Polyhydroxyalkanoate (PHA) Production Using Volatile Fatty Acids Derived from the Anaerobic Digestion of Waste Paper

Waste paper as a resource for polyhydroxyalkanoate (PHA) production through anaerobic digestion is a low-cost strategy to produce bioplastic. In this study, volatile fatty acids (VFAs) produced from waste paper, one of the significant constituents of municipal solid waste, was utilized as a feedstock for polyhydroxyalkanoate (PHA) production. PHA production from synthetic VFAs byCupriavidus necatorwas initially optimized under different VFAs concentrations, VFAs ratios, and nitrogen sources. VFAs concentration of 10 g/L, 5:1:4 ratio of acetic, propionic, and butyric acids (HAc:HPr:HBu) and NaNO(3)as nitrogen source were considered the optimum conditions with 56.98% PHA and 0.31 g/g yield. Anaerobic digestion of shredded office paper (OP/S) produced the maximum VFAs (521.50 mg/L) after 15 days of incubation and were utilized for PHA synthesis. Almost 2.24-fold increase in the yield of PHA was achieved with limited nutrient medium compared to nutrient contained medium with a PHA content of 53.50 and 23.88%, respectively. PHA production using anaerobic effluent of waste paper is a promising approach where a series of pretreatment processes, the expensive enzymatic hydrolysis, and detoxification were no longer required, suggesting an environmentally friendly way of biopolymer production.

Automated summary

The study demonstrated that utilizing waste paper as a resource for PHA production through anaerobic digestion is a low-cost strategy. By optimizing the synthesis conditions of PHA from VFAs produced from waste paper, a significantly higher yield of PHA was achieved with a limited nutrient medium.