To address climate change and the increasing energy demand, several studies have been conducted over the past to find ways to produce energy from renewable sources. Hydrogen is an excellent energy carrier, as it has a high calorific value and, unlike hydrocarbons, does not release CO2 during combustion. Another environmental issue is waste management. One way to tackle both this problem and the sustainable production of energy-rich gases is through metabolic processes carried out by various microorganisms. These processes include dark fermentation and anaerobic digestion, which can be conducted individually or in a combined process called two-stage anaerobic digestion. This thesis focused on experimenting with different types of biomasses derived from agro-industrial waste to achieve high yields of hydrogen and methane.