Characterization of the Candida rugosa lipase system and overexpression of the lip1 isoenzyme in a non-conventional yeast.

The fungus C. rugosa produces lipase isoenzymes (CRLs) homologous to the Geotrichum candidum and Yarrowia lipolytica lipases to which they share ca. 40 and 30% sequence identity, with a domain of sequence conservation at the N-terminal half of the protein. CRL proteins have high sequence homology but are not identical in their catalytic activity, therefore calling for the resolution of isoforms via heterologous expression. The non-conventional use of a serine codon in several Candida species frustrates overexpression in the currently available host systems. The LIP1 gene, coding for the major CRL form, was therefore expressed in C. maltosa, a related fungus with the same codon usage as C. rugosa. A recombinant lipase was produced and secreted in an active form in the culture medium upon engineering the 5' and 3' ends of the gene.