THE INFLUENCE OF HYDROSTATIC PRESSURE ON THE GROWTH AND VIABILITY OF TERRESTRIAL AND MARINE BACTERIA

Abstract

The influence of hydrostatic pressures up to 9000 lbs. per sq. in. on the growth and viability of representative spp. of 16 genera of bacteria and 5 genera of yeasts in pure culture, initially in the logarithmic growth-phase in broth, was studied at 20[degree], 30[degree], and 40[degree]C. In all cases the effects of pressure depended on the temp. of incubation, lower temps. generally accentuating a growth-retarding and disinfecting action of pressure, whereas pressure apparently opposed the unfavorable effects of above-opt. temps. In some cases, increased pressure permitted growth to occur at temps. too high for growth at atmospheric pressure. In general, bacteria isolated from the deep sea were more resistant to the harmful effects of pressure than those from the surface or from terrestrial sources, and in some cases grew faster under pressure. Growth of most terrestrial spp. at 30[degree]C was retarded, and death accelerated, by 4500 lbs. p.s.i. Growth of terrestrial spp. failed to occur perceptibly, and the cultures were sterilized, within 48 hrs. under 9000 lbs. p.s.i. at 30[degree]C.