Candidate ye strains for use in the inversion process were first screened based on their lack of capacity to utilize sucrose in a fermen- tation test using a model medium. To evaluate the sucrose-negative and reducing sugars-positive phenotypes simultaneously. we measured the ethanol concentration using liquid medium instead of the plate medium Yeast strains were precultured in 1 mL of D at 30 c for 24 h. The precultured medium was centrifuged (5000 xg. 5 min) to obtain the yeast cells. The yeast cells were en inoculated into of the model medium lyeast extract 10 g L Bacto peptone 20 g L 15 g L fructose 15 g L and sucrose 120 g L-1), which mimicked the typ ical composition of sugarcane at 30ec with recip (120 Next, the cultured for 24 h (soco xg. rpm) medium was 5 min) and the ethanol concentration of the sup was analyzed as described below.