Development of a novel solid-state fermentation strategy for the production of poly-3-hydroxybutyrate using polyurethane foams by Bacillus sphaericus NII 0838

Abstract

The extensive use of synthetic plastics has caused serious waste disposal problems in our environment. Poly-3-hydroxybutyrates (PHB) are eco-friendly bacterial polyesters which are produced under unbalanced nutrient conditions. Few reports are available on PHB production by solid state fermentation (SSF). We have developed a novel SSF bioprocess in which polyurethane foam (PUF) is used as a physical inert support for the production of PHB by Bacillus sphaericus NII 0838. Media engineering for optimal PHB production was carried out using response surface methodology (RSM) adopting a Box–Behnken design. The factors optimized by RSM were inoculum size, pH and (NH4)2SO4 concentration. Under optimized conditions—6.5 % inoculum size, 1.7 % (w/v) (NH4)2SO4 and pH 9.0—PHB production and biomass were 0.169 ± 0.03 and 0.4 ± 0.002 g/g PUF, respectively. This is the first report on PHB production by SSF using PUF as an inert support. Our results demonstrate that SSF can be used as an alternative strategy for the production of PHB.