Ecobiotechnological Approach for Exploiting the Abilities of Bacillus to Produce Co-polymer of Polyhydroxyalkanoate

Ecobiotechnological approach is an attractive and economical strategy to enrich beneficial microbes on waste biomass for production of Polyhydroxyalkanoate (PHA). Here, six strains of Bacillus spp. were used to produce co-polymers of PHA from pea-shells. Of the 57 mixed bacterial cultures (BCs) screened, two of the BCs, designated as 5BC1 and 5BC2, each containing 5 strains could produce PHA co-polymer at the rate of 505-560 mg/l from feed consisting of pea-shell slurry (PSS, 2 % total solids) and 1 % glucose (w/v). Co-polymer production was enhanced from 65-560 mg/l on untreated PSS to 1,610-1,645 mg/l from PSS treated with defined hydrolytic bacteria and 1 % glucose. Supplementation of the PSS hydrolysate with sodium propionate enabled 5BC1 to produce co-polymer P(3HB-co-3HV) with a 3HV content up to 13 % and a concomitant 1.46-fold enhancement in PHA yield. Using the principles of ecobiotechnology, this is the first demonstration of PHA co-polymer production by defined co-cultures of Bacillus from biowaste as feed under non-axenic conditions.