BIOTRANSFORMATION OF LINDANE AND 2,4-D IN BATCH ENRICHMENT CULTURES

Experimental data describing microbially mediated transport and transformation processes for two pesticides are presented. A mixed culture of microorganisms maintained in a minimal basal salts media supplemented with a single, low energy carbon source provided inoculum for a series of small, aerobic batch reactors containing varying concentrations of either lindane or 2,4-D. Controls were simultaneously established to monitor microbial performance without pesticides as well as any non-biological pesticide removals. Data were collected daily enumerating pesticide and primary substrate removal, bacterial numbers, pH and dissolved oxygen. Rate constants, assumed to be first order in form were calculated for pertinent substrate and microbial population properties. Lindane removal initially consisted of adsorption-desorption from the microbial biomass followed by decomposition, which began as the primary substrate concentration decreased to detection levels. 2,4-D removal did not include significant adsorption and proceeded with the removal of the primary substrate. Complex interactions exist between low energy, non-toxic primary substrates, high energy-increasingly toxic secondary materials, and the microbial populations involved in transport and transformation of the pesticides.