Growth and cometabolic reduction kinetics of a uranium‐ and sulfate‐reducing Desulfovibrio/Clostridia mixed culture: Temperature effects

Abstract

Bioremediation of contaminated soils and aquifers is subject to spatial and temporal temperature changes that can alter the kinetics of key microbial processes. This study quantifies temperature effects on the kinetics of an ethanol-fed sulfate-reducing mixed culture derived from a uranium-contaminated aquifer subject to seasonal temperature fluctuations. The mixed culture contains Desulfovibrio sp. and a Clostridia-like organism. Rates of growth, ethanol utilization, decay, and uranium reduction decreased with decreasing temperature. No significant uranium reduction was observed at 10 degrees C. While both Monod saturation kinetics and pseudo second-order kinetics adequately described the rates of growth and utilization of electron donor (ethanol), model parameters for the pseudo second-order expression had smaller uncertainties. Uranium reduction kinetics were best described by pseudo second-order kinetics modified to include a term for inactivation/death of cells.

How sulphate-reducing microorganisms cope with stress: lessons from systems biology

“…The local groundwater in the vicinity of the site contains one of the most concentrated mobile, subsurface uranium plumes in the United States. Numerous SRM species (particularly from the Deltaproteobacteria and the Firmicutes) have been detected at various locations within the FRC site 97,108,113,[127][128][129][130][131][132][133][134][135][136][137][138][139][140][141] , suggesting that SRMs have successfully adapted to this environment.…”

Experimental and mathematical modeling studies on Cr(VI) reduction by CRB, SRB and IRB, individually and in combination

“…Thus, a proper understanding of the interaction between different inorganic compounds and microbial flora is essential for the design and appropriate management of any bioremediation system. Also, biokinetic models are available only for individual systems like CRB [4,27,31,33,34], SRB [13,[35][36][37], and IRB [38][39][40][41][42]. To the best of authors' knowledge, no model is available to describe the combined action of CRB, SRB and IRB in wastewaters/contaminated aquifers containing Cr(VI), sulphate and Fe(III).…”

Can microbially-generated hydrogen sulfide account for the rates of U(VI) reduction by a sulfate-reducing bacterium?

“…The enrichment was capable of reducing U(VI) in the absence of hydrogen sulfide (Nyman et al 2007;Boonchayaanant et al 2008). Others have also observed enzymatic reduction by Desulfovibrio spp.…”