Gyozo Terui

Kinetics of hydrolase production by microorganisms

ABSTRACT The enzyme-forming systems (EFSs) concerned with the amylase of Bacillus subtilis, and the glucamylase and acid protease of Aspergillus niger, have been shown to be highly stable in the cultural conditions applied owing to the low decay rate of mRNAs specific for these respective enzymes. The quantity per cell of mRNAs for any of these enzymes is regarded as limiting the specific rate of enzyme production in the conditions used for enzyme production. Investigations on the repression, derepression and the preferential synthesis of these hydrolases have led to simple hypothetical relationships.

Freezing and freeze-drying of Spirulina platensis

Abstract A species of blue-green alga, Spirulina platensis, is extremely susceptible to freezing and drying. However, young cells grown autotrophically with a high intensity of light were resistant to freeze-thawing if the rate of temperature change in the operation was in the range of 20–50 °C/min. Several amino acids, gum arabic, and gelatin were effective in protecting cells from injury caused by freezing. In the case of drying only gum arabic and gelatin could protect cells from injury. The gum arabic-plug method of freeze-drying was shown to be the most suitable method for the maintenance of viability in this alga. The freeze-thawed or freeze-dried cells grew to form abnormally long cells after a period of long lag in the first stage of transfer.