Fermentative biohydrogen production from a novel combination of vermicompost as inoculum and mild heat-pretreated fruit and vegetable waste

María J Pascualone,Pablo R Dalmasso,Marcos B Gómez Costa

doi:10.18331/brj2019.6.3.5

Abstract

This study reports for the ﬁrst time on biohydrogen production by dark fermentation using a novel combination of mild heat-pretreated fruit and vegetable waste (FVW) as raw material and vermicompost as an economical source of hydrogen-producing bacteria. A suspension rich in reducing sugars obtained from FVW was used at different initial concentrations (5 to 25 g reducing sugars/L) during the bioprocess conducted in batch reactors at mesophilic temperature of 35 °C. The use of a mild heat-pretreated substrate and the consequent elimination of the natural microbiota present in the FVW led to higher hydrogen production than the control. Clostridium species, hydrogen-producing bacteria via butyric acid fermentation pathway, were the dominant microorganisms in the bioprocess. Hydrogen production, volumetric hydrogen production rate, and pretreated substrate degradation efficiency (63.0 mL/g VS, 372.6 mL/L/d, and 50% BOD5, respectively) obtained in the experiments performed with the highest substrate concentration demonstrated that the developed bioprocess was promising simultaneously leading to high hydrogen contents in biogas and high substrate removal efficiencies.

Highlights

The current challenges of global warming and climate change on one hand and atmospheric pollution resulting from increasing fossil fuels consumption on the other hand are the main driving forces behind the research on alternative energy carriers (Emodi et al, 2019)
This study reports for the first time on biohydrogen production by dark fermentation using a novel combination of mild heatpretreated fruit and vegetable waste (FVW) as raw material and vermicompost as an economical source of hydrogen-producing bacteria
Vermicompost as economical source of hydrogen-producing bacteria and FVW as a low-cost substrate were innovatively combined for biohydrogen production

Summary

Introduction

The current challenges of global warming and climate change on one hand and atmospheric pollution resulting from increasing fossil fuels consumption on the other hand are the main driving forces behind the research on alternative energy carriers (Emodi et al, 2019). While steam reforming of natural gas is the dominant hydrogen production process and is still associated with extensive consumption of fossil fuels (Xia et al, 2016), the biological production route has emerged as one of the most vigorous research areas in the field of hydrogen production (Cai and Wang, 2016). It has the advantages of reducing greenhouse gas emissions by 57-73%, and the ability to run on a cheap and less energy intensive technology (Arimi et al, 2015). Carbon dioxide, and volatile fatty acids (VFA) are produced during the acidogenesis phase of carbohydrate-rich organic wastes degradation by anaerobic fermentative bacteria (Keskin et al, 2018)

Methods

Results

Conclusion