Aspergillus niger KKS, isolated from a farmland near Suwon, was immobilized on Celite and polyurethane foams. Enzyme activities produced by the immobilized cell system in a bubble column were higher than that of shake-flask culture. The enzyme productivities were twice as high. beta-Glucosidase, beta-xylosidase, and xylanase activities obtained in a bubble column were significant when the ground rice straw was used as a substrate.