초록
<P>Ursolic acid and oleanolic acid are pentacyclic triterpenoid compounds with a variety of biological activities. A mixture of ursolic acid and oleanolic acid has higher antitumor activity than the individual acids. We have developed a simultaneous biosynthesis pathway for different proportions of ursolic acid and oleanolic acid in <I>Saccharomyces cerevisiae</I>. The ScLCZ08 strain produced 175.15 mg/L of the ursolic acid precursor α‐amyrin, the highest amount reported. Ursolic and oleanolic acid titers and proportions were optimized using <I>Medicago truncatula</I> amyrin C‐28 oxidase and <I>Arabidopsis thaliana</I> cytochrome P450 reductase. Using glucose and ethanol fed‐batch fermentation strategies, the final ursolic acid and oleanolic acid titers were 123.27 and 155.58 mg/L, respectively, demonstrating 4.77‐fold and 4.95‐fold higher production than the parent strain. The ScLCZ11 strain displayed the highest ursolic acid production obtained <I>via</I> microbial fermentation in fed‐batch culture to date. © 2018 American Institute of Chemical Engineers <I>AIChE J</I>, 64: 3794–3802, 2018</P>