Progress towards a controlled culture of the marine sponge Pseudosuberites andrewsi in a bioreactor Ronald Osinga a, *, El Hassan Belarbi a,b , Emilio Molina Grima b , Johannes Tramper a , Rene ´ H. Wijffels a a Food and Bioprocess Engineering Group, Department of Food Science and Technology, Wageningen Agricultural University, PO Box 8129, 6700 EV Wageningen, The Netherlands b Department of Chemical Engineering, University of Almerı ´a, E-04071 Almerı ´a, Spain Received 9 November 2001; received in revised form 29 April 2002; accepted 6 June 2002 Abstract Explants of the tropical sponge Pseudosuberites andrewsi were fed with the marine diatom Phaeodactylum tricornotum . The food was supplied either as intact algae or as a filtered crude extract. Growth (measured as an increase in underwater weight) was found in both experiments. The explants fed with intact algae increased to an average underwater weight of 255% of the initial weight in 45  /60 days. The explants fed with crude extract increased to an average of 200% of the initial weight in 30 days. These results show that it is possible to grow a sponge using a single microorganism species as a food source. In addition, it was demonstrated that sponges are also capable of growing on non-particulate food. Therefore, this study is an important step forward towards the development of controlled, in vivo sponge cultures. # 2002 Elsevier Science B.V. All rights reserved. Keywords: Sponges; In vivo cultivation; Pseudosuberites andrewsi ; Phaeodactylum tricornotum 1. Introduction Many secondary metabolites of marine sponges have the potential to be used as therapeutic drugs (Munro et al., 1999; Faulkner, 2000). Until now, development of these potential drugs into com- mercial products has been hampered by what is referred to as the ‘supply problem’ (Osinga et al., 1999a; Hart et al., 2000). The amount of target compound needed for preclinical and clinical research can not be obtained due to an insufficient supply of sponge biomass. Hence, there is a growing interest in biotechnological methods to produce sponges (Pomponi et al., 1997; Osinga et al., 1999a; Hart et al., 2000). Currently, in situ culture (also termed aquacul- ture, mariculture or sponge farming) is the only production method for sponge biomass that has been applied successfully (Mu ¨ ller et al., 1999; Pronzato et al., 1999; Hart et al., 2000). The major * Corresponding author. Tel.:  /31-317-48-5097; fax:  /31- 317-48-2237; http://www.ftns.wau.nl/prock/research/rene/ marine.html E-mail address: ronald.osinga@algemeen.pk.wau.nl (R. Osinga). Journal of Biotechnology 100 (2003) 141  /146 www.elsevier.com/locate/jbiotec 0168-1656/02/$ - see front matter # 2002 Elsevier Science B.V. All rights reserved. PII:S0168-1656(02)00257-2