Abstract
Erwinia herbicola cells with tyrosine phenol lyase activity were entrapped in polyacrylamide and carrageenan gels and used for L-DOPA synthesis from ammonia, pyruvate and pyrocatechol. Immobilized cells retained 50-53% of the activity of free cells and were sensitive to substrate inhibition by pyrocatechol and pyruvate. The synthesis of L-DOPA in batch reactors reached 9.4 g 1−1 in 6h (productivity 1.6g 1−1 h−1). In continuous reactors stability was only observed when cells were immobilized in a carrageenan gel (immobilized viable cells). The effluent L-DOPA concentration reached 1.4 g 1−1 (productivity 0.1 g 1−1 h−1) and the reactors (fluidized bed or column) were stable for more than 62 days.