Dark fermentative hydrogen production from sucrose and molasses

Abstract

Summary There are many factors affecting the dark fermentative hydrogen production. The interaction of these factors, that is, their combined effects, should be investigated for better design of the systems with stable and higher hydrogen yields. This study aimed to investigate the combined effects of initial substrate, pH, and biomass (or initial substrate to biomass) values on hydrogen production from sucrose and sugar‐beet molasses. Therefore, optimum initial chemical oxygen demand (COD), pH, and volatile suspended solids (VSS) or initial substrate to biomass (VSS) ratio (S/Xo) values leading to the highest dark fermentative hydrogen production were investigated in batch reactors. An experimental design approach (response surface methodology) was used. Results revealed that when sucrose was the substrate, maximum hydrogen production yield (HY) of 2.3 mol H2/mol sucroseadded was obtained at initial pH of 7 and COD of 10 g/L. Initial S/Xo values studied (4–20 g COD/g VSS) had no effect on HY, while the initial pH was found as the parameter mostly affecting both HY and hydrogen production rate (HPR). When substrate was molasses, initial COD concentration was the only variable affecting HY and HPR. Maximum of both was achieved at 10 g/L initial COD. Initial VSS values studied (2.5–7.5 g/L) had no effect on HPR and HY. This study also indicated that molasses leads to homoacetogenesis for potentially containing intrinsic microorganism and/or natural constituents; thus, sucrose is more advantageous for hydrogen production via fermentation. Homoacetogenesis should be prevented for effective optimization via response surface methodology, if substrate is a natural carbon source potential to have intrinsic microorganisms. Copyright © 2017 John Wiley & Sons, Ltd.

Biohydrogen production from pretreated sludge and synthetic and real biodiesel wastewater by dark fermentation

“…Carbon dioxide and other less‐reduced organic compounds are also produced by hydrogen‐producing microorganisms, which directly affect the hydrogen productivity and yield. To make hydrogen production through dark fermentation profitable in large‐scale applications, several studies have applied new cost reduction strategies, for example, the utilization of organic‐rich wastes (as feedstock) and mixed cultures (as inoculum) in the process and the optimization of the main process variables …”

“…However, mixed cultures must be pretreated to either eliminate or inhibit H 2 ‐consuming microorganisms . Therefore, several studies have evaluated the effect of different kinds of inoculum pretreatments, such as heat, acid, alkaline, chemical, and others, on hydrogen productivity and yield . In this study, four different types of sludge pretreatments were tested on an anaerobic sludge with potential to be used as inoculum for hydrogen production by dark fermentation.…”

“…To make hydrogen production through dark fermentation profitable in large-scale applications, several studies have applied new cost reduction strategies, for example, the utilization of organic-rich wastes (as feedstock) and mixed cultures (as inoculum) in the process and the optimization of the main process variables. [6][7][8][9] In the last decade, the biodiesel production in Brazil has risen significantly due to the introduction of biodiesel into the country's energy matrix as a substitute for conventional diesel. Nevertheless, its production generates large amounts of wastewater, approximately from 0.2 to 3 L of wastewater per liter of biodiesel, which is considered an environmental and economic problem because of its high-pollutant capacity and treatment cost.…”

Evaluation of the Two-Stage Fermentative Hydrogen Production from Sugar Beet Molasses

“…This was followed by an evaluation of its suitability for industrial application, however using a simplified economic model and cost data from the period before 2013 [12]. Research on fermentative hydrogen production from molasses was later continued dealing separately with dark fermentation [13,14] and photofermentation [15]. Economic analysis of hydrogen production from molasses by mesophilic dark fermentation was performed assuming a rather small energy output of 0.008-0.04 MW [16].…”

Produção de hidrogênio e metabólitos com valor biotecnológico a partir do melaço da cana-de-açúcar utilizando reatores de leito granular expandido mesofílicos

“…al., 2006;LAY et al, 2010;CHANG et al, 2011;HAN et al, 2011;HAN et al, 2012a;HAN et al, 2012b;ZHU et al, 2013;WANG et al, 2013). Tunçay et al (2017) realizaram testes em batelada utilizando sacarose e melaço como substratos. Foram testadas três concentrações iniciais de DQO (10, 30 e 50 g L -1 ), de modo que a PVH máxima obtida para melaço foi de 0,19 L d -1 L -1 em concentração inicial de DQO de 10 g L -1 .…”