초록
<P>The rhamnose utilization pathway in <I>Pichia pastoris</I> has not been clarified although this strain can grow well on rhamnose as a sole carbon source. In this study, four genes, <I>PAS_chr4_0338</I>, <I>PAS_chr4_0339</I>, <I>PAS_chr4_0340</I>, and <I>PAS_chr4_0341</I>, were, for the first time, predicted to be involved in rhamnose metabolism along with the previously identified gene <I>PAS_chr1_4-0075</I>. Moreover, expression of these genes, especially <I>PAS_chr4_0341</I> and <I>PAS_chr1_4-0075</I> designated as <I>LRA4</I> and <I>LRA3</I>, was confirmed to significantly increase and clearly decrease in the presences of rhamnose and glucose, respectively. <I>LRA4</I> encoding a putative L-2-keto-3-deoxyrhamnonate aldolase, was further confirmed via gene disruption and gene complementation to participate in rhamnose metabolism. Using β-galactosidase and green fluorescent protein as reporters, the promoters of <I>LRA4</I> and <I>LRA3</I> performed well in driving efficient production of heterologous proteins. By using food grade rhamnose instead of the toxic compound methanol as the inducer, the two promoters would be excellent candidates for driving the production of food-grade and therapeutically important recombinant proteins.</P>