Production of Polyhydroxyalkanoate by Bacillus thuringiensis Isolated from Agricultural Soils of Cascas-Peru

Abstract

Polyhydroxyalkanoates (PHA) are biodegradable biopolymers of microbial origin that can be alternative materials to decrease the extensive use of plastics of petrochemical or synthetic origin. Thus, the selection of microorganisms with potential for PHA production from unexplored natural sources is a strategy to find bacterial species of high value. In the current study, 55 microbial strains related to bacteria were isolated from agricultural soils from Cascas, Peru. Initially, 4 strains were selected by Sudan Black B staining and Nile blue A fluorescence methods, subsequently, they were screened to examine its production capacity of PHA. Bacillus thuringiensis SP7-1 strain was selected based on its high production of PHA at 0.54 ± 0.16 g/L with an accumulation of 19 % by weight of cell biomass, during 72 h at 30 ºC. The isolate was characterized by its morphology, biochemical and molecular tests through the 16S rRNA gene. The extracted HIGHLIGHTS• Bacillus thuringiensis SP7-1 from agricultural soils producing polyhydroxyalkanoate.• The strains SP7-1 with a PHA accumulation of 0.54 g/L and 19 % in dry biomass.• PHA was characterized with FTIR, DSC and TGA with remarkable chemical properties.• A thermic degradation in a range of 270-303°C and a Melting Temperature of 166.88°C.