关键词: 深海适冷菌, 蛋白酶, 离子 , 胞外酶分泌

Abstract: The deepsea bacterium Pseudoalteromonas sp. SM9913 can secret abundant extracellular proteases when cultured in sea water ferment culture medium ( swfcm ). The effects of different ions on the extracellular protease secretion were studied. It is shown that the protease activity increases while the concentration of NaCl increases from 1% (w/v) to 5% (w/v). Mg2+ inhibit the extracellular proteases secretion obviously. The effect of Fe3+ is not remarkable. The addition of K+, Ca2+ and phosphate at the same time could improve the extracellular protease secretion. Sr2+, F- and B- could improve the extracellular protease secretion of P. sp. SM9913 when acting separately, which combined effects are lower than their separate effects on the protease secretion. The combination of the above ions is shown to be able to increase the extracelluar protease secretion. New light has been shed on the scheme of extracellular protease secretion of coldadapted deepsea bacterium P. sp. SM9913.

Key words: ions , extracellular protease secretion, protease, coldadapted bacteria