2.2 Isolation of yeast Isolation of yeast was carried out using the enrichmentculture technique as described by Limtong et al. (3). Onegram of samples was inoculated into 100-mL of autoclavedyeast extract-malt extract broth (YM broth) containing0.3% yeast extract, 0.3% malt extract, 0.5% polypeptoneand 1% glucose. The medium was also supplementedwith 4% (v/v) ethanol. After inoculation, the culture brothswere incubated in a shaker incubator (150 rpm) at 35oCfor 3 days. 1% of the active culture was transferred into afresh YM medium supplemented with 4% (v/v) ethanoland continuously culturing for 3 days as previouslydescribed. After 3 days of incubation, enriched cultureswere streaked on YM agar plates and then incubated at35oC. Colony appeared on the YM agar medium wascollected and re-streaked until the pure cultures wereobtained. All pure cultures were maintained on YM agarslants at 4oC and subculturing was performed every 3months. For long-term storage, the cultures were kept in50% (v/v) glycerol solution and stored at -20oC.