Molecular Characterization of Alcohol Dehydrogenase 1 (ADH1) Gene in Indigenous Yeast, Pichia spp

Abstract

Pichia anomala (Wickerhamomyces anomalus) and P. kudriavzevii belong to non-conventional yeast groups that are less explored compared to conventional yeast, Saccharomyces cerevisiae. Nonetheless, yeast genera of Pichia have a high potential to produce bioethanol under fermentation-related stress conditions. However, the comprehensive study of the key enzyme, alcohol dehydrogenase, in ethanol fermentation in these genera of yeast is limited. Thus, this study aimed to analyze the ADH1 gene encoding alcohol dehydrogenase from seven indigenous Pichia spp.,  isolates at the molecular level. Multiple sequence alignments and the phylogenetic tree of amino acids showed that ADH1 gene from P. anomala and P. kudriavzevii 1P4 were closely related to alcohol dehydrogenase encoding genes from the S. cerevisiae sequence and Streptococcus pneumoniae, respectively. The enzyme modeling structure revealed 90.5% for W. anomalus and 89.7% for P. kudriavzevii in the favored area based on Ramachandran Plot analysis. ADH1 protein model from two Pichia isolates has conserved two Zn binding domains. Docking studies indicate that this enzyme has a high affinity towards NADH and ethanol. Our data indicate that the ADH1 gene from P. anomala potentially expressed alcohol dehydrogenase homolog to S. cerevisiae. Yet, more studies are required to characterize ADH1 gene from P. kudriavzevii.