Prospecting volatile compounds produced by Brazilian cyanobacteria with allelopathic effects

Resumo

Co-occurrence of toxic cyanobacteria blooming in different aquatic environments in several regions of Brazil (Northeast, Center east, Southeast and South) has already been registered. Among the negative consequences, the production of volatile organic compounds (VOCs) is of major importance. The most commonly VOCs are geosmin and 2-methylisoborneol, which resist to conventional water treatment procedures, causing odor issues, and can bioaccumulate in fish and shellfish. Moreover, allelopathic effects of VOCs in the aquatic community have been observed. In this regard, competition studies between cyanobacterial strains or between cyanobacteria and other organisms may shed light on the role played by VOCs in the environment. Thus, this study aims to evaluate the production of VOCs by different strains of cyanobacteria isolated from Brazilian reservoirs while developing effective analytical routines for their determination. The effect of environmental variables (light, temperature and pH) on the production of VOCs will also be evaluated. In order to investigate the possible allelopathic effects of these compounds, culture exudates will be tested in mixed cultivation flasks or in single species cultures. VOCs production will be followed by GC/MS employing methods developed for their correct identification. At the end, we aim to collect evidence over the production of VOCs and their effect on the physiologic parameters of cyanobacteria, providing data on the role played by these compounds and contributing to increase the scarce information currently available in Brazil and other countries. (AU)