Biological fermentation pilot-scale systems and evaluation for commercial viability towards sustainable biohydrogen production.

Featuring high caloric value, clean-burning, and renewability, hydrogen is a fuel believed to be able to change energy structure worldwide. Biohydrogen production technologies effectively utilize waste biomass resources and produce high-purity hydrogen. Improvements have been made in the biohydrogen production process in recent years. However, there is a lack of operational data and sustainability analysis from pilot plants to provide a reference for commercial operations. In this report, based on spectrum coupling, thermal effect, and multiphase flow properties of hydrogen production, continuous pilot-scale biohydrogen production systems (dark and photo-fermentation) are established as a research subject. Then, pilot-scale hydrogen production systems are assessed in terms of sustainability. The system being evaluated, consumes 171,530 MJ of energy and emits 9.37 t of CO2 eq when producing 1 t H2, and has a payback period of 6.86 years. Our analysis also suggests future pathways towards effective biohydrogen production technology development and real-world implementation.

Depolymerization of lignin: Recent progress towards value-added chemicals and biohydrogen production.

The need for alternative sources of energy became increasingly urgent as demand for energy and the use of fossil fuels both soared. When processed into aromatic compounds, lignin can be utilized as an alternative to fossil fuels, however, lignin's complex structure and recalcitrance make depolymerization impractical. This article presented an overview of the most recent advances in lignin conversion, including process technology, catalyst advancement, and case study-based end products. In addition to the three established methods (thermochemical, biochemical, and catalytic depolymerization), a lignin-first strategy was presented. Depolymerizing different forms of lignin into smaller phenolic molecules has been suggested using homogeneous and heterogeneous catalysts for oxidation or reduction. Limitations and future prospects of lignin depolymerization have been discussed which suggests that solar-driven catalytic depolymerization through photocatalysts including quantum dots offers a unique pathway to obtain the highly catalytic conversion of lignin.

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.

Advances in the catalyzed photo-fermentative biohydrogen production through photo nanocatalysts with the potential of selectivity, and customization.

Photo nanocatalyst have shownpromise in a variety of fields, including biohydrogen production where their catalytic efficiency is related to size, surface-to-volume ratio, and increasing the number of atoms on the surface. They can harvest solar light to create electron-hole pairs which is the key mechanism to define its catalytic efficiency, thus requiring suitable excitation wavelength, band energy, and crystal imperfections. In this review, a discussion on the role of photo nanocatalysts to catalyze biohydrogen production has been carried out. Photo nanocatalysts feature a large bandgap, andhigh defect concentration, thus having the ability to be tuned for their characteristics. Customization of the photo nanocatalyst has been addressed. Mechanism of the photo nanocatalysts in catalyzing biohydrogen has been discussed. Limiting factors of photo nanocatalysts were highlighted and several recommendations have been made to enhance the effective utilization of these photo nanocatalysts to enhance photo-fermentative biohydrogen production from biomass wastes.

Estimating the potential of biohydrogen production and carbon neutralization contribution from crop straw.

In order to achieve the carbon neutrality goal set by Chinese government, the potential contribution of hydrogen production from crop residues by microbial fermentation technology and Greenhouse gas (GHGs) reduction have been studied. Firstly, the annual yield of crop straw was estimated according to crop yield and grass grain ratio, and then the grey model GM (1, 1) was applied to predict the crop residues resources available for hydrogen production in various provinces in China in 2021. The results showed that the maximum resource of straw being available for hydrogen production is about 4.54 × 108 t, corresponding to 1.31 × 1011 m3 of hydrogen, the energy carried by the obtained hydrogen was 73 % and 1.15 times than the energy of national civil natural gas consumption and energy of transportation gasoline consumption, respectively. The potential reduction of greenhouse gas emission was 2.42 × 108 t/a CO2-eq, representing 2.4 % of GHGs emissions.

Enhancing biohydrogen production from lignocellulosic biomass of Paulownia waste by charge facilitation in Zn doped SnO2 nanocatalysts.

The goal of this research was to study the role of excess charges in regulating biohydrogen production from Paulownia. The excess charges were generated through charge compensation in SnO2 nanocatalysts by Zn doping. The maximum hydrogen yield of 335 mL was observed at 8%Zn doping with a concentration of 150 mg/L, 47% higher as compared to standard sample. It was observed that the hydrogen production rate increased with Zn doping and the highest value (77 mL/h) was observed for 8%Zn at 24 h. The decrease in the total amount of byproducts (2.52 g/L from 4.28 g/L) at 8% Zn indicates an increase in bacterial metabolism. The lowest value of oxidation-reduction potential (-525 mV) at 24 h for 8%Zn confirms that Zn doping provides excessive electrons to the fermentative medium which helps the bacteria to transfer electrons faster during the redox reaction, hence, enhancing the enzymatic process and eventually hydrogen production.

Catalytic pyrolysis of lignocellulosic biomass for bio-oil production: A review.

Catalytic pyrolysis has been widely explored for bio-oil production from lignocellulosic biomass owing to its high feasibility and large-scale production potential. The aim of this review was to summarize recent findings on bio-oil production through catalytic pyrolysis using lignocellulosic biomass as feedstock. Lignocellulosic biomass, structural components and fundamentals of biomass catalytic pyrolysis were explored and summarized. The current status of bio-oil yield and quality from catalytic fast pyrolysis was reviewed and presented in the current review. The potential effects of pyrolysis process parameters, including catalysts, pyrolysis conditions, reactor types and reaction modes on bio-oil production are also presented. Techno-economic analysis of full-scale commercialization of bio-oil production through the catalytic pyrolysis pathway was reviewed. Further, limitations associated with current practices and future prospects of catalytic pyrolysis for production of high-quality bio-oils were summarized. This review summarizes the process of bio-oil production from catalytic pyrolysis and provides a general scientific reference for further studies.

Assessment of renal and hepato-protective potential of guava leaves in male Sprague dawley rats.

Present research project was an attempt to explore the functional/nutraceutical worth of guava leaves from two locally grown varieties (Ruby & Safeda). For the purpose, guava leaves extract was fed to experimental male Sprague Dawley rats to explore the nutraceutical potential of guava leaves against hepatotoxicity. Two studies were performed on two types of rats i.e. study I (normal rats), study II (hepatotoxic rats). In both studies, 250 mg/kg each of pink guava leaves extracts (T1) and white guava leaves extracts (T2) was added in the feed. Feed intake and body weights of the rats were recorded. At the end of the first and eighth week of study, the blood samples of the rats were analyzed to check the effect of guava leaves extracts on renal functioning (Alkaline Phosphatase, Alanine Transaminase and Aspartate Transaminase) as well as liver functioning parameters including urea and creatinine. In both studies, comparatively higher feed consumption was observed in the control group than the rest of the treatments. At the end of study I, the highest weight (207±9.21 g) was observed in T0 whereas, during study II, the maximum value (202±5.58 g) was found in T2 (rats consuming white guava leaves extract) that indicates its effectiveness against hepatotoxicity. Regarding renal functioning tests, pink guava leaves were more effective in decreasing urea and creatinine levels in rats as compared to the white guava leaves in both study plans. Likewise, in each of study trial, pink guava leaves were more effective in reducing AST, ALT and ALP than white guava leaves and control. From the present investigation, it is deduced that guava leaves were effective against hepatotoxicity.

Exploring the prospective of weeds (Cannabis sativa L., Parthenium hysterophorus L.) for biofuel production through nanocatalytic (Co, Ni) gasification.

BACKGROUND: While keeping in view various aspects of energy demand, quest for the renewable energy sources is utmost. Biomass has shown great potential as green energy source with supply of approximately 14% of world total energy demand, and great source of carbon capture. It is abundant in various forms including agricultural, forestry residues, and unwanted plants (weeds). The rapid growth of weeds not only affects the yield of the crop, but also has strong consequences on the environment. These weeds can grow with minimum nutrient input requirements, have strong ability to grow at various soil and climate environments with high value of cellulose, thus can be valuable source of energy production. RESULTS: Parthenium hysterophorus L. and Cannabis sativa L. have been employed for the production of biofuels (biogas, biodiesel and biochar) through nano-catalytic gasification by employing Co and Ni as nanocatalysts. Nanocatalysts were synthesized through well-established sol-gel method. SEM study confirms the spherical morphology of the nanocatalysts with size distribution of 20-50 nm. XRD measurements reveal that fabricated nanocatalysts have pure standard crystal structure without impurity. During gasification of Cannabis sativa L., we have extracted the 53.33% of oil, 34.66% of biochar and 12% gas whereas in the case of Parthenium hysterophorus L. 44% oil, 38.36% biochar and 17.66% of gas was measured. Electrical conductivity in biochar of Cannabis sativa L. and Parthenium hysterophorus L. was observed 0.4 dSm-1 and 0.39 dSm-1, respectively. CONCLUSION: Present study presents the conversion of unwanted plants Parthenium hysterophorus L. and Cannabis sativa L. weeds to biofuels. Nanocatalysts help to enhance the conversion of biomass to biofuel due to large surface reactivity. Our findings suggest potential utilization of unwanted plants for biofuel production, which can help to share the burden of energy demand. Biochar produced during gasification can replace chemical fertilizers for soil remediation and to enhance the crop productivity.

Enhanced buffer capacity of fermentation broth and biohydrogen production from corn stalk with Na2HPO4/NaH2PO4.

The remarkable buffer capacity of buffer solution can significantly improve the biohydrogen production yield and energy conversion efficiency. In the present study, the effect of buffer solution Na2HPO4/NaH2PO4 on buffer capacity of fermentation broth and photo-fermentation biohydrogen production (PFHP) was studied. Gas characteristics, fermentation broth properties, and kinetic parameters in PFHP were investigated. With the increase in pH values (5-7) of buffer solution Na2HPO4/NaH2PO4, firstly hydrogen yield increased and then decreased. Maximum energy conversion efficiency 9.84%, hydrogen yield 132.69 mL/g corn stalk, and hydrogen content 53.88% were achieved at pH value of 6. The results of one-way ANOVA showed that pH values of fermentation broth and cumulative hydrogen production were strongly affected by pH values of buffer solution. Buffer solution Na2HPO4/NaH2PO4 retarded the decrease of pH value of photo-fermentation broth, and significantly improved the PFHP.

Biohydrogen production through active saccharification and photo-fermentation from alfalfa.

Studying biohydrogen production from alfalfa is of practical significance to cleaner production and biomass utilization. The performances of biohydrogen production through active/passive saccharification and photo-fermentation were compared. The effects of initial pH, substrate concentration, and cellulase loading on biohydrogen production from alfalfa by photosynthetic bacteria HAU-M1 were presented. It was found that the maximum hydrogen yield of 55.81 mL/g was achieved at initial pH of 6.90, substrate concentration of 31.23 g/mL, and cellulase loading of 0.13 g/g. Hydrogen yield of active saccharification and photo-fermentation was much higher as compare to passive saccharification and photo-fermentation. Initial pH value showed a more significant influence on photosynthetic bacteria in comparison to cellulase in active saccharification and photo-fermentation biohydrogen production. The low yield of propionic acid suggested that it was an efficient photosynthetic hydrogen production. Photo-fermentation hydrogen production from alfalfa provides a novel path for efficient utilization of alfalfa.

Enhancement of bio-hydrogen yield and pH stability in photo fermentation process using dark fermentation effluent as succedaneum.

The photo fermentation hydrogen yield from dark fermentation effluents (DFEs) can be promoted by adding corn straw enzymatic hydrolysate adjusts the nutritional composition of DFEs. As compared with the control group (without enzymatic hydrolysate addition), the effect of adding enzymatic hydrolysate make H2 yield increase from 312.54 to 1287.06 mL H2/g TOC, and maximum hydrogen production rate increase 2.14 to 10.23 mL/h. On the other hand, buffer reagents remained in DFEs make which can replace part sodium citrate buffer to maintain pH stability in synchronized saccharification and photosynthetic fermentation process with corn straw as substrate, the best result was observed at the ration of 1:2 (33 mL DFEs, 67 mL sodium citrate buffer) with the hydrogen yield of 436.30 ± 10 mL, and which can cut down the GHG in the life cycle of hydrogen production.

Grid columnar flat panel photobioreactor with immobilized photosynthetic bacteria for continuous photofermentative hydrogen production.

A biophotoreactor with a transparent glass flat panel with polymethyl methacrylate (PMMA) grid columnar for enhanced biofilm growth with Rhodopseudomonas palustris GCA009 was developed and tested at 590 nm incident light. Continuous photofermentative hydrogen production from glucose was tested using this novel reactor. At light intensity of 210 W/m2, feed substrate concentration of 56.0 mmol/L, and crossflow velocity of 1.68 × 10-6 m/s, a maximum hydrogen production rate of 32.6 mmol/L-d (3.56 mmol/m2-h), hydrogen yield of 1.15 mol H2/mol glucose and light conversion efficiency of 5.34% can be achieved. Since the revised grid columnar effectively enlarged the surface area of reactor and enhanced cell attachment, the present reactor design led to higher hydrogen production rates than literature works.

Evolution of magnetic domain structure formed by ion-irradiation of B2-Fe0.6Al0.4.

Magnetic domains and magnetization reversal in 40 nm thick films of Fe0.6Al0.4, have been studied by longitudinal magneto-optical Kerr effect. By varying the Ne(+) ion-energy E between 2 and 30 keV (keeping a constant fluence), we varied the depth-penetration of the ions, and thereby influenced the homogeneity of the induced saturation magnetization M(s). The dependence of coercivity on ion energy shows maximum for 5 keV Ne(+). Considerable differences in the magnetic domain formation and magnetization reversal processes were observed: at low E (≤ 5keV), the reversal process is dominated by domain nucleation mechanism (high density of domain nucleation sites), consistent with the occurrence of an inhomogeneous M(s). Films irradiated with E > 5keV ions exhibit significantly low domain nucleation density, and the reversal is dominated by domain propagation mechanism, suggesting homogeneity in induced M(s). These results demonstrate the tunability of magnetization reversal behavior in materials possessing disorder induced magnetic phase transitions.

Heterointerface engineered electronic and magnetic phases of NdNiO3 thin films.

Mott physics is characterized by an interaction-driven metal-to-insulator transition in a partially filled band. In the resulting insulating state, antiferromagnetic orders of the local moments typically develop, but in rare situations no long-range magnetic order appears, even at zero temperature, rendering the system a quantum spin liquid. A fundamental and technologically critical question is whether one can tune the underlying energetic landscape to control both metal-to-insulator and Néel transitions, and even stabilize latent metastable phases, ideally on a platform suitable for applications. Here we demonstrate how to achieve this in ultrathin films of NdNiO3 with various degrees of lattice mismatch, and report on the quantum critical behaviours not reported in the bulk by transport measurements and resonant X-ray spectroscopy/scattering. In particular, on the decay of the antiferromagnetic Mott insulating state into a non-Fermi liquid, we find evidence of a quantum metal-to-insulator transition that spans a non-magnetic insulating phase.

Oat: unique among the cereals.

This review is intended to focus on the composition of oat and its therapeutic potential in the pharmacology that supports its use to cure various maladies. Oat (Avena sativa) is distinct among the cereals due to its multifunctional characteristics and nutritional profile. Recent advancement in food and nutrition has revealed the importance of its various components. It is a good source of dietary fiber especially beta-glucan, minerals and other nutrients. Oat and oat by products have been proven to be helpful in the treatment of diabetes and cardiovascular disorders. Oat bran in particular, is good source of B complex vitamins, protein, fat, minerals besides heart healthy soluble fiber beta-glucan. The beta-glucan has outstanding functional properties and is of immense importance in human nutrition. Different physiological effects of beta-glucan are related to its viscosity, attenuation of postprandial plasma glucose and insulin responses, high transport of bile acids towards lower parts of the intestinal tract and high excretion of bile acids thereby lowering of serum cholesterol levels. Moreover, it is helpful against coeliac disease. The incorporation of oat grains and oat bran in the food products improves not only the nutrition but also a therapy against various maladies.