Isolation and Identification of Microorganism, Producing Microbial Alkaline Proteinase Inhibitor (MAPI)

Abstract

In the screening of actinomycetes' culture filtrate for inhibitor of subtilisin and various microbial alkaline proteinases, a novel inhibitor was found in a cultured broth of strain WT-27. This inhibitor was named as MA-PI, abbreviation of microbial alkaline proteinase inhibitor.
Judging from the morphological and physiological properties of the actinomycetes which produced MA-PI, this strain was identified as Streptomyces nigrescens.
For the production of MAPI, this strain was aerobically cultured at 25_??_27°C in a jar fermentor which contained an optimum medium consisting of polypepton 3%, meat extract 1%, glucose 1%, NaCl 0.1%, K₂HPO₄ 0.1% and MnSO₄•nH₂O 0.0001%, pH 7.0. The production of MAPI reached its maximum after 21_??_24hr cultivation.
MAPI had an inhibitory activity against various microbial alkaline proteinases, α-chymotrypsin and papain but not against trypsin, kallikrein, thermolysin, or pepsin.