A potental solution to biofouling?

Within marine ecosystems one biological feature which is commonly found is biofilms. Biofilms consist of a layer attached to a hard surface, of several micro-organisms held together by extracellular polymeric matrix (EPM). Other organisms such as species of algae, fungi and bacteria can then inhibit this layer of biofilm, leading to the building of a relatively stable community.  Biofilms, and the inhabitation by other species, can however be problematic in human activities leading to economic costs.  Biofouling (The formation of biological material on a solid surface upon their immersion in a biological fluid) is most known for its cost to aquaculture as well as the shipping industry. Due to the economic costs, there has been a large investment in finding solutions to stop biofilms from forming on anthropogenic structures within the marine environment.  These solutions can usually be placed in two categories (Physical and Chemical). Physical solutions include the active removal of organisms by manual labour. This is however expensive and less effective, leading to decreased popularity. The chemical solutions include having trace amounts of heavy metals within the paints used to paint the anthropogenic structures, this has led to ecological problems with the marine environment. Therefore, due to the problems of the two solutions, alternative solutions must be found.  One potential solution is the use of marine fungi to produce naturally occurring anti-microbial substances to stop bio-fouling, hence the purpose of this study was to isolate marine fungi and any potential anti-fouling substances.

The investigation successfully isolated 16 morphologically distinct fungi, 6 from a mangrove forest and 10 from an estuary system. Out of these 16 distinct fungi, 1 was identified as having the capability to inhibit 5 bacteria selected to test for antifouling ability in the investigation (Methylococcus sp., Flavobacterium sp., Marinococcus sp., Serratia sp. And Pseudomonas sp.), This fungal strain was identified as Aspergillus sp.. It was found that Aspergillus sp. produced anti-fouling compounds in 4-5 days, comparative to the other antifouling agent organisms in other studies referenced in the paper, this was efficiency was better (Cladosporium sp.-14 days, Ampelomyces sp. and Letendraea helminthicola -21 days). They also looked at which carbon source optimized the production of the antifouling compound.  It was found that the carbon source raffinose best achieved the maximal production of the anti-fouling agent.

The investigation showed a lot of promise in helping to combat the economical problems of biofouling as well as potential providing a less ecologically damaging solution.  However, the results all came from in vitro experiments induced on a limited number of tested bacterial species. Therefore, this experiment is more likely to ‘open the door’ to others studies potentially finding viable solutions rather than having shown a viable solution itself to biofouling. Hopefully, it will encourage more work on the subject on finding anti-fouling compounds in biological systems rather than finding and using more chemical solutions.

Reviewed Paper: Thiyagarajan, S., Bavya, M. & Jamal, A. (2016). Isolation of marine fungi Aspergillus sp. and its in vitro antifouling activity against marine bacteria. Journal of Environmental Biology, 37, 895-903