“…[33,36] The subsequent oxidation of the al-A C H T U N G T R E N N U N G dyhyde group by the NAD-dependent benzaldehyde dehydrogenase (MdlD) leads to the formation of benzoic acid. [32] In analogy to these reaction steps, we propose that the MdlC homologue Ken5 transforms 3,5-DHPGO into 3,5-dihydroxybenzaldehyde (3,5-DHBAL), which is subsequently oxidized by the MdlD homologue Ken6 to the corresponding acid (3,5-dihydroxybenzoic acid, 3,5-DHBA; see Scheme 1). Because two additional biosynthetic genes (ken9 and ken10) are located downstream of ken7, we assume that the starter unit is further modified before entering the type I PKS assembly process.…”