processed material culture medium changed from a role to a processed material based on on Aug 22, 2011 dev call. Details see the tracker item: http://sourceforge.net/tracker/?func=detail&aid=3325270&group_id=177891&atid=886178 Modification made by JZ. a processed material that provides the needed nourishment for microorganisms or cells grown in vitro. A growth medium or culture medium is a substance in which microorganisms or cells can grow. Wikipedia, growth medium, Feb 29, 2008 OBI Person: Jennifer Fostel, Jie Zheng culture medium ready for release