[L-asparatic acid synthesis from ammonium fumarate by free and immobilized Escherichia coli cells]

E. coli 85 cells with a high aspartate-ammonia-lyase activity were immobilized through polyacrylamide gel incorporation. Proper conditions to assay aspartase activity of E. coli cells were developed. Kinetic patterns of aspartate-ammonia-lyase reaction catalyzed by free and immobilized E. coli 85 cells were studied. The synthesis of L-aspartic acid from ammonium fumarate had the following characteristics: specific activity of (4--6) . 10(-5) mmole/mg.sec for free cells and (6--8) . 10(-5) mmole/mg.sec for immobilized cells with their content in polyacrylamide gel of 5--10 mg protein per g wet gelm pH 8.3--10.0.