Bioconversion of ferulate into vanillin by Escherichia coli strain JM109/pBB1 in an immobilized-cell reactor

The present work deals with a novel bioconversion of ferulate into vanillin using resting cells of Escherichia coli strain JM/109pBB1 as a biocatalyst. Biomass recycling from four successive bioconversion steps demonstrated the possibility of employing the proposed resting cell system for the continuos production of vanillin. Among the tested immobilization supports (polyurethane, synthetic sponge and porous glass)the synthetic sponge proved to be the best material in terms of both vanillin formation (Cv=0.080 g/l) and productivity (Qv=0.019 g/lh) at the end of entrapment tests. Thus, it was used in preliminary continuos tests using a fixed-bed column with immobilized E. coli JM/109pBB1 cells. The highest vanillin yield (YP/S=0.851 mol/mol) was obtained at a dilution rate of 0.022 1/h.