NOVELTY - Production (M1) of butanol involves: contacting composition comprising microorganism capable of producing butanol and an enzyme or combination of enzymes capable of converting a 5-carbon sugar to xylulose or xylulose-5-phosphatev with a carbon substrate comprising mixed sugars; and culturing the microorganism under conditions of limited oxygen utilization.    USE - For production of butanol (selected from isobutanol) (claimed) as fuel additive, feed stock chemical in plastic industry, and food-grade extractant in the food and flavor industry.    ADVANTAGE - The composition is capable of producing butanol and ethanol; is capable of producing butanol at least about 0.4 g/g % theoretical yield. The method increase butanol production from sugars and recovers the butanol through in situ product recovery method. The method improve the production of butanol from lignocellulosic hydrolysates by providing methods to efficiently convert 5-carbon sugars, obtainable from the lignocellulosic hydrolysates, to butanol and processes for recovering butanol from fermentation in the presence of mixed sugars. The method produces butanol in an environmentally friendly atmosphere.    DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for the following:    (1) a butanol composition (c1) obtained by the method (M1), (M2), (M3) or culturing the composition of under conditions of limited oxygen utilization; and    (2) a composition (c2) for producing butanol comprising microorganism capable of producing butanol; enzyme or combination of enzymes capable of converting a 5-carbon sugar to xylulose or xylulose-5-phosphate; source of 5-carbon sugars; and fermentation media;    (3) growing (M2) a butanol-producing microorganism in lignocellulosic material involving: providing a composition containing lignocellulosic material; contacting the composition with microorganism capable of producing butanol and enzyme or combination of enzymes capable of converting a 5 -carbon sugar to xylulose or xylulose-5-phosphate; and maintaining the composition under conditions of limited oxygen utilization; and    (4) inhibiting (M3) the growth of microorganisms that do not produce butanol in a composition comprising a lignocellulosic material involving: providing a composition containing lignocellulosic material; contacting the composition with microorganism capable of producing butanol and an enzyme or combination of enzymes capable of converting a 5-carbon sugar to xylulose or xylulose-5-phosphate; and maintaining the composition under conditions of limited oxygen utilization.