FACTORS AFFECTING GROWTH YIELD OF ARTHROBACTER SIMPLEX IN ITS HEAT-KILLED CELL SUSPENSION

Abstract

Growth of Arthrobacter simplex in its heat-killed cell suspension was studied. Growth yield increased in the culture supplemented with inorganic salt mixture. The effect was common to many inorganic salts including chlorides of alkaline and alkaline earth metals and ammonium. The optimum concentrations of inorganic salts were 0.5 to 1.0mM for chlorides of bivalent cations and 2.5 to 10mM for univalent cations.Inorganic salts were effective in the utilization of the compounds present in the insoluble part of the heat-killed cell suspension. Protein, amino acids, DNA, and RNA were utilized as growth substrates. When inorganic salt was not supplemented, growth was dependent mostly on the materials released from the cells by heating. The growth substrates were amino acids and a part of RNA.It was also observed that the larger the number of heat-killed cells supplied was, the higher was the ratio of viable cell number attained to that of heat-killed cells. This observation was explained in relation to the effect of inorganic salts on the growth. Possible mechanism of the stimulating effect of inorganic salts was discussed.