Production of poly(3-hydroxybutyrate) by solid-state fermentation with Ralstonia eutropha.

The use of solid-state fermentation is examined as a low-cost technology for the production of poly(hydroxyalkanoates) (PHAs) by Ralstonia eutropha. Two agroindustrial residues (babassu and soy cake) were evaluated as culture media. The maximum poly(hydroxybutyrate) (PHB) yield was 1.2 mg g(-1) medium on soy cake in 36 h, and 0.7 mg g(-1) medium on babassu cake in 84 h. Addition of 2.5% (w/w) sugar cane molasses to soy cake increased PHB production to 4.9 mg g(-1) medium in 60 h. Under these conditions, the PHB content of the dry biomass was 39% (w/w). The present results indicate that solid-state fermentation could be a promising alternative for producing biodegradable polymers at low cost.