Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 9/18/2010
Publication Date: N/A
Technical Abstract: Furfural and 5-hydroxymethylfurfural (HMF) are inhibitory compounds commonly encountered during lignocellulose-to-ethanol conversion for cleaner transportation fuels. It is possible to in situ detoxify the aldehyde inhibitors by tolerant ethanologenic yeast strains. Multiple gene-mediated reductions of the inhibitors have been characterized and numerous yeast reductase genes recognized in association with the in situ detoxification of furfural and HMF. Recently, we identified a novel nicotinamide adenine dinucleotide phosphate (NADPH)-dependent aldehyde reductase gene, ARI1 (YGL157W), from Saccharomyces cerevisiae involved in the detoxification of the inhibitors. In this study, we present two uncharacterized open reading frames (ORFs) representing two new members of the newly identified aldehyde reductase gene family of S. cerevisiae. Crude protein extracts and partially purified proteins of these new aldehyde reductase gene clones displayed specific enzyme reduction activity toward at least 14 aldehydes including lignocellulose-derived inhibitors such as furfural, HMF, anisaldehyde, benzaldehyde, cinnamaldehyde, and phenylaldehyde. Based on deduced amino acid sequence similarity, the most conserved functional motif analysis, enzyme assays, and gene clone tests, we designated these two ORFs as ARI2 and ARI3 of S. cerevisiae, new members of aldehyde reductase in subclass "intermediate" of the short-chain dehydrogenase/reductase (SDR) superfamily. These genes, functioning in concert with other important reductase genes and regulatory elements, contributed in situ detoxification of aldehyde inhibitors by the tolerant yeast.