Free and MicroencapsulatedErwinia Herbicolafor the Production of Tyrosine

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Abstract
Erwinia herbicola (ATCC 21434) was grown in a medium which caused the cells to induce tyrosine phenol-lyase (TPL) activity. Whole cells of Erwinia herbicola were then microencapsulated within alginate-poly-L-lysine-alginate membraned microcapsules (diameter 800 μm). In a rotary shaker-incubator with a 1.9 cm horizontal throw, an agitation rate of at least 240 revolutions per minute (rpm) was required before the TPL activity of the microencapsulated cells was equal to that of the free cells. The TPL activity of the cells, whether free or microencapsulated, could be used for the conversion of ammonia, pyruvate and phenol into tyrosine at 37°C. The results indicate that free cells and microencapsulated cells effect the conversion of these reactants to tyrosine equally well if the agitation rate is 240 rpm. In liver failure the concentrations of both ammonia, phenol and pyruvate are elevated. Hence the TPL activity of microencapsulated Erwinia herbicola could possibly find application in a novel approach for the removal of toxic phenol and ammonia during liver failure.