A RELATIONSHIP BETWEEN MULTIPLE TEMPERATURE OPTIMA FOR BIOLOGICAL SYSTEMS AND THE PROPERTIES OF WATER

Abstract

An unnamed sulfate-reducing bacterium in pure [probably a Clostridium] exhibited multiple temperature optima for growth at 11, 25, and 39[degree]C and minima near 16, 31, and 43[degree]C. Experimental medium consisted of peptone, 1.0 g; Na2SO3, 0.2 g; yeast extract, 1.0 g; Na lactate, 4 ml; Na2SO4, 0.5 g; distilled water, 100 ml; pH adjusted to 7.0. Experiments were carried out in a polythermostat, consisting of an insulated aluminum bar heated at one end and cooled at the other, which provided a linear temperature between 8 and 45[degree] C. The evidence for multiple optima supports a theory which suggests that at 15, 30, 45 and 60[degree]C abrupt changes or "kinks" occur in the properties of water. It is suggested that micro-organisms, influenced by the presence of the kinks, may grow optimally at different temperatures by using different metabolic pathways.