Fermentative Biohydrogen Production Research Articles

Comparative Analysis of Various Seed Sludges for Biohydrogen Production from Alkaline Pretreated Rice Straw

The present work studied the effects of alkali pretreatment on the cellulosic biomass of rice straw. The improvement in the cellulose content and reduction in the lignin and hemicellulose percentage was observed with alkali pretreatment. Fourier transformation infrared spectroscopy (FTIR) and Scanning electron microscopy (SEM) analysis confirm the modification in the surface structure of alkali rice straw. Further, the study investigated the potential of different types of seed sludge as inoculum sources for dark fermentative biohydrogen production. In comparison to other sludge samples (beverage industry, food industry, and sewage treatment plant sludge), the mixed culture of sewage treatment plant sludge had the highest cumulative volume of biohydrogen (90.52 mL), as well as the highest hydrogen production yield (0.75 moleH2/mole) with the substrate utilization of 86.72%. The results provide information on the best sludge source for enhancing biohydrogen production in the dark fermentation method.

Hydrogel immobilized microalgae-alginate beads to model the fermentation of phenol-containing wastewater into biohydrogen molecules

The potential of hydrogel immobilized microalgae-alginate beads to concurrently remove phenol and produce biohydrogen molecules from phenol-containing wastewaters with different phenol concentrations of 0.2 g/L to 1.2 g/L via dark fermentation had been successfully modelled and proven. Highest biohydrogen production and phenol removal were achieved at phenol concentration of 1.2 g/L. The lag phase of biohydrogen production increased with increasing of phenol concentration as the microalgal cells entailed a longer time to acclimatize in inhibitory medium of high phenol strength. The extended period for fermentation could also generate more biohydrogen molecules as compared with batch setup that was easily inhibited due to inadequate acclimatization allocation. Then, a new kinetic model was rederived from the modified Gompertz model and Andrew’s inhibition model to describe the relationship between phenol concentration impacting the microalgal growth and subsequent biohydrogen production. Low concentration of phenol could serve as an alternative source of carbon to promote the microalgal growth and development; but high phenol concentration could hinder the growth of microalgae, afflicting the fermentative biohydrogen production. The rederived kinetic model was able to fit the experimental data for all phenol concentrations with coefficients of determination of greater than 0.95. This study had ultimately evidenced that the immobilized microalgae were able to ferment phenol and produce biohydrogen molecules simultaneously from phenol-containing wastewater.

Biosurfactant induced microwave disintegration of macroalgae for fermentative biohydrogen production

Biosurfactant-induced microwave disintegration (BSMD), an energy and cost effective pretreatment method, has been proposed to increase biohydrogen production from marine macroalgae (Chaetomorpha antennina). Microwave disintegration (MD) was performed for microwave powers from 90 to 540 Watts in varied periods from 0 to 60 mins. During this MD process, a disintegration time of 25 mins and microwave power of 360 W were obtained as optimum conditions, resulting in the dissolvable organics release (DOR) of 1860 mg/L and a disintegration efficiency (DE) of 14.3%. BSMD was implemented by adding the biosurfactant dosages from 0.005 to 0.05 g/g TS with the optimum power of MD at various intervals of time of 0–30 min. The optimum biosurfactant dosage for efficient disintegration in BSMD was 0.03 g/g TS, resulting in 19.55% DE and 2542 mg/L of DOR in 10 mins. BSMD sample showed increased volatile fatty acid (VFA) production of about 1393 mg/L than MD (1000 mg/L). In addition, BSMD consumed less input energy (IE) of (480 kWh / kg of solids) than MD (1200kWh / kg of solids). The highest amount of biohydrogen was produced by BSMD (120 mL H2/g COD) than MD (78 mL H2/g COD). The results showed BSMD method was energy-efficient for producing biohydrogen with an energy ratio of 1.96, and economical with a net profit of 74.78 $.

A bibliometric analysis of the role of nanotechnology in dark fermentative biohydrogen production.

Recently, nanoparticles have drawn a lot of interest as catalysts to enhance the effectiveness and output of biohydrogen generation processes. This review article provides a comprehensive bibliometric analysis of the significance of nanotechnology in dark fermentative biohydrogen production. The study examines the scientific literature from the database of The Web of Science© while the bibliometric investigation utilized VOSviewer© and Bibliometrix software tools to conduct the analysis. The findings revealed that a total of 232 articles focused on studying dark fermentation for hydrogen production throughout the entire duration. The extracted data was used to analyze publication trends, authorship patterns, and geographic distribution along with types and effects of nanoparticles on the microbial community responsible for dark fermentative biohydrogen production. The findings of this bibliometric analysis provide valuable insights into the advancements and achievements in the utilization of nanoparticles in the dark fermentation process used to produce biohydrogen.

Investigating the quantum size effects of multi-walled carbon nanotubes (MWCNTs) in photocatalytic fermentative biohydrogen production

Nanocatalysts' quantum size impacts their catalytic activity, hence surface area in nanomaterials plays a key role in controlling the charge transferring. Since multi-walled carbon nanotubes (MWCNTs) possess a large surface area as compared to bulk activated carbon (AC), thus their role in photo fermentative biohydrogen production (PFHP) from corn stover has been investigated. The physio-optical characteristics of the studied MWCNTs, and AC were characterized through the Brunauer Emmett Teller (BET), scanning electron microscope (SEM), and Raman spectroscopy. The experimental finding revealed that MWCNTs has a larger specific surface area (SSA) of 227.69 m2/g than activated carbon (AC) (126.26 m2/g). SEM and Raman results confirmed that MWCNTs have smaller sizes and more defects due to surface dangling bonds. The incorporation of MWCNTs in a photo fermentative medium showed a pronounced effect on hydrogen production. The optimal concentration of 20 mg/L MWCNTs increased the hydrogen production rate to 132.96 mL/h, 46.66% and 17.85% greater than the control group (CG) and AC, respectively, and reduced the lag period by 12 h. At 20 mg/L loading concentration, total hydrogen production was 293.84 mL, 2-fold and 16.24% greater than CG. The 44.85%, 100.39%, and 126.49% increase in byproducts, energy conversion efficiency (ECE), and light conversion efficiency (LCE), respectively compared to CG indicated an increase in metabolic processes, which increased total hydrogen production, suggesting that catalyst surface area is the key parameter affecting fermentative biohydrogen production catalytic efficiency.

Biohydrogen production kinetics from cacao pod husk hydrolysate in dark fermentations: Effect of pretreatment, substrate concentration, and inoculum

This study aims to explore the impact of pretreatment on cacao pod husk (CPH) and investigate the kinetics of biohydrogen production in a dark fermentation (DF) batch reactor with consideration for substrate and inoculum concentration. As the first study focused on biohydrogen production from CPH, the Taguchi orthogonal array was utilized to determine the optimal pretreatment condition for powdered CPH. This study examined different substrate concentrations (3–100 g VS/L) and inoculum concentrations (5 and 10 % v/v). The study showed that biohydrogen production was significantly increased by 74.4 ± 0.1 % by pretreatment with 5.5 % HCl compared to the untreated CPH as control. Furthermore, the optimal performance was achieved by 35 g VS/L of CPH in the mixture with inoculated by 10 % v/v inoculum, resulting in a biohydrogen production and concentration of 257.05 ± 7.97 mL/L and 23.87 ± 0.15 %, respectively. The inoculum's microbial community analysis using Illumina 16S sequencing showed a dominance of the Ethanoligenes (30.4 %), which was positively correlated with the profiles of hydrogen production and the proportion of VFAs. The Aiba model with an exponential substrate concentration and inhibitory constant (R2 of 0.93) was statistically the most precise mathematical model to predict the specific growth rate during the fermentative biohydrogen production by CPH substrate.

Fermentative Biohydrogen and Biomethane Production from High-Strength Industrial Food Waste Hydrolysate Using Suspended Cell Techniques

Fermentative Biohydrogen and Biomethane Production from High-Strength Industrial Food Waste Hydrolysate Using Suspended Cell Techniques

Comparative effect of acid and heat inoculum pretreatment on dark fermentative biohydrogen production

This study delves into the impact of various pretreatment methods on the inoculum in dark fermentation trials, specifically exploring thermal shock at different temperatures (60, 80, and 100 °C) and durations (15, 30, and 60 min), as well as acid shock at pH 5.5. Initial acidification of the substrate/inoculum mixture facilitates H2 generation, making acid shock an effective pretreatment option. However, it is also observed that combining thermal and acid pretreatments boosts H2 production synergistically. The synergy between thermal and acid pretreatments results in a significant improvement, increasing the overall hydrogen production efficiency by more than 9% compared to assays involving acidification alone. This highlights the considerable potential for optimizing pretreatment strategies. Furthermore, the study sheds light on the critical role of inoculum characteristics in the process, with diverse hydrogen-generating bacteria significantly influencing outcomes. The established equivalent performance of HCl and H2SO4 in inoculum pretreatment demonstrates the versatility of these acids in shaping the microbial community and influencing hydrogen production. The analysis of glucose conversion data highlights a prevalence of butyric acid in all trials, irrespective of the pretreatment method, emphasizing the dominance of the butyrate pathway in hydrogen generation. Additionally, an examination of the microbial community offers valuable insights into the intricate relationships between temperature, pH, and microbial diversity. Bacteroidota established its dominance among the bacterial populations, with a relative abundance exceeding 20–25% in the raw inoculum, and this dominance further increased following the treatment. Thermal and acid pretreatments result in significant shifts in dominant microbial communities, with some non-dominant phyla like Cloacimonadota and Spirochaetota becoming more prominent. These shifts in microbial diversity underscore the sensitivity of microbial communities to environmental conditions and pretreatment methods, further highlighting the importance of understanding their dynamics in dark fermentation processes.

Screening of microalgae strains for efficient biotransformation of small molecular organic acids from dark fermentation biohydrogen production wastewater

Dark fermentation biohydrogen production is a rapidly advancing and well-established field. However, the accumulation of volatile organic acid (VFAs) byproducts hinder its practical applications. Microalgae have demonstrated the ability to efficiently utilize VFAs while also treating waste gases and other nutrient elements. Integrating microalgae cultivation with dark fermentation is a promising approach. However, low VFAs tolerance and slow VFAs consumption restrict their application. To find suitable wastewater treatment microalgae, this work screened eight microalgae strains from five family. The results demonstrated that Chlamydomonas reinhardtii exhibited significant advantages in VFAs utilization, achieving a maximum removal of 100% for acetate and 52.5% for butyrate. Among the tested microalgae strains, CW15 outperformed in terms of photobioreactor adaptability, VFAs utilization, biomass productivity, and nutrient removal, making it the most promising microalgae for practical applications. This research demonstrates the feasibility of integrating microalgae cultivation with dark fermentation and providing a viable technical solution for integrated-biorefining.

Reaching the operating limit of the continuous multiple tube reactor: Still a promising technology for maximizing fermentative biohydrogen production?

This study simulated the application of the continuous multiple tube reactor (CMTR), a promising technology capable to replace fixed-film reactors in biohydrogen (bioH2) production via dark fermentation, in the processing of sucrose-rich wastewater (COD of up to 16 g L−1). The long-term impacts on both the bioH2 evolution and the dynamics of biomass growth and retention were assessed, aiming to identify the operating limits of the reactor. The bioH2 production was maximized (1445 NmL H2 L−1 d−1) when using moderately concentrated wastewaters (COD = 8 g L−1) at an OLR of 48.0 g COD L−1 d−1, with much lower hydrogenogenic activity (< 200 NmL H2 L−1 d−1) observed at OLR levels of 72.0 and 96.0 g COD L−1 d−1. Inhibition of the fermentative activity by excess substrate and limitations in the retention capacity of suspended biomass in the reactor still limit the application of higher OLR at the current stage of the technology. Strategies stimulating the cell growth (nitrogen dosing) and biofilm formation (calcium dosing) have potential to expand the operating limit of the CMTR without requiring constructive modifications.

Influence of titanate photocatalyst in biohydrogen yield via photo fermentation from corn stover

The effects of three common titanate photocatalysts (TPC) on the photo fermentation biohydrogen production (PFHP) from corn stover were studied in this paper. Compared with CaTiO3 and BaTiO3, the experimental group with the addition of MgTiO3 showed stronger potential for PFHP, the maximum hydrogen yield of 344 mL (68.8 mL/g TS) was obtained at 3 g/L MgTiO3, increased by 48.3%. For CaTiO3, BaTiO3, the optimal amount of addition was 8 and 7 g/L, respectively, in which, the hydrogen yield was 308 and 288 mL (61.6 and 57.6 mL/g TS). TPC addition could shorten the delay period of hydrogen production lower the Oxidation-Reduction Potential (ORP) of fermentation broth, especially MgTiO3 addition, the delayed hydrogen production could be shortened by 33.2% compared with control group, and the ORP could reach the lowest value of −371 mV.

Triggering photo fermentative biohydrogen production through NiFe2O4 photo nanocatalysts with various excitation sources

The triggering effects of nickel ferrite (NiFe2O4) photo nanocatalysts on photo fermentative hydrogen production (PFHP), and metabolic pathways under various excitation sources (incandescent lamp, Xenon lamp, and 532 laser) have been investigated. Compare to the control group (CG) highest cumulative hydrogen volume (CHV) and the maximum hydrogen production rate (HPR) of 568.8 mL and 9.17 mL/h, respectively were achieved at a loading centration of 150 mg/L excited with an incandescent lamp. The change in metabolites with NiFe2O4 incorporation suggests that bacterial activity is significantly affected by photo nanocatalysts. Triggering of NiFe2O4 by laser excitation showed the highest HPR of 7.83 mL /h within 24 h, which greatly reduces the lag time. The microbial community investigation showed that the addition of NiFe2O4 photo nanocatalysts and the change of light source effectively improved the microbial community structure and increased the abundance of hydrogen-producing bacteria (HPB) which leads to enhanced hydrogen production.

Comparison of biorefinery characteristics: Photo-fermentation biohydrogen, dark fermentation biohydrogen, biomethane, and bioethanol production

Biorefinery technology promotes the realization of the Paris Agreement, China’s achievement of its carbon peak, and carbon neutralization. Photo-fermentation biohydrogen production, dark fermentation biohydrogen production, biomethane production, and bioethanol production are several promising biorefinery methods. In this study, corn stover was used as the raw material, and the gas, liquid, and kinetic characteristics of four biorefinery methods were investigated. The production yield, gross thermal energy, economy, and greenhouse gas emissions of the target product per gram of corn stover were studied. The maximum yields of photo-fermentation biohydrogen production, dark fermentation biohydrogen production, biomethane production, and bioethanol production were 68.4 mL/g dry matter (DM), 47.4 mL/g DM, 196.0 mL/g DM, and 2.7 g/L, respectively. The maximum gross thermal energy obtained from biomethane production was 7017.3 J/g DM. The maximum economy of 1.4 RMB/g DM was observed in photo-fermentation biohydrogen production. The highest greenhouse gas emission of the target product from biomethane production was 196.0 mL/g DM. The results provide a reference for the efficient utilization of biomass resources and a comprehensive evaluation of biorefinery technology.

Feasibility of semi-pilot scale up-flow anaerobic sludge blanket fixed-film reactor for fermentative bio-hydrogen production from palm oil mill effluent

The present study focuses on bio-hydrogen production using palm oil mill effluent (POME) at a semi-pilot scale of an “up-flow anaerobic sludge blanket fixed-film (UASFF) reactor”. The reactor was operated in the palm oil mill industry for over 180 days of operation at ambient temperature through dark fermentation process with different organic loading rates (OLR) of 22–36 g-COD/l.d, depending on the COD concentration of POME. By acclimatizing the sludge, the semi-pilot scale UASFF reactor achieved hydrogen content, and hydrogen production rate (HPR) of 20%–68%, and 12 L H2/d to 39 L H2/d, respectively with a maximum COD removal of 35%. Moreover, from high through pyrosequencing analysis, hydrogen fermentation was attributed to Clostridium sensu stricto, Lactobacillus, and thermoanaerobium spp. This study offers an extensive approach to developing a semi-pilot scale bio-hydrogen production and, provides further prospects for profitable exploitation which could be a promising approach for reaching sustainability and economic feasibility (using wastewater as a low-cost feedstock) in commercial applications for future studies.

Metabolic engineering approaches for scale-up of fermentative biohydrogen production–A review

Significant efforts are being made to produce biofuels to replace fossil fuels and address the issues caused by global climate change. Due to its potential better conversion efficiency to useable power, decreased emission of pollutants, and high energy density, H2 is one of the prospective options that are seen as a desirable future clean energy carrier. Although there are numerous technologies available for producing H2, this review concentrates on fermentative H2 production techniques, their drawbacks, and current developments. While being a promising method, fermentative strategies still have several drawbacks, including low H2 production yields. Many approaches have been used to address these issues; among them, the field of metabolic pathway engineering has made enormous strides. To improve H2 generation, this paper reviewed and discussed several metabolic pathways and modified strains. As well as the challenges involved in H2 scale-up from a laboratory setting to a commercial scale.

Recent advances in fermentative biohydrogen production

Utilization of unsustainable fossil fuels as energy resources releases greenhouse gases into the atmosphere leading to global warming and environmental pollution. An eye-catching solution would be the production of biological liquids like hydrogen, which is a clean renewable fuel using dark/light fermentative approach. A brief insight into the effect of parameters that could enhance H2 production is the major focus of this review. Although dark/light fermentative approaches for H2 production is known for quite long, scaling up this technology has seen major hurdles. The review thus throws light on the need for novel tactics such as microbial immobilization, nanotechnologies, and genetic engineering to varying the microbial genomes for improvement of H2 yield. Further, thoughts on the difficulties that could be faced and potential solutions about the prospects for H2 technology to be commercially used as a sustainable fuel in the near future are also emphasized.

Application of modern approaches to the synthesis of biohydrogen from organic waste

Hydrogen production with the use of biological processes and renewable feedstock may be considered an economical and sustainable alternative fuel. The high calorific value and zero emission in the production of biohydrogen make it the best possible source for energy security and environmental sustainability. Solar energy, microorganisms, and feedstock such as organic waste and lignocellulosic biomasses of different feedstock are the only requirements of biohydrogen production along with specific environmental conditions for the growth of microorganisms. Hydrogen is also named as ‘fuel of the future’. This study presents different pathways of biohydrogen production. Because of breakthroughs in R&D, biohydrogen has been elevated to the status of a viable biofuel for the future. However, significant problems such as the cost of preprocessing, oxygen-hypersensitive enzymes, a lack of uniform light illumination for photobiological processes, and other expenses requiring intensification process limits are faced throughout the biohydrogen production process. Despite concerns regarding nanoparticle (NP) toxicity at higher concentrations, proper NP concentrations may improve hydrogen production dramatically by dissolving the substrates for bacterial hydrogen transformation. The data-driven Machine Learning (ML) model allows for quick response approximation for fermentative biohydrogen production while accounting for non-linear interactions between input variables. Scaling up biohydrogen production for future commercial-scale applications requires combining cost-benefit evaluations and life cycle effects with machine learning.

Enhanced fermentative biohydrogen production from milk processing wastewater by magnetic spinel ferrites nanoparticles

ABSTRACT In the present study, metal ferrites nanoparticles (MFNPs), comprising nickel ferrite (NiFe2O4), cobalt ferrite (CoFe2O4), and copper ferrite (CuFe2O4) nanoparticles (NPs), were synthesized and characterized for investigating their effect on biohydrogen production by thermophilic dark fermentation of milk processing wastewater (MPWW). The MFNPs were synthesized using the chemical coprecipitation method and were characterized using XRD, SEM-EDS, and VSM analysis. According to the characterization results, the average nanocrystallite sizes of NiFe2O4, CoFe2O4 and CuFe2O4 spinels were 25.8 nm, 33 nm, and 20.7 nm, respectively. The NPs prepared were pure and showed a ferromagnetic behavior. Dark fermentation tests revealed that the MFNPs had a promoting effect on biohydrogen production. In comparison with the control assay, biohydrogen yield was enhanced by 2.71, 2.58, and 2 folds higher for optimal concentrations of CuFe2O4, NiFe2O4, and CoFe2O4, respectively. The maximum biohydrogen yield of 246.13 ± 3.69 mL/g VS was obtained by adding 2 mg/L of CuFe2O4 NPs. The experimental data of MFNPs-assisted dark fermentation were well predicted by the Gompertz kinetic model.

Effect of nanoparticles synthesized from green extracts on dark fermentative biohydrogen production

Research on the production of nanoparticles with sustainable methods using different leaf extracts as a reducing agent has gained momentum. In this study, green synthesis of two types of iron oxide nanoparticles were produced to investigate the impact of nanoparticles on bio-hydrogen yield. Olive leaf extract and microalgae extract were used as reducing agents for production. The synthesized nanoparticles were characterized via SEM, EDX, XRD and UV–Visible spectrum analyses. The nanoparticles have a stable appearance and mean particle sizes of 90.26 and 124.68 nm. Iron oxide nanoparticles produced from olive leaf extract were more effective in dark fermentation. Dark fermentation yields by Clostridium sp. were assessed utilizing various proportions of generated two types of nanoparticles (50–400 mg/L). The addition of 200 mg/L olive leaf extract-based iron oxide nanoparticles and 300 mg/L microalgae extract-based iron oxide nanoparticles enhanced the hydrogen production capacity by 41% and 28%, respectively.

Synergetic effect evaluation of light and mass transfer enhancement strategies on photo fermentative biohydrogen production process: Illumination, shake, and high solid level

During the process of photo fermentative biohydrogen production (PFHP) with high substrate concentration from agricultural waste, the interphase light and mass transfer behavior is hindered, caused by the suspension flow of substrates, resulting in low hydrogen production performance. In the paper, shake and lighting supplied strategy was investigated to soften the restrictions of high substrate concentration of corncob to improve the hydrogen yield and light energy conversion. The response surface methodology (RSM) was adopted to optimize the influence of variables on hydrogen production (substrate concentration, light intensity and shake intensity). Results showed that the maximum hydrogen yield of 48 mL/g TS and the maximum light energy conversion efficiency of 11.04% were obtained at the condition of 150 rpm, 6000 Lux and substrate concentration 55.56 g/L, increased by 603.85% and 598.63% than the static condition, respectively. RSM showed the synergistic effect between variables significantly affected the hydrogen production performance, the optimal enhancement strategies were: shake intensity 153.33 rpm, light intensity 6155.56 Lux and substrate concentration 57.71 g/L. 4.71% error of the predicted cumulative hydrogen yield (490.41 mL) and the actual cumulative hydrogen yield (468.34 mL) indicating the fitting effect of the model was satisfactory.