Eleven flavoproteins from the old yellow enzyme family were found to catalyze the disproportionation (dismutation) of conjugated enones. Incomplete conversions, which were attributed to enzyme inhibition by the co-product phenol could be circumvented via in situ co-product removal by scavenging the phenol using the polymeric adsorbent MP-carbonate. The optimized system allowed to reduce an alkene activated by ester groups in a coupled-substrate approach via nicotinamide-free hydrogen transfer with >90% conversion and complete stereoselectivity. Biotechnol. Bioeng. 2013;110: 3085-3092. (c) 2013 The Authors. Biotechnology and Bioengineering Published by Willey Periodicals, Inc.