Abstract
Lactic acid fermentation broth derived from pig manure and apple waste is a potential high-quality feedstock for production of the biodegradable plastic polyhydroxyalkanoate (PHA). Enrichment of active PHA-synthesizing bacterial consortia, namely mixed microbial culture (MMC), is an important factor in high-efficiency synthesis of PHA. In this study, two types of aerobic sludge (pig farm sludge and municipal sludge) were selected to acquire active MMCs in the enrichment process with sludge retention times of 2 and 8 days using the lactic acid fermentation broth. Batch reactors and PHA accumulation reactors were used to evaluate the MMC activity. Results showed that pig farm sludge was acclimated to the superior MMC with the maximum PHA content of 25% during the enrichment process with sludge retention time of 8 days. The structure of microbial communities in all treatments tended to be similar after 45 days’ enrichment, and the dominant bacteria were genus Paracoccus with abundance of 15.41–41.45%. The maximum dry cell weight, PHA content, and PHA yield of batch reactors using the superior MMC were 0.69 g/L, 36%, and 0.86 g PHA-COD/g COD, respectively. Dry cell weight concentrations reached 3.16 g/L in the PHA accumulation reactor with PHA content of 40–50% and PHA yield of 0.57 g PHA-COD/ g COD. The findings of this study provide an effective enrichment strategy for MMCs, which could improve the high efficiency synthesis of PHA from the fermentation broth of agricultural wastes and enhance the economy of PHA production at a marketable scale.
Published Version
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call