Location: Bioenergy ResearchTitle: Production of xylitol from biomass using an inhibitor-tolerant fungal strain
Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 11/8/2016
Publication Date: 11/8/2016
Citation: Nichols, N.N., Saha, B.C., Frazer, S.E. 2016. Production of xylitol from biomass using an inhibitor-tolerant fungal strain [abstract]. Frontiers in Biorefining International Conference, 11/8-11/2016, St. Simons Island, GA.
Technical Abstract: Inhibitory compounds arising from physical–chemical pretreatment of biomass feedstock can interfere with fermentation of biomass sugars to product. A fungus, Coniochaeta ligniaria NRRL30616 improves fermentability of biomass sugars by metabolizing a variety of microbial inhibitors including furan aldehydes and aromatic- and aliphatic acids and aldehydes. Wild-type C. ligniaria incorporates xylose as a source of carbon and energy. A mutant of C. ligniaria, unable to grow on xylose, had xylose reductase (XR), and xylitol dehydrogenase activities reduced by approximately 70% compared to wild-type activity. The mutant retained ability to metabolize inhibitors in biomass hydrolysates and produced up to 0.46 g xylitol/g xylose in corn stover dilute acid hydrolysate. Optimal temperature and pH for xylitol production by C. ligniaria are 32°C and pH 5-8. Productivity (0.08 g/L h) was lower than values reported for yeast. Addition of a heterologous XR gene restored XR activity to near-WT levels, and increased xylitol yield by 17% (0.55 g xylitol/g xylose) in rich medium. These results suggest use of an inhibitor-tolerant strain in a sequential process, in which xylitol could be obtained as a coproduct of a lignocellulosic ethanol process.