Efficient production of biohydrogen from African lignocellulosic residues

Biohydrogen by dark fermentation using organic wastes is a promising technology towards energy transition and green economy. Unfortunately, H2 production is still limited as several parameters must be finely tuned. This study aims at the development of an efficient process to convert African lignocellulosic residues into H2. An alkaline H2O2 pre-treatment of coffee and pineapple skins, which are hugely produced as waste in many African countries, has been developed. The goal was to get simple sugars, under mild conditions, to foster H2 production. Once pre-treated, the feedstocks were converted by a heat-treated inoculum into H2 at two pH values (5.5 and 6.0). The results indicate that coffee and pineapple skins were efficiently transformed into H2 (up to 47.99 and 91.80 mL/gVS, respectively) at an optimal pH of 6 with a concentration of 1.25 % H2O2. These results proved that H2O2 pre-treatment and the fine tuning of pH can be the key drivers to boost H2 production of lignocellulosic matrices. This combined approach performed successfully and stands for a promising way towards the optimization of the H2-producing processing from waste streams also in African countries. This will contribute to the United Nation (UN)’s ‘Agenda 2030’ for green energy and sustainable economic growth.