Ethanol Fermentation From Hot-Water Wood Extract Hydrolysate with A Modified Pichia Stipitis Strain HWR

Hot-water extraction can be viewed as an efficient pre-treatment technology for woody biomass bioconversion. Promoting the extraction to a process step rather than a pre-treatment step significantly improves the outlook of the overall process. The acid hydrolysate of the wood extracts contains mainly 5-carbon sugars. Our earlier studies has shown that Pichia stipitis NRRL Y-11543 was promising in utilization the mixed sugars in the wood extract hydrolysate. However, NRRL Y-11543 was inhibited in dilute sulfuric acid hydrolysate. Repeated adaptation of Pichia stipitis strain NRRL Y-11543 were carried out to improve the ethanol production efficiency for conversion of hot-water wood extract hydrolysates. Fermentation experiments indicated that fbwhr was resistant to the toxicity of hydrolysate in the fermentation media of concentrated hydrolysate, and xylose was completely utilized by the strain to produce ethanol. HWR was grown in the concentrated hydrolysate without any treatment and yielded ~40 g/L ethanol.