Saccharification of cassava starch by Saccharomycopsis fibuligera YCY1 isolated from Loog-Pang (rice cake starter)

Abstract

The main objectives of this study were to select amylolytic yeasts from Loog-Pang, a traditional starter culture for production of alcoholic foods and drinks in southern Thailand, and to optimize the saccharification of cassava starch to reducing sugar by the selected yeast isolate. Seventy-four yeast isolates were obtained from ten samples of Loog-Pang. The isolates were tested for amylolytic activity on Yeast-Peptone Cassava medium (YPC) contained 30 g/l of cassava starch. Only three isolates showed amylolytic activity which produced clear zone on the YPC agar. The best amylolytic strain with clear zone of 8 mm was identified by 26s rDNA as Saccharomycopsis fibuligera. The optimum medium for saccharification by Saccharomycopsis fibuligera. YCY1 was only 50 g/l of cassava starch in distilled water without nitrogen sources added and pH adjustment. The optimal saccharification conditions were 200 ml cassava starch (50 g/l) in 500 ml Erlenmeyer flask, shaking at 100 rpm and 37°C. Under these conditions, the highest reducing sugar was obtained 46±0.53 g/l after 120 h cultivation (84% of the theoretical yield).