Biological Hydrogen Research Articles

Platinum-Gold Alloy Catalyzes the Aerobic Oxidation of Formic Acid for Hydrogen Peroxide Synthesis.

On-site hydrogen peroxide production through electrocatalytic and photocatalytic oxygen reduction reactions has recently attracted broad research interest. However, practical applications have thus far been plagued by the low activity and the requirement of complex equipment. Here, inspired by the process of biological hydrogen peroxide synthesis catalyzed by enzymes, we report a Pt-Au alloy to mimic the catalytic function of natural formate oxidase for hydrogen peroxide synthesis through aerobic oxidation of formic acid. The mass activity of the Pt-Au alloy is three times higher than that of formate oxidase. Density functional theory calculations revealed that the efficient dehydrogenation of formic acid and the high selectivity of the subsequent reduction of oxygen to hydrogen peroxide account for the high hydrogen peroxide productivity. In addition, the formic acid aqueous solution provides an acidic environment, which is conducive to the utilization of the in situ generated hydrogen peroxide for oxidation reactions, including C-H bond oxidation and sterilization.

Living intracellular inorganic-microorganism biohybrid system for efficient solar hydrogen generation

<h2>Summary</h2> The thirsty demand for renewable, sustainable, and efficient hydrogen production has promoted the rapid development of advanced technologies, and whole-cell microorganism-based biological hydrogen production is one of the most promising strategies. Herein, we demonstrate the solar-light-induced enhancement of biological hydrogen production on the typical non-photosynthetic and non-genetic engineered bacteria. Furthermore, an intracellular inorganic-biological hybrid system is proposed to improve the hydrogen generation rate. The formation of intrinsic inorganic-biological junctions facilitates photo-electron separation and transfer and thus reaches a high biohybrid hydrogen generation rate of 7,800 ± 12 μmol g⁻¹ h⁻¹. Our work sheds light on the advantages of an intracellular inorganic-biological hybrid system by combining the light-harvesting capacity of inorganic materials with the metabolic power of microbes to produce biofuels and chemical compounds and indicates the promising potential for solar-to-chemical conversion in a desirable and selective manner with higher diversity and functionality.

Landfill leachate valorization: A potential alternative to burden off resources and support energy systems

Landfilling is the globally adopted, low cost approach for disposing municipal solid waste. Landfilling contributes to environmental deterioration due to the emission of landfill gases especially methane (CH4), and release of hazardous organic and inorganic substances in the form of landfill leachate (LL). Proliferation of LL in the environment degrades the quality of soil, groundwater and surface water body (if any) and thus needs to be contained and treated before discharge. A wide range of treatment methods have been used for minimizing the contaminant load of LL. Nowadays stakeholders are moving towards more sustainable waste management practices and are utilizing waste as a resource to produce energy, fuel and other value-added products. However, unfortunately, the energyvalorization from LL is lacking and it can fascinate global researchers for the treatment of LL with renewable energy production. Therefore in this study, we reviewed (1) the quality of LL generated from landfilling and its impact on the environment, (2) The energy valorization such as biogas, biological hydrogen, and bio-energy from LL through anaerobic digestion, dark fermentation, and Microbial Fuel Cells, respectively, and (3) Challenges and future prospects of energy valorization from LL. The resources present in leachate such as the organic matter, inorganic substances, and nutrients like N&P, can be converted to energy, and other value-added resources through valorization. LL valorisation can be a potential solution not only to reduce the contaminant load from the natural resources (air, water and soil) but also to utilize the energy resources in the form of either electricity and/or heat and serve as a potential alternative to non-renewable energy. Beside this, the other advantages of valorisation include amelioration of waste malodours and environmental pollution, and reduction of waste volume etc.

Thiol-Activated 1,2,4-Thiadiazolidin-3,5-diones Release Hydrogen Sulfide through a Carbonyl-Sulfide-Dependent Pathway.

Recent efforts have expanded the development of small molecule donors that release the important biological signaling molecule hydrogen sulfide (H2S). Previous work on 1,2,4-thiadiazolidin-3,5-diones (TDZNs) reported that these compounds release H2S directly, albeit inefficiently. However, TDZNs showed promising efficacy in H2S-mediated relaxation in ex vivo aortic ring relaxation models. Here, we show that TDZNs release carbonyl sulfide (COS) efficiently, which can be converted to H2S by the enzyme carbonic anhydrase (CA) rather than releasing H2S directly as previously reported.

Enhancement of biological hydrogen production from organic wastes with the application of nanomaterials

Enhancement of biological hydrogen production from organic wastes with the application of nanomaterials

Enhancing biohydrogen gas production in anaerobic system via comparative chemical pre-treatment on palm oil mill effluent (POME)

Biological hydrogen production using palm oil mill effluent (POME) as a carbon source through dark fermentation process has been suggested to be a promising bioenergy potential and enacts as alternative renewable energy source. Results have indicated that among various 1.5% (w/v) chemical pre-treatments (sodium hydroxide, NaOH; hydrochloric acid, HCl; sulphuric acid, H2SO4; phosphoric acid, H3PO4 and nitric acid, HNO3) on POME, using H3PO4 would generate maximum biohydrogen production of 0.193 mmol/L/h, which corresponded to a yield of 1.51 mol H2/mol TCconsumed with an initial total soluble carbohydrate concentration of 23.52 g/L. Among H3PO4 concentrations (1%–10%), the soluble carbohydrate content and the biohydrogen produced was highest and increased by 1.70-fold and 2.35-fold respectively at 2.5% (w/v), as compared to untreated POME. The batch fermentation maximum hydrogen production rate and yield of 0.208 mmol/L/h and 1.69 mol H2/mol TCconsumed were achieved at optimum pre-treatment conditions of pH 5.5 and thermophilic temperature (60 °C). This study suggests that chemical pre-treatment approaches manage to produce and improve the carbohydrate utilisation process further. Continuous fermentation in CSTR at the optimum conditions produce heightened 1.5-fold biohydrogen yield for 2.5% H3PO4 at 6 h HRT as compared to batch scale. Bacterial community via next-generation sequencing analysis at optimum HRT (6 h) revealed that Thermoanaerobacterium thermosaccharolyticum registered the highest relative frequency of 20.24%. At the class level, Clostridia, Bacilli, Bacteroidia, Thermoanaerobacteria, and Gammaproteobacteria were identified as the biohydrogen-producing bacteria in the continuous system. Insightful findings from this study suggest the substantial practical utility of dilute chemical pre-treatment in improving biohydrogen production.

Production of hydrogen from beverage wastewater by dark fermentation in an internal circulation reactor: Effect on pH and hydraulic retention time

• Interaction and the RSM should be performed to determine the optimal zone for H 2 . • Interaction between factors established that the pH was main factor in the operation. • Distribution of VFAs and multivariate statistics allow an integral analysis. Energy demand currently is mostly satisfied by the use of fossil fuels that present not only problems for the environment, but also are not renewable. Dark fermentation (DF) is a biological process that can provide an alternative to meet energy needs. The use of industrial effluents from carbon-rich waters in the production of hydrogen and volatile fatty acids (VFAs) through the DF is a promising strategy. However, determining the optimal operating conditions to increase the production of the sub-products has been not being thoroughly studied. This study aims at determining the optimal condition of hydraulic retention time (HRT) and pH to improve hydrogen production in an internal recirculation (IC) reactor treating beverage wastewater using Response Surface Methodology and interaction between factors. The study also assessed VFAs concentrations when operating at optimal conditions. The results showed that the combination of an 8.0 h HRT and 5.5 produced 30% of hydrogen and the interaction between factors established that the pH was the main factor influencing the results. Also, it was observed that the concentration of lactic acid did not inhibit the production of H 2 for the optimal value of pH. However, it is evident that more studies using HRT of less than 8 h and of VFAs distribution are needed. Future optimization technique considerations are necessary to reduce uncertainties for biological hydrogen production purposes.

Fluorescent Probes for Sensing and Imaging Biological Hydrogen Sulfide

AbstractHydrogen sulfide (H2S) is an important endogenous biological signal molecule that plays an essential role in various pathological and physiological processes. Abnormal expression of H2S in vivo is associated with the occurrence and development of many diseases. Therefore, sensing biological H2S level and distribution is significant and has been extensively studied presently. A few reviews about H2S sensing and imaging have been reported, most of which focus on the sensing mechanisms and construction of probes. In this review, we firstly summarized and classified the H2S‐activated fluorescent probes over the past 5 years according to sensing modality and then mainly discussed their biological applications, including detection of physiological and pathological processes, diagnosis of diseases, and disease treatments. It is expected that this review can deepen the readers′ understanding of the biological role of H2S and provide them with biomedical background knowledge for the construction of the H2S probes.

Inside Front Cover: Synthetic nanoprobes for biological hydrogen sulfide detection and imaging (View 4/2022)

In article number 20210008, Rona Chandrawati and co-workers have evaluated the current advances of five different synthetic-based nanomaterials for in vitro and in vivo H2S sensing and imaging. The analytical methods associated with the various signal outputs, existing challenges in developing H2S nanoprobe, and aspects that affect the probe's performance are also discussed.

Application of Metabolic Engineering Approaches in Enhancing Biological Hydrogen Production

Hydrogen is useful as a fuel and could be produced by a variety of means. One approach uses artificial photosynthesis where energy from sunlight powers the splitting of water into hydrogen and oxygen. But, biological methods for producing hydrogen has emerged strongly over the past decades. In particular, specific microorganisms could use different substrates to produce hydrogen at differing yields. Such fundamental discoveries with industrial applications thus motivated the use of metabolic engineering approaches and methodologies in enhancing biological hydrogen production through a series of enzyme over-expression, pathway debottlenecking, and gene deletion. However, such approaches heavily rely on the selection of an appropriate microbial chassis for biohydrogen production. With the proper strain in hand, use of alternative substrates may engender greater hydrogen productivities. But learning from the bioprocessing field, co-culture of two compatible microorganisms have been sought after for improving biohydrogen production. In addition, thermophilic microbes may also be useful candidates for exploiting hydrogen production from composting. Future outlook in the field looks into filling our gaps in understanding of the metabolic network that feeds into hydrogen production in different organisms. But, more importantly, problems such as reduced growth rate in engineered microbes point to fundamental issues with using genetically engineered microorganisms for improved biohydrogen production, to which clever bioprocess engineering may yield solutions.

Biological hydrogen storage and release through multiple cycles of bi-directional hydrogenation of CO2 to formic acid in a single process unit

<h2>Summary</h2> Hydrogen is a promising fuel in a carbon-neutral economy, and many efforts are currently undertaken to produce hydrogen. One of the challenges is to store and transport the highly explosive gas in a safe and easy way. One option that is intensively analyzed by chemists and biologists is the conversion of hydrogen and CO₂ to formic acid, the liquid organic hydrogen carrier. Here, we demonstrate for the first time that a bio-based system, using <i>Acetobacterium woodii</i> as the biocatalyst, allows multiple cycles of bi-directional hydrogenation of CO₂ to formic acid in one bioreactor. The process was kept running over 2 weeks producing and oxidizing 330 mM formic acid in total. Unwanted side-product formation of acetic acid was prevented through metabolic engineering of the organism. The demonstrated process design can be considered as a future "bio-battery" for the reversible storage of electrons in the form of H₂ in formic acid, a versatile compound.

Responses of anaerobic hydrogen-producing granules to acute microplastics exposure during biological hydrogen production from wastewater

Anaerobic hydrogen-producing granule (AHPG) has been successfully applied in hydrogen production from wastewater. While various types of microplastics in large amounts are readily detected in both municipal and industrial wastewaters, however, to date the response of AHPG to multiple coexisting microplastics in wastewater is unknown yet. Herein, this study provided a first insight into the acute exposure-response relationship between multiple coexisting microplastics and the AHPG during biological hydrogen production from wastewater. Fluorescence tagging found that many microplastics accumulated and covered on the surface of the whole granule. Morphology and particle size of microplastics-bearing AHPG were characterized by microscopic observation, showing that the shock load of microplastics in the wastewater at the studied concentrations (40 and 80 mg/L) made the granule loose and even break down with the decreased particle size. The visualization of extracellular polymeric substances (EPS) structure revealed that microplastics decreased EPS production by 8.8–16.7%. Microbial community analysis demonstrated that the acute exposure of microplastics did not drive the change in the microbial community diversity and composition. However, toxic leachates and upgraded oxidative stress induced by microplastics increased cell death up to 14.7% and decreased hydrogen production by 18.7%, when the AHPG exposed to 80 mg/L of microplastics. This work gained a new insight into the response of anaerobic microorganisms to coexisting microplastics in the real environment.

Promotion of biological H2 (Bio-H2) production by the nitrogen-fixing anaerobic microbial consortia using humin, a solid-phase humic substance

Dark fermentative biological hydrogen (Bio-H2) production is expected to be a clean and sustainable H2 production technology, and the technologies have been studied to increase in the product yield as index. This study achieved high product yields of Bio-H2 using nitrogen-fixing consortia under nitrogen-deficient conditions with glucose or mannitol as substrate and humin as the extracellular electron mediator: 4.12mol-H2/mol-glucose and 3.12mol-H2/mol-mannitol. The high Bio-H2 production was observed under the conditions where both nitrogenase and hydrogenase were active in the presence of humin. Nitrogenase activity was confirmed by acetylene reduction activity and hydrogenase activity by Bio-H2 production under nitrogenase-inhibiting conditions with NH4NO3. [Fe-Fe] hydrogenase detected by a specific PCR and acetate, butyrate, formate, lactate, and pyruvate produced as by-products suggested the involvement of both pyruvate-ferredoxin-oxidoreductase and pyruvate formate lyase pathways in Bio-H2 production. Humin promoted the Bio-H2 production beyond the capacity of the consortium, which had reached saturation with the optimum concentrations of glucose and mannitol. Carbon balance suggested the concurrent H2 consumption by hydrogenotrophic methanogenesis and acetogenesis. Bio-H2 production of the washed and starved consortium with reduced humin under conditions with or without NH4NO3 suggests that humin promoted hydrogenase and nitrogenase activity by donating extracellular electrons. Clostridium and Ruminococcus in the consortia were considered major hydrogen producers. Thus, this study demonstrated the outstanding potential of nitrogen-fixing consortia under nitrogen-deficient conditions with humin as an extracellular electron mediator for dark fermentative Bio-H2 production with high yields.

Techno-economic assessment of green hydrogen valley providing multiple end-users

A techno-economic analysis of a hydrogen valley is carried out in this paper. A hydrogen generator fed by a wind farm (WF) and/or a photovoltaic (PV) plant supplies four end-users: a stationary fuel cell, a hydrogen refuelling station, the injection in the natural gas pipeline and, in case of sufficient hydrogen surplus, a biological hydrogen methanation (BHM) process.The results demonstrated that an efficiency improvement and a reduction in hydrogen production costs arise from a balanced supply from wind and solar energy. Without the inclusion of a BHM process, hydrogen production costs lower than 7 €/kg were achieved by a hydrogen generator using 10–12% of the PV + WF annual energy with a PV share of 20%–50%. The hydrogen production costs were further reduced to 5 €/kg by introducing a BHM process and increasing the percentage of electrical energy supplied by the PV + WF system to 25% of its overall production.

Production of Hydrogen by Biological Method from Crude Glycerol

Pollution and energy crises are the major problems faced by the world, so many developments and innovation are made in the field of renewable sources of energy, such as solar, wind, improvement in energy storage technology, etc. One such renewable, green, and non-polluting form of energy like hydrogen can be used as it is a clean, effective, and green fuel. Unlike other fuels, hydrogen doesn’t leave carbon traces. It suits the best for the environment. Bio diesel is one of those alternative fuels which have picked up keen interest of people due to its similar properties of diesel [1]. The aim of this project is to use crude glycerol along as a base nutrient medium for Klebsiella pneumoniae bacteria, which is done under anaerobic batch dark fermentation condition. The parameters such as inoculum size and pH are varied to find the optimal condition for high yield or hydrogen production content. When the strain is grown in the optimized condition in a bioreactor for batch production, hydrogen yield reaches maximum in some conditions which are shown in graph {4(b), 4(c), 4(d)} and some of the other gases are also produced which is sent for the gas analysis and H2 concentration is also measured. The main aim is to utilize the crude glycerol effectively as substrate for biological hydrogen production process which has socio-economic advantages [2].

Review on Bio-hydrogen Production Methods

Abstract: Hydrogen is a promising replacement for fossil fuels as a long-term energy source. It is a clean, recyclable, high efficient nature and environmentally friendly fuel. Hydrogen is now produced mostly using water electrolysis and natural gas steam reformation. However, biological hydrogen production has substantial advantages over thermochemical and electrochemical. Hydrogen can be produced biologically by bio-photolysis (direct and indirect), photo fermentation, dark fermentation. The methods for producing biological hydrogen were studied in this study. Keywords: Biological hydrogen, steam reformation, bio-photolysis, photo-fermentation, dark fermentation

Production of Bio-Hydrogen from Banana Waste by Using Anaerobic Fermentation

Abstract: This research aimed to study the production of biological hydrogen using banana waste as renewable biomass and was carried out by anaerobic fermentation. Clostridium acetobutylicum MTCC 11274 was used as micro-organism for the hydrogen generation. The substrate were hydrolysis by diluted 5% H2SO4 and 5 N NaOH by acidic and alkali pre-treatment method respectively. The volume of gas produced was calculated by the water displacement method. Keywords: Biological hydrogen, banana waste, anaerobic fermentation, Clostridium acetobutylicum, water displacement method

Synthetic nanoprobes for biological hydrogen sulfide detection and imaging

AbstractHydrogen sulfide (H2S) is a gaseous molecule involved in multiple biological and physiological processes, including various diseases such as cancer and neurodegenerative disorders. This has led to the development of various analytical methods to monitor H2S in biological settings. Among these, fluorescence‐based assays, specifically organic small‐molecule probes, have been thoroughly utilized. They offer good sensitivity and specificity as sensors, and noninvasive detection with high spatiotemporal resolution in in vitro and in vivo imaging. Despite attempts to decrease the rate of photobleaching and enhance the photostability of these dyes, they are still limited by low survival time and complex reagent pretreatment. Fortunately, nanotechnology has been applied to develop effective, highly sensitive, and specific fluorescent nanoprobes. Specifically, nanomaterial‐based H2S probes have emerged as promising candidates for real‐time detection and imaging. In contrast to their organic molecule‐based counterparts, they offer higher versatility in imaging modes due to their unique optical properties, improved photostability and solubility within physiological fluids, as well as easily modifiable surfaces and tuneable structures for improved specificity. Recently, many nanomaterial‐based probes, ranging from inorganic nanoparticles to self‐assembled nanocomposites, have been developed. These have, for the most part, achieved sensitive and specific endogenous H2S detection and in vivo imaging. In this review, we evaluate five different nanomaterials currently being researched to detect and image endogenous H2S within the last 5 years. Furthermore, analytical methods associated with the various signal outputs, current challenges in H2S nanoprobe design, and possible future research interests are outlined and discussed.

Evaluating the effect of diclofenac on hydrogen production by anaerobic fermentation of waste activated sludge

Hydrogen production from waste-activated sludge (WAS) anaerobic fermentation is considered to be an effective method of resource recovery. However, the presence of a large number of complex organic compounds in sludge will affect the biological hydrogen production process. As an extensively applied prevalent anti-inflammatory drug, diclofenac (DCF) is inevitably released into the environment. However, the effect of diclofenac on hydrogen production from WAS anaerobic fermentation has not been fully investigated. This work therefore aims to comprehensively investigate the removal efficiency of DCF in mesophilic anaerobic fermentation of WAS and its effect on hydrogen yield. Experiment results showed that 32.5%–38.3% of DCF was degraded in the fermentation process when DCF concentration was ranged from 6 to 100 mg/kg TSS (total suspended solids). DCF at environmental level inhibited hydrogen production, the maximal hydrogen yield decreased from 24.2 to 15.3 mL/g VSS (volatile suspended solids) with an increase of DCF addition from 6 to 100 mg/kg TSS. This is because the presence of DCF caused inhibitions to acetogenesis and acidogenesis, the processes responsible for hydrogen production, probably due to that the polar groups of DCF (i.e., carboxyl group) could readily bind to active sites of [FeFe]- Hydrogenase. Besides, the microbial analysis revealed that DCF increased the microbial diversity but had few influences on the microbial structure.

Effect of 5-HMF and furfural additives on bio-hydrogen production by photo-fermentation from giant reed

Substances harmful to photo-fermentative biological hydrogen production (PFHP) were produced during cellulose hydrolysis. This study aimed to evaluate the effect of by-products (5-hydroxymethylfurfural (5-HMF) and furfural) released from lignocellulose during enzymatic hydrolysis process on PFHP. The exist of 5-HMF inhibited the hydrogen production. However, 0.2 g/L furfural improved the hydrogen production by 19 % compared to no addition (511.6 mL) with a maximum concentration of nitrogenase (109.96 IU/L) at 96 h. Furthermore, a 18.7 % enhancement of hydrogen production was also observed when 0.2 g/L 5-HMF and furfural were mixed at a ratio of 1:1, while decrement of hydrogen production at higher addition was observed as well. Through the scatter matrix analysis, it was concluded that 5-HMF and furfural additives had significant effects on PFHP. This study gave an insight into effect of lignocellulosic by-products on biohydrogen production.