title: Influence of carbon-to-nitrogen ratio on the mixed-acid fermentation of wastewater sludge and pretreated bagasse.
abstract: In mixed-acid fermentation, carbon and nitrogen are critical nutrients for cell synthesis, growth, and metabolism. To study the effect of C/N ratio on the yield of carboxylic acids, wastewater sludge was co-digested with pretreated bagasse; the amount of sludge was varied from 0% to 100% (dry weight basis). Fermentation was performed at 55°C at a solids concentration of 50 g dry solids/L, and Iodoform was used to inhibit methane formation. It was observed that C/N ratio significantly affects yield, especially at extreme ratios. The highest carboxylic acid yield (0.36 g acids/g VS fed) was obtained for C/N ratios ranging from 13 to 25 g C/g N. C/N ratio also affected the composition profile of carboxylic acids. In all mixtures, acetic acid was the major fraction, followed by butyric acid. However, i-butyric, valeric acid, and i-valeric acid increased with increasing sludge content, which likely resulted from protein degradation.
authors.affiliation: Department of Chemical & Environmental Engineering, University of Mauritius, Réduit, Mauritius. hrkin@yahoo.com
authors.forename: Hema
authors.initials: H
authors.lastname: Rughoonundun
authors.forename: Romeela
authors.initials: R
authors.lastname: Mohee
authors.forename: Mark T
authors.initials: MT
authors.lastname: Holtzapple
mesh_terms: D019149:Bioreactors; D002244:Carbon / Q000032:analysis*; D002264:Carboxylic Acids / Q000378:metabolism*; D002482:Cellulose / Q000737:chemistry*; D005285:Fermentation; D009584:Nitrogen / Q000032:analysis*; D012722:Sewage / Q000737:chemistry*; D014865:Waste Disposal, Fluid
chemical_list: D002264:Carboxylic Acids; D012722:Sewage; D002244:Carbon; D002482:Cellulose; C027433:bagasse; D009584:Nitrogen