Efficiency Of Biohydrogen Production Research Articles

Synergising hydrothermal pre-treatment and biological processes for enhancing biohydrogen production from palm oil mill effluent

The high quantity of nutrient-rich palm oil mill effluent (POME) waste in the industry will have a severe negative environmental impact and a high cost of treatment. However, POME waste could be converted into bioenergy via environmentally sustainable processes. Several studies have explored using hydrothermal carbonisation for solid biomass products in biofuel production, but the potential of the liquid phase produced during these processes has received less attention. Therefore, this study aims to assess the potential of biohydrogen production from treated POME as a substrate by hydrothermal process. This study is presented in two phases: the first phase involves substrate pre-treatment using a hydrothermal process to improve biomass properties at different temperatures, and the second phase explores the potential for biohydrogen production from treated POME through dark fermentation. Substrate pre-treatment was conducted at 180, 210, and 240 °C using 100 % raw POME. Next, the treated POME was incubated for biohydrogen production at 50 °C for 24 h. A microbial analysis was conducted to determine the most dominant species present in the sample. Our findings show that at 180 °C, the total chemical oxygen demand (COD) removal efficiency was 80 %, and acetic acid concentration was 28 %. Compared to raw POME, treated POME generated a maximum hydrogen yield and rate (HPR) of 52.19 mL H2 g−1 CODrem and 0.59 mL H2 mL POME−1 day−1 with a 2.32-fold and 1.59-fold increase, respectively. Meanwhile, Clostridium was a dominant bacterial species identified in the treated POME. These findings demonstrated the feasibility of implementing a hydrothermal process to treat POME and improve its biohydrogen production efficiency. The treated POME from the hydrothermal process is more homogenous and readily consumable by microorganisms used in dark fermentation. Hydrothermal pre-treatment could potentially increase the rate and efficiency of microbial digestion, leading to enhanced hydrogen production. The high COD removal efficiency during the process significantly reduces the environmental impact of POME discharge, and converting POME into a valuable resource through the hydrothermal and dark fermentation process aligns with sustainable waste management practices.

Enhancing biohydrogen production from xylose at low temperature (20 °C) using natural FeS2 Ore: Thermodynamic analysis and mechanistic insights

This study investigates the efficacy of pyrite in enhancing biohydrogen production from xylose at low temperature (20 °C). Higher hydrogen yield rates (Rm) and reduced lag time (λ) were achieved across initial xylose concentrations ranging from 2-10 g/L. At an optimal xylose concentration of 5 g/L, pyrite reduced λ by 2.5 h and increased Rm from 1.3 to 2.7 mL h−1. These improvements are attributed to pyrite’s ability to enhance the secretion of extracellular polymeric substance and flavins, facilitate NADH and NAD+ generation and transition, and favor biohydrogen production. Thermodynamic analyses and Gibbs free energy calculations further elucidated pyrite’s role in the full reaction process and rate-limiting steps at low temperature. This study offers valuable insights into improving the efficiency of biohydrogen production at low temperature, with significant implications for energy conservation.

Outdoor biohydrogen production by thermotolerant Rhodopseudomonas pentothenatexigens KKU-SN1/1 in a cluster of ten bioreactors system.

In tropical regions, the viability of outdoor photo-fermentative biohydrogen production faces challenges arising from elevated temperatures and varying light intensity. This research aimed to explore how high temperatures and outdoor environments impact both biohydrogen production and the growth of purple non-sulfur bacteria. Our findings revealed the potential of Rhodopseudomonas spp. as a robust outdoor hydrogen-producing bacteria, demonstrating its capacity to thrive and generate biohydrogen even at 40°C and under fluctuating outdoor conditions. Rhodopseudomonas harwoodiae NM3/1-2 produced the highest cumulative biohydrogen of 223mL/L under anaerobic light conditions at 40°C, while Rhodopseudomonas harwoodiae 2M had the highest dry cell weight of 2.93g/L. However, R. harwoodiae NM3/1-2 demonstrated the highest dry cell weight of 3.99g/L and Rhodopseudomonas pentothenatexigens KKU-SN1/1 exhibited the highest cumulative biohydrogen production of 400mL/L when grown outdoors. In addition, the outdoor enhancement of biohydrogen production was achieved through the utilization of a cluster of ten bioreactors system. The outcomes demonstrated a notable improvement in biohydrogen production efficiency, marked by the highest daily biohydrogen production of 493mL/Ld by R. pentothenatexigens KKU-SN1/1. Significantly, the highest biohydrogen production rate was noted to be 17 times greater than that observed in conventional batch production methods. This study is the first to utilize R. pentothenatexigens and R. harwoodiae for sustained biohydrogen production at high temperatures and in outdoor conditions over an extended operational period. The successful utilization of a clustered system of ten bioreactors demonstrates potential to scale-up for industrial biohydrogen production.

Dark fermentative hydrogen production: Potential of food waste as future energy needs

Globally, food waste (FW) is found to be one of the major constituents creating several hurdles in waste management. On the other hand, the energy crisis is increasing and the limited fossil fuel resources available are not sufficient for energy needed for emerging population. In this context, biohydrogen production approach through valorization of FW is emerging as one of the sustainable and eco-friendly options. The present review explores FW sources, characteristics, and dark fermentative production of hydrogen along with its efficiency. FW are highly biodegradable and rich in carbohydrates which can be efficiently utilized by anaerobic bacteria. Based on the composition of FW, several pretreatment methods can be adapted to improve the bioavailability of the organics. By-products of dark fermentation are organic acids that can be integrated with several secondary bioprocesses. The versatility of secondary products is ranging from energy generation to biochemicals production. Integrated approaches facilitate in enhanced energy harvesting along with extended wastewater treatment. The review also discusses various parameters like pH, temperature, hydraulic retention time and nutrient supplementation to enhance the process efficiency of biohydrogen production. The application of solid-state fermentation (SSF) in dark fermentation improves the process efficiency. Dark fermentation as the key process for valorization and additional energy generating process can make FW the most suitable substrate for circular economy and waste based biorefinery.

Supplementation of magnetic nanoparticles for enhancement of dark fermentative hydrogen production from pretreated garden wastes using Enterobacter aerogenes

The supplementation of magnetic nanoparticles (NPs) to the dark fermentative hydrogen production system mediated by Enterobacter aerogenes using pretreated garden wastes as feedstock was investigated to determine the enhancement of biohydrogen production efficiency. The optimized pretreatment conditions of 2% sulfuric acid with sonication (AS) and 2% Viscozyme L with sonication (ES) of garden wastes yielded a maximum of 33 and 37% total reducing sugar, respectively. In addition, the supplementation of 30 mg/L of magnetic NPs to dark fermentative system of AS and ES yielded 32 and 30% increased hydrogen production compared with the control without NPs, respectively. A maximum yield of 2.43 mol H2/mol sugar utilized was achieved in the optimized system supplemented with NPs. The reusability of the magnetic NPs offers an additional advantage showing more than 90% relative hydrogen production retained after four consecutive cycles. The proposed mechanisms suggest that the optimum level of magnetic NPs supplementation increases the electron transfer rate and modifies the E. aerogenes metabolic pathway, limiting ethanol production and increasing acetate proportion in the end metabolite analysis. Overall, the addition of magnetic NPs to the dark fermentative system improved the biological hydrogen production.

Biochar prepared from human feces (HFBC) as a promoter in biohydrogen production using simulated feces as substrate

Human feces contain a lot of nutrients and organic matter, which can be used in many fields. In this study, biochar (HFBC) was prepared at 300, 500 and 800 °C using human feces as substrate, and the characteristics of HFBC prepared at different pyrolysis temperatures were investigated. It was confirmed that HFBC prepared at 800 ℃ (HFBC-800) had a better pH buffer capacity, more proportion of π-π shake-up satellites, better graphitization degree and higher conductivity, which could promote the efficiency of biohydrogen production of bacteria. Furthermore, the biohydrogen production of Thermoanaerobacterium thermosaccharolyticum M18 using different concentrations of simulated human feces (SHF) was further investigated. The best biohydrogen production was found for 40 wt%-SHF, with 128.54 mmol H2/L produced in 180 h. The highest biohydrogen production of 148.75 mmol H2/L was obtained by adding 6 g/L HFBC-800 to the biohydrogen production process. This study provides a feasibility for high-performance hydrogen production from human feces and presents an insight into the resource utilization of human waste.

Hydrogenase and Nitrogenase: Key Catalysts in Biohydrogen Production.

Hydrogen with high energy content is considered to be a promising alternative clean energy source. Biohydrogen production through microbes provides a renewable and immense hydrogen supply by utilizing raw materials such as inexhaustible natural sunlight, water, and even organic waste, which is supposed to solve the two problems of "energy supply and environment protection" at the same time. Hydrogenases and nitrogenases are two classes of key enzymes involved in biohydrogen production and can be applied under different biological conditions. Both the research on enzymatic catalytic mechanisms and the innovations of enzymatic techniques are important and necessary for the application of biohydrogen production. In this review, we introduce the enzymatic structures related to biohydrogen production, summarize recent enzymatic and genetic engineering works to enhance hydrogen production, and describe the chemical efforts of novel synthetic artificial enzymes inspired by the two biocatalysts. Continual studies on the two types of enzymes in the future will further improve the efficiency of biohydrogen production and contribute to the economic feasibility of biohydrogen as an energy source.

Investigation of the effects of magnetite addition on biohydrogen production from apple pulp waste

Along with advancing technologies, the interest in producing renewable hydrogen by biological methods has recently increased due to its economic and eco-friendly properties. Various pretreatment methods or additives, such as enzymes and conductive materials, applied to increase the efficiency of biohydrogen production have been recently studied. In the current research, magnetite was utilized to increase the bioactivity of hydrogen-producing microorganisms during dark fermentation (DF). In the study, reactors with a S/I ratio of 2 gVS/gVS were set up, and magnetite was added at concentrations of 0, 50, 100, and 200 mg/L. The maximum biohydrogen production of 73.59 ml/gVS was obtained at 100 mg/L magnetite addition. Biohydrogen production increased by 46 % with 100 mg/L magnetite addition. In the magnetite-supported reactor, the dominant bacterial genera were Sporolactobacillus (39 %), Clostridium (15 %), and Coprothermobacter (10 %). It was thought that the change in microbial distribution positively affected biohydrogen production with the addition of magnetite.

Biohydrogen—A Green Fuel for Sustainable Energy Solutions

Energy plays a crucial role in the sustainable development of modern nations. Today, hydrogen is considered the most promising alternative fuel as it can be generated from clean and green sources. Moreover, it is an efficient energy carrier because hydrogen burning only generates water as a byproduct. Currently, it is generated from natural gas. However, it can be produced using other methods, i.e., physicochemical, thermal, and biological. The biological method is considered more environmentally friendly and pollution free. This paper aims to provide an updated review of biohydrogen production via photofermentation, dark fermentation, and microbial electrolysis cells using different waste materials as feedstocks. Besides, the role of nanotechnology in enhancing biohydrogen production is examined. Under anaerobic conditions, hydrogen is produced during the conversion of organic substrate into organic acids using fermentative bacteria and during the conversion of organic acids into hydrogen and carbon dioxide using photofermentative bacteria. Different factors that enhance the biohydrogen production of these organisms, either combined or sequentially, using dark and photofermentation processes, are examined, and the effect of each factor on biohydrogen production efficiency is reported. A comparison of hydrogen production efficiency between dark fermentation, photofermentation, and two-stage processes is also presented.

Bio-Hydrogen Production in Packed Bed Continuous Plug Flow Reactor—CFD-Multiphase Modelling

This research study investigates the modelling and simulation of biomass anaerobic dark fermentation in bio-hydrogen production in a continuous plug flow reactor. A CFD multiphase full transient model in long-term horizons was adopted to model dark fermentation biohydrogen production in continuous mode. Both the continuous discharge of biomass, which prevents the accumulation of solid parts, and the recirculation of the liquid phase ensure constant access to the nutrient solution. The effect of the hydraulic retention time (HRT), pH and the feed rate on the bio-hydrogen yield and production rates were examined in the simulation stage. Metabolite proportions (VFA: acetic, propionic, butyric) constitute important parameters influencing the bio-hydrogen production efficiency. The model of substrate inhibition on bio-hydrogen production from glucose by attached cells of the microorganism T. neapolitana applied to the modelling of the kinetics of bio-hydrogen production was used. The modelling and simulation of a continuous plug flow (bio)reactor in biohydrogen production is an important part of the process design, modelling and optimization of the biological H2 production pathway.

Insights into the mechanism of naproxen inhibiting biohydrogen production from sludge dark fermentation

In order to explore the effect of emerging pollutant naproxen (NPX) on the hydrogen production from excess sludge(ES) dark fermentation, six groups of laboratory-scale sequencing batch anaerobic reactor were constructed. The biohydrogen production efficiency, the transformation characteristics of organic matter and the activities of key enzymes were analyzed to explore the effect of NPX on the ES dark fermentation hydrogen production. The effect of NPX on ES dark fermentation is closely related to its exposure content, that is, low-dose NPX had no obvious effect on biohydrogen production, while high-dose NPX inhibited biohydrogen production. 12.0 mg NPX/Kg reduced biohydrogen production to 14.6 mL/g, about 12.5 % of the control. NPX can be partially removed in the process of ES dark fermentation, and the removal efficiency was about 23.3∼42.5 %. NPX promoted the release of dissolved chemical oxygen demand (COD) and increased the soluble organic matter in the fermentation broth. However, NPX significantly suppressed the acidification process, which was also the key reason for the decline of biohydrogen production. Enzyme activity analysis also verified the inhibition of NPX on key enzymes involved in volatile fatty acids (VFA) and biohydrogen production. The results of this study enriched the influence behavior of NPX in the environment, and provided a certain theoretical basis for the ES resource utilization.

A novel conversion of marine macroalgal biomass to biofuel (biohydrogen) via calcium hypochlorite induced dispersion

Environmental pollution due to the consumption of non-renewable energy lead the search for alternative eco-friendly renewable fuel. The study details the biohydrogen production efficiency by potential macroalgal (Ulva reticulata) biomass improved by a disperser combined with calcium hypochlorite pretreatment technology. Calcium hypochlorite was added to decrease the surface energy of the medium induced by sole disperser pretreatment. Optimum condition for algal disperser treatment was 10,000 rpm with 30 min as dispersion time. The specific energy spent for the disintegration of the macroalgal biomass was 1231.58 kJ/kg TS. COD solubilization rate of 11.79% was attained with mechanical pretreatment whereas increased to 20.23% with combined pretreatment. Combination of disperser with calcium hypochlorite significantly reduced the specific energy input spent to 500 kJ/kg TS. The amount of organic materials such as carbohydrates, proteins and lipids released were 680 mg/L, 283 mg/L and 136 mg/L respectively. Thus, the combinative pretreatment with disperser rotor speed (10,000 rpm) for pretreatment time (12 min) and calcium hypochlorite dosage (0.1 g/g) derived as optimum condition for effective solubilization of macroalgal biomass. Biohydrogen production potential was maximum in the macroalgae pretreated with both disperser and calcium hypochlorite recorded highest yield (54.6 mL H2/g COD) compared to the macroalgae pretreated with disperser alone (31.7 mL H2/g COD) and untreated macroalgae (11.5 mL H2/g COD).

Deep eutectic solvent with Lewis acid for highly efficient biohydrogen production from corn straw

To boost saccharification and biohydrogen production efficiency from corn straw, Lewis acid enhanced deep eutectic solvent (DES) pretreatment using choline chloride/glycerol was developed. A notable enhancement of the enzymatic hydrolysis efficiency from 26.3 % to 87.0 % was acquired when corn straw was pretreated with aqueous DES at 100 °C for 5 h using 2.0 wt% AlCl3. A maximum biohydrogen yield of 114.8 mL/g total solids (TS) was achieved in the sequential dark fermentation stage, which was 2.1 times higher than that of the raw feedstock (37.1 mL/g TS). The enhanced efficient conversion was ascribed to the effective removal of lignin and hemicellulose, which led to the bio-accessibility of the straw. This work provides new sights for the rational design of efficient AlCl3-aided aqueous DES system toward biohydrogen production from lignocellulosic biomass.

Screening of biohydrogen production based on dark fermentation in the presence of nano-sized Fe2O3 doped metal oxide additives

Increasing the biohydrogen production efficiency through the dark fermentation process has become the biggest challenge in recent years. We aim to enhance biohydrogen production yield by adding nano-sized iron oxide doped metal oxides prepared by the wet impregnation method. Biohydrogen production in the presence of additives was evaluated by the screening of (i) type (Fe 2 O 3 @Al 2 O 3 , Fe 2 O 3 @ZrO 2 , and Fe 2 O 3 @TiO 2 ) and (ii) concentration (0–200 mg/L) of additives. During the screening of additive type, approximately 14 wt% nano-sized (6 nm) hematite (Fe 2 O 3 ) doped Al 2 O 3 showed the highest improvement for biohydrogen production yield among all additives. Batch experiments conducted through dark fermentation demonstrated that 50 mg/L Fe 2 O 3 @Al 2 O 3 addition caused an acceleration in biohydrogen production by 34% and an increment in yield by 15%, despite even low concentrations Al 2 O 3 addition inhibited the process. • Hematite doped metal oxides synthesized using hydrothermal methods. • Biohydrogen production activity of Fe 2 O 3 @Al 2 O 3 , Fe 2 O 3 @ZrO 2 , Fe 2 O 3 @TiO 2 were tested. • Buffer solution and concentration selection carried out. • Fe 2 O 3 @Al 2 O 3 showed best enhancement with 15% increment in yield. • 50 mg/L Fe 2 O 3 @Al 2 O 3 accelerated biohydrogen production 34%.

The Effect of Autotrophic Cultivation of Platymonas subcordiformis in Waters from the Natural Aquatic Reservoir on Hydrogen Yield

Biological processes run by microalgae are prospective but still little known methods of hydrogen production. A prerequisite for their increased advancement is the development of economically viable and efficient technologies. The study presented in this manuscript focused on determining the efficiency of biohydrogen production by P. subcordiformis using a culture medium prepared based on natural waters. The rate of P. subcordiformis biomass growth reached 317.6 ± 42.3 mgODM/dm3·d and ensured a biomass concentration of 3493 ± 465 mgODM/dm3. The percentage concentration of hydrogen in the biogas reached 63.2 ± 1.4%, and its production rate ranged from 0.53 ± 0.05 cm3/h to 0.70 ± 0.01 cm3/h.

Application of Nanotechnology in the Production of Biohydrogen: A Review

AbstractHydrogen is an outstanding source of energy that does not create any hostile carbon footprint as it produces only water during combustion. The application of nanotechnology is one of the recent advanced technologies used to enhance the rate of hydrogen production from biomass. The use of nanoparticles (NPs) in the conversion process enhances this rate. Biological methods such as dark fermentation and photobiological route of conversion of biomass to hydrogen are the most suitable and cost‐effective paths. Hydrogen production with nanotechnology in dark fermentation utilizes organic or inorganic NPs in the bioreactor membrane. The efficiency of biohydrogen production depends on the concentration and nature of the NPs used, and the kind of biowastes or biomass feed. The effectiveness of both processes is discussed.

An overview on the efficiency of biohydrogen production from cellulose

Biohydrogen produced from cellulosic feedstock is a promising candidate for future energy needs as a renewable energy carrier. The thermochemical route and biological processes have great potential for biohydrogen production. In particular, pyrolysis/gasification and dark fermentation are the methods to enhance the biohydrogen production from cellulose. The review compiles the essential information on both processes, including pretreatment of cellulose since it has a complex structure. The operating conditions for both processes, for example, the influence of cellulose pyrolysis/gasification such as temperature, heating rate, and vapor residence time, while for dark fermentation, including the temperature, inoculum source, hydraulic retention time, and pH, are discussed. The bioreactor configurations and economic aspects of both processes are also discussed. The review aims are to present the current state of knowledge about the two processes using cellulose as substrates. Surprisingly, dark fermentation is a promising method for application of cellulose for biohydrogen production since many works were done on dark fermentation compared to pyrolysis/gasification. The future perspectives on enhancing hydrogen production from cellulose have also been discussed.

Characteristics of Biohydrogen Production and Performance of Hydrogen-Producing Acetogen by Increasing Normal Molasses Wastewater Proportion in Anaerobic Baffled Reactor.

The biohydrogen production efficiency and performance of hydrogen-producing acetogen in a four-compartment anaerobic baffled reactor (ABR) were studied by gradually increasing the influent normal molasses wastewater (NMWW) proportion. When the influent NMWW proportion increased to 55%, ABR could develop microbial community with methanogenic function in 63 days and reach a stable operation. When the influent NMWW proportion increased to 80% and reached a stable state, ethanol fermentation was established from butyric acid fermentation in the first three compartments, whereas butyric acid fermentation in the fourth compartment was strengthened. The average biohydrogen production yield and biohydrogen production capacity by COD removal increased to as high as 12.85 L/day and 360.22 L/kg COD when the influent NMWW proportion increased from 55% to 80%, respectively. Although the biogas yield and the specific biogas production rate reached 61.54 L/day and 232 L/kg MLVSS·day, the biohydrogen production yield and specific biohydrogen production rate were only 12.85 L/day and 48 L/kg MLVSS·day, which results in hydrogen consumption by homoacetogenesis and methanogenesis.

Pretreatment of antibiotic fermentation residues by combined ultrasound and alkali for enhancing biohydrogen production

Antibiotic fermentation residues has been classified as “Hazardous Waste” in China since 2008, but its effective disposal and resource recovery remains a problem. Due to its high content of bioavailable organic matters, antibiotic fermentation residues can be utilized as a potential candidate for biohydrogen production. However, the complex matrix of antibiotic fermentation residues can restrict its efficiency of biohydrogen production. In this study, the effect of ultrasonic, alkaline and their combined pretreatments on the solubility of antibiotic fermentation residues was investigated to improve biohydrogen production. The results showed that the combined ultrasonic-alkaline pretreatment effectively disrupted the complex matrix of antibiotic fermentation residues and synergistically improved the biohydrogen production. Soluble chemical oxygen demand (SCOD) and soluble carbohydrate content were improved by 61.6% and 105% after the combined pretreatment, respectively. Due to the solubilization effect and the enhanced enzymatic hydrolysis, the hydrogen yield reached 17.0 mL/g-volatile solids (VS) with the combined pretreatment, which was 78.9% higher compared to the control group. The combined pretreatment also improved the hydrogen production rate and substrate utilization, and decreased the lag time. Microbial community analysis showed that the hydrogen-producing bacteria (e.g. Paraclostridium, Escherichia-Shigella and Hafnia-Obesumbacterium) were more enriched with the combined pretreatment, while hydrogen-producing competitors were inhibited, which contributed to the more efficient hydrogen fermentation. This study demonstrated the technical feasibility of using ultrasonic-alkaline pretreatment to improve the biohydrogen production from antibiotic fermentation residues.

Effect of Hydraulic Retention Time on Anaerobic Baffled Reactor Operation: Enhanced Biohydrogen Production and Enrichment of Hydrogen-producing Acetogens

Biohydrogen production by fermentation has become a promising technology developed in the world. In this study, diluted normal molasses wastewater is used as the raw material, and biohydrogen production efficiency and operation characteristics of an anaerobic baffled reactor (ABR) are studied. The effect of hydraulic retention time (HRT) on biohydrogen production efficiency and operating characteristics of ABR is extensively discussed. Experimental results showed that methanogen residuals were still observed in the last three compartments under HRT of 24 h and COD(Chemical oxygen demand) concentration of 8000 mg/L. Meanwhile, the first three compartments presented an ethanol fermentation type. The characteristics of butyric acid fermentation in Compartment IV were also enhanced. The average removal efficiency of COD was reduced to 15.4%. The average rates of biohydrogen production and specific biohydrogen production were 12.85 and 360.22 L/kg COD, respectively. The extension of HRT was beneficial to enrich hydrogen-producing acetogens and could increase the production rate of biohydrogen by a factor of 1.65. However, with the decrease in the bioactivity of acidogenic fermentation bacteria, the biohydrogen production efficiency of ABR was significantly reduced when HRT was longer than 30 h. The specific biogas production rate decreased from 191 to 92 L/(kg MLVSS·d). The specific biohydrogen production rate also decreased from 24.34 to 2.7 L/(kg MLVSS·d).