The biotransformation of 14-deoxy-14-methylenetriptolide by Neurospora crassa CGMCC AS 3.1604 to produce a new hydroxylation derivative was studied. The structure of this novel compound was determined using spectral data. This biotransformation using whole cells conditioned for 4 days transformed approximately 65% (mol ratio) of the substrate into the compound (5R)-5-hydroxy-14-deoxy-14-methylenetriptolide. (c) 2013, The Society for Biotechnology, Japan. All rights reserved.