[Novel immobilization of arginase I via cellulose-binding domain and its application in producing of L-ornitine].

The recombinant Escherichia coli strain pET35b-ARG, which overexpresses arginase I fused to a cellulose-binding domain (CBD), was developed. After preparing cellulose microspheres, arginase I was immobilized via the CBD of the fusion protein. Under optimal reaction conditions (40 degrees C, pH 9.5, 1 mM of Mn2+, 30 microl/ml of immobilized enzyme, 30 g/l of L-Arg, and for I h), the conversion rate of L-Arg was 98.7%. After 7 reuses of 30 microl of immobilized enzyme in 1 ml of catalytic solution, 153 mg of L-Orn with 97.3% purity was obtained. This indicated that the immobilization method was effective, feasible and could be used for the industrial production of L-Orn in the future.