2.1. Cultivation of microalgae
C. sorokiniana AB731602.1 and S. obliquus FR751179.1 were
selected for ECH experiments. Selected microalgal strains were isolated from Durban area, Kwa Zulu Natal, South Africa. Isolation and
purification was carried out by streaking plate method on 1.2% agar
Blue Green (BG-11) medium providing photoautotrophic condition
[25]. Microphotography and measurement of cell size was done
using Nikon eclipse 80i microscope. Purified colonies of microalgal
strains were inoculated into 100 mL culture flasks containing
50 mL BG11 growth medium under photoautotrophic condition.
For the harvesting experiments mass culture for selected microalgal strains was done in 5000 mL flask with culture volume of
3000 mL for 14 days. Cultures were grown at 16 h:8 h light dark
cycle, at 25 C, at a photon flux of approximately 120 lmol m 2
s 1 , on an orbital shaker at 110 rpm. Sterilization of growth medium used was done by autoclave at 121 C for 15 min and purity of strains was checked by regular microscopic observation with
Nikon eclipse 80i microscope under 1000 magnification. Biomass
(g L1 ) was estimated using gravimetric method which was found
to be 2.8 g L1 for C. sorokiniana and 0.92 g L1 for S. obliquus.