screening, and Characterization of Polyhydroxyalkanoate-Producing Bacteria from Hypersaline Lakes in Kenya

Extremophilic microorganisms such as those that thrive in high-salt and high-alkaline environments are promising candidates for the recovery of useful biomaterials including polyhydroxyalkanoates (PHAs). PHAs ideal alternatives to synthetic plastics because they biodegradable, biocompatible, environmentally friendly. This work was aimed at conducting a bioprospection bacteria isolated from hypersaline-alkaliphilic lakes Kenya potential production PHAs. In present study, 218 isolates were screened by Sudan Black B Nile Red A staining. Of these isolates, 31 positive PHA characterized using morphological, biochemical, molecular methods. Through 16S rRNA sequencing, we found belonged genera Arthrobacter spp., Bacillus Exiguobacterium Halomonas Paracoccus Rhodobaca spp. Preliminary experiments revealed sp. JSM-1684023 Lake Magadi had highest accumulation ability, with an initial biomass-to-PHA conversion rate 19.14% on 2% glucose substrate. Under optimized fermentation conditions, MO22 maximum concentration 0.516 g/L 1.99 cell dry weight 25.9% conversion, equivalent yield 0.02 g/g biomass. The optimal media pH 9.0, temperature 35 °C, salinity 3%, incubation period 48 h 2.5% sucrose 0.1% peptone carbon nitrogen sources, respectively. study suggests hypersaline alkaliphilic tropical polyhydroxyalkanoates.