Endo-1,5-a-l-arabinanases are glycosyl hydrolases that are able to cleave the glycosidic bonds of a-1,5-l-arabinan, releasing arabino-oligosaccharides and l-arabinose. Two extracellular endo-1,5-a-l-arabinanases have been isolated from Bacillus subtilis, BsArb43A and BsArb43B (formally named AbnA and Abn2, respectively).