GROWTH AND SURVIVAL OF BACTERIA IN PEAT: I. POWDERED PEAT AND RELATED PRODUCTS

Abstract

Comparative tests of various powdered materials showed that well humified peat was superior to other preparations in maintaining the test bacteria in viable condition. Under the test conditions, sterilization of peat improved it as a medium for the maintenance of high numbers of viable cells. Neutralization was important, and more satisfactory following, than preceding, sterilization. Potassium carbonate was more suitable than sodium carbonate as neutralizing agent for promoting longevity of bacteria. Though peat allowed to dry immediately after inoculation did not permit the same high increase in bacterial numbers observed in peat kept at suitable moisture content, it was able to maintain large numbers of organisms in viable condition. Peat allowed to dry following the initial rise continued to support an increased load of living cells. After the initial increase at growth temperatures, peat stored at 4 °C. maintained numbers of bacteria better than at the higher temperature. Though immediate storage at 4 °C. resulted in a pronounced decline in numbers, subsequent removal to a temperature suitable for growth, even though delayed for as long as 12 wk., was followed by a rapid increase of bacteria to very high numbers.