A system and a method for concentrating traces of tissue from aquatic organisms in a water sample and use thereof

摘要

A system and a method for concentrating traces of tissue from aquatic organisms (eDNA), in particular aquatic animal species and/or aquatic plant species or non- aquatic organisms, including humans, which may lose tissue to the water environment, in a water sample (2) is disclosed. The method comprises subjecting the water sample (2) to membrane filtration in one or more membrane module(s) (12), preferably microfiltration or ultrafiltration module(s) using tangential flow filtration and repeating the membrane filtration step one or more times on the retentate for concentration of the sample up to 1000 times, preferably up to 100-1000 or more preferred up to 200-1000 times. The retentate is either recycled from a retentate outlet (14) of the membrane module(s) (12) to a sample inlet (11) of the membrane module(s) (12) or the flow is reversed through the membrane module(s) (12). Hereby a concentration of the retentate to a high degree is obtained and it is possible to extract eDNA in sufficient quantities to enable detection of certain species of animal and/or plant species in the aquatic environment even if the animal or plant species is present in very low numbers in the aquatic environment. The method and the system enable DNA extraction from the concentrated retentate by simple standard methods developed for extraction of nucleic acids from suspended samples. Any efforts to release the sample from any filter surfaces during extraction are avoided.