Production of polyhydroxyalkanoates using sewage and cheese whey

Young-Cheol Chang; M Venkateswar Reddy; Yusei Tsukiori; Yasuteru Mawatari; DuBok Choi

doi:10.1016/j.heliyon.2023.e23130

Production of polyhydroxyalkanoates using sewage and cheese whey

Heliyon. 2023 Dec 2;9(12):e23130. doi: 10.1016/j.heliyon.2023.e23130. eCollection 2023 Dec.

Authors

Young-Cheol Chang¹, M Venkateswar Reddy², Yusei Tsukiori¹, Yasuteru Mawatari³, DuBok Choi⁴

Affiliations

¹ Course of Chemical and Biological Engineering, Division of Sustainable and Environmental Engineering, Muroran Institute of Technology, Hokkaido, 050-8585, Japan.
² Department of Civil and Environmental Engineering, Colorado State University, Fort Collins, CO, 80523, USA.
³ Research Center for Environmentally Friendly Materials Engineering, Muroran Institute of Technology, Hokkaido, 050-8585, Japan.
⁴ Faculty of Advanced Industry Convergence, Chosun University, Gwangju, 61452, South Korea.

Abstract

Recently, polyhydroxyalkanoates (PHAs) have been produced using raw sewage in our laboratory; however, the production concentrations are low. Therefore, this study aimed to enhance PHA production by applying different strategies. PHA production was higher in sewage-containing medium than in mineral salt medium and was enhanced 22-fold after glucose supplementation. A relatively high degree of glucose consumption (83.6 ± 1.59 %) was also achieved. Bacteria incubated with cheese whey diluted with sewage showed higher PHA production than bacteria incubated with cheese whey diluted with distilled water did. The expression of the PHA synthase gene (phaC) was evaluated via real-time polymerase chain reaction using low- and high-carbon-containing sewage. Relatively higher phaC expression levels were observed in high-carbon-containing sewage but at lower nitrogen concentrations. The characteristics of the produced PHA were comparable to those of standard PHA. Therefore, this study revealed that the bacterium Bacillus sp. CYR1 can produce PHA from low- or high-carbon-containing wastewater.

Keywords: Bioplastic; Polyhydroxyalkanoates; Reuse; Sewage; phaC gene expression; poly(3-hydroxybutyrate).