Enhancement of fermentative hydrogen production by Thermotoga maritima through hyperthermophilic anaerobic co-digestion of fruit-vegetable and fish wastes

Abstract

In this work, different proportions of model fruit and vegetable wastes (MFVW) and acid hydrolyzed fish wastes (AHFW) were used for hydrogen production in a minimum culture medium based on seawater. Experiments were performed in pH-controlled Stirred Tank Reactor (STR) with or without the addition of nitrogen and sulfur sources. The total H2 production and the maximum hydrogen productivity of T. maritima in the culture medium, containing MFVW and AHFW (45 mmol L−1 carbohydrates) at a C/N ratio of 12, were 132 mmol L−1 and 15 mmol h−1 L−1, respectively. However, tripling the concentration of carbohydrates to reach a C/N ratio of 22, has increased two times the maximum H2 productivity (28 mmol h−1 L−1) due to the improvement in nutrient balance. The cumulative H2 production was 285 mmol L−1, yielding a potential energy generation of 0.12103 MJ ton−1 wastes, which could be an interesting alternative for energy recovery.