An airlift loop bioreactor (ALB) with microbubble dosing was used to grow microalgae on high CO₂ content steel plant exhaust gas, generated from the combustion of offgases from steel processing.  The gas analysis of CO₂ uptake in the 2200 litre bioreactor showed a specific uptake rate of 0.1 g l^-1 h^-1, an average 14% of the CO₂ available in the exhaust gas with a 23% composition of CO₂. This uptake led to a steady production of chlorophyll, biomass and total lipid content in the bioreactor, with a best doubling time of 1.8 days.  The gas analysis also showed anti-correlation of CO₂ uptake and O₂ production, which along with the apparent stripping of the O₂ to the equilibrium level by the microbubbles, strongly suggests that the bioreactor is not mass-transfer limited, nor O₂ inhibited. Subsequently, an array of 3 litre laboratory bench ALBs have been developed for screening purposes, with the notion that conventional shake flask incubation for screening is oxygen inhibited. The small ALBs achieve accelerating exponential growth, resulting in the desired levels of algae density an order of magnitude faster than the undosed control. Large-scale screening time in industrial laboratories can thus be decreased significantly while using environmental conditions appropriate for full scale production, including stack gas as part of the medium. Finally, microbubble gas exchange with an airlift loop effect is not limited to photobioreactors. The circulation and mixing benefits can be replicated by engineering algal ponds, as the baffles and diffusers needed to direct the airlift loop effect are inexpensive.