Vacuum air-lift bioreactor for microalgae production

Microalgae production is receiving an increasing interest both by research institutions and commercial companies (Di Caprio et al., 2016). This is due to the growing consciousness of the need to move towards renewable, sustainable feedstoks for commodities production (Wang et al., 2012). However, process development at industrial scale, either based on open or closed photobioreactors, still is in a rather early stage and there is room for further development (Morweiser et al., 2010), especially aimed at reducing process costs. In this work an innovative low-cost technology for microalgae production, currently under development at Palermo University, is described. The main ways through which the goal of costs containment is pursued are (i) the adoption of thin walled transparent tubing for the photo bioreactor, and (ii) an evacuated-head air-lift system. To the aim of providing a proof-of-concept of these ideas, a 500-liter pilot plant was built. This is presently being operated in semi-continuous mode under solar irradiation and external climatic conditions.