Identification of Glucoamylase cDNA Sequence of Saccharomycopsis (Syn. Endomycopsis) bubodii 2066

Abstract

Saccharomycopsis (Syn. Endomycopsis) bubodii 2066 is an isolate from bubod, a starter used in making rice wine in northern Philippines. We have shown that the yeast has amylolytic activity on raw sago starch. In our attempt to identify the putative raw starch-digesting amylase in S. bubodii, we determined the cDNA sequence of a glucoamylase gene. One primer pair that was designed based on a glucoamylase of Saccharomycopsis fibuligera HUT7212 (GLU1, NCBI Accession Number L25641.1) produced a sequence of 1234 base pairs. To obtain a wider coverage, a primer walking strategy was carried out using four primer pairs designed based on GLU1 gene. The generated sequence of 1535 base pairs shows 98.7 to 100% homology when aligned with glucoamylase genes from four strains of S. fibuligera suggesting that this glucoamylase is highly conserved between the Saccharomycopsis species. This work further reports a gene sequence of glucoamylase derived from Philippine-isolated yeast. The sequence is deposited in GenBank and assigned the accession number KP068007.1. The gene may be heterologously expressed in Saccharomyces cerevisiae for possible utilization in the direct conversion of raw sago starch to bioethanol.