Cold-active lipolytic activity of psychrotrophic Acinetobacter sp strain no. 6

A lipolytic bacterium, strain no. 6, was isolated from Siberian tundra soil . It was a gram-negative coccoid rod capable of growing at 4 degreesC but n ot at 37 degreesC and was identified as a psychrotrophic strain of the genu s Acinetobacter. Strain no. 6 extracellularly produced a lipolytic enzyme t hat efficiently hydrolyzed triglycerides such as soybean oil during bacteri al growth even at 4 degreesC; it degraded 60% of added soybean oil (initial concentration, 1% w/v) after cultivation in LB medium at 4 degreesC for 7 d. Thus, the bacterium is potentially applicable to in-situ bioremediation or bioaugumentation of fat-contaminated cold environments. We partially pur ified the lipolytic enzyme from the culture filtrate by acetone fractionati on and characterized it. The enzyme preparation contained a single species of cold-active lipase with significant activity at 4 degreesC, which was 57 % of the activity at the optimum temperature (20 degreesC). The enzyme show ed a broad specificity toward the acyl group (C-8-C-16) of substrate ethyl esters.