Microalgae perform oxygenic photosynthesis and are capable of taking up a large amount of $CO_2$, using an inducible $CO_2$ concentrating mechanism (CCM), and fixing $CO_2$ into higher compounds. These characteristics make the microalgae potentially useful for removal and utilization of $CO_2$ emitted from industrial plants and, generally, the usage of photosynthetic microorganisms has increased and significantly improved as a solution for $CO_2$ emissions. In this light and based on previous research using Anabaena cylindrica IAM M1 and Spirulina platensis IAM M 135, enhancement was sought for $CO_2$ fixation and biomass production by Chlorella vulgaris Buitenzorg by increasing the photon flux density concurrent with increases in culture biomass during the cellular growth phase and was compared to cultures of Chlorella grown at optimal constant illumination, with all cultures grown using Bennick basal medium, $29^{circ}C$, and a flow of 1.0 atm. 10% $CO_2$ enriched air delivered to three in serial photobioreactors of 0.200 $dm^3$ capacity each. The results showed that increasing illumination during culture increased biomass production of Chlorella by -60% as well as increased $CO_2$ fixation ability by -7.0%. It was also demonstrated that the non-competitive inhibition of [${HCO_{3}}^-$] as a carbon source significantly affected the cultivation in both the increasing and constant photon flux density regimes.