Biotechnological potential of Neolyngbya (Cyanobacteria), a new marine benthic filamentous genus from Brazil

Abstract Marine filamentous cyanobacteria are sources of biologically active secondary metabolites with potential biotechnological application. Despite the extension and environmental variety of the Brazilian coast, floristic surveys of filamentous cyanobacteria are scarce. Studies on their biotechnological potential are even more limited. In this work, we sampled Neolyngbya (Oscillatoriaceae) populations along the Brazilian coast and evaluated the antimicrobial, antioxidant, and cytotoxic activities of their organic extracts. We also assessed the strains' genetic potential for production of cyanotoxins. The strains were cultivated in SWBG-11 medium. Extraction of biomass was carried out with methanol, ethanol, and acetic acid. Antimicrobial (against seven bacterial strains and the yeast Candida albicans ), antioxidant (DPPH and ABTS radicals), and cytotoxic (brine shrimp) potential were evaluated. PCR reactions were performed to analyze the genetic potential for the production of microcystin, saxitoxin, and cylindrospermopsin. Brazilian marine filamentous cyanobacteria presented relevant antimicrobial capacity. Seven extracts from four Neolyngbya strains inhibited growth of almost all bacteria, while nine extracts from four strains inhibited C. albicans , with a minimum inhibitory concentration (MIC) range from 2.5 to 10.0 mg·mL −1 . Methanolic extracts presented the greatest antioxidant potential for both DPPH and ABTS radicals, ranging from 50.0 to 98.3% at a concentration of 10 mg·mL −1 . Cytotoxicity assays showed a LC 50 ranging from 0.8 to 6.6 mg·mL −1 . We detected toxic genotypes in eight of the analyzed strains, in which the most frequent gene clusters were mcyG (microcystin) and cyrJ (cylindrospermopsin). All Neolyngbya strains screened in this study have potential for biotechnological application, which highlights the economical and pharmacological importance of studying this underestimated biodiversity in tropical areas.