Nocardia tartaricans cells immobilized in sodium alginate-cellulose sulfate-poly (methylene-co-guanidine)capsules: mechanical resistance and operational stability

The stereospecific hydrolysis of cis‐epoxysuccinate (CES) to L‐(+)‐tartrate, catalysed by the action of CES hydrolase activity in whole Nocardia tartaricans bacterial cells, has been chosen as a model biotransformation system. The performance of cells was studied by immobilization in polyelectrolyte complex (sodium alginate–cellulose sulfate–poly(methylene‐co‐guanidine, SA–CS/PMCG) capsules based on sodium alginate and cellulose sulfate as polyanions, poly(methylene‐co‐guanidine) as polycation, CaCl2 as gelling agent and NaCl as antigelling agent. The encapsulated cells showed a preservation of 80% of the initial catalytic activity in encapsulated cells compared with 15% of retained catalytic activity in free cells after 10 repeated biotransformation cycles. Uniformity of batches of capsules was achieved by the use of an air‐stripping extrusion device fitted with a multiloop reactor. The capsules produced using this device had narrow standard deviations for capsule diameter (