Microbial Synthesis of 3‐Dehydroshikimic Acid: A Comparative Analysis of d‐Xylose, l‐Arabinose, and d‐Glucose Carbon Sources

Abstract 3‐Dehydroshikimic acid is a hydroaromatic precursor to chemicals ranging from l ‐phenylalanine to adipic acid. The concentration and yield of 3‐dehydroshikimic acid microbially synthesized from various carbon sources has been examined under fed‐batch fermentor conditions. Examined carbon sources included d ‐xylose, l ‐arabinose, and d ‐glucose. A mixture consisting of a 3:3:2 molar ratio of glucose/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‐titer, high‐yielding synthesis of 3‐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.