2RUTHEFURD S M, CHUNG T K, MOREL P C, et al. Effect of microbial phytase on ileal digestibility of phytate phospho- rus, total phosphorus, and amino acids in a low-phosphorus diet for broilers[J].Pouh Sci,2004,83(1):61-68.
3CABRAL C M, CHERQUI A, PEREIRA A, et al.Purification and characterization of two distinct metalloproteases secreted by the entomopathogenic bacterium Photorhabdus sp. strain Az29 [J]. Appl Environ Microbiol, 2004, 70(7):3831-3838.
5LEI X G, STAHL C H. Biotechnological development of ef- fective phytases for minera/ nutrition and environmental p ro- tection[J]. Appl Microbiol Biotechnol,2001,57(4) :474-481.
6VOHRA A, SATYANARAYANA T. Phytases: Microbial sources, production, purification, and potential biotechnological appli- cations [J 1. Crit Rev Biotechnol, 2003,23 ( 1 ) : 29-60.
