Lysobacter gummosus grows on whey, utilizing lactose and producing proteolytic enzyme activity with optimum at pH 8 and 50 degrees C. A preliminary characterisation of the polymer produced by L. gummosus detected uronic and neutral sugar residues. Plasmid DNA was not present. This bacterium may have a role in biotechnology for the production of enzyme and biopolymer from whey or in the disposal of dairy effluent in waste treatment systems.