Strains of S. thermophilus grown on partially deproteinized whey produced an exocellular polysaccharide which contained L-rhamnose and D-galactose in the ratio 1:1.47. Methylation analysis showed the existence of 3 and 6-substituted D-galactose, 2-substituted L-rhamnose and nonreducing terminal D-galactose. A polysaccharide was also obtained from the cell surface after sonication. Molecular weights of both polysaccharides were estimated by gel filtration on HPLC at about 9.000.000 and 1.100.000. resnectivelv. These oolvsaccharides were different from the previously reported products' by S. rhermophilus strains and their presence may contribute to the ropy property of yogurt.
Conditions for the production of the trypsin inhibitor from Cephalosporium sp. KM 388 were investigated. Polypeptone-meat extract-glucose medium supported excellent production of the trypsin inhibitor. In this medium, polypeptone and meat extract were utilized both as carbon and nitrogen sources and as limiting substrates for the cell growth. Glucose was consumed during the stationary growth phase and prevented the disappearance of inhibitor activity. Cephalosporium sp. KM 388 grew at a rate of a first-order reaction for the cell concentrations. Trypsin inhibitor production paralleled cell growth. At 27°C, the maximum specific rates of growth and inhibitor production were 0.14 h-1 and 2.1 U of inhibitor/h per mg of cell, respectively. The production rate and the maximum yield of the inhibitor were increased 1.5-and 1.2-fold, respectively, when the initial pH 6.3 was maintained throughout the fermentation.
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