Effect of culture conditions on the competitive interaction between lactate oxidizers and fermenters in a biological sulfate reduction system

• Published in: Bioresource technology Vol. 104; pp. 616 - 621
• Main Authors: Oyekola, Oluwaseun O., Harrison, Susan T.L., van Hille, Robert P.
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01-01-2012
• Subjects: Acid mine drainage; Bacterial Physiological Phenomena; Biological sulfate reduction; Bioreactors - microbiology; Cell Culture Techniques - methods; Culture Media - metabolism; Fermentation; Kinetics; Lactic Acid - metabolism; Oxidation; Oxidation-Reduction; Stoichiometry; Sulfates - metabolism; Stoichiometry; Oxidation; Kinetics; Acid mine drainage; Biological sulfate reduction; Fermentation
• ISSN: 0960-8524; 1873-2976
• DOI: 10.1016/j.biortech.2011.11.052

► Lactate used as substrate for microbial growth in sulfate reducing condition. ► Microbial growth parameters (μs and Ks) determined from experimental data. ► μs and Ks incorporated into mathematical models to predict microbial competition. ► Increasing lactate concentration leads to the predominance of lactate fermentation. ► Decreasing lactate concentration leads to the predominance of lactate oxidation.
Kinetic constants (μmax and Ks) 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 1.0–10.0gl−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 μmax of 0.2h−1 and Ks value of 0.6gl−1 compared with a μmax of 0.3h−1 and Ks of 3.3gl−1 for the lactate fermenters (LF). Using mathematical models, it was shown that LO competed more effectively for lactate at low lactate concentrations (⩽5gl−1) and high sulfide concentrations (0.5gl−1). Lactate fermenters outcompeted the oxidizers under conditions of excess lactate (>5gl−1) and low sulfide (0.014–0.088gl−1).