OPERATION OF MIXED-CULTURE IMMOBILIZED CELL REACTORS FOR THE METABOLISM OF META-NITROBENZOATE AND PARA-NITROBENZOATE BY COMAMONAS SP. JS46 AND COMAMONAS SP. JS47

The treatment of meta-and para-nitrobenzoic acid in an industrial wast estream by Comamonas sp. JS46 and Comamonas sp. JS47 is investigated. The most important feature of the wastestream is the constantly changi ng concentration ratio of the two isomers. The most extreme occurrence is considered here: the complete change in feed carbon source from on e isomer to the other. A series of immobilized cell airlift reactor ex periments are described to examine the operation and response of the s ystem to these changes in the feed carbon source. Separate reactors co ntaining each species immobilized are compared with a reactor containi ng both species immobilized within the same bead, and to a reactor con taining both species with each species confined to separate beads. On the basis of response time necessary to recover the appropriate activi ty, the reactor containing both species immobilized within the same be ad offers the most effective arrangement. Interactions occurring betwe en the two organisms in the coimmobilized system, mediated by the nitr obenzoate metabolites, are discussed relative to the improved response of this arrangement. (C) 1998 John Wiley & Sons, Inc.