title: Evaluation of succinic acid continuous and repeat-batch biofilm fermentation by Actinobacillus succinogenes using plastic composite support bioreactors.
abstract: Continuous and repeat-batch biofilm fermentations using Actinobacillus succinogenes were performed with immobilized and suspended-cell systems. For the immobilized continuous system, plastic composite supports (PCS) containing 50% (w/w) polypropylene (PP), 35% (w/w) ground soybean hulls, 5% (w/w) dried bovine albumin, 2.5% (w/w) soybean flour, 2.5% (w/w) yeast extract, 2.5% (w/w) dried red blood cells, and 2.5% (w/w) peptone, or PP tubes (8.5 cm in length) were arranged around the agitator shaft in a grid formation. Agitation was controlled at 125 rpm and 150 rpm. Samples were taken at dilution rates of 0.2, 0.4, 0.6, 0.8, 1.0, and 1.2 h(-1) and analyzed for succinic acid production and glucose consumption (g l(-1)). For PCS bioreactors, the highest final succinic acid concentrations (10.1 g (-1), 10.4 g l(-1)) and percentage yields (62.6%, 71.6%) occurred at the dilution rate of 0.2 h(-1). PCS disks were evaluated in a repeat-batch biofilm reactor. Suspended-cell batch fermentations were performed in flasks and a repeat-batch bioreactor. The maximum concentration of succinic acid produced was 40 g l(-1). Peak succinic acid percentage yields in continuous and repeat-batch fermentations of A. succinogenes were observed in suspended-cell continuous fermentations at a dilution rate of 1.0 h(-1) (76.2%) and in PCS repeat-batch fermentations with an initial glucose concentration of 40 g l(-1) (86.7%).
authors.affiliation: Department of Microbiology, Iowa State University, 207 Science I, Ames, IA 50011, USA.
authors.forename: Susan E
authors.initials: SE
authors.lastname: Urbance
authors.forename: Anthony L
authors.initials: AL
authors.lastname: Pometto
authors.forename: Alan A
authors.initials: AA
authors.lastname: Dispirito
authors.forename: Yuksel
authors.initials: Y
authors.lastname: Denli
mesh_terms: D000188:Actinobacillus / Q000254:growth & development / Q000378:metabolism*; D018441:Biofilms / Q000254:growth & development; D019149:Bioreactors; D001709:Biotechnology / Q000379:methods*; D018914:Cells, Immobilized; D003470:Culture Media / Q000737:chemistry; D005285:Fermentation; D005947:Glucose / Q000378:metabolism; D010969:Plastics; D019802:Succinic Acid / Q000378:metabolism*
chemical_list: D003470:Culture Media; D010969:Plastics; D019802:Succinic Acid; D005947:Glucose