(3) Screening of thermotolerant, fermentative yeasts
a) Fermentation activity test at 40℃ YPD screening
medium containing 1% yeast extract, 2% polypeptone and
2% glucose was used. Each of the isolated strains was grown
on YM agar (24 − 48 h at 25℃) and then inoculated into 5
mL of YPD screening medium in a test tube containing a
Durham tube and incubated at 40℃ for 5 days. The yeast
fermentation activity was scored by the accumulation of gas
in the Durham tubes. Strains fermenting glucose and produc