title: Integration of poly-3-(hydroxybutyrate-co-hydroxyvalerate) production by Haloferax mediterranei through utilization of stillage from rice-based ethanol manufacture in India and its techno-economic analysis.
abstract: Haloferax mediterranei has potential for economical industrial-scale production of polyhydroxyalkanoate (PHA) as it can utilize cheap carbon sources, has capacity for nonsterile cultivation and allows simple product recovery. Molasses-based Indian distilleries are converting themselves to cereal-based distilleries. Waste stillage (14 l) of rice-based ethanol industry was used for the production of PHA by H. mediterranei in the simple plug-flow reactor configuration of the activated sludge process. Cells utilized stillage and accumulated 63 ± 3 % PHA of dry cell weight and produced 13.12 ± 0.05 g PHA/l. The product yield coefficient was 0.27 while 0.14 g/l h volumetric productivity was reached. Simultaneous lowering of 5-day biochemical oxygen demand and chemical oxygen demand values of stillage by 82 % was attained. The biopolymer was characterized as poly-3-(hydroxybutyrate-co-17.9 mol%-hydroxyvalerate) (PHBV). Directional properties of decanoic acid jointly with temperature-dependent water solubility in decanoic acid were employed for two-step desalination of the spent stillage medium in a cylindrical baffled-tank with an immersed heater and a stirrer holding axial and radial impellers. 99.3 % of the medium salts were recovered and re-used for PHA production. The cost of PHBV was estimated as US$2.05/kg when the annual production was simulated as 1890 tons. Desalination contributed maximally to the overall cost. Technology and cost-analysis demonstrate that PHA production integrated with ethanol manufacture is feasible in India. This study could be the basis for construction of a pilot plant.
authors.affiliation: School of Environmental Studies, Jadavpur University, Kolkata, 700 032, India.
authors.forename: Anirban
authors.initials: A
authors.lastname: Bhattacharyya
authors.forename: Kuntal
authors.initials: K
authors.lastname: Jana
authors.forename: Saubhik
authors.initials: S
authors.lastname: Haldar
authors.forename: Asit
authors.initials: A
authors.lastname: Bhowmic
authors.forename: Ujjal Kumar
authors.initials: UK
authors.lastname: Mukhopadhyay
authors.forename: Sudipta
authors.initials: S
authors.lastname: De
authors.forename: Joydeep
authors.initials: J
authors.lastname: Mukherjee
mesh_terms: D001709:Biotechnology / Q000191:economics* / Q000379:methods*; D000431:Ethanol / Q000378:metabolism; D019623:Haloferax mediterranei / Q000235:genetics* / Q000378:metabolism*; D007194:India; D007220:Industrial Waste; D012275:Oryza / Q000378:metabolism*; D011091:Polyesters / Q000378:metabolism*; D000094122:Polyhydroxybutyrates
chemical_list: D000431:Ethanol; D007220:Industrial Waste; D011091:Polyesters; C052620:poly(3-hydroxybutyrate)-co-(3-hydroxyvalerate); D000094122:Polyhydroxybutyrates