干旱区生态环境知识资源中心

The objective of this work has been to investigate the possibility of using fermented whey as an organic growth supplement in order to enhance the aerobic degradation of n-hexadecane in soil. Fermented whey was added at different dosages to nutrient amended soil microcosms contaminated with 5000 mg dieselfuel kg(-1) dry weight (dw). The target substance was C-14-labeted n-hexadecane, and the biodegradation was monitored by analysis of evolved (CO2)-C-14. Biodegradation curves were fitted to a three-half-order kinetics model. Enhanced biodegradation was observed in sand at 7 and 22 degrees C and in loamy sand at 22 degrees C but the effect was most pronounced in the sand soil at 22 degrees C. The addition of 6 or 60 ml fermented whey kg(-1) soil dw increased the degree of n-hexadecane biodegradation at the end of the experiment, 167 days, from 49% in the untreated sand to 60 or 67%, respectively. This increase in biodegradation was characterized by an increase in the amount of substrate biodegradation by first-order kinetics despite a decrease in the first order rate constant, k(1). The highest concentration of fermented whey, 60 ml kg(-1), gave rise to substrate competition, diauxie, which resulted in an extended lag phase.