| 摘要 |
The dimorphic yeast Candida rugosa has an unusual codon-usage which hampers the functional expression of genes derived from this yeast in a conventional heterologous host. Lipases produced by this yeast are extensively used in industrial bioconversions, but commercial lipase samples contain several different isoforms encoded by the LIP genes family. In a first laborious attempt the LIP1 gene, encoding the major isoform of the C. rugosa lipases (CRLs), was systematically modified by site-directed mutagenesis to gain functional expression in S. cerevisiae. As alternative approach, the gene (1688 bp) was completely synthesised with an optimised nucleotide sequence in terms of heterologous expression in yeast and simplified genetic manipulation. The synthetic gene was functionally overexpressed in Pichia pastoris. The recombinant CRL was produced at high level and purity, accounting for 90-95 % of the secreted proteins. The physical-chemical and catalytic properties of the recombinant lipase were compared with those of a commercial, non-recombinant C. rugosa lipase preparation. |
