The present invention discloses novel polypeptides and enzyme preparations containing them, which enhance the efficiency of the cellulosic degradation even at elevated temperatures. The polypeptides are produced by recombinant technology, and means for their production are described. The novel polypeptides are useful in processing biomass, and in biofuel, starch, textile, detergent, pulp and paper, food, feed or beverage industries. They may also be used e.g. in cleaning the interior of a dishwashing machine or for biofinishing or biostoning. The novel polypeptides are also useful in animal feed.