The Investigation on the Optimum Culture Conditions and the Ice Nucleating Activity of Bacterium Xanthomonas translucem KCTC 2751

摘要

The optimum culture conditions for the ice nucleating activity and the cell growth of Xanthomonas translucem KCTC 2751 were investigated. The optimum initial pH and temperature for the cell growth and the ice nucleating activity were 6.5 and 25°C, respectively. The optimum culture medium for the ice nucleating activity was composed of 1.0% maltose, 1.4% yeast extract, 0.8% digested of gelatin, and 0,03% KC1 in distilled water. Freezing operations carried out on distilled water showed that the degrees of supercooling were -7.90°C without ice nucleators, -1.56°C with silver iodide as a commercial ice nucleator, and -1.36°C when Xanthomonas translucem KCTC 2751 were added. During progressive freeze-concentration assays, the addition of Xanthomonastranslucem KCTC 2751 led to lower saccharose concentrations in the crystals, while the cells led to higher saccharose concetrations in the concentrated phase.