A chemostat system for investigating pesticide biodegradation in continuous mixed bacteria cultures originating from surface water

To be able to predict the degradation (rate) of organic chemicals (e.g. pes ticides) in the field, knowledge of the environmental conditions that are o f influence on the degradation process are of importance. In the present st udy an experimental system is described which is used to study the degradat ion of organic pollutants in mixed bacteria cultures originating from surfa ce water. With this system the degradation of compounds can be followed for relatively long experimental periods (months). In addition, it is possible to vary different environmental parameters in order to investigate their i nfluences on the degradation of the chemical. These preliminary experiments show that growth and 'composition' of the bacteria culture have comparable patterns in parallel experiments. The first order degradation rate constan t for the test compound dichloran, as calculated from these experiments und er these circumstances, is about 0.002 h(-1). (C) 2000 Elsevier Science Ltd . All rights reserved.