Effect of temperature on oil degradation by a psychrotrophic yeast in liquid culture and in soil

Abstract

The influence of temperature (4–30°C) on diesel oil biodegradation in a mineral medium and in soil was tested. The abiotic loss of diesel oil increased with incubation time and with temperature and was lower in mineral medium than in soil. The maximum degradation activity of a psychrotrophic yeast ( Yarrowia lipolytica) in liquid culture (containing 5000 mg diesel oil l −1) occurred at 10–20°C. When inoculated into an alpine soil (containing 5000 mg diesel oil kg −1 soil dry weight), degradation activity of the inoculum was only observed at temperatures ≤15°C and was significantly lower than in the liquid culture. The indigenous soil microorganisms degraded diesel oil over the whole temperature range tested. With increasing incubation time and temperature, diesel oil utilization by the inoculum in the soil decreased, whereas degradation activity of the indigenous soil microorganisms and abiotic losses increased.