lip2, a novel lipase gene cloned from Aspergillus niger exhibits enzymatic characteristics distinct from its previously identified family member

We have cloned a novel lipase gene, lip2, from Aspergillus niger and expressed it in Escherichia coli. Upon purification of the recombinant Lip2 protein, its properties were characterized. In comparison with a previously identified lipase Lip1, both enzymes are acid lipases (optimal pH <6.5), Ca²⁺-dependent and PMSF-sensitive, but have different molecular weights (35 and 43 kDa), optimal substrate spectra (C10 and C8), optimal reaction temperatures (45 and 50°C) and thermal stability. Circular dichroism spectroscopy revealed that Lip2 contains a typical Ca²⁺-active site. This first report on the cloning of the Lip2 gene and its enzymatic characteristics may greatly facilitate its potential industrial application.