Eukaryotic unicellular organisms are an important part of the soil microbial community, but they are often
neglected in soil functional microbial diversity analysis, principally due to the absence of specific investiga-
tion methods in the special soil environment. In this study we used a method based on high-density centri-
fugation to specifically isolate intact algal and yeast cells, with the aim to analyze them with flow cytometry
and sort them for further molecular analysis such as deep sequencing. Recovery efficiency was tested at low
abundance levels that fit those in natural environments (104to 106cells per g soil). Five algae and five yeast
morphospecies isolated from soil were used for the testing. Recovery efficiency was between 1.5 to 43.16%
and 2 to 30.2%, respectively, and was dependent on soil type for three of the algae. Control treatments without
soil showed that the majority of cells were lost due to the method itself (58% and 55.8% respectively). However,
the cell extraction technique did not much compromise cell vitality because a fluorescein di-acetate assay indi-
cated high viability percentages (73.3% and 97.2% of cells, respectively). The low abundant algae and yeast
morphospecies recovered from soil were cytometrically analyzed and sorted. Following, their DNA was isolated
and amplified using specific primers. The developed workflow enables isolation and enrichment of intact auto-
trophic and heterotrophic soil unicellular eukaryotes from natural environments for subsequent application of
deep sequencing technologies.