The recombinant Escherichia coli strain, TG2 (p1/1), can bd used for biotransformation of toluene to toluene cis-glycol. However, toluene caused substantial inhibition of both growth and toluene cis-glycol production at concentrations above 0.04%. Tetradecane was found to be non-toxic at a phase ratio of 0.23 and provided protection against toluene toxicity. Thus, growth was still possible in the presence of 1.5% toluene. Furthermore, the yield of toluene cis-glycol was increased 1.7-fold compared with the yield in the absence of tetradecane.