Pseudomonas fluorescens isolated from soil samples contaminated with molasses, decolourised molasses wastewater (MWW) samples up to 76% under non-sterile conditions in four days at 30 degreesC. Immobilised cells could be reused for decolourisation activity. However, in subsequent cycles, this was found to decrease from 76% to 50% and from 50% to 24%. Decolourisation activity was regenerated from 30%, to 45% by recultivating the immobilised cells in a fresh growth medium. Cellulose carrier coated with collagen was found to be most effective carrier, which produced the highest decolourisation activity of 94% in a 4-day process. This carrier could be reused with 50% of the decolourisation activity retained until the seventh day. (C) 2001 Elsevier Science Ltd. All rights reserved.