One of the big challenges of microalgae culture is the search for alternative (and cheap) culture media. Some microalgal species can accumulate up to 70% of lipids but only when cultured in a specific balanced medium, as mentioned by Chisti (2007).

Medium costs are difficult to estimate because much depends on the species of microalga to be cultured. In the literature, medium cost is described as between US$0.27 and $0.588 per kg algal biomass (Molina-Grima et al., 2003; Tapie and Bernard, 1988). Such high cost, the major drawback in biofuel production processes involving microalgae, makes these processes unfeasible. (Just the biomass production step represents almost 40% of the price of the final product.) The necessity to exploit inexpensive and abundantly produced nutritional sources to substitute artificial media is clear.

In this context, the patented technology developed by the company Ourofino Agronegcicio, in partnership with the Laboratory of Biotechnological Processes (Federal University of Parana, Brazil), is a very interesting and economical alternative for the production of biofuels from high-lipid-content microalgal biomass cultured in wastewater from ethanol distilleries. (The present technology was patented: PI0705520-0.)