Chlorophyll estimation
The growth of microalgae was monitored on daily basis by determining
its chlorophyll content. The chlorophyll content of
microalgae is determined by methanol extraction followed by
spectrophotometric analysis [23]. 3 ml algae culture was centrifuged
at 10,000 rpm for 10 min. The supernatant was drained
off and the sample was re-suspended in ethanol/diethyl ether and
kept boiling for 5 min. After boiling, the sample was made up to
5 ml with ethanol/diethyl ether. The optical density was measured
at 660 nm and 642.5 nm with solvent as a blank. The
chlorophyll content was determined using the following formula:
Chlorophyll ðmg=lÞ¼ð9:9 OD660Þð0:77 OD642:5Þ