Dry weight and cell density of individual algal and cyanobacterial cells for algae research and development

Abstract

Phototrophs have received more and more attention due to their nutrient removal, biomass production as well as the potential for biofuel feedstock. This research determined the dry weight of algal and cyanobacterial cells and compared with that of regular bacteria. For microbes growing during exponential phase in batch studies, the average dry weights of green alga Chlorella vulgaris, cyanobacterium Microcystis aeruginosa and facultative bacterium E.coli were (2.24 ± 0.16) x 10[superscript -11] g/cell, (1.21 ± 0.09) x 10[superscript -11] g/cell and (1.69 ± 0.36) x 10[superscript -13] g/cell, respectively. By using fluorescent microscopy, the average sizes of Chlorella vulgaris and Microcystis aeruginosa were (4.34 ± 0.90) μm and (2.29 ± 0.61) μm, respectivily. It is obvious that the dry weight of individual cells increases as cell size increase. Correspondingly, the average density of single cells were (0.57 ± 0.04) g/cm3 and (0.87 ± 0.02) g/cm[superscript 3] for algae and cyanobacteria, respectively. In a continuous flow algal cultivation system, individual algal cell weight was (3.91 ± 0.26) x 10[superscript -11] g/cell and cell density was (0.51 ± 0.07) g/cm[superscript 3] with an average cell size of (5.28 ± 1.33) μm under steady-state conditions. The results could be used for the estimation of algal biomass production for algae research and development.