The BioTran project was initiated to examine the effects of microbes on sub-surface transport processes, especially in the context of geological disposal of radioactive waste. Early work focussed on hard rock environments using dioritic material from the Aspo Underground Research Laboratory (URL). In 2008-2009, the scope of Biotran broadened to encompass batch experiments on mudstones, host rocks relevant to radioactive waste management in Japan. The 2009-2010 BioTran work programme used column experiments to investigate the effects of microbes on fractured mudstone. This work was undertaken on behalf of the Japanese Atomic Energy Authority (JAEA) and part-funded by the Ministry of Economy, Trade and Industry of Japan (METI), Japan.