Bioconversion of food waste to poly (3-hydroxybutyrate-co-3-hydroxyvalerate) biopolymer using Stenotrophomonas geniculata: study of operating parameters and process optimization

Abstract

In order to address the growing concerns regarding the environmental impact of plastics and the related environmental implications of food waste, this study was conducted with the objective of producing poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) by Stenotrophomonas geniculata bacteria isolated from a municipal landfill and utilizing food waste as a substrate. FTIR, ¹H-NMR, GC–MS and thermal analyses were used to confirm the production of PHBV. The produced biopolymer has thermoplastic elastomer properties similar to those of natural rubber. Temperature, concentration of nitrogen and carbon sources and pH were considered as the main factors for optimizing PHBV production. At the optimum conditions, i.e., temperature 32.3 °C, pH 9, nitrogen and glucose concentrations of 13.25 g/L and 27.71 g/L, respectively, maximum produced PHBV and yield of 2.835 g/L, and 0.746 g/g cell dry weight were obtained empirically. Notably, this study is the first to demonstrate the use of the S. geniculata strain Flmat 1 species for the production of PHBV using structurally unrelated simple carbon source. This study's strategy deals with the global burden of food waste and subsequently produces the biopolymer, which is a waste-to-wealth conversion.