Optimization of biohydrogen production by dark fermentation of African food-processing waste streams

In the challenge of mitigating greenhouse gases produced mainly by fossil fuels, the recovery of agricultural and food waste to produce biohydrogen by dark fermentation is considered a promising source for the future. However, industrial-scale production remains challenging and several parameters significantly influencing the application of the technology need to be finely tuned. In the present study, an evaluation of the production of biohydrogen from cassava and pineapple waste, widely available in many African countries, was carried out using different microbial consortia originating from industrial biogas plants in Italy. The production of biohydrogen was defined both by screening the most appropriate inoculum and by using a “centered composite design” to optimize the inoculum pretreatment time and the pH. From cassava waste, which is abundant of starch (43%), the highest hydrogen levels (62.32 mL H2/gVS) were obtained at pH 7.72 adopting a 4-h heat treated inoculum originating fro...