The optimal conditions for the production of carboxymethylcellulase (CMCase) by Cellulophaga lytica LBH-14 at flask scale has been previously reported. In this study, we optimized the parameters involved in dissolved oxygen in 7 and 100 L bioreactors for pilot-scaled production of CMCase by C. lytica LBH-14. The optimal conditions of agitation speed and aeration rate for cell growth in 7 L bioreactors were 395 rpm and 0.98 vvm, whereas those for production of CMCase were 357 rpm and 0.55 vvm. The optimal inner pressures for cell growth and production of CMCase by C. lytica LBH-14 in 100 L bioreactors were 0.00 and 0.06MPa, respectively. The production of CMCase under an optimized inner pressure was 1.38 times higher than that without an inner pressure. The maximal production of CMCase by C. lytica under optimized conditions at pilot scale using rice bran and ammonium chloride was 153.6U/mL, which was 1.39 times higher than that at flask scale.