title: Production of polyhydroxyalkanoates from agricultural waste and surplus materials.
abstract: To be competitive with common plastics, the production costs of polyhydroxyalkanoates (PHAs) have to be minimized. Biotechnological polymer production occurs in aerobic processes; therefore, only about 50% of the main carbon sources and even a lower percentage of the precursors used for production of co-polyesters end up in the products wanted. A second cost factor in normally phosphate-limited production processes for PHAs is the costs for complex nitrogen sources. Both cheap carbon sources and cheap nitrogen sources are available from agricultural waste and surplus materials and make a substantial contribution for minimizing PHA production costs. In this study, fermentations for PHA production were carried out in laboratory-scale bioreactors on hydrolyzed whey permeate and glycerol liquid phase from the biodiesel production using a highly osmophilic organism. Without any precursor, the organism produced a poly[3(hydroxybutyrate-co-hydroxyvalerate)] copolyester on both carbon sources. During the accumulation phases, a constant 3-hydroxyvalerate content of 8-10% was obtained at a total PHA concentration of 5.5 g/L (on hydrolyzed whey permeate) and 16.2 g/L (glycerol liquid phase). In an additional fermentation, an expensive nitrogen source was substituted by meat and bone meal beside the glycerol liquid phase as a carbon source, resulting in a final PHA concentration of 5.9 g/L.
authors.affiliation: Institute of Biotechnology & Bioprocess Engineering, Graz University of Technology, Petersgasse 12, A-8010 Graz, Austria.
authors.forename: Martin
authors.initials: M
authors.lastname: Koller
authors.forename: Rodolfo
authors.initials: R
authors.lastname: Bona
authors.forename: Gerhart
authors.initials: G
authors.lastname: Braunegg
authors.forename: Carmen
authors.initials: C
authors.lastname: Hermann
authors.forename: Predrag
authors.initials: P
authors.lastname: Horvat
authors.forename: Markus
authors.initials: M
authors.lastname: Kroutil
authors.forename: Julia
authors.initials: J
authors.lastname: Martinz
authors.forename: Jose
authors.initials: J
authors.lastname: Neto
authors.forename: Luis
authors.initials: L
authors.lastname: Pereira
authors.forename: Paula
authors.initials: P
authors.lastname: Varila
mesh_terms: D000383:Agriculture; D019149:Bioreactors; D002244:Carbon / Q000378:metabolism; D004785:Environmental Pollutants / Q000378:metabolism*; D005285:Fermentation; D006885:Hydroxybutyrates / Q000138:chemical synthesis*; D007220:Industrial Waste; D009584:Nitrogen / Q000378:metabolism; D011091:Polyesters / Q000138:chemical synthesis*; D014866:Waste Products; D000094122:Polyhydroxybutyrates
chemical_list: D002244:Carbon; D004785:Environmental Pollutants; D006885:Hydroxybutyrates; D007220:Industrial Waste; D009584:Nitrogen; D011091:Polyesters; D014866:Waste Products; C003182:poly-beta-hydroxybutyrate; D000094122:Polyhydroxybutyrates