XENOBIOTIC BIODEGRADATION TEST USING ATTACHED BACTERIA IN SYNTHETIC SEAWATER

The aerobic biodegradability of aniline, used as reference chemical, h as been performed in synthetic seawater with attached biomass in a con tinuously fed reactor (biofilm chemostat reactor, BCR). Marine bacteri a inocula came from local marine fish aquarium filters to limit the ge ographic and seasonal variations in quality. A pretreatment of these i nocula combining 5-mu m filtration and centrifugation was used to conc entrate bacteria and remove organic carbon contamination of the test. The performances of the BCR were tested in comparison with simple shak e flask tests. Among the different variables tested, the ratio S(0)X(0 ) (initial concentration of xenobiotic to initial density of the inocu lum), the presence of dissolved oxygen, and the hydraulic residence ti me appear to be the key parameters controlling the length of the biode gradation process. On the other hand, the addition of a cosubstrate (e asily biodegradable compound) does not provide advantages. Thus, marin e biofilm chemostat reactors with a high density of attached bacteria (around 10(7) cells cm(-2)) and fed with synthetic seawater plus nitro gen provide good tools for screening biodegradability of chemicals in the marine environment. (C) 1995 Academic Press, Inc.