1a.Objectives (from AD-416):
Identify genomic basis and relationships between enhanced inhibitor tolerance and efficient heterogeneous sugars utilization derived from lignocelluolosic biomass; engineer tolerant Saccharomyces cerevisiae NRRL Y-50049 for improved and balanced utilization of pentoses and hexoses from lignocellulosic hydrolysates.
1b.Approach (from AD-416):
Comparative genome sequence analysis will be carried out to underline genetic fundamentals of the tolerance and in situ detoxification of the biomass conversion inhibitors.
Comparative genome expression analysis will be carried out to establish gene regulatory networks involving tolerance and heterogeneous sugar utilizations including pentoses and hexoses.
Genetic engineering will be carried out to incorporate heterogeneous genes into the tolerant Y-50049 for improved pentose utilization.
The research focused mainly on comparative genome sequence analysis. Ethanologenic yeast strain NRRL Y-12632 and its stress-tolerant derivative NRRL Y-50049 were sequenced and compared in this study. Phase I of genome sequencing in this research was completed. Phase II of this collaborative research consists of two parts. The current progress represents part one of the phase II. This research found more than 30,000 single nucleotide variations in a type industrial yeast strain of Saccharomyces cerevisiae compared with a lab model strain. Genes involved in signaling transduction pathways displayed a higher frequency of sequence variations. Many of these genes demonstrated enhanced signature expressions under challenges of furfural and hydroxymethylfurfural (HMF). This research concludes that the industrial yeast has a genome with more robust signaling transduction pathways that are of great interest for further advanced biofuels research and development. A manuscript of this original research is currently under preparation and intensive revisions. It is anticipated to be submitted in 2013.