title: Kinetics of propionate conversion in anaerobic continuously stirred tank reactors.
abstract: The kinetic parameters of anaerobic propionate degradation by biomass from 7 continuously stirred tank reactors differing in temperature, hydraulic retention time and substrate composition were investigated. In substrate-depletion experiments (batch) the maximum propionate degradation rate, Amax, and the half saturation constant, Km, were initially estimated by applying the integrated Michaelis-Menten equation. Amax was in the range from 22.8 to 29.1 micromol gVS(-1) h(-1) while Km was in the range from 0.46-0.95 mM. In general, Amax gave a good reflection of the reactor performances. Secondly, the accuracy of the applied method was evaluated by use of radiotracer methodology. Amax was found to be 14-15% lower in the substrate-depletion experiment than in the radioisotope experiment due to endogenous propionate production. By including the endogenous propionate production, a 42-49% lower Km was estimated. The results demonstrate that the rate of endogenous substrate (propionate) production should be taken into account when estimating kinetic parameters in biomass from manure-based anaerobic reactors.
authors.affiliation: Biosystems Department, Risø National Laboratory, Technical University of Denmark-DTU, Building 301, P.O. Box 49, DK-4000 Roskilde, Denmark.
authors.forename: H B
authors.initials: HB
authors.lastname: Nielsen
authors.forename: Z
authors.initials: Z
authors.lastname: Mladenovska
authors.forename: B K
authors.initials: BK
authors.lastname: Ahring
mesh_terms: D000693:Anaerobiosis; D001673:Biodegradation, Environmental; D018533:Biomass; D019149:Bioreactors; D004867:Equipment Design; D006868:Hydrolysis; D007700:Kinetics; D011422:Propionates / Q000032:analysis*; D015203:Reproducibility of Results; D013997:Time Factors; D014865:Waste Disposal, Fluid / Q000379:methods; D018505:Waste Management; D018508:Water Purification
chemical_list: D011422:Propionates