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: 3.22). 07/2009; 29(9):2558-65. DOI: 10.1016/j.wasman.2009.04.008
Source: PubMed


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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Available from: M Suresh Kumar, Sep 26, 2014
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    • "Vinasse is one of the most difficult waste products to dispose because of low pH, high temperature, dark brown color, high ash content and high percentage of dissolved organic and inorganic matter (Pant and Adholeya, 2007). In attempts to utilize vinasse as a low cost carbon source for commercial synthesis of PHAs, polyhydroxybutyrate (PHB) was produced from spent wash obtained from a distillery producing ethanol by fermentation of sugarcane molasses (Khardenavis et al. 2009) as well as rice grain and jowar grain based distillery vinasse (Khardenavis et al. 2007) by mixed culture of microbes. Halophilic microorganisms are an important source of PHAs and hold promise for providing an economically competitive industrial scale production process. "
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    ABSTRACT: Vinasse, a highly polluting waste of the ethanol industry was utilized for the production of polyhydroxyalkanoate (PHA) by the extremely halophilic archaeon, Haloferax mediterranei in shake-flasks. Following pre-treatment through adsorption on activated carbon, 25%-50% (v/v) pre-treated vinasse was utilized leading to 70% maximum accumulation of PHA. Maximum PHA concentration of 19.7 g/l, product yield coefficient (based on total carbohydrates) of 0.87 and 0.21 g/l h volumetric productivity were achieved. Concomitant lowering of BOD5 of pre-treated vinasse by at least 78% and COD by at least 80% was attained at the end of this process. The PHA was recovered by osmotic lysis of the cells and purification by sodium hypochlorite and organic solvents. Through UV-Vis spectroscopy, gas chromatography, differential scanning calorimetry and nuclear magnetic resonance spectroscopy, the PHA was identified as poly-3-(hydroxybutyrate-co-hydroxyvalerate). The 3-hydroxyvalerate content was 12.36 mol % (utilizing 25% pre-treated vinasse) and 14.09 mol % (utilizing 50% pre-treated vinasse). High salt concentration in the medium allowed this process without sterile conditions and thus reduction in costs of sterilization can be envisaged. Activated charcoal pre-treatment of vinasse is economical than competing processes such as ultrafiltration of whey, extrusion and enzymatic treatment of rice and corn starch. Without impacting sugar prices, this process can easily be integrated into a distillery that has fermentation equipment and trained personnel. High PHA content, productivity, zero-cost carbon source, low-cost isolation of a high-purity product and potential integration into ethanol manufacturing unit with concomitant wastewater treatment should merit further development of this process to higher scales.
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    ABSTRACT: Molasses-based distilleries are one of the most vulnerable to pollution industries, which always generate large volumes of high strength vinasse. Recently, one of the most effective re-applications/reuse of vinasse is concentrating the molasses vinasse to prepare as fodder additive for animal food. However, the dosage of molasses vinasse to be added as animal feed is always limited because of the unexpectedly high potassium content in molasses vinasse. In present study, potassium ions were firstly extracted from molasses vinasses using a strong acid–cation exchange resin, and then desorbed from the resin and dissolved into the eluate by H2SO4 solution as the strong acid–cation exchange resin was regenerated. Finally, evaluation to recycle and reuse the mother liquor (once-used eluant), after extracting K2SO4 crystals from the eluant, was investigated. Results indicated that using the mother liquor to elute the resin column which absorbing K+ from molasses vinasse was a potential means for industrial production of potassium salt. Meanwhile, the molasses vinasse which has removed most potassium ions might be used as animal feed.
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    ABSTRACT: Backgrounds and Objectives: Owing to the fact that the major environmental problem is production of surplus sludge in wastewater treatment plant, reducing the volume of produced sludge was objective of this research. Materials and Methods: An anaerobic-aerobic SBR with working volume of 10 L was used to make micro-organism adapted and a polymer production reactor (PPR) with working volume of 1.5 L was used for producing polymer munisipal wastewater which contained different concentration of volatile fatty acids was consodered as the feed source (acetate and propionate) and this system was evaluated with SRT of 5, 7 and 10 days. Results: The maximum polymer production efficiency observed within 5 days (SRT=5 days) though this efficiency was not significant in comparison with the two others time courses study. In this research the maximum polymer production efficiency at optimum condition was 25% of the sludge dry weight. Conclusion: Experiment revealed that producing polymer from activated sludge reduced the volume of sludge and the maximum reduced sludge volume was obtained 19%.
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