Screening and characterization of newly isolated thermotolerant and ethanogenic strain of Pichia kudriavzevii

Screening and characterization of thermotolerant and ethanogenic yeast with improved economics for ethanol production was attempted in present study. Eight thermotolerant and ethanogenic isolates of yeast were isolated from the diverge ecosystem. All the isolates grew at 40°C but EM12 and ST1 showed better growth than other six. Evaluation of ethanol tolerance showed that five isolates tolerate up to 12% ethanol. Enzyme profiling of these isolates revealed that they were found to possess β-galactosidase. The EM12 isolate was found to produce maximum of 49.21 IU/ml β-galactosidase amongst all. Isolate EM12 was most potential ethanogenic amongst all, with yield of 44.4% and fermentation efficiency of 86.38%. This isolate found to produce 38 g/l of ethanol. This thermotolerant and ethanogenic strain EM12 showed better economic for ethanol fermentation at elevated temperature in laboratory experiment. Therefore, it was selected for further thorough characterization. Based on the morphological, cultural and biochemical characterization followed by molecular analysis of 18S rDNA, EM12 isolate was identified as the strain of Pichia kudriavzevii.

Eight thermotolerant and ethanogenic yeast isolates were obtained after extensive screening from the diverge ecosystem.

Further screening based on ethanol tolerancewas attempted and then selected five isolates were adapted to 12% ethanol concentration.

Yeast isolates were finally evaluated for ethanol fermentation by shake flask studies.

The results showed EM12 isolate as the most as most efficient ethanol produce with a yield of 44.4% and fermentation efficiency of 86.38%.

This selected thermotolerate isolate found to 38 g/l of ethanol.

Selected EM12 isolate is characterized as newly isolated strain of Pichia kudriavzevii.