Cumulative Hydrogen Yield Research Articles

Effect of single and multi-additives on the performance of hydrogen fermentation from food waste

Hydrogen as an alternative energy source receives primary importance considering the greenhouse gas emission from conventional fossil fuels. In this study, calcium peroxide (CaO2), calcium carbonate (CaCO3), zinc oxide (ZnO), and copper oxide (CuO) were used as single additives, whereas CaO2+CaCO3, CaO2+CuO, CaO2+ZnO, CaCO3+ZnO, CaCO3+CuO, and CuO+ZnO were used as multi-additives to improve hydrogen fermentation using food waste and cow dung as substrate and sludge solution as inoculum. As a result, maximum hydrogen content was enhanced up to 33.85% with multi-additive (CaO2+CaCO3), whereas it was restricted to 26.34% using single additives. Compared to the control reactor, maximum hydrogen content was increased by 10 and 17% with single and multi-additives, respectively. Further, cumulative hydrogen yield was considerably enhanced from 114.1 to 146.62 mL g-1 TS by adding multi-additives, especially CaO2+CaCO3. Results demonstrated that multi-additives improved the system performance due to the enhanced process stability during fermentative hydrogen production.

Analysis of the characteristics of paulownia lignocellulose and hydrogen production potential via photo fermentation

Paulownia biomass is rich in carbohydrates, making which a potential feedstock for biohydrogen production. In the study, different parts and varieties of Paulownia were chose as substrates to evaluate hydrogen production potential of paulownia lignocellulose via biohydrogen production by photo fermentation (BHPPF) and energy conversion efficiency (ECE). Results showed the highest cumulative hydrogen yield (CHY) of 67.11 mL/g total solids (TS) and ECE of 4.74% were obtained from leaves of Paulownia, which were 121.06% and 115.45% higher than those of the branches. Moreover, Paulownia jianshiensis leaves were found to be the best variety for BHPPF, with the maximum CHY of 98.83 mL/g TS and ECE of 7.18%. Using Paulownia waste as the substrate to produce hydrogen helps broaden the range of raw materials for BHPPF and improve the economic utilization of forestry waste.

Green-synthesized nickel oxide nanoparticles enhances biohydrogen production of Klebsiella sp. WL1316 using lignocellulosic hydrolysate and its regulatory mechanism

Green synthesis of nickel oxide nanoparticle (NiO-NP) from Eichhornia crassipes (Ec) extract was novelly conducted, and regulatory effect of this NP on fermentative hydrogen production was evaluated. Characterization of the Ec-NiO-NP revealed their cubic and spherical shape, small diameter (9.1 ± 2.6 nm) and high purity. The maximum cumulative hydrogen production and hydrogen yield Y(H2/S) reached 4842.19 ± 23.43 mL/L and 101.45 ± 3.32 mL/gsubstrate, respectively, in the presence of 20 mg/L Ec-NiO-NP, which were 47.29% and 37.78% higher than the control without NPs addition. Evaluation of glucose and xylose utilization efficiency as well as key node metabolites further established the potential of Ec-NiO-NP to improve the reducing sugar conversion and metabolic flux distribution in hydrogen synthesis pathway. Furthermore, addition of 20 mg/L Ec-NiO-NP resulted in enhanced hydrogenase activity with a maximum increase of 623% comparing to the control, and led to changes in the gene expression of both hydrogenase and formate-hydrogen lyase, which play important roles in promoting hydrogen production at different stages of fermentation. This study demonstrates that supplementation with green-synthesized Ec-NiO-NP effectively improves fermentative hydrogen production and regulates key node metabolites alteration and functional gene expression.

Photo‐catalytic reforming of aqueous phase derived from hydrothermal liquefaction of Nostoc ellipsosporum for bio‐hydrogen production

In this study, green fuel (hydrogen energy) was produced from the aqueous phase obtained from the hydrothermally liquefied Nostoc ellipsosporum biomass via photo-catalytic reforming. Initially, algae were cultivated in municipal wastewater and fog medium (80:20) in photo bio-reactor for biomass production. Later the algae biomass was liquefied under varying temperature of 220°C to 320°C at 5Mpa for 60 min. From the results, it was seen that the maximum bio-oil yield was 31 wt% for biomass to solvent ratio of 0.05 g/mL at 300°C. Gas Chromatography-Mass Spectroscopy (GC-MS) analysis of bio-oil showed the presence of hydrocarbons like octadecane, heptadecane, etc. Aqueous phase comprised of hydrogen generating low molecular weight compounds. Photo-catalytic reforming process with 0.1 g of TiO2 catalyst at time of 2 h resulted in hydrogen yield of 27 wt%. Catalyst reusability study resulted in cumulative hydrogen yield of 76 wt% from five consecutive cycles.

Nanoparticle-associated single step hydrogen fermentation for the conversion of starch potato waste biomass by thermophilic Parageobacillus thermoglucosidasius

In the present study, starch-based potato peel waste biomass (PWB) was utilized as a potential substrate for hydrogen production via dark fermentation by the thermophillic amylase producing strain Parageobacillus thermoglucosidasius KCTC 33548. Supplementation of Fe3O4 nanoparticles (300 mg/L) led to a 4.15-fold increase in hydrogen production as compared to the control. The addition of optimized concentrations of both Fe3O4 nanoparticles (300 mg/L) and L-cysteine (250 mg/L) during hydrogen fermentation using pure starch and PWB generated maximum cumulative hydrogen yields of 167 and 71.9 mL with maximum production rates of 2.81 and 1.26 mL/h, respectively. Further, the correlation between Fe3O4 and the expression of hydrogenase isoforms and the related hydrogenase activity was explored. The possible mechanisms of the action of Fe3O4 on enhanced hydrogenase activity and hydrogen production was elucidated. To our knowledge, there are no such studies reported on enhanced hydrogen production from PWB in a single step.

Photo-fermentative biohydrogen production from corncob treated by microwave irradiation

The complex structure of corncob is the bottleneck that restricts its efficient biohydrogen production. Hence, effective treatment is an important exploration to break this limitation. The effect of microwave irradiation (MI) on photo-fermentative biohydrogen production (PFHP) process was evaluated in this paper. Diverse conditions (irradiation time, microwave power, and surfactant addition) were applied. Comparisons of cumulative hydrogen yield (CHY), microstructure, liquid products, and substrate conversion efficiency (Sconv) were conducted. Results showed that the highest CHY of 27.34 ± 1.13 mL/g TS was achieved when the corncob was treated by MI assisted with surfactant addition. Optimal treatment conditions (5.51 min irradiation time, 772.03 W microwave power, and 0.08 g/L rhamnolipids addition) were obtained. MI assisted with surfactant addition helped with the structure destroys and content degradation, displaying a great improves on PFHP. Lower ethanol content and higher butyric acid content were obtained. An 80.94% increase in CHY and Sconv of 90.44% were obtained than untreated corncob.

Role of surfactant in affecting photo-fermentative bio-hydrogen production performance from corncob

Surfactant addition can cause a significant change in the interface state of the solution system, which is helpful to avoid agglomeration and sedimentation of solid state, and improve the mass transfer capacity. Hence, the performance of high-solid photo-fermentative bio-hydrogen production system with bio-surfactant addition was evaluated in this work. Corncob was selected as raw material, and cumulative hydrogen yield (CHY) was taken as reference. The effect of Rhamnolipids (RLs) and Tea Saponin (TSn) addition on hydrogen yield capacity was investigated. The results showed that CHY was effectively increased by the addition of RLs and TSn, the highest CHY of 356.42 ± 16.5 mL and 265.38 ± 7.5 mL appeared when the concentrations of surfactant addition were 0.08 g/L RLs and 1.5 g/L TSn, which were 67.85% and 24.97% higher than control group, respectively. The maximum energy conversion efficiency reached 5.47% and 4.08% with an increase of 67.8% and 25.2%.

Comparison of fermentative hydrogen production from glycerol using immobilized and suspended mixed cultures

This study explored the fermentative hydrogen production by immobilized microorganisms from glycerol, which is the byproduct of biodiesel production, and compared it with suspended fermentation. The effect of immobilization on hydrogen production process was examined. Results showed that both cumulative hydrogen production (CHP) and hydrogen yield (HY) were enhanced by microbial immobilization. The highest CHP and HY of 64 mL/100 mL and 0.52 mol H2/mol glycerol were obtained by immobilized microorganisms, compared to 9 mL/100 mL and 0.29 mol H2/mol glycerol in suspended microorganisms. Immobilization enhanced CHP and HY by 611.1% and 79.3%. In addition, immobilized microorganisms showed stronger tolerance to high substrate concentration and higher capability in glycerol utilization, which is of great significance for hydrogen production from glycerol. The enhanced hydrogen production may be due to the favorable micro-environment for different microorganisms in immobilized beads.

Hydrogen production from acidic, alkaline, and steam-exploded Bambusa stenostachya hydrolysates in dark fermentation process

Bambusa stenostachya Hack. was subjected to two pretreatment methods including hydrothermal pretreatment and steam explosion methods for evaluating their feasibility hydrolysis to obtain sugars. Batch cultivation by a mixture of microorganisms isolated from sludge in 48 h was carried out to investigate the influence of these pretreatment methods on hydrogen production under sterile conditions. The sugar production yields by sulfuric acid (ST), phosphoric acid (PT), sodium hydroxide (HT), and ammonia (AT) solutions in an autoclave at 121 °C were 42%, 25%, 10%, and 5%, respectively. Steam explosion of raw bamboo (SE) and bamboo treated with 0.8% sulfuric acid (SES) at 230 °C for 3 min had 23% and 72% of the total sugar derived from bamboo carbohydrates, respectively. The maximum cumulative hydrogen yields were 798 (mL H2/L culture) of ST, 545.9 (mL H2/L culture) of PT, 76.7 (mL H2/L culture) of HT, 43.7 (mL H2/L culture) of AT, 204.4 (mL H2/L culture) of SE, and 1055.8 (mL H2/L culture) of SES. Ammonia solution could remove 73.6% lignin in biomass compared to 6.5% of ST, 8.3% of PT, 51.9% of HT, 14.7% of SE, and 32.4% of SES. The integration of acid and steam explosion process had enhanced hydrogen fermentation efficiency directly from bamboo biomass hydrolysate, which could be considered a desirably potential procedure for large-scale applications.

Dosing effect of nano zero valent iron (NZVI) on the dark hydrogen fermentation performance via lake algae and food waste co-digestion

The effect of nano zero valent iron (NZVI) on hydrogen production by the co-digestion of dry lake algae and food waste was investigated. The results showed that 10 mg.gTS−1 addition of NZVI improved the performance of the co-digestion system, with the cumulative hydrogen increased by 29.20% to 40.04 mL.gVS−1, compared to that of the control. However, the cumulative hydrogen yield decreased to 14.77 and 5.37 mL.gVS−1 when the NZVI dosage was increased to 20 and 40 mg.gTS−1, respectively. The oxidation reduction potential (ORP) of the reaction system was decreased dramatically to -331∼-490 mV at the initial reaction stage. The degradation rates of carbohydrate and protein also reached their peaks at the NZVI dosage of 10 mg.gTS−1. The concentration of end product in the liquid phase and the dehydrogenase activity was first increased then decreased when enhancing the NZVI dosage. Analysis of the transmission electron microscopy images revealed that excessive NZVI dosage could destroy the cells of microorganisms.

An experimental approach to produce hydrogen from food waste, cow dung, and sludge solution

Abstract The effect of substrate (food waste and cow dung) and inoculum (sludge solution) ratio on the hydrogen fermentation is experimentally investigated in this study. Five reactors are prepared using various ratios of substrate and inoculum on volume basis and the hydrogen (H2) and carbon dioxide (CO2) generation is observed for 15 days. Result revealed that variation in the ratio cause substantial effect on the fermentation process. The reactor with substrate to inoculum ratio of 1:3 showed maximum hydrogen concentration (19.73%) in the produced biogas. The cumulative hydrogen yield is increased with the ratio and the highest value (114.4 mL/g total solid) is obtained with the ratio 1:3. The carbon dioxide concentration showed the least value in 1:3 ratio indicating the maximum conversion of the feedstock to hydrogen compared to the other samples. The result suggested that proper substrate to inoculum ratio is the deciding factor to improve the fermentation process. A ratio of food waste and cow dung with sludge solution (1:3) appeared the best combination for enhanced co-digestion process.

Effect of calcium peroxide and sodium hydroxide on hydrogen and methane generation during the co-digestion of food waste and cow dung

Anaerobic co-digestion of food waste, cow dung, and sludge solution was experimentally evaluated to produce hydrogen and methane considering the effect of calcium peroxide (CaO2) and sodium hydroxide (NaOH) addition with the feedstock. The various substrate to inoculum ratios (v/v) of 1:1(S1), 1:2(S2), 1:3(S3), 1:4(S4), and 1:5(S5) were evaluated in separate fermentative and methanogenic reactors. The optimum hydrogen and methane production was observed in S3 compared to the other samples. The biogas generation was increased up to 17% with an enhancement of methane concentration up to 10% by using NaOH compared to CaO2. The cumulative methane yield was increased by 12% due to the addition of NaOH as compared to CaO2. The maximum hydrogen concentration was improved by 7% with a substantial enhancement of cumulative hydrogen yield up to 37% by adding CaO2 with the feedstock as compared to NaOH. It was evident from the experiment that the production of hydrogen was significantly enhanced by adding CaO2 while the methane generation was influenced by the addition of NaOH during the co-digestion.

Hyperthermophilic Treatment of Grass and Leaves to Produce Hydrogen, Methane and VFA-Rich Digestate: Preliminary Results

In this study, the feasibility of hydrogen and methane production from grass and leaves via hyperthermophilic anaerobic digestion was investigated. The hyperthermophilic treatment of grass at 70 °C resulted in the highest concentrations of volatile fatty acids (TVFA) and reducing sugars in the supernatant of over 21 and 6.5 g/L reported on day 3 and 4 of the experiment. In contrast, hydrolysis and acidification of leaves performed slower and with lower efficiency, as the peak concentrations of TVFA and reducing sugars were observed at the end of the process. However, the highest cumulative hydrogen and methane yields of 69.64 mLH2/gVS and 38.63 mLCH4/gVS were reported for leaves digested at 70 °C, whereas the corresponding maximum productions observed for grass were 50 mLH2/gVS and 1.98 mLCH4/gVS, respectively. A temperature increase to 80 °C hampered hydrogen and methane production and also resulted in lower yields of volatile fatty acids, reducing sugars and ammonia as compared to the corresponding values reported for 70 °C.

Investigation of the interaction between lighting and mixing applied during the photo-fermentation biohydrogen production process from agricultural waste

To better clarify the effect of lighting and mixing on the hydrogen production from agricultural waste, experiments under diverse constant and dynamic light intensities and mixing speeds were conducted. Cumulative hydrogen yield, hydrogen production rate, OD660, pH, reducing sugar concentration were monitored. Results showed that mixing had positive effects on high substrate concentration. The interaction between lighting and mixing was drawn. Higher light intensity (7000 Lux) was suitable for hydrogen production under mixing. Higher light intensity with higher mixing speed (150 RPM) showed the highest cumulative hydrogen yield of 78.1 mL/g TS. Different periods of hydrogen production process required distinct lighting and mixing. Combined with Gompertz model, dynamic lighting and mixing strategies were discussed. Dynamic light intensity (4000-7000-4000 Lux) accompanied with dynamic mixing speed (50-150-50 RPM) was the optimal condition for PFHP. Highest hydrogen yield of 84.7 mL/g TS and highest light conversion efficiency of 36.32% were obtained.

Capacity Analysis of Photo-Fermentation Bio-Hydrogen Production from Different Food Wastes

Food waste is rich in starch or cellulose, which can be utilized as carbon source for fermentation. Hence, in this paper, different food wastes (vegetable, rice, corn, potato) were taken as substrate to evaluate their hydrogen yield potential. The characteristics of fermentation broth, cumulative hydrogen yield, and hydrogen production rate were investigated in the photo-fermentation bio-hydrogen production process. Modified Gompertz Model was utilized to deal with experiment data. Results showed that food waste can be effectively utilized by photosynthetic bacteria. Waste rice was determined to have the best hydrogen production capacity with hydrogen yield of 696 mL, and the maximum hydrogen production rate of 17.71 mL/h, the average hydrogen concentration was 55.78%.

Effect of Substrate Concentration on Photo-Fermentation Bio-Hydrogen Production Process from Starch-Rich Agricultural Leftovers under Oscillation

China has plenty of starch-rich agricultural leftovers, which can be degraded and further utilized for biogas production. Potato, which has more and more cultivated areas, was taken as a substrate. The pH, OD540, biogas yield, hydrogen yield, biogas production rate, and hydrogen production rate were determined to evaluate the effect of substrate concentration on the photo-fermentation bio-hydrogen production process under an oscillation condition. Results showed that the photo-fermentation period was extended to 264 h under oscillation, which was two times longer than the static condition. It was found that 8 g per 100 mL fermentation broth was the most suitable substrate concentration under oscillation, the cumulative hydrogen yield was 510 mL VS−1, and the hydrogen content was 38.36%.

Enhanced Biohydrogen Production Influenced by Magnetic Nanoparticles Supplementation Using Enterobacter cloacae

The effects of synthesized magnetic nanoparticles (0–50 mg/L) on biohydrogen production from cotton stalk hydrolysate using Enterobacter cloacae were investigated, to find out the enhancement of the bacterial hydrogen production efficiency. The magnetic Fe3O4NPs with uniform size approximately 50 nm were well synthesized and applied in the fermentative hydrogen production system, accordingly, the addition of optimum concentration of 40 mg/L Fe3O4NPs resulted in the maximum daily hydrogen production, cumulative hydrogen production, glucose utilization, xylose utilization and hydrogen yield of 462.0 ± 9.6 mL, 1625.2 ± 18.0 mL/L, 84.29 ± 0.34%, 92.36 ± 0.16%, 0.37 ± 0.004 mol H2/mol sugar separately. Moreover, the dynamically fitted parameters of hydrogen production potential (P) and hydrogen production rate (Rm) increased to 1851.92 mL/L and 20.27 mL/(L h) respectively, and the lag phase time shortened to 1.30 h also following the addition of 40 mg/L Fe3O4NPs as compared with the control treatment (0 mg/L). These results indicated the positive effects of Fe3O4NPs supplementation on fermentative hydrogen production from cotton stalk hydrolysate by E. cloacae, revealing the feasibility of applying Fe3O4NPs supplementation for enhancement of such hydrogen production system.

Effects of different pretreatment methods on the structural characteristics, enzymatic saccharification and photo-fermentative bio-hydrogen production performance of corn straw

In this study, the effects of different pretreatment methods, including hydrothermal, acid, alkali, acid-heat, and alkali-heat on the structural characteristics, enzymatic saccharification and photo-fermentative bio-hydrogen production performance of corn straw were investigated. Results revealed that all the studied pretreatments effectively destroyed the corn straw structure and improved its enzymatic saccharification potential. The alkali-heat and alkali pretreatment showed significant advantage in reducing sugars release, and the highest total reducing sugar concentration of 23.07 g/L was obtained under the pretreatment condition of 2% NaOH-Heat. The maximum cumulative hydrogen yield of 137.76 mL/g TS was achieved from 2% NaOH pretreated corn straw, while corn straw pretreated with 4% NaOH-heat had the minimum cumulative hydrogen yield of 44.20 mL/g TS. These results suggest that appropriate pretreatment can effectively destroy the corn straw structure and enhance its enzymatic saccharification and hydrogen production performance.

Evaluation of hydrogen yield potential from Chlorella by photo-fermentation under diverse substrate concentration and enzyme loading

Chlorella is widely distributed, can be cultured in waste water and had short growth cycle. The high carbohydrate composition shows great potential for bioenergy output. In this work, concentrated Chlorella solution was adopted as raw material. Reducing sugar concentration, pH, and cumulative bio-hydrogen yield were taken as indexes, the effects of substrate concentration and enzyme (cellulase or neutral protease) load on photo-fermentation bio-hydrogen production process from microalgae biomass were investigated. Results showed that highest cumulative hydrogen yield was obtained at the optimal substrate concentration of 25 g/L, when the load of cellulase and protease are both 15%, the effect is the best which were 16.65 mL, 29.44 mL, and 43.62 mL, respectively. Results fitted well to the Gompertz model, indicating the feasibility of photo-fermentative bio-hydrogen production from concentrated Chlorella.

Effect of Mixing Ratios in a Batch Reactor for Biological Hydrogen Production

This study was to evaluate the cause on the production of bio-hydrogen utilizing Distillery Spent Wash (DSW) and starch mixed wastewater in various mixing ratios under dark fermentation conditions with varying Hydraulic Retention Time in a batch reactor. The pH was kept constantly at 5.5 throughout the study. Thus the hydrogen production investigated in the batch reactor for following Hydraulic Retention Time 24h, 16h, 12h and 8h, the results revealed an extended and steady period of reactor operation with hydrogen percent in the biogas and hinders the methane production. The perfect mixing ratios and Hydraulic Retention Time were seen to be 50:50 (DSW: Starch wastewater) and 16h to 12h HRT with contrasting cumulative hydrogen yields of 3256.5ml and 2674.3ml with specific maximum production of hydrogen rate 468ml/L/d as well as 236.64ml/L/d with the best biomass improvement combination of 4.7g/l and 4.5g/l. The maximum Chemical Oxygen Demand removal rates of 68 and 50 percentage for the optimum HRT of 16h and 12h.