ENVIRONMENTAL-INFLUENCES ON DIETHYL PHTHALATE BIODEGRADATION KINETICS

The effects of temperature, dissolved oxygen level, and diethyl phthalate (DEP) concentration on the rates of DEP biodegradation have been investigated in shake flask and fermenter experiments, using aerobic and facultatively aerobic microorganisms. The aerobic strain followed Monod growth kinetics, and was negatively affected by temperatures lower than 25-degrees-C and dissolved oxygen levels lower than 0.8 mg/L, whereas the specific DEP-degrading activity of the facultative strain was substrate inhibited under anaerobic conditions, higher at 15-degrees-C than 25-degrees-C under aerobic conditions, and unaffected by the dissolved oxygen level. Studies were also carried out in soil columns to identify additional factors that might be important for modeling DEP biodegradation.