As you have mentioned about extracellular release, you can go for pelleting down the biomass (by centrifugation) and resuspend the pellets in TE for optical analysis.
Hi Arvind try to take a UV/Vis spectra and stay out of a false positive wavelenght of the pigment for measuring or change your settings from absorption to transmission. Dry cell mass is a good indicator, but mostly slower in the determination
as Dr Asif mentioned, you could harvest the cells and do dry weight measuring after drying, or you can centrifuge the cells and re suspend the pellet in fresh medium to measure the OD