| 摘要 |
A method for preserving immobilized or unimmobilized microbial cells having nitrilase activity and for stabilizing the nitrilase activity of unimmobilized or immobilized microbial cells has been developed. The unimmobilized or immobilized microbial cells are stored in an aqueous solution containing from about 0.10 M to the saturation concentration of an inorganic salt of bicarbonate or carbonate, including ammonium, sodium and potassium salts of bicarbonate or carbonate. Aqueous suspensions containing at least 100 mM bicarbonate or carbonate limit microbial contamination of the stored enzyme catalyst, as well as stabilize the desired nitrilase activity of the uninmmobilized or immobilized cells. Microorganisms which are characterized by an nitrilase activity and are stabilized and preserved by this method include Acidovorax facilis 72-PF-15 (ATCC 55747), Acidovorax facilis 72-PF-17 (ATCC 55745), Acidovorax facilis 72W (ATCC 55746), and transformed microbial cells having nitrilase activity, preferably E. coli SS1001 (ATCC PTA-1177) which is transformed with Acidovorax facilis 72W nitrilase activity.
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