Overexpression of the genes PDC1 and ADH1 activates glycerol conversion to ethanol in the thermotolerant yeast Ogataea (Hansenula) polymorpha

Abstract Conversion of byproduct from biodiesel production glycerol to high‐value compounds is of great importance. Ethanol is considered as promising product of glycerol bioconversion. Methylotrophic thermotolerant yeast Ogataea (Hansenula) polymorpha is of great interest for this purpose as byproduct glycerol contains methanol and heavy metals as contaminants and this yeast utilizes methanol and is relatively resistant to heavy metals. Besides, O. polymorpha shows robust grows on glycerol and produces ethanol from different carbon sources. Thermotolerance of this yeast is an additional advantage that allows increasing the fermentation temperature to 45° ‐ 48 °C leading to the increase of the rate of the fermentation process and to drop of the costs of distillation. Wild‐type strain of O. polymorpha produces insignificant amounts of ethanol from glycerol (0.8 g/L). Overexpression of PDC1 coding for pyruvate decarboxylase enhanced ethanol production till 3.1 g/L whereas simultaneous overexpression of PDC1 and ADH1 (coding for alcohol dehydrogenase) led to further increase in ethanol production from glycerol. Moreover, the increased temperature of fermentation up to 45 °C stimulated the production of ethanol from glycerol used as the only carbon source up to 5.0 g/L which exceeds data obtained by methylotrophic yeast strains reported so far.
Source: Yeast - Category: Molecular Biology Authors: Tags: ISSY32 Special Issue Source Type: research