title: Effect of culture conditions on the competitive interaction between lactate oxidizers and fermenters in a biological sulfate reduction system.
abstract: Kinetic constants (μ(max) and K(s)) describing the predominance of lactate oxidation and fermentation were determined in chemostat cultures. The kinetics of sulfate reduction and lactate utilization were determined from 0.5 to 5d residence times at feed sulfate concentrations of 1.0-10.0 g l(-1). The kinetics of lactate fermentation in the absence of sulfate were investigated at residence times of 0.5-5d. The lactate oxidizers (LO) were characterized by a μ(max) of 0.2h(-1) and K(s) value of 0.6 g l(-1) compared with a μ(max) of 0.3h(-1) and K(s) of 3.3 g l(-1) for the lactate fermenters (LF). Using mathematical models, it was shown that LO competed more effectively for lactate at low lactate concentrations (≤5 g l(-1)) and high sulfide concentrations (0.5 g l(-1)). Lactate fermenters outcompeted the oxidizers under conditions of excess lactate (>5 g l(-1)) and low sulfide (0.014-0.088 g l(-1)).
authors.affiliation: Centre for Bioprocess Engineering Research, Department of Chemical Engineering, University of Cape Town, Private Bag, Rondebosch 7701, South Africa. oyekolas@cput.ac.za
authors.forename: Oluwaseun O
authors.initials: OO
authors.lastname: Oyekola
authors.forename: Susan T L
authors.initials: ST
authors.lastname: Harrison
authors.forename: Robert P
authors.initials: RP
authors.lastname: van Hille
mesh_terms: D018407:Bacterial Physiological Phenomena; D019149:Bioreactors / Q000382:microbiology*; D018929:Cell Culture Techniques / Q000379:methods; D003470:Culture Media / Q000378:metabolism*; D005285:Fermentation; D019344:Lactic Acid / Q000378:metabolism*; D010084:Oxidation-Reduction; D013431:Sulfates / Q000378:metabolism*
chemical_list: D003470:Culture Media; D013431:Sulfates; D019344:Lactic Acid