Biological diversity of Lemna aequinoctialis Welw. isolates influences biomass production and wastewater phytoremediation

Abstract

Duckweeds are promising biomass producers for bioenergy and other biotechnological applications such as phytoremediation. Genetic diversity of duckweed species could influence their biotechnological potential. Nine isolates of Lemma aequinoctialis Welw. that are native of the Recife metropolitan area, Pernambuco state, in northeastern Brazil, were characterized in vitro under 1X and 0.5X Schenk and Hildebrandt (SH) culture media. Molecular identification by plastid DNA atpF-atpH barcoding sequences revealed very low genetic diversity. In contrast, exposure to environmental stimuli under 0.5X SH growth medium revealed phenotypic differentiation between the isolates. Three of the nine isolates were evaluated further for their ability to remediate the effluent from a domestic sewage treatment plant. They were able to reduce up to 94.8% of the chemical oxygen demand and to remove up to 39.3% of total nitrogen and 57.1% of phosphorus in the effluent, while producing biomass that has potential as feedstock for bioenergy production.