Trans-enoyl reductase; part of the gene cluster that mediates the biosynthesis of ilicicolin H, a 4-hydroxy-2-pyridonealkaloid that has potent and broad antifungal activities by inhibiting the mitochondrial respiration chain (PubMed:30905148). IccB collaborates with the hybrid PKS-NRPS synthetase iccA to assemble the backbone of ilicicolin H (PubMed:30905148). The PKS portion of iccA and trans-acting enoyl reductase iccB work together to construct an octaketide, and two methyl groups are introduced by the MT domain of iccA during the chain assembly (PubMed:30905148). The nascent chain is then condensed with tyrosine, catalyzed by the iliA C domain, and the resulting PKS-NRPS hybrid is offloaded by the iliA RED domain to form an advanced tetramic acid intermediate (PubMed:30905148). The biosynthesis of ilicicolin H starts with formation of the tetramic acid by the hybrid PKS-NRPS synthetase iccA with the partnering trans-enoyl reductase iccB since iccA lacks a designated enoylreductase (ER) domain. The cytochrome P450 monooxygenase iccC then catalyzes the ring expansion of the tetramate to the acyclic 2-pyridone. The pericyclase iccD further converts the acyclic 2-pyridone into 8-epi-ilicicolin H. Finally, the epimerase iccE converts 8-epi-ilicicolin H into ilicicolin H via epimerization. IccA to iccE are sufficient for ilicicolin H biosynthesis and the roles of the remaining enzymes, iccF, iccG and iccH within the pathway have still to be determined (PubMed:30905148) (Probable). N-[(4E,6E,10S,12Z,14E)-6,10-dimethyl-3-oxohexadeca-4,6,12,14-tetraenoyl]-L-tyrosyl-[ACP] = (3E,5S)-3-[(2E,4E,8S,10E,12Z)-1-hydroxy-4,8-dimethyltetradeca-2,4,10,12-tetraen-1-ylidene]-5-[(4-hydroxyphenyl)methyl]pyrrolidine-2,4-dione + H(+) + holo-[ACP] Mycotoxin biosynthesis. Monomer. Belongs to the zinc-containing alcohol dehydrogenase family.