An optimized DNA extraction protocol for benthic Didymosphenia geminata

• D. geminata (aka rock snot) have negative ecologic and economical consequences.
• D. geminata mats constitute a valuable but recalcitrant DNA source.
• The mats' polysaccharide and heavy metal contents interfere with molecular studies.
• A DNA extraction protocol is described that help circumvent this problem.

Didymosphenia geminata mats display few cells in relation to extracellular material and contain polysaccharides and heavy metals that interfere with molecular studies. We describe an optimized DNA extraction protocol that help to overcome these difficulties. Our protocol outperformed five previously described DNA extraction techniques.