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Consolidated bioprocessing of sugarcane bagasse and chicken manure to ammonium carboxylates by a mixed culture of marine microorganisms
- Fu, Zhihong, Holtzapple, Mark T.
- Bioresource technology 2010 v.101 no.8 pp. 2825-2836
- biomass, renewable energy sources, biorefining, sugarcane bagasse, lignocellulose, cellulose, poultry manure, ammonium bicarbonate, carboxylic acids, calcium carbonate, buffers, batch fermentation
- The MixAlco process, an example of consolidated bioprocessing (CBP), was utilized for anaerobic fermentation of 80% lime-treated sugarcane bagasse/20% chicken manure at 55°C by a mixed culture of marine microorganisms. NH₄HCO₃ was recommended by this study to replace CaCO₃ buffer to neutralize the produced carboxylic acids. The resulting ammonium carboxylates can be converted to gasoline or mixed alcohol fuels by downstream processing. Four-stage countercurrent fermentations at various volatile solids loading rates (VSLR) and liquid residence times (LRT) showed the highest acid productivity (1.27g/(L·day)) and highest conversion (76%) occurred at a total acid concentration of 24.4 and 31.3g/L, respectively. The Continuum Particle Distribution Model (CPDM) predicted the experimental total acid concentrations and conversions within 9.05% and 14.39%, respectively. The CPDM “map” indicates that both high acid concentrations (>50g/L) and high conversions (>72%) are possible with 300g substrate/(L liquid) concentration, 30 days liquid residence time, 5.4g/(L·day) solid loading rate, and NH₄HCO₃ buffer. The present study suggests that mixed culture biotechnology in the MixAlco process provides an alternative “carboxylate platform” for biomass conversion.