The gene encoding D-amino acid oxidase (DAAO) from Trigonopsis variabilis CBS 4095 has been cloned and expressed in Escherichia coli BL21 (DE3). Unfortunately, it was observed that the host cell was negatively affected by the expressed DAAO, resulting in a remarkable decrease in cell growth. To overcome this problem, we investigated several factors that affect cell growth rate and DAAO production such as addition time of inducer and dissolved oxygen (DO) concentration. The addition time of lactose, which was used as an inducer, and DO concentration appeared to be critical for the cell growth of E. coli BL21(DE3)/pET-DAAO. A two-stage DO control strategy was developed, in which the DO concentration was controlled above 50% until specific stage of bacterial growth($OD_{600}$ 30-40) and then downshifted to 30% by changing the agitation speed and aeration rate, and they remained at these rates until the end of fermentation. With this strategy, the maximum DAAO activity and cell growth reached 18.5 U/mL and $OD_{600}$ 81, respectively. By reproducing these optimized conditions in a $12-m^3$ fermentor, we were able to produce DAAO at a productivity of 19U/mL with a cell growth of $OD_{600}$ 80.