PHA production using low-cost agro-industrial wastes by Bacillus sp.strain COL1/A6

Abstract

Recycling of wastes generated from agro based industries for polyhydroxyalkanoate production is not only crucial for waste management but also in economizing and commercializing the polymer. In this study, the heterotrophic bacterium Bacillus sp. strain COL1/A6 isolated from humus was biologically characterized and explored for its potential to synthesize PHA using agroindustrial wastes. Qualitative analysis using Nile blue A staining revealed that starch, wafer residue, citrus pulp and cane molasses proved to be excellent carbon substrates for PHA accumulation. Growth and PHA producing ability of the isolate on cane bagasse and rice chaff improved after dilute acid hydrolysis. Highest cellular PHA content was obtained using wastes such as hydrolyzed wafer residue (62.41 +/- 1.04 percent of dry cell wt.) followed by cane molasses (54.68 +/- 1.36 percent of dry cell wt.) and hydrolyzed citrus pulp (47.5 +/- 1.01 percent of dry cell wt.). This is the first report wherein a Bacillus sp. has been reported to grow and utilize wastes such as wafer residue and citrus pulp as carbon feedstock for PHA production.