A psychrotrophic Pseudomonas fluorescens was isolated that utilizes ethylene glycol as a sole carbon source, with removal efficiencies of 98% and 96% in 20 and 55 days at 25 degrees and 5 degrees C, respectively, The response of the psychrotroph to environmental shifts was investigated using two-dimensional SDS-PAGE and computing scanning laser densitometry. During a 25 degrees C to 5 degrees C cold shock, the microorganism induced ten cold shock proteins. Under conditions of constant growth at 5 degrees C, five cold acclimation proteins were synthesized, Ethylene glycol shock induced 14 ethylene glycol shock proteins. Ten ethylene glycol acclimation proteins were found. Similarities between the shock proteins and acclimation proteins for cold shock and acclimation and the ethylene glycol shock and acclimation may suggest that these proteins are of significance to both shock recovery as well as constant growth in a new environment.