RESUMO
A model for screening the yeast which can ferment xylose to produce the ethanol was constructed.An ethanol yeast was obtained using the lignocellulose as substrate production the ethanol.By malt extract medium pre-culturing,soil samples use the plate with xylose as sole carbon source as the primary screening,then finally screen by the potassium dichromate color-displaying method.A strain named Y2-3 was screened from the soil.Phenotypic analysis including morphology and physiology and biochemical characteristics and 26D1/D2 sequence analysis were carried out.Based on taxonomy results,the Y2-3 was identified as Pichia caribbica.The strain Y2-3 ferments using xylose as sole carbon source: biomass 23.5 g/L,xylose utilization rate 94.7 %,ethanol final yield 4.57 g/L;using mixture sugar:biomass 28.6 g/L,xylose utilization rate 94.2 %,glucose utilization rate 95.6%,ethanol final yield 20.6 g/L.Pichia caribbica is a yeast which can utilize xylose and mixture sugar as substrate.It established the foundation for further research fermentation of ethanol by yeast using lignocellulose.