A lipase with broad temperature range from an alkaliphilic gamma‐proteobacterium isolated in Greenland

A gamma‐proteobacterium related to the genera Alteromonadales and Pseudomonadales, isolated from a cold and alkaline environment in Greenland, has been shown to produce a lipase active between 5°C and 80°C, with optimal activity at 55°C and pH 8. PCR‐based screening of genomic DNA from the isolated bacterium, followed by genome walking, resulted in two complete open reading frames, which were predicted to encode a lipase and its helper protein, a lipase foldase. The amino acid sequence derived for the lipase showed resemblance to lipases from Pseudomonas, Rhodoferax, Aeromonas and Vibrio. The two genes were cloned into different expression systems in E. coli with or without a putative secretion sequence, but despite the fact that both recombinant lipase and lipase foldase were observed on SDS–PAGE, no recombinant lipase activity was detected. Attempts to refold the recombinant lipase in vitro using a purified lipase foldase remained unsuccessful.