Reactor start-up strategy as key for high and stable hydrogen production from cheese whey thermophilic dark fermentation

The aim of this study was to determine the optimal conditions for dark fermentation using agro-industrial liquid wastewaters mixed with sweet sorghum stalks (i.e., 55% sorghum, 40% cheese whey, and 5% liquid cow manure). Batch experiments were performed to investigate the effect of controlled pH (5.0, 5.5, 6.0, 6.5) on the production of bio-hydrogen and volatile fatty acids. According to the obtained results, the maximum hydrogen yield of 0.52 mol H2/mol eq. glucose was measured at pH 5.5 accompanied by the highest volatile fatty acids production, whereas similar hydrogen productivity was also observed at pH 6.0 and 6.5. The use of heat-treated anaerobic sludge as inoculum had a positive impact on bio-hydrogen production, exhibiting an increased yield of 1.09 mol H2/mol eq. glucose. On the other hand, the pretreated (ensiled) sorghum, instead of a fresh one, led to a lower hydrogen production, while the organic load decrease did not affect the process performance. In all experiments, the main fermentation end-products were volatile fatty acids (i.e., acetic, propionic, butyric), ethanol and lactic acid.

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A two-stage process for hydrogen production from cheese whey: Integration of dark fermentation and biocatalyzed electrolysis

International Journal of Hydrogen Energy ◽

10.1016/j.ijhydene.2014.10.120 ◽

2015 ◽

Vol 40 (1) ◽

pp. 168-175 ◽

Cited By ~ 45

Author(s):

R. Moreno ◽

A. Escapa ◽

J. Cara ◽

B. Carracedo ◽

X. Gómez

Keyword(s):

Hydrogen Production ◽

Cheese Whey ◽

Dark Fermentation ◽

Two Stage ◽

Stage Process ◽

Biocatalyzed Electrolysis

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Fast start-up structured CuFeMg/Al2O3 catalyst applied in microreactor for efficient hydrogen production in methanol steam reforming

Chemical Engineering Journal ◽

10.1016/j.cej.2021.130644 ◽

2021 ◽

pp. 130644

Author(s):

Guiru Zhang ◽

Jiali Zhao ◽

Qiang Wang ◽

Taotao Yang ◽

Qi Zhang ◽

...

Keyword(s):

Hydrogen Production ◽

Steam Reforming ◽

Methanol Steam Reforming ◽

Start Up ◽

Fast Start ◽

Al2o3 Catalyst

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Zeolite addition to improve biohydrogen production from dark fermentation of C5/C6-sugars and Sargassum sp. biomass

Scientific Reports ◽

10.1038/s41598-021-95615-1 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

R. M. Silva ◽

A. A. Abreu ◽

A. F. Salvador ◽

M. M. Alves ◽

I. C. Neves ◽

...

Keyword(s):

Hydrogen Production ◽

Anaerobic Bacteria ◽

Dark Fermentation ◽

Inorganic Materials ◽

Biohydrogen Production ◽

High Rate ◽

Continuous Reactor ◽

Organic Loading Rate ◽

Fermentation Products ◽

Zeolite Type

AbstractThermophilic biohydrogen production by dark fermentation from a mixture (1:1) of C5 (arabinose) and C6 (glucose) sugars, present in lignocellulosic hydrolysates, and from Sargassum sp. biomass, is studied in this work in batch assays and also in a continuous reactor experiment. Pursuing the interest of studying interactions between inorganic materials (adsorbents, conductive and others) and anaerobic bacteria, the biological processes were amended with variable amounts of a zeolite type-13X in the range of zeolite/inoculum (in VS) ratios (Z/I) of 0.065–0.26 g g−1. In the batch assays, the presence of the zeolite was beneficial to increase the hydrogen titer by 15–21% with C5 and C6-sugars as compared to the control, and an increase of 27% was observed in the batch fermentation of Sargassum sp. Hydrogen yields also increased by 10–26% with sugars in the presence of the zeolite. The rate of hydrogen production increased linearly with the Z/I ratios in the experiments with C5 and C6-sugars. In the batch assay with Sargassum sp., there was an optimum value of Z/I of 0.13 g g−1 where the H2 production rate observed was the highest, although all values were in a narrow range between 3.21 and 4.19 mmol L−1 day−1. The positive effect of the zeolite was also observed in a continuous high-rate reactor fed with C5 and C6-sugars. The increase of the organic loading rate (OLR) from 8.8 to 17.6 kg m−3 day−1 of COD led to lower hydrogen production rates but, upon zeolite addition (0.26 g g−1 VS inoculum), the hydrogen production increased significantly from 143 to 413 mL L−1 day−1. Interestingly, the presence of zeolite in the continuous operation had a remarkable impact in the microbial community and in the profile of fermentation products. The effect of zeolite could be related to several properties, including the porous structure and the associated surface area available for bacterial adhesion, potential release of trace elements, ion-exchanger capacity or ability to adsorb different compounds (i.e. protons). The observations opens novel perspectives and will stimulate further research not only in biohydrogen production, but broadly in the field of interactions between bacteria and inorganic materials.

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The Start-Up of Continuous Biohydrogen Production from Cheese Whey: Comparison of Inoculum Pretreatment Methods and Reactors with Moving and Fixed Polyurethane Carriers

Applied Sciences ◽

10.3390/app11020510 ◽

2021 ◽

Vol 11 (2) ◽

pp. 510

Author(s):

Elza R. Mikheeva ◽

Inna V. Katraeva ◽

Andrey A. Kovalev ◽

Dmitriy A. Kovalev ◽

Alla N. Nozhevnikova ◽

...

Keyword(s):

Cheese Whey ◽

Hydraulic Retention Time ◽

Continuous Production ◽

Oxygen Demand ◽

Organic Load ◽

Anaerobic Sludge ◽

Acid Pretreatment ◽

Methanogenic Activity ◽

Start Up ◽

Load Rate

This article presents the results of the start-up of continuous production of biohydrogen from cheese whey (CW) in an anaerobic filter (AF) and anaerobic fluidized bed (AFB) with a polyurethane carrier. Heat and acid pretreatments were used for the inactivation of hydrogen-scavengers in the inoculum (mesophilic and thermophilic anaerobic sludge). Acid pretreatment was effective for thermophilic anaerobic sludge to suppress methanogenic activity, and heat treatment was effective for mesophilic anaerobic sludge. Maximum specific yields of hydrogen, namely 178 mL/g chemical oxygen demand (COD) and 149 mL/g COD for AFB and AF, respectively, were obtained at the hydraulic retention time (HRT) of 4.5 days and organic load rate (OLR) of 6.61 kg COD/(m3 day). At the same time, the maximum hydrogen production rates of 1.28 and 1.9 NL/(L day) for AF and AFB, respectively, were obtained at the HRT of 2.02 days and OLR of 14.88 kg COD/(m3 day). At the phylum level, the dominant taxa were Firmicutes (65% in AF and 60% in AFB), and at the genus level, Lactobacillus (40% in AF and 43% in AFB) and Bifidobacterium (24% in AF and 30% in AFB).

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