Foam fractionation can be used to concentrate hydrophobic proteins (such as bovine serum albumin) in solution. However, it cannot be used directly to concentrate cellulase because cellulase solution alone produces only a small amount of foam when aerated. The addition of a surfactant to a cellulase solution makes it possible to foam nonfoaming proteins, such as cellulase. In this paper, three surfactants, namely, cetyltrimethylammonium bromide (CTAB, a cationic detergent), sodium dedecyl sulfate (SDS, an anionic detergent), and pluronic F-68 (a nonionic detergent), were individually added to a 200 mg/L cellulase solution and then aerated. The addition of these surfactants increased the amount of foam produced and enhanced the volume of foamate, the collapsed foam product. The detergent CTAB exhibited the highest enrichment and mass recovery ratios of the three detergents tested. Small changes in the pH in the cellulase foam fractionation process had a strong effect on the cellulase enrichment ratio. At an air flow rate of 4 mL/min, the enrichment ratio at pH 5.0 was 2.7, whereas the enrichment ratios at pH 4.8, 5.2, and 5.5 were less than 2.0. Increases in the buffer concentration resulted in increases in the mass recovery and decreases in the enrichment ratio.