No abstract

The physiological behaviour of Thermoactinomyces vulgaris - producing a thermostable serine-protease - was analyzed during fermentation. During 38 h the consumption of nutrients and oxygen as well as the rates of macromolecular and protease synthesis were measured. The morphological and ultrastructural changes of the mycelia were also studied. The mycelia grew exponentially for about 5 hours. After a short lag and a second slower growth phase, growth continued about linearly until the end, as was indicated by a constant rate of incorporation of labelled thymidine. However, at the same time a changing portion of hyphae - up to 45% - underwent lysis. According to the changing ratio of growing and lysing material, regarding the physiological activity of the culture the fermentation process could be divided into 4 periods. The formation of the protease started at the transition to the slow growth phase and continued linearly. The ability to produce the protease was attributed to a mycelium being formed after the shift down caused by limitation of supply of utilizable nitrogen compounds. The end of protease production 10 h later was correlated to a drastic decrease of the respiratory activity of the mycelia, probably caused by exhaustion of easily utilizable carbohydrates.

A method for automatic determination of proteolytic activity during fermentation is described. Therefore the autoanalyzer ADM 300 of the PRUEFGERAETEWERK MEDINGEN F.R.G. is connected to a fermenter. After filtration of the biomass, the culture filtrate is diluted and then incubated with casein solution (0.75%, p H 8.0, 55OC); low moleculare cleavage products are separated from higher molecular ones by dialysis. The absorbence is measured a t 600 nm after addition of alkaline copper tartrate and FOLIN solution. By use of different dilution rates, a range of 0 -32 units ml-1. may be measured. The coefficient of variation is 5.5.

No abstract

The physiological behaviour of Thermoactinomyces vulgaris — producing a thermostabile serine‐protease — was analyzed during fermentation. During 38 h the consumption of nutrients and oxygen as wll as the rates of macromolecular and protease synthesis were measured. The morphological and ultrastructural changes of the mycelia were also studied. The mycelia grew exponentially for about 5 hours. After a short lag and a second slower growth phase, growth continued about linearly until the end, as was indicated by a constant rate of incorporation of labelled thymidine. However, at the same time a changing portion of hyphae — up to 45% — underwent lysis. According to the changing ratio of growing and lysing material, regarding the physiological activity of the culture the fermentation process could be divided into 4 periods. The formation of the protease started at the transition to the slow growth phase and continued linearly. The ability to produce the protease was attributed to a mycelium being formed after the shift down caused by limitation of supply of utilizable nitrogen compounds. The end of protease production 10 h later was correlated to a drastic decrease of the respiratory activity of the mycelia, probably caused by exhaustion of easily utilizable carbohydrates.