Evaluation of Fermentative Hydrogen Production from Single and Mixed Fruit Wastes

Abstract

Abstract:The economic viability of employing dark fermentative hydrogen from whole fruit wastes as a green alternative to fossil fuels is limited by low hydrogen yield due to the inhibitory effect of some metabolites in the fermentation medium. In exploring means of increasing hydrogen production from fruit wastes, including orange, apple, banana, grape and melon, the present study assessed the hydrogen production potential of singly-fermented fruits as compared to the fermentation of mixed fruits. The fruit feedstock was subjected to varying hydraulic retention times (HRTs) in a continuous fermentation process at 55 °C for 47 days. The weight distributions of the first, second and third fruit mixtures were 70%, 50% and 20% orange share, respectively, while the residual weight was shared equally by the other fruits. The results indicated that there was an improvement in cumulative hydrogen yield from all of the feedstock when the HRT was five days. Based on the results obtained, apple as a single fruit and a fruit mixture with 20% orange share have the most improved cumulative hydrogen yields of 504 (29.5% of theoretical yield) and 513 mL/g volatile solid (VS) (30% of theoretical yield ), respectively, when compared to other fruits.

Bioengineering of anaerobic digestion for volatile fatty acids, hydrogen or methane production: A critical review

“…The general similarities that exist between VFAs and hydrogen as metabolites of the anaerobic digestion process are that they are biosynthesized as intermediaries and serve as precursors of biogas production. Due to the potential of obtaining these metabolites from organic residues, many researchers have successfully limited the methanogens activities with the aim of optimizing the formation of either VFAs or hydrogen [17,[88][89][90]. From these studies, it can be concluded that bioprocesses that are favorable for the formation of the VFAs at high yields usually produce the hydrogen gas as a by-product, and vice versa.…”

Biohydrogen production from hyperthermophilic anaerobic digestion of fruit and vegetable wastes in seawater: Simplification of the culture medium of Thermotoga maritima

“…The sampling was performed during the winter period, when the waste was composed of different quantities of apples, carrots, potatoes, tomatoes, pears, onions, fennel, spinach, parsley and citrus fruits (oranges and tangerines). Many studies have shown a decrease in H 2 production related to the presence of flavor compounds in citrus fruit (esters, alcohols, aldehydes, ketones, lactones and terpenoids), which inhibit the growth of many microorganisms (Akinbomi and Taherzadeh, 2015). For instance, d-limonene (a citrus flavor belonging to a class of terpenoids) was found to have an antimicrobial effect at a very low concentration of 0.01% w/v (Mizuki et al, 1990).…”

Seed Pretreatment for Increased Hydrogen Production Using Mixed-Culture Systems with Advantages over Pure-Culture Systems

“…The maximum molar yield of hydrogen will be around 4 mol from 1 mol of glucose with complete conversion to acetate as the end-product [115]. The highest hydrogen yield reported was around 2.8 mol/mol of glucose in case of mixed-culture systems [116] and was around (4.5 and 5.77 mol/mol of glucose) using an engineered Thermotoga maritima (Tma100 and Tma200) strain [117].…”