The invention relates to a method for the production of xylitol, the method comprising (a1) providing (i) a microorganism having xylanolytic activity, and (ii) a microorganism capable of converting a pentose sugar to xylitol; or (a2) providing a microorganism having xylanolytic activity and being capable of converting a pentose sugar to xylitol, (b) culturing the microorganism of step (a1) (i) or the microorganism of step (a2) in a medium comprising polymer or oligomer materials containing pentose sugars in conditions sufficient for enabling hydrolysis of said polymers or oligomers by the microorganism; (c) producing xylitol in the microorganism of step (a1) (ii) or in the microorganism of step (a2) by bioconversion of the hydrolysis products obtained in step (b), and (d) recovering said xylitol produced. The invention also relates to a microorganism, which has xylanolytic activity and has been genetically modified (i) to enhance its xylanolytic activity, and (ii) to reduce its xylitol metabolism.