BIOETHANOL FERMENTATION OF ACID HYDROLYSATES FROM YELLOW POPLAR USING Pichia stipitis

We investigated acid hydrolysis characteristics of yellow poplar woodmeal with concentrated sulfuric acid for high concentration of monosaccharides production, and its bioethanol fermentability. The ethanol fermentability in deacetylated yellow poplar hydrolysate (DYPH) by Pichia stipitis was also investigated. The 94% of acetyl group in xylan of yellow poplar hemicellulose fraction was extracted by NaOH at mild condition. P stipitis was affected seriously on cell growth and ethanol production in the synthetic medium added 7.1 g/l of acetic acid or yellow poplar hydrolysate (YPH) containing 7.1 g/l of acetic acid. On the other hand, ethanol production in DYPH was slightly higher than that of the control although cell growth decreased by 34%. In the case of DYPH, ethanol yield, volumetric ethanol productivity, and theoretical yield % were 0.48 g/g, 0.40 g/l h, and 93.2%, respectively. The alkaline-pretreatment method greatly enhanced the ethanol fermentability of yellow poplar hydrolyzate.