Selection of Co-Substrate and Aeration Conditions for Vanillin Production by Escherichia coli JM109/pBB1

Paolo Torre¹, Danilo De Faveri¹, Patrizia Perego¹, Attilio Converti¹*, Paolo Barghini², Maurizio Ruzzi² and Fabrícia P. Faria<sup>3

1</sup>Department of Chemical and Process Engineering, Genoa University, via Opera Pia 15, I-16145 Genoa, Italy
²Department of Agrobiology and Agrochemistry, Tuscia University, I-01100 Viterbo, Italy
³Departamento de Ciências Fisiológicas, Laboratório de Biologia Molecular, ICB2, Campus Samambaia, Universidade Federal de Goiás, 74001-970 Goiânia, GO, Brazil

Article history:
Received April 26, 2004
Accepted July 6, 2004

Key words:
Escherichia coli, vanillin, ferulic acid, resting cells, vanillic acid

Summary:
Yeast extract, Luria-Bertani medium and tryptone were tested as co-substrates for vanillin production from ferulic acid by resting cells of Escherichia coli JM109/pBB1. Yeast extract proved to be the best component for sustaining such a bioconversion, which is not self-sustained from the bioenergetic point of view. Tests were also performed under variable aeration conditions by simultaneously varying the ratio of medium to vessel volume and the agitation speed. The results of these tests suggest that, under excess aeration, a non-specific oxidase activity was very likely responsible for the oxidation of a significant portion of vanillin to vanillic acid, thus reducing the vanillin yield.

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