Pretreating lignocellulose with oxalic acid (OA) or diethyl oxalate (DEO) allows for the efficient release of hemicellulosic sugars.  The sugars extracted from both wood and corn dry milling residue consisted of xylose, arabinose, glucose and their oligomers, small amounts of cellobiose, galactose and mannose.  For this study, the concentration of sugars in the extracts varied from 6 to 12% along with 0.6 to 1.2% phenol compounds.  Detoxification and neutralization was required before the extracts could support fermentation.  The detoxification consisted of two steps (1) addition of Pichia stipitis cell pellets and 1% polyvinylpolypyrrolidone (PVPP) at pH 3.0, at 6-8 ºC for ~2 h and (2) pH adjustment to 6.0 at 25 ºC by lime addition. The pellet/PVPP treatments removed more than 50% phenol compounds and adsorbed other small molecular weight toxic substances with insignificant loss of sugars.  Pichia stipitis strains such as CBS-6054, FPL-061, FPL-DX26 and FPL Shi-21 grew well on the detoxified extracts and produced up to 2.5% ethanol from xylose and the hexoses. However, arabinose was not converted to ethanol.  Instead, it was partially respired at the end of fermentation.  Controls without the pellet/PVPP detoxification but with the lime neutralization exhibited poor growth.  Optimization of factors affecting PVPP and cell pellet treatments will enhance ethanol yield and productivity from fermentation of hydrolyzate produced with OA or DEO.