Figure 1From: Optimisation of engineered Escherichia coli biofilms for enzymatic biosynthesis of l-halotryptophans Formation and breakdown of 5-halotryptophan in E. coli . (a) Reaction scheme for biocatalytic conversion of 5-haloindole and serine to 5-halotryptophan, catalysed by tryptophan synthase TrpBA. (b) Reaction scheme for the reverse reaction, catalysed by tryptophanase TnaA. X = F, Cl or Br.Back to article page