Objective: Alkaline Carboxymethyl Cellulase (CMCase) is an attractive enzyme for the textile, laundry, pulp, and paper industries; however, commercial preparations with sufficient activity at alkaline conditions are scarce.

Methods: High CMCase-producing bacterial isolate, SX9-4, was screened out from soil bacteria, which was identified as Flavobacterium sp. on the basis of 16S rDNA sequencing.

Results: The optimum pH and temperature for CMCase reaction were 8.0 and 55°C, respectively. Alkaline CMCase was stable over wide pH (3.0-10.6) and temperature (25-55°C) ranges. Enzyme activity was significantly inhibited by the bivalent cations Mn²⁺ and Cu²⁺, and was activated by Fe²⁺. To improve the alkaline CMCase production of SX9-4, fermentation parameters were selected through onefactor- at-a-time and further carried out by response surface methodologies based on a central composite design.

Conclusion: High CMCase production (57.18 U/mL) was achieved under the optimal conditions: 10.53 g/L carboxymethylcellulose sodium, 7.74 g/L glucose, 13.71 g/L peptone, and 5.27 g/L ammonium oxalate.

目的：碱性羧甲基纤维素酶（CMCase）是一种对纺织，洗衣，制浆和造纸行业有吸引力的酶；然而，缺乏在碱性条件下具有足够活性的商业制剂。

方法：从土壤细菌中筛选出高产CMCase的细菌分离株SX9-4，鉴定为黄杆菌属。基于16S rDNA测序。

结果：CMCase反应的最佳pH和温度分别为8.0和55°C。碱性CMCase在宽pH（3.0-10.6）和温度（25-55°C）范围内均稳定。酶活性被二价阳离子Mn ²⁺和Cu ²⁺显着抑制，并被Fe ²⁺激活。为了提高SX9-4的碱性CMCase产量，一次通过一个因子选择发酵参数，然后通过基于中央复合设计的响应面方法进一步进行发酵。

结论：在最佳条件下可实现高CMCase产量（57.18 U / mL）：10.53 g / L羧甲基纤维素钠，7.74 g / L葡萄糖，13.71 g / L蛋白one和5.27 g / L草酸铵。