Respirometry kinetics of phenol oxidation by Comamonas testosteroni Pb50 under various conditions of nutritional stress

Abstract

Kinetics of phenol biodegradation using suspended biomass of Comamonas testosteroni Pb50 (monoculture) was measured under conditions of nutrient abundance, limitation, and prolonged cell starvation in a fed-batch reactor, with phenol being the sole carbon and energy source. The pre-washed cells were applied for measurement of the phenol and oxygen uptake rates at varied starting phenol concentrations with the kinetic parameters calculated using the Haldane model. The results revealed that nutrient limitation significantly suppressed the maximum value of exogenous respiration rate while the endogenous respiration rate, affinity and tolerance to phenol increased. By contrast, cell starvation resulted in a drop of both the exogenous and endogenous respiration rates by an order of magnitude.