EFFECTS OF AUTOCLAVE-INDUCED CARBOHYDRATE HYDROLYSIS ON THE GROWTH OF BETA-VULGARIS CELLS IN SUSPENSION

Media of de Greef & Jacobs (1979) were autoclaved either with all the nutrient components in a single vessel (medium 1) or with the following components in separate vessels: FeNa-EDTA + CaCl2 (medium 2), FeNa-EDTA + NaH2PO4 (medium 3) or sucrose (medium 4). Medium 5 was prepared by autoclaving FeNa-EDTA + NaH2PO4 and sucrose in two separate vessels. It was found that the dry mass yield of cell suspensions of Beta vulgaris was lowest in medium 1, followed by media 2 and 3. There was no significant difference among media 3, 4, and 5. The plot of dry mass yield of the cell suspensions against the rates of cyanide-initiated oxygen consumption which indicate the extent of carbohydrate hydrolysis of the media during autoclaving, indicated the presence of a threshold rate of about 17-20 nmol ml-1 min-1. Dry mass yield of the suspensions decreased rapidly when the rate exceeded this value. For media with glucose as the source of carbohydrate, the rate of cyanide-initiated oxygen consumption exceeded the threshold value by a factor of 1.5 to 2, depending on the volume of the media autoclaved.