Based on contour plots and variance analysis, optimum conditions for endomannanase production from Bacillus sp. CFR1601 were attained when defatted coconut residue was supplemented with sesame oil meal (10.0, w/w), Tween-80 (0.2%, v/v) and inoculated with bacterial cells from log phase (12h old; OD600nm ≈ 3.6).