Marine sponge aquaculture towards drug development: An ongoing history of technical, ecological, chemical considerations and challenges

Marine sponges have a long history of farming, starting with bath sponges over 5000 years ago in the Mediterranean. Many species have since been found appropriate for distinct types of commercial assessment. Drug development relies on the isolation of sponge-derived secondary metabolites as natural compounds having a wide range of ecological functions, from deterring predation to preventing microbial infection/proliferation on the sponge body. For human society, they feature a broad array of pharmacological properties with some applications still being discovered. Their limited supply has however been faced as a major obstacle to the conduct of clinical trials. Marine aquaculture has to prove more integrated and sustainable to remain an interesting way to ensure sufficient amounts of biological substances for the early processing and production of drugs. This review presents sponge farming methods that were tested, the undergoing challenges they faced and the interest they raised on environmental and metabolic factors to explain contrasting spatiotemporal performances. Through global experiments, sometimes involving other marine organisms, technicity of sponge aquaculture has long been evolving to ensure efficient and cost-effective strategies. Further ways to make sponge farming more attractive and diversify its commercial applications are investigated, such as recent studies in collagen or chitin production for bone tissue engineering or bioremediation as an alternative to existing wastewater management. Overall, marine sponges exhibit astonishing intra and interspecific variation, which is why they should be considered with respect to the purpose of their economic valuation, their environmental context and all the symbiotic interactions they rely on.