Lipids are one of the primary metabolites of microalgae and cyanobacteria, which enrich their utility in the pharmaceutical, feed, cosmetic, and chemistry sectors. This work describes the isolation, structural elucidation, and the antibiotic and antibiofilm activities of diverse lipids produced by different microalgae and cyanobacteria strains from two European collections (ACOI and LEGE-CC). Three microalgae strains and one cyanobacteria strain were selected for their antibacterial and/or antibiofilm activity after the screening of about 600 strains carried out under the NoMorFilm European project. The total organic extracts were firstly fractionated using solid phase extraction methods, and the minimum inhibitory concentration and minimal biofilm inhibitory concentration against an array of human pathogens were determined. The isolation was carried out by bioassay-guided HPLC-DAD purification, and the structure of the isolated molecules responsible for the observed activities was determined by HPLC-HRESIMS and NMR methods. Sulfoquinovosyldiacylglycerol, monogalactosylmonoacylglycerol, sulfoquinovosylmonoacylglycerol, α-linolenic acid, hexadeca-4,7,10,13-tetraenoic acid (HDTA), palmitoleic acid, and lysophosphatidylcholine were found among the different active sub-fractions selected. In conclusion, cyanobacteria and microalgae produce a great variety of lipids with antibiotic and antibiofilm activity against the most important pathogens causing severe infections in humans. The use of these lipids in clinical treatments alone or in combination with antibiotics may provide an alternative to the current treatments.

Although a variety of protocols to isolate high-molecular-weight genomic DNA exist, the isolation and preservation of ultra-high-molecular-weight genomic DNA of sufficient quality and length for error-free third-generation sequencing remains challenging. Inspired by the isolation of high-molecular-weight DNA in agarose plugs suitable to be separated by pulsed-field gel electrophoresis, we report the construction of an incubation chamber for DNA isolation. The chamber is flanked by semi-permeable polycarbonate membranes of variable pore size for the selective diffusion of compounds and components, which allows efficient cell lysis and the subsequent isolation of ultra-high-molecular-weight genomic DNA without shearing. The designed experimental approach is simple, but effective in isolating high-quality ultra-long genomic DNA that is suitable for third-generation sequencing by Oxford Nanopore Technology from challenging bacterial samples. We envisage that genomic DNA isolation using the incubation chamber, or variations thereof, will facilitate the regular sequencing of megabasepair-long DNA fragments, with a multitude of applications in microbiology, immunology, oncology, paleontology and forensic science.