The aim of this review was to characterise of bacterial and fungal enzymes taking part in the degradation of arabinoxylans. This study especially describes ferulic acid esterase, xylanase and acethylesterase. This paper presents the sum of results concerning the possibility of ferulic acid production from barley spent grain using purified enzymes or commercial enzyme preparations of microbial origin. Barley spent grain is the most valuable by-product of brewing industry, rich in precious dietary components like proteins, dietary fiber, fatty acids and others. Ferulic acid is a natural, strong antioxidant commonly present in Graminaceae family plants and in a number of by-products of brewing industry – barley spent grain. Ferulic acid can be also microbiologically transformed into other compounds used in food industry, like antioxidant caffeic acid or vanillin, precious flavoring agent.