Microbial Enzymes for the Production of Xylooligosaccharides

In the last years, the attention in hemicellulose has significantly grown due to its interesting properties and unexplored applications. Converting xylan from the hemicellulosic fraction of lignocellulose into xylooligosaccharides (XOS) has recently appeared as a novel strategy to obtain high added-value products. These XOS are emerging prebiotic compounds that are considered among the most promising functional food ingredients. Enzymes are well-known biocatalysts produced from bacteria, yeast, and fungi widely applied in different biotechnological processes. Enzymes’ mode of action is bond-specific. In the particular case of hemicellulose valorization, enzymatic hydrolysis gives rise to a great depolymerization of xylan, which ultimately results in XOS release. To make the final product suitable for the food industry, very high degree of purity is required. Because of that, xylooligosaccharide-rich media should be subjected to purification processes to remove impurities and increase the quality of the prebiotic compounds. This chapter gives a general overview on the production of XOS via enzymatic hydrolysis of hemicellulose. Required enzymatic activities for efficient XOS release are described and the most efficient downstream processes for prebiotics purifications are discussed. Besides, future perspectives in the field of XOS production from hemicellulose are also highlighted.