LONG-TERM STABILIZATION OF SULFITE OXIDATION IN WHOLE CELLS OF THIOBACILLUS THIOOXIDANS S3

Abstract

We studied different factors which affect sulfite oxidation in Thiobacillus thiooxidans S3 cells during storage. The cells continued the oxidation for 27 days when they were preserved at 4°C in a 0.1M citrate buffer (pH 6.0), or for 22 days when 20% glycerol was added to the same buffer and storage was at -20°C. When the cells were stored at 4°C, they kept full activity even after 45 days. If the cells were immobilized before they were stored at 4°C in the buffer, they kept their full activity for 90 days. The cells treated by lyophilization or drying at room temperature lost about 90% of the original activity. T. thiooxidans S3 cells were more stable than T. novellus cells under the same storage conditions.