Figure 4From: Biosynthesis of caffeic acid in Escherichia coli using its endogenous hydroxylase complexHPLC analysis of caffeic acid produced by engineered E. coli (A) Standard, 50 mg/L caffeic acid. (B) A sample taken from the fermentation culture of YL-2 after 24 hours. Peak 1 corresponded to caffeic acid. The retention time was 10.1 min. UV absorbance profiles are shown beside the peaks.Back to article page