Production of extracellular trypsin and chymotrypsin inhibitors by a Streptomyces sp

The production of extracellular inhibitors by Streptomyces sp. 1–72, specific either to trypsin (TI‐1), or to chymotrypsin (CI‐1), was investigated in relation to the cell growth and composition of the cultivation media. The biosynthesis of the inhibitors was found to be of a growth‐associated type which reached a maximum level at late exponential phase. All of the investigated carbon sources, including starch, disaccharides and monosaccharides, equally supported the production of both inhibitors, while the effect of the different nitrogen sources considerably varied, some of then being totally ineffective. The sources which mostly supported the biosynthesis of the inhibitors were tryptone (3%) for TI‐1, and peptone (3%) for CI‐1 respectively.