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Enhanced biotransformations and product recovery in a membrane bioreactor through application of a direct electric current.

Research output: Contribution to journalJournal article

  • Roberta Mustacchi
  • Christopher J. Knowles
  • Hong Li
  • Ian Dalrymple
  • Garry Sunderland
  • Wolfgang Skibar
  • Simon A. Jackman
<mark>Journal publication date</mark>5/01/2005
<mark>Journal</mark>Biotechnology and Bioengineering
Issue number1
Number of pages6
Pages (from-to)18-23
<mark>Original language</mark>English


The simultaneous enhancement of biotransformation coupled to product recovery, purification and concentration is presented. The nitrilase of Rhodococcus rhodochrous LL100-21 catalyses the single-step hydrolytic biotransformation of benzonitrile to benzoic acid and ammonia. When a direct electric current is applied across a bioreactor containing the bacterium and benzonitrile, the charged product (benzoic acid) can be removed in situ across an anion exchange membrane and recovered in a separate compartment. Over the course of a 24-hour biotransformation, benzonitrile was converted to benzoic acid which was completely removed from the bioreactor chamber and concentrated 3-fold in a separate chamber. The rate of production of benzoic acid increased by 42% when the current was applied (0.044 mmol/min/g dry cell weight in the presence of current as compared to 0.03 mmol/min/g dry cell weight in its absence). The enhanced reaction rate was achieved irrespective of product separation and therefore appears to be a direct effect upon the bacterial cells. This process has potential for enhanced productivity from biotransformations through a simultaneous increase in metabolic activity and in situ product recovery.

Bibliographic note

Funded by: the United Kingdom Department of Trade and Industry and the Biotechnology and Biological Sciences Research Council