title: Fermentation of lactose and its constituent sugars by Escherichia coli WDHL: impact on hydrogen production.
abstract: Fermentations of lactose, glucose and galactose using Escherichia coli WDHL, a hydrogen over producer strain, were performed. With glucose as substrate pyruvate was mainly routed to the lactate pathway, resulting in hydrogen production and yield of 1037 mL and 0.30 mol H(2)/mol of glucose, respectively. When galactose was the substrate, the pyruvate formate lyase pathway was the main route for pyruvate and a fermentation yield of 1.12 mol H(2)/mol of galactose and a hydrogen production of 2080 mL were obtained. The fermentation of lactose or glucose plus galactose showed a similar yield of 1.02 mol H(2)/mol of hexose consumed. This work clearly demonstrated that the kinetics of hydrogen and metabolites production as well as the hydrogen yield were affected by the type of sugar used as substrate as reflected by the deviations from the metabolic hydrogen-production pathway.
authors.affiliation: División de Biología Molecular, Instituto Potosino de Investigación Científica y Tecnológica, Camino a la Presa San José 2055, Col. Lomas 4ª secc. CP 78216, San Luis Potosí, SLP, Mexico. manuel@biosintetica.mx
authors.forename: Luis Manuel
authors.initials: LM
authors.lastname: Rosales-Colunga
authors.forename: Elías
authors.initials: E
authors.lastname: Razo-Flores
authors.forename: Antonio
authors.initials: A
authors.lastname: De León Rodríguez
mesh_terms: D050260:Carbohydrate Metabolism; D004926:Escherichia coli / Q000378:metabolism*; D005285:Fermentation; D006859:Hydrogen / Q000378:metabolism*; D007785:Lactose / Q000378:metabolism*
chemical_list: D006859:Hydrogen; D007785:Lactose