Protease-producing Bacterium Isolated from Intestines of Anguilla anguilla

A bacterial strain,MJ15, that secreted high amount of proteases was isolated on a casein plate culture from the intestines of Anguilla anguilla. Activity of the enzyme was determined by using a fishmeal as the substrate for the digestion. By means of morphological observations, biolog identification, and phylogenetic analysis on 16S rRNA sequences,MJ15 was identified as Lactococcus lactis subsp.The activity of the crude protease it secreted peaked at 40℃ and pH 5.0.The thermal and alikali stabilities of the protease were relatively poor. The metal ions, K+, Na+, Cu2+, and Fe2+, enhenced the enzymatic activity, while Zn2+ or pepstatin Aslightly inhibited it.The Kmand Vmaxof the enzyme were determined to be 8.77 mgmL-1 and 53.48 gmin-1mL-1, respectively.