Discussion

Fungi have long been a source of a wide variety of bioactive compounds, but fungi isolated from marine environments are now providing a new range of interesting compounds. A marine isolate of Calcarisporium sp. KF525 has been found to produce novel cyclic and linear polyesters (calcarides), several of which have antibacterial activity (Silber et al. 2013 Mar. Drugs 11: 3309).
Calcarisporium sp. KF525 is a slow-growing fungus (µmax ~ 0.06 h-1) and the calcarides are produced during the later stages of growth (or during stationary phase). Large amounts may accumulate if cultures are allowed to stand for months. However, this is not practical as a sustainable production method. Therefore, production of calcarides was assessed in various media in flask cultures so that a medium suitable for producing calcarides in stirred tank bioreactors could be developed. These studies provide a basis for developing an improved production process, which could provide sufficient material e.g. for further bioactivity testing.
This research has been funded through the EU's 7th Framework project "MARINE FUNGI".

Anu Tamminen, Yanming Wang, Marilyn G. Wiebe
VTT Technical Research Centre of Finland, P.O. Box 1000, FI-02044 VTT, Finland