Upgrading the organic fraction of municipal solid waste to poly(3-hydroxybutyrate)

The organic fraction of municipal solid waste was studied as feedstock for the production of poly(3-hydroxybutyrate) (P(3HB)). To release the monosaccharides, a diluted acid pre-treatment followed by an enzymatic hydrolysis was applied. A sugar yield of 49% was achieved using a pre-treated waste and an enzyme cocktail of Pentopan 500 BG and Celluclast BG. The addition of Glucoamylase NS 22035 helped to hydrolyze the starch fraction, improving the hydrolysis yield to 56%. The hydrolysate was used as culture medium to produce P(3HB) by Burkholderia sacchari DSM 17165. Assays at shaking flask scale showed that when the hydrolysate was used as substrate, the attained cell concentration was slightly higher than in the control medium. It was necessary to supplement the hydrolysate with extra glucose to increase the C/N ratio and with a mineral solution to overcome the nutritional deficiencies. The P(3HB) accumulation using the supplemented hydrolysate was 58% (g polymer/g biomass).