stabilization (8 h) (Fig. 1). As can be noted, in all cases a typical cumulative hydrogen production behavior was observed, with an initial lag phase (variable according to the microalga), followed by a rapid increase (exponential) in the bioH2 production, and finally reaching a stationary phase which occurs around 4–5 h for all algae. This is highly advantageous in terms of the short process-ing time required and reducing energy expenditure. These results show that the strain of the bacteria E. aerogenes (facultative anaer-obic) used in this study proved to be efficient in converting differ-ent microalgal biomass into hydrogen through a dark fermentation process. In addition, the process was faster when compared to the ones that use other fermentative microorganisms, namely strict anaerobic bacteria, such as C. butyricum