Utilization of molasses spentwash for production of bioplastics by waste activated sludge.

Environmental Genomics Unit, National Environmental Engineering Research Institute, Nehru Marg, Nagpur 440 020, India.
Waste Management (Impact Factor: 3.16). 07/2009; 29(9):2558-65. DOI: 10.1016/j.wasman.2009.04.008
Source: PubMed

ABSTRACT Present study describes the treatment of molasses spentwash and its use as a potential low cost substrate for production of biopolymer polyhydroxybutyrate (PHB) by waste activated sludge. Fluorescence microscopy revealed the presence of PHB granules in sludge biomass which was further confirmed by fourier transform-infra-red spectroscopy (FT-IR) and (13)C nuclear magnetic resonance (NMR). The processing of molasses spentwash was carried out for attaining different ratios of carbon and nitrogen (C:N). Highest chemical oxygen demand (COD) removal and PHB accumulation of 60% and 31% respectively was achieved with raw molasses spentwash containing inorganic nitrogen (C:N ratio=28) followed by COD removal of 52% and PHB accumulation of 28% for filtered molasses containing inorganic nitrogen (C:N ratio=29). PHB production yield (Y(p/s)) was highest (0.184 g g(-1) COD consumed) for deproteinized spentwash supplemented with nitrogen. In contrast, the substrate consumption and product formation were higher in case of raw spentwash. Though COD removal was lowest from deproteinized spentwash, evaluation of kinetic parameters suggested higher rates of conversion of available carbon to biomass and PHB. Thus the process provided dual benefit of conversion of two wastes viz. waste activated sludge and molasses spentwash into value-added product-PHB.

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    ABSTRACT: Polyhydroxybutyrate (PHA) synthesis was based on pure culture of Cupriavidus necator DSMZ 545. Due to the high production cost of PHAs, the use of cheaper and available carbon sources was considered. The aim of this research was to investigate the impact of sugarcane molasses as a low cost substrate and acetate as media supplements in mineral medium for the cell growth and poly(3-hydroxybutyrate), P(3HB). C. necator was cultivated in a 500ml shake flasks with 100 ml of the medium at 30°C for 96h, with agitation rate of 250 rpm. Samples for product analysis were taken at 12h time interval. Sodium acetate was used as supplementary substrate, it was added to molasses for the production of P(3HB). The obtained results showed that with addition of acetate as supplementary carbon source, enhanced the biopolymer concentration to 2.85g/l.


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