Vol. 15 No. 124- 133 (2023): Isolation and Characterisation of pH and Temperature Tolerant Yeast from Local Brews for Bio-ethanol Production

The use of yeast for ethanol production from biomass has been well reported, however the
performance of various yeast strains is limited due to high temperature involved of the fermentation
process as well as the ethanol concentration. Efficient production of bioethanol, therefore, requires
strains that are both thermo-tolerant and ethanol tolerant. This paper aimed at producing bioethanol
using ethanol, pH and temperature tolerant yeast species from isolated from local brews in Nigeria.
The study involves the isolation, identification and characterisation of yeast strains using
morphological techniques from local brews samples in Minna, Niger state, Nigeria. All isolates
assimilated xylose sugar; however they showed significant variations in sugar fermentation pattern.
The growth of all the yeast isolates at 45 °C was observed in temperature tolerant activity and
between pH range of 2 to 6; also, all isolates were tolerant to 14% ethanol, however, some showed
the ability to grow at 17% ethanol. All yeast isolates produced ethanol in quantities between 0.73 –
18.43 g/L, however the highest production was observed by isolate B21 on day 2. The study
demonstrated that most of the identified yeast species are temperature and alcohol tolerate up to 45
oC and 14% ethanol. The assimilation of pentose sugars further suggests that these isolates could be
applied for the production of high yield bioethanol and the use of indigenous local brews could be
exploited by various industries for alternative fuel production.