Isolation and Identification of Local Ethanol Tolerant Yeast Populating Distillation and Milling Sites in Nigeria

摘要

Two yeast strains referred to as OY and SY were isolated and characterised from local distillery and cereal milling sites. Isolation was done using potato dextrose media supplemented with 0.2% chloramphenicol. Morphological and biochemical results together with the rDNA internal transcribed spacer region (ITS) were identified as Pichia kudriavzevii strains GY1 and L9 respectively. OY and SY are ethanol tolerant strains, withstanding ethanol concentrations of up to 20% (v/v) in yeast extract, peptone, malt extract, glucose media. OY and SY displayed good growth in ethanol supplemented medium with pH ranging from 4.8-5.5 at 30℃. Growth measurements were determined by measuring optical density of the cells in broth using spectrophotometer at 570nm. The results obtained suggested that OY and SY demonstrated good parameters as ideal candidates for bioethanol production.