title: Succinic acid production by Actinobacillus succinogenes from batch fermentation of mixed sugars.
abstract: Succinic acid production from the monosaccharides xylose, arabinose, glucose, mannose and galactose was studied using the bacterium Actinobacillus succinogenes. In Duran bottle cultures, containing 10 g/L of each of sugar, succinic acid was produced from all sugars except for galactose. The highest succinate yield, 0.56 g/g, was obtained with glucose, whereas the succinate yield was 0.42, 0.38 and 0.44 g/g for xylose, mannose and arabinose, respectively. The specific succinate productivity was 0.7 g/g h for glucose, but below 0.2 g/g h for the other sugars. Batch bioreactor fermentations were carried out using a sugar mixture of the five sugars giving a total concentration of 50 g/L, mimicking the distribution of sugars in spent sulfite liquor (SSL) from Eucalyptus which is rich in xylose. In this mixture, an almost complete conversion of all sugars (except galactose) was achieved resulting in a final succinate concentration of 21.8-26.8 g/L and a total yield of 0.59-0.68 g/g. There was evidence of co-consumption of glucose and xylose, whereas mannose was consumed after glucose. The main by-products were acetate 0.14-0.20 g/g and formate 0.08-0.13 g/g. NADH balance calculations suggested that NADH required for succinate production was not met solely from formate and acetate production, but other means of NADH production was necessary. Results from mixed sugar fermentations were verified using SSL as substrate resulting in a succinate yield of 0.60 g/g. In addition, it was found that CO2 sparging could replace carbonate supply in the form of MgCO3 without affecting the succinate yield.
authors.affiliation: Department of Chemical Engineering, Lund University, P.O. Box 124, 221 00, Lund, Sweden. henrik.almqvist@chemeng.lth.se.
authors.forename: Henrik
authors.initials: H
authors.lastname: Almqvist
authors.affiliation: Department of Food Science and Human Nutrition, Agricultural University of Athens, Iera Odos 75, 118 55, Athens, Greece.
authors.forename: Chrysanthi
authors.initials: C
authors.lastname: Pateraki
authors.affiliation: Department of Food Science and Human Nutrition, Agricultural University of Athens, Iera Odos 75, 118 55, Athens, Greece.
authors.forename: Maria
authors.initials: M
authors.lastname: Alexandri
authors.affiliation: Department of Food Science and Human Nutrition, Agricultural University of Athens, Iera Odos 75, 118 55, Athens, Greece.
authors.forename: Apostolis
authors.initials: A
authors.lastname: Koutinas
authors.affiliation: Department of Chemical Engineering, Lund University, P.O. Box 124, 221 00, Lund, Sweden.
authors.forename: Gunnar
authors.initials: G
authors.lastname: Lidén
mesh_terms: D000188:Actinobacillus / Q000378:metabolism*; D019149:Bioreactors; D050260:Carbohydrate Metabolism; D005285:Fermentation; D005947:Glucose / Q000378:metabolism; D019802:Succinic Acid / Q000378:metabolism*
chemical_list: D019802:Succinic Acid; D005947:Glucose
keywords: Actinobacillus succinogenes; CO2 fixation; Fermentation; Mixed sugars; Succinate