For the isolation of new strains from natural habitats, traditional cultivation tech­niques may be used, such as enrichment cultures (Andersen and Kawachi, 2005). A preferred preliminary step toward single-cell isolations would be enrichment cultures with growth media, soil and/or water extract, or supplementing with nutri­ents such as nitrate, ammonium, and phosphate or a trace metal. Alternatively, the proximate nutrient composition of the source samples may be analyzed and supplemented to the growth media. Algae survive under natural environments despite the fact that natural samples are often deficient in one or more nutrients. This may be due to the fact that bacterial action, grazing, and death of organ­isms recycle those nutrients. Sampling reduces the population of specific spe­cies that help recycle nutrients, and this nutrient stress leads to a decline of the target species. Enrichment can also be disadvantageous if the target species is unable to compete with the other autochthonous flora. Hence, selective culturing is a unique tool suited for enrichment culturing of lipid-producing microalgae. Once enriched, suspensions containing algae from samples may be centrifuged to increase the biomass concentration of desired cell density; then diluted in sterile water and passed through a 60-pm plankton net to remove zooplankton, and col­lected again using a 0.45-pm glass filter. The cells on the filter should be rinsed several times with sterile saline to remove bacteria and then inoculate to BG-11 medium (Rippka et al., 1979) for enrichment. However, some algal strains take weeks to months to be isolated by traditional methods (Anderson, 2005). For large-scale sampling and isolation efforts, high-throughput automated isolation techniques involving fluorescence-activated cell sorting (FACS) have proven extremely useful (Sieracki et al., 2005). Because of morphological similarities when comparing many algal species, actual strain identification should be based on molecular methods such as rRNA sequence comparison or, in the case of closely related strains, other gene markers.