Screening was carried out using the procedure expressed in Fig. 3. The procedural order was: sampling, automated isolation, pre-screening and screening. Pre-screening, mainly based on NR fluorescence of stained algal cells, and cellular neutral lipid droplets was detected under epifluorescence microscopy. Strains that contained cellular lipid droplets were further screened with respect to cell division and lipid production. For cell division, growth rate and biomass concentration of each strain were examined. Simultaneously, lipid production of these strains was investigated in two aspects i.e. total lipid content and fatty acid profile. To determine lipid content, gravimetric extraction and NR fluorescence measurements were conducted. Fatty acid profile is a critical factor for decision of selection of candidate strain as it ultimately determines biodiesel quality. Selection criteria for screening were based on biomass productivity and intracellular lipid content. Strains which demonstrated comparatively high biomass productivity, lipid content, and a suitable fatty acid profile were selected.