Vlicrobial Synthesis of 3-Dehydroshikimic Acid: A Comparative Analysis of D-Xylose, L-Arabinose, and D-Glucose Carbon Sources

3-Dehydroshikimic acid is a hydroaromatic precursor to chemicals ranging from L-phenylalanine to adipic acid. The concentration and yield of3-dehydroshikimic acid microbially synthesized from various carbon sources has been examined under fedbatch fermentor conditions. Examined carbon sources included D-xylose, L-arabinose, and D-glucose. A mixture consisting of a 3:3:2 molar ratio ofglucose/xylose/arabinose was also evaluated as a carbon source to model the composition of pentose streams potentially resulting from the hydrolysis of corn fiber. Escherichia coli KL3/pKL4.79B, which overexpresses feedback-insensitive DAHP synthase, synthesizes higher concentrations and yields of 3-dehydroshikimic acid when either xylose, arabinose, or the glucose/xylose/arabinose mixture is used as a carbon source relative to when glucose alone is used as a carbon source. E. coli KL3/pKL4.124A, which overexpresses transketolase and feedback-insensitive DAHP synthase, synthesizes higher concentrations and yields of 3-dehydroshikimic acid when the glucose/xylose/arabinose mixture is used as the carbon source relative to when either xylose or glucose is used as a carbon source. Observed high-liter, high-yielding synthesis of3-dehydroshikimic acid from the glucose/xylose/arabinose mixture carries significant ramifications relevant to the employment of corn fiber in the microbial synthesis of value-added chemicals.