The present invention provides a multi-component enzyme system that hydrolyzes hemicellulose oligomers from hardwood which can be expressed, for example, in yeast such as Saccharomyces cerevisiae. In some embodiments, this invention provides for the engineering of a series of biocatalysts combining the expression and secretion of components of this enzymatic system with robust, rapid xylose utilization, and ethanol fermentation under industrially relevant process conditions for consolidated bioprocessing. In some embodiments, the invention utilizes co-cultures of strains that can achieve significantly improved performance due to the incorporation of additional enzymes in the fermentation system.

The disclosure provides thermostable enzymes isolated from Caldicellulosiruptor bescii and fragments thereof useful for the degradation of cellulose and/or hemicellulose, including thermostable cellulases and hemicellulases. The disclosure further provides nucleic acids encoding the thermostable enzymes of the disclosure. The disclosure also provides methods for the conversion of cellulose and hemicellulose into fermentable sugars using thermostable enzymes of the disclosure. The disclosure also provides enzyme cocktails containing multiple enzymes disclosed herein. The enzymes can be used to release sugars present in cellulose or hemicellulose for subsequent fermentation to produce value-added products.

A xylosidase having improved enzymatic activity is disclosed. The amino acid sequence of the xylosidase is a modified amino acid sequence of SEQ ID NO: 2, wherein the modification is a substitution of phenylalanine at position 35 with glutamate, and/or a substitution of glutamine at position 41 with histidine.

A xylosidase having improved enzymatic activity is disclosed. The amino acid sequence of the xylosidase is a modified amino acid sequence of SEQ ID NO: 2, wherein the modification is a substitution of phenylalanine at position 35 with glutamate, and/or a substitution of glutamine at position 41 with histidine.