The invention relates to a polypeptide comprising an exoglucanase catalytic domain comprising a sequence selected from the group consisting of SEQ ID NO: 1, SEQ ID NO: 2 and SEQ ID NO: 3,and to a polypeptide having beta-glucosidase activity comprising a sequence selected from the group consisting of SEQ ID NO: 6, SEQ ID NO: 7 and SEQ ID NO: 8, and to functionally equivalent variants thereof that maintain or improve their catalytic activity. Additionally, the invention relates to an enzyme cocktail comprising said polypeptide(s) and an endoglucanase. Further, the invention also relates to methods for hydrolysing cellulose to cellobiose and/or cellotetraose, cellobiose and/or cellotetraose to glucose and cellulose to glucose, and to produce bioethanol, using the polypeptides or enzyme cocktails of the invention, and to the uses of the polypeptides and enzyme cocktails of the invention for hydrolysing cellulose to cellobiose and/or cellotetraose, cellobiose and/or cellotetraose to glucose and cellulose to glucose, and to produce bioethanol.