Role of Nanotechnology in Bioenergy Production: Comparison
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Please note this is a comparison between Version 2 by Jessie Wu and Version 1 by Wai Siong Chai.

The issue of global warming calls for a greener energy production approach. To this end, bioenergy has significant greenhouse gas mitigation potential, since it makes use of biological products/wastes and can efficiently counter carbon dioxide emission. However, technologies for biomass processing remain limited due to the structure of biomass and difficulties such as high processing cost, development of harmful inhibitors and detoxification of produced inhibitors that hinder widespread usage. Additionally, cellulose pre-treatment is often required to be amenable for an enzymatic hydrolysis process. Nanotechnology (usage of nanomaterials, in this case) has been employed in recent years to improve bioenergy generation, especially in terms of catalyst and feedstock modification. The role of nanotechnology to assist in bioenergy generation is discussed, particularly from the aspects of enzyme immobilization, biogas production and biohydrogen production. 

  • nanomaterials
  • enzyme
  • biogas

1. Introduction

Research on bioenergy generation has been growing at a relentless pace owing to the concerns that arose from dwindling fossil fuel reserves and the environmental pollution associated with the exploitation of these resources. Studies have reported that emission of greenhouse gases such as carbon dioxide (CO2) from the burning of fossil fuels has led to climate change issues [1,2][1][2]. Since the transportation sector accounts to 60% of the estimated oil demand for the year 2030 (116 million barrels per day), it is essential to replace fossil-fuel-based energy sources in vehicles with renewable energy sources [3,4,5][3][4][5]. In an attempt to gradually replace petroleum and coal resources, various renewable energy sources such as solar, wind, hydrothermal and biomass have been explored to date, with an increased interest in the latter, since lignocellulosic biomass is available abundantly from agriculture and forestry, with an estimated annual production of 2 × 1011 tonnes [6]. It was also reported that in 2011, 38 million tonnes of biomass were used for biofuels in the EU, out of 1.2 billion tonnes of biomass that were generated from various crops [7].
Despite the availability of lignocellulosic biomass in abundance, the technologies for biomass processing remain limited. For instance, the biomasses are recalcitrant in nature due to their cellulose crystallinity and non-reactive lignin, thus requiring pre-treatment techniques to allow the cellulose to be amenable for an enzymatic hydrolysis process [8]. This is required for the extraction of fermentable sugar for subsequent biofuel generation processes [9,10][9][10]. Figure 1 shows the cellulose and hemicellulose that accommodate 6 and 5 carbon sugars rigidly bounded with the lignin, where cellulose forms structure of the cell walls, while hemicellulose assists in the cross-linking between the non-cellulosic and cellulosic polymer via covalent bonding [11]. It is noteworthy that biomass resources currently deployed as feedstock in human or non-human food chains should not be used for chemical processing to ensure sustainability. For instance, wheat straw is a common fodder for raising animals and therefore is available in short supply due to increase in meat consumption; wheat straw should not be considered as a viable option for bioenergy generation [12].
Materials 15 07769 g001 550
Figure 1. Lignocellulosic biomass as bioenergy crop; plant cell wall is made of lignocellulose containing carbohydrate polymers (cellulose, hemicellulose and aromatic polymer lignin). The cellulose and hemicellulose accommodate 6 and 5 carbon sugars, which are rigidly bounded with the lignin.
Generally, biochemical or thermochemical routes can be employed for the conversion of lignocellulosic raw materials into bioenergy. The biochemical route uses microorganisms and various enzymes to convert components of the feedstock into sugars, followed by fermentation to produce ethanol [13]. Since the biochemical route uses various enzymes to convert feedstock to biofuel, the efficacy of the enzyme is important to improving the conversion process. On the other hand, the thermochemical route involves gasification technologies to produce simple sugars that are fermentable for biofuel production. In a study by Daystar et al. [14], it was highlighted that thermochemical conversion can use a wider range of feedstock compared to biochemical conversion and produces considerably higher alcohol yields. Additionally, unlike the biochemical process, the thermochemical process is not affected by the lignin in the biomass, although presence of moisture content can affect alcohol yield as well emissions in the thermochemical process. A general finding from most studies indicates that high cost and limited availability of existing infrastructure have posed limitations on obtaining high quality and yield of bioenergy.
However, with the emergence of nanotechnology, the limitations can be addressed efficiently since nanotechnology involves nanomaterials, which exhibit unprecedented characteristics and properties, all of which are highly useful in areas of bioenergy generation.

2. Enzyme Immobilization

Enzyme immobilization on support materials is useful to enhance enzyme characteristics such as high activity at most pH values, reusability and selectivity and reduce their inhibition. Some studies have reported that immobilization of cellulase enzyme makes it more resistant to structural alterations which may be caused by increase in the temperature [29][15]. An excellent enzyme immobilization on solid support ensures good distribution of the catalyst with minimal agglomeration. For instance, covalent binding between the support and enzyme have been reported to increase the enzyme activity [53,69][16][17]. Other than covalent binding, approaches such as adsorption, ionic bonding, entrapment and encapsulation have been reported for enzyme immobilization. In comparison to other NPs, MNPs have gained significant interest as promising support carriers in enzyme immobilization due to factors highlighted in Section 2.1 of this work. Most importantly, in enzyme immobilization, the large surface-area-to-volume ratio of MNPs is highly advantageous to loading a large number of enzymes on their surface, which in turn increases the catalytic activity of the enzymes. Several techniques can be used for immobilization of enzymes on the MNP support. For example, MNP functionalization for cellulase immobilization can be on silica-functionalized MNP, amino-functionalized MNPs, composite-functionalized MNPs, chitosan-functionalized MNPs or carrier-free functionalized MNPs.
For instance, sulfonated magnetic carbonaceous nanoparticles, which were used for the hydrolysis of various lignocellulosic biomass, showed significant levels of glucose yields of jatropha, bagasse and plukenetia hulls of 35.6%, 58.3% and 35.8%, respectively, with the capability of recycling the catalyst at least seven times with a high catalyst recovery rate of 92.8% [70][18]. In another study by Goh et al., enzyme immobilization was performed on magnetic single-walled carbon nanotubes for application in biofuel production. It was reported that the enzyme was recyclable, which reduced the cost of biofuel production while also retaining their activity for a month in acetate buffer at 4°C [71][19]. In another study, 93% binding efficiency and 50% activity retainment after 16th cycle was achieved with a nanobiocatalyst system for biofuel production using functionalized magnetic nanoparticles immobilized with β-glucosidase isolated from fungus [72][20]. In biodiesel production, immobilization of lipase on polydopamine-coated magnetic nanoparticles enhanced the pH and thermal stability while achieving 73.9% binding efficiency, more than 70% of activity even after 21 repeated cycles and easy recoverability from reaction mixture [73][21]. Similar findings were also reported in a study by Hu et al., where immobilization on magnetic nanoparticles increased biodiesel production by 95% when a reaction was performed at 65 °C for a duration of 3 h. Additionally, the catalyst was reusable 14 times while allowing recoverability of more than 90% [74][22]. To date, various MNPs have been explored as support carriers in enzyme immobilization. A summary of the various MNPS that have been used as the support carriers in enzyme immobilization and their effect on bioenergy production is summarized in Table 1.
Table 1.
Summary of various MNPs explored as support carriers in enzyme immobilization for bioenergy generation.
Bioenergy MNPs Feedstock Enzyme Summary Ref.
Bioethanol Fe3O4 Aspergillus fumigatus AA001 Cellulase Thermal stability for 8 h at 70 °C [18][23]
Fe3O4 Potato peels Amylase/Amyloglucosidase Bioethanol yield: 93% [75][24]
Fe3O4 Allamanda schottii L. Cellulase Bioethanol yield (free enzymes): 182 g/L; (immobilized enzymes): 252 g/L [76][25]
FeCl3 Sesbania aculeata Cellulase Bioethanol yield: 5.31 g/L [29][15]
MnO2 Aspergillus fumigatus JCF Cellulase Cellulase binding efficiency of 75%

Bioethanol yield: 21.96 g/L		 [77][26]
Biodiesel Fe2O3 Neochloris oleoabundans Lipase Maximum biodiesel yield: 81% [78][27]
Fe3O4 Soybean oil Lipase Biodiesel yield: 90% with 60% immobilized lipase [79][28]
Fe3O4 Soybean oil Lipase Conversion rate: 47.60% after 24 h; >30% enzyme activity even after 10 cycles [30][29]
Fe3O4 Soybean oil Lipase Conversion rate: 88% after 192 h and 75% after 240 h [80][30]
Fe3O4 Microalgae (Chlorella vulgaris) Lipase Maximum biodiesel yield: 97.1% [81][31]
Fe3O4 Jatropha curcas oil Rhizomucor miehei lipase Maximum biodiesel yield: 70% [82][32]
Polyporous magnetic cellulose beads (PMCBs) Yellow horn seed oil Candida antarctica lipase B Maximum biodiesel yield: 92.3%; catalyst easily removed by magnet and can be recycled at least 5 times. [83][33]

3. Biogas Production

In the biogas production process, nanoparticles have proven to show promising results in the anaerobic processes (biochemical processes to convert various organic materials into biogas and its constituents), in particular as electron donors, acceptors and cofactors of key enzymes such as [Fe]- and [Ni-Fe]-hydrogenase [84][34]. For example, nanoparticles increase the hydrolysis of organic matter due to their large surface-area-to-volume ratio, which enables microorganisms to bind onto the active sites of the molecule. This subsequently stimulates the biochemical process for the activity of hydrogenase enzymes and ferredoxins. Various nanoparticles have been used in the anaerobic digestion process such as zero-valent metals, metal oxides and carbon-based nanomaterials.
Generally, the anaerobic digestion process involves four important steps: (i) hydrolysis, (ii) acidogenesis, (iii) acetogenesis and (iv) methanogenesis. Nanoparticles such as carbon-based materials have been reported to be useful in all the four stages. For example, in a study by Velimirovic et al. [85][35], carbon-based nanomaterials in the hydrolysis stage, when available as electron donors, can lower the oxygen reduction potential of the water environment, which is highly beneficial in the hydrolysis reaction. In the acidogenesis and acetogenesis processes, studies have reported that the addition of 12.5 g/L biochar enhanced the biohydrogen production from 22.6 to 96.3 mL/g [86][36], the addition of 8.3 g/L of biochar increased the biohydrogen yield from 750.4 to 944.5 mL/L from food waste [87][37], and the addition of 600 mg/L of sawdust biochar improved biohydrogen production from 31.5 to 36.5 mL [88][38]. In all the aforementioned studies, it was highlighted that addition of carbon-based nanomaterials enhanced the performance of acid formation processes, which resulted in improved yield of hydrogen. Similar enhancement in biogas production were also reported in other studies using zero-valent ions (ZVI); i.e., 0.1 wt.% ZVI using waste-activated sludge enhanced biogas production by 30.4% [89][39], whereas the highest methane formation rate (0.310 mmol CH4 formed/mol Fe0. day) was reported using the finest grade iron ZVI [90][40].
Studies have also been performed to study the effect of nanoparticles on microbial communities in the anaerobic digestion process. For example, Wang et al. used four types of nanoparticles, i.e., ZVI, Ag, Fe2O3 and MgO, to investigate their effect on biogas production from waste-activated sludge, and it was reported that ZVI (10 mg/g) and Fe2O3 (100 mg/g TSS) increased biogas production by 120% and 117%, respectively, which suggests that ZVI and Fe2O3 nanoparticles improve the activity of the methanogenic bacteria [91][41]. This was also supported in another study by Yang et al., which reported that addition of ZVI nanoparticles increases the population of methanogens in an anaerobic digester [92][42].

4. Biohydrogen Production

Biohydrogen production is performed by anaerobic bacteria via metabolic routes to generate molecular hydrogen. It has been reported that the activity of these microorganisms can be enhanced with the use of nanoparticles to increase electron transfers and kinetics in metabolic processes to produce biohydrogen due to their capability to react faster with electron donors. The role of nanoparticles in various biohydrogen process is as described below.

4.1. Dark Fermentative Biohydrogen Process

Nanoparticles have been reported to improve the dark fermentation process. For instance, 5 nm gold nanoparticles improved substrate utilization and biohydrogen yield by 56% and 46%, respectively, owing to the large surface-area-to-volume ratio of gold nanoparticles, which provided a stimulatory effect to produce biohydrogen [93][43]. It has also been highlighted in other studies that gold nanoparticles enhance the activity of biohydrogen-producing enzymes, which mediate the transfer of electrons such as [Fe-Fe]- and [Ni-Fe]-hydrogenases and ferredoxins [94,95][44][45]. In other studies, zero-valent iron (Fe0) nanoparticles were used for dark fermentation of grass, and it was shown that Fe0 nanoparticles stimulated activity of a hydrogenase enzyme to produce a higher yield of biohydrogen (i.e., maximum hydrogen yield of 64.7 mL/g dry grass; 73% higher than control experiments) [96][46]. Other studies have also reported the use of metallic nanoparticles such as Pb, Ag and Cu along with FeO nanoparticles immobilized on porous silica (SiO2), and highest yield and production rate was achieved using FeO nanoparticles, i.e., 38% and 58%, respectively, in comparison to control experiments [97][47]. Ni-graphene-based nanoparticles have also been reported to enhance dark fermentative biohydrogen production, in a study where maximum yield of 41.3 H2/g COD with 105% increase in H2 yield was obtained [98][48].

4.2. Photo-Fermentative Biohydrogen Production

Nanoparticles have also drawn significant interest as means to improve the biomass growth, photosynthetic activity, nitrogen metabolism and protein level of microalgal species to produce biohydrogen. The key roles of nanoparticles in photo-fermentative biohydrogen production are as summarized below:
  • Nanoparticles behave as the catalytic agents to generate metabolic pathways to promote synthesis of chlorophyll a, chlorophyll b, carotenoids and anthocyanin, lipid production and nitrogen metabolism [99,100][49][50].
  • Nanoparticles enhance production of carbohydrates, which results in increased growth of algal cells. For example, silica nanoparticles enhanced growth of microalgal cells (measured from chlorophyll concentration), because silica nanoparticles scattered light within a reactor to ensure uniform light distribution during the photosynthetic process, which in turn promoted growth of microalgal cells [101][51]. Similar findings were also reported using zero-valent iron (Fe0) [102][52] and TiO2 nanoparticles, which increased chlorophyll and carotenoid pigments [103][53].
  • Nanoparticles enhance activity of key enzymes for metabolism of microalgal species such as glutamate dehydrogenase, glutamate–pyruvate transaminase, glutamine synthase and nitrate reductase [104,105][54][55]. The capability of nanoparticles to maintain the pH of a medium and to promote the activity of hydrogenase enzymes and substrate hydrolysis may promote higher biohydrogen yield by enhancing biohydrogen-producing metabolic pathways such as acetate and butyrate reactions [32,103,106][53][56][57].

4.3. Photocatalytic Hydrogen Production

Photocatalytic biohydrogen production involves the breaking of water molecules into H2 and O2 in the presence of an illuminating source. A photocatalyst such as TiO2 has been commonly preferred owing to its high photocatalytic performance, non-toxicity, chemical stability and cost effectiveness [107,108][58][59]. For instance, nanoparticles such as Pt-TiO2-activated carbon generated a high hydrogen production rate of 7490 µmol/h/g photocatalyst, which is 75 times higher than conventional Aeroxide TiO2 P25 catalyst [107][58]. Other studies have reported the combination of TiO2-graphene has higher light absorption efficiency than TiO2 alone, which resulted in higher charge separation efficiency to yield higher hydrogen [109][60]. The effect of various nanoparticles on the hydrogen yield rate is summarized in Table 2.
Table 2.
Effect of various nanoparticles on the H
2 yield rate. Modified from [110].
yield rate. Modified from [61].
NP Feedstock Microorganism H2 Yield Rate H2 Yield Increase (%) Ref.
Au Artificial wastewater Clostridium butyricum 4.48 mol H2/mol sucrose 61.7 [93][43]
Ag Inorganic salts Clostridium butyricum 2.48 mol H2/mol glucose 67.5 [111][62]
Pd Glucose Enterobacter cloacae + mixed culture 2.48 mol H2/mol glucose 6.4 [112][63]
Ni Inorganic salts Granular sludge 2.54 mol H2/mol glucose 22.7 [113][64]
Cu Glucose Clostridium acetobutylicum 1.74 mol H2/mol glucose N/A [114][65]
Cu Glucose Enterobacter clocae 1.44 mol H2/mol glucose N/A [114][65]
Fe Inorganic salts Enterobacter clocae 1.9 mol H2/mol glucose 68.4 [115][66]
Fe Growth medium Rhodobacter sphaeroides + Escherichia coli 3.1 mol H2/mol malate N/A [116][67]
Fe2O3 Casava starch Enterobacter aerogenes 192.4 mL H2/g casava starch 17 [117][68]
Fe2O3 Distillery wastewater Mixed culture 44.28 mL H2/g COD N/A [118][69]
Fe2O3 Growth medium Clostridium acetobutylicum 2.33 mol H2/mol glucose 52 [119][70]
FeO Growth medium Mixed culture 1.92 mol H2/mol glucose 7.9 [120][71]
TiO2 Growth medium Rhodopseudomonas palustris N/A 46.1 [121][72]
SiO2 Air: CO2 (97:3) Chlamydomonas reinhardtii CC124 3121.5 H2/L/h 45.2 [101][51]
Biochar Municipal solid waste Enterobacter aerogenes + Escherichia coli 96.3 mL/g N/A [86][36]
Biochar Food waste N/A 944.5 mL/L 31 [87][37]
Biochar + ZV iron NP Grass biomass N/A 50.6 mL/g dry grass 89.8 [88][38]
Ni + graphene Industrial wastewater Mixed culture 41.3 mL/gCOD 105 [98][48]
CNT Glucose Anaerobic sludge 2.45 mol/mol substrate N/A [122][73]
Hematite + TiO2 Glucose Clostridium pasteurianum CH5 2.20 mol/mol substrate 5 [123][74]

5. Bioethanol Production

Generally, lignocellulosic materials are processed for bioethanol production via three major operations, which include (i) pretreatment for delignification to liberate the cellulose and hemicellulose, (ii) hydrolysis to produce fermentable sugars such as glucose, xylose, arabinose, galactose or mannose and (iii) fermentation of reducing sugars. In a very recent study, Saeed et al. [124][75] used graphitic carbon nitride (g-C3N4) nanomaterials (Figure 2A) and laser irradiation (Figure 2B)  to increase bioethanol production from potato waste. Authors reported that the control sample without laser irradiation or g-C3N4 showed only 4% yield of bioethanol, while the addition of g-C3N4 coupled with laser irradiation increased bioethanol yield to 56.8% (Figure 2D).
Materials 15 07769 g006 550
Figure 2. (A) SEM image of prepared g-C3N4 nanoparticles used to increase bioethanol production. (B) Irradiation using blue and red laser to increase bioethanol production from potato waste. (C) Effect of ZnO nanoparticles on bioethanol yield from rice straw. (D) Effect of various processing conditions of g-C3N4 nanoparticles on the production of bioethanol. Reproduced with permission from [124] Springer Nature and [125] Elsevier.
In another study by Gupta et al. [125][76], zinc oxide nanoparticles were used to enhance bioethanol production from rice straw, and a maximum ethanol yield of 0.0359 g/g dry weight-based plant biomass was attained at 200 mg/L concentration of ZnO nanoparticles (Figure 2C). Additionally, the possibility for reusability and recovery of the nanoparticles makes the entire process more economical. Similarly, in another study by Ivanova et al. [126][77], it was reported that bioethanol fermentation was enhanced with the use of alginate magnetic nanoparticles entrapped with yeast cells, with the productivity rate reaching up to 264 g/Lh at 70% particle loading. It was also interesting to note that the magnetic particles with fixed yeast cells were stable for more than a month at 4 °C in saline condition. In a similar vein, Kim et al. [127][78] reported enhanced bioethanol production in syngas fermentation using methyl-functionalized silica nanoparticles. After 9 h of cultivation time, it was reported that ethanol concentrations without and with nanoparticles were 0.1150 and 0.3060 g/L,w respectively, which indicates that ethanol production was enhanced by 166.1% by the use of nanoparticles. When producing liquid fuels through fermentation, it is expected that nanomaterials will influence the biochemical conversion process by affecting the enzymatic activity or the mass transfer rate.

References

  1. Erickson, P.; Lazarus, M.; Piggot, G. Limiting fossil fuel production as the next big step in climate policy. Nat. Clim. Chang. 2018, 8, 1037–1043.
  2. Johnsson, F.; Kjärstad, J.; Rootzén, J. The threat to climate change mitigation posed by the abundance of fossil fuels. Clim. Policy 2019, 19, 258–274.
  3. Antunes, F.A.F.; Gaikwad, S.; Ingle, A.P.; Pandit, R.; dos Santos, J.C.; Rai, M.; da Silva, S.S. Bioenergy and Biofuels: Nanotechnological Solutions for Sustainable Production; Springer: Berlin/Heidelberg, Germany, 2017; ISBN 9783319454597.
  4. Chai, W.S.; Bao, Y.; Jin, P.; Tang, G.; Zhou, L. A review on ammonia, ammonia-hydrogen and ammonia-methane fuels. Renew. Sustain. Energy Rev. 2021, 147, 111254.
  5. Du, H.; Shen, P.; Chai, W.S.; Nie, D.; Shan, C.; Zhou, L. Perspective and analysis of ammonia-based distributed energy system (DES) for achieving low carbon community in China. iScience 2022, 25, 105120.
  6. Elumalai, S.; Agarwal, B.; Runge, T.M.; Sangwan, R.S. Advances in Transformation of Lignocellulosic Biomass to Carbohydrate-Derived Fuel Precursors. In Biorefining of Biomass to Biofuels; Springer: Berlin/Heidelberg, Germany, 2018; pp. 87–116. ISBN 9783319676784.
  7. Scarlat, N.; Dallemand, J.-F.; Monforti-Ferrario, F.; Nita, V. The role of biomass and bioenergy in a future bioeconomy: Policies and facts. Environ. Dev. 2015, 15, 3–34.
  8. Den, W.; Sharma, V.K.; Lee, M.; Nadadur, G.; Varma, R.S. Lignocellulosic biomass transformations via greener oxidative pretreatment processes: Access to energy and value added chemicals. Front. Chem. 2018, 6, 141.
  9. Sindhu, R.; Binod, P.; Pandey, A. Biological pretreatment of lignocellulosic biomass—An overview. Bioresour. Technol. 2016, 199, 76–82.
  10. Singhvi, M.; Kim, B.S. Current developments in lignocellulosic biomass conversion into biofuels using nanobiotechology approach. Energies 2020, 13, 5300.
  11. Sankaran, R.; Markandan, K.; Khoo, K.S.; Cheng, C.K.; Ashokkumar, V.; Deepanraj, B.; Show, P.L. The Expansion of Lignocellulose Biomass Conversion Into Bioenergy via Nanobiotechnology. Front. Nanotechnol. 2021, 3, 96.
  12. Varma, R.S. Biomass-Derived Renewable Carbonaceous Materials for Sustainable Chemical and Environmental Applications. ACS Sustain. Chem. Eng. 2019, 7, 6458–6470.
  13. Rai, A.K.; Al Makishah, N.H.; Wen, Z.; Gupta, G.; Pandit, S.; Prasad, R. Recent Developments in Lignocellulosic Biofuels, a Renewable Source of Bioenergy. Fermentation 2022, 8, 161.
  14. Daystar, J.; Treasure, T.; Gonzalez, R.; Reeb, C.; Venditti, R.; Kelley, S. The NREL biochemical and thermochemical ethanol conversion processes: Financial and environmental analysis comparison. BioResources 2015, 10, 5083–5095.
  15. Baskar, G.; Naveen Kumar, R.; Heronimus Melvin, X.; Aiswarya, R.; Soumya, S. Sesbania aculeate biomass hydrolysis using magnetic nanobiocomposite of cellulase for bioethanol production. Renew. Energy 2016, 98, 23–28.
  16. Poorakbar, E.; Shafiee, A.; Saboury, A.A.; Rad, B.L.; Khoshnevisan, K.; Ma’mani, L.; Derakhshankhah, H.; Ganjali, M.R.; Hosseini, M. Synthesis of magnetic gold mesoporous silica nanoparticles core shell for cellulase enzyme immobilization: Improvement of enzymatic activity and thermal stability. Process Biochem. 2018, 71, 92–100.
  17. Misson, M.; Zhang, H.; Jin, B. Nanobiocatalyst advancements and bioprocessing applications. J. R. Soc. Interface 2015, 12, 20140891.
  18. Su, T.C.; Fang, Z.; Zhang, F.; Luo, J.; Li, X.K. Hydrolysis of Selected Tropical Plant Wastes Catalyzed by a Magnetic Carbonaceous Acid with Microwave. Sci. Rep. 2015, 5, 17538.
  19. Goh, W.J.; Makam, V.S.; Hu, J.; Kang, L.; Zheng, M.; Yoong, S.L.; Udalagama, C.N.B.; Pastorin, G. Iron oxide filled magnetic carbon nanotube-enzyme conjugates for recycling of amyloglucosidase: Toward useful applications in biofuel production process. Langmuir 2012, 28, 16864–16873.
  20. Verma, M.L.; Chaudhary, R.; Tsuzuki, T.; Barrow, C.J.; Puri, M. Immobilization of β-glucosidase on a magnetic nanoparticle improves thermostability: Application in cellobiose hydrolysis. Bioresour. Technol. 2013, 135, 2–6.
  21. Ren, Y.; Rivera, J.G.; He, L.; Kulkarni, H.; Lee, D.K.; Messersmith, P.B. Facile, high efficiency immobilization of lipase enzyme on magnetic iron oxide nanoparticles via a biomimetic coating. BMC Biotechnol. 2011, 11, 63.
  22. Hu, S.; Guan, Y.; Wang, Y.; Han, H. Nano-magnetic catalyst KF/CaO-Fe3O4 for biodiesel production. Appl. Energy 2011, 88, 2685–2690.
  23. Srivastava, N.; Srivastava, M.; Mishra, P.K.; Singh, P.; Ramteke, P.W. Application of Cellulases in Biofuels Industries: An Overview. J. Biofuels Bioenergy 2015, 1, 55.
  24. Sanusi, I.A.; Suinyuy, T.N.; Kana, G.E.B. Impact of nanoparticle inclusion on bioethanol production process kinetic and inhibitor profile. Biotechnol. Rep. 2021, 29, e00585.
  25. Vijayalakshmi, S.; Govindarajan, M.; Al-Mulahim, N.; Ahmed, Z.; Mahboob, S. Cellulase immobilized magnetic nanoparticles for green energy production from Allamanda schottii L: Sustainability research in waste recycling. Saudi J. Biol. Sci. 2021, 28, 901–910.
  26. Cherian, E.; Dharmendirakumar, M.; Baskar, G. Immobilization of cellulase onto MnO2 nanoparticles for bioethanol production by enhanced hydrolysis of agricultural waste. Cuihua Xuebao/Chin. J. Catal. 2015, 36, 1223–1229.
  27. Banerjee, S.; Rout, S.; Banerjee, S.; Atta, A.; Das, D. Fe2O3 nanocatalyst aided transesterification for biodiesel production from lipid-intact wet microalgal biomass: A biorefinery approach. Energy Convers. Manag. 2019, 195, 844–853.
  28. Xie, W.; Ma, N. Immobilized Lipase on Fe 3 O 4 Nanoparticles as Biocatalyst for Biodiesel Production. Energy Fuels 2009, 23, 1347–1353.
  29. Wang, X.; Dou, P.; Zhao, P.; Zhao, C.; Ding, Y.; Xu, P. Immobilization of lipases onto magnetic Fe3O4 nanoparticles for application in biodiesel production. ChemSusChem 2009, 2, 947–950.
  30. Wang, X.; Liu, X.; Zhao, C.; Ding, Y.; Xu, P. Biodiesel production in packed-bed reactors using lipase-nanoparticle biocomposite. Bioresour. Technol. 2011, 102, 6352–6355.
  31. Chiang, Y.D.; Dutta, S.; Chen, C.T.; Huang, Y.T.; Lin, K.S.; Wu, J.C.S.; Suzuki, N.; Yamauchi, Y.; Wu, K.C.W. Functionalized Fe3O4@Silica Core-Shell Nanoparticles as Microalgae Harvester and Catalyst for Biodiesel Production. ChemSusChem 2015, 8, 789–794.
  32. Zhou, Z.W.; Cai, C.X.; Xing, X.; Li, J.; Hu, Z.E.; Xie, Z.B.; Wang, N.; Yu, X.Q. Magnetic COFs as satisfied support for lipase immobilization and recovery to effectively achieve the production of biodiesel by great maintenance of enzyme activity. Biotechnol. Biofuels 2021, 14, 156.
  33. Zhang, H.; Liu, T.; Zhu, Y.; Hong, L.; Li, T.; Wang, X.; Fu, Y. Lipases immobilized on the modified polyporous magnetic cellulose support as an efficient and recyclable catalyst for biodiesel production from Yellow horn seed oil. Renew. Energy 2020, 145, 1246–1254.
  34. Abdelsalam, E.; Samer, M.; Attia, Y.A.; Abdel-Hadi, M.A.; Hassan, H.E.; Badr, Y. Influence of zero valent iron nanoparticles and magnetic iron oxide nanoparticles on biogas and methane production from anaerobic digestion of manure. Energy 2017, 120, 842–853.
  35. Velimirovic, M.; Schmid, D.; Wagner, S.; Micić, V.; von der Kammer, F.; Hofmann, T. Agar agar-stabilized milled zerovalent iron particles for in situ groundwater remediation. Sci. Total Environ. 2016, 563–564, 713–723.
  36. Sharma, P.; Melkania, U. Biochar-enhanced hydrogen production from organic fraction of municipal solid waste using co-culture of Enterobacter aerogenes and E. coli. Int. J. Hydrogen Energy 2017, 42, 18865–18874.
  37. Sunyoto, N.M.S.; Zhu, M.; Zhang, Z.; Zhang, D. Effect of biochar addition on hydrogen and methane production in two-phase anaerobic digestion of aqueous carbohydrates food waste. Bioresour. Technol. 2016, 219, 29–36.
  38. Yang, G.; Wang, J. Synergistic enhancement of biohydrogen production from grass fermentation using biochar combined with zero-valent iron nanoparticles. Fuel 2019, 251, 420–427.
  39. Su, L.; Shi, X.; Guo, G.; Zhao, A.; Zhao, Y. Stabilization of sewage sludge in the presence of nanoscale zero-valent iron (nZVI): Abatement of odor and improvement of biogas production. J. Mater. Cycles Waste Manag. 2013, 15, 461–468.
  40. Karri, S.; Sierra-Alvarez, R.; Field, J.A. Zero valent iron as an electron-donor for methanogenesis and sulfate reduction in anaerobic sludge. Biotechnol. Bioeng. 2005, 92, 810–819.
  41. Wang, T.; Zhang, D.; Dai, L.; Chen, Y.; Dai, X. Effects of metal nanoparticles on methane production from waste-activated sludge and microorganism community shift in anaerobic granular sludge. Sci. Rep. 2016, 6, 25857.
  42. Yang, Y.; Guo, J.; Hu, Z. Impact of nano zero valent iron (NZVI) on methanogenic activity and population dynamics in anaerobic digestion. Water Res. 2013, 47, 6790–6800.
  43. Zhang, Y.; Shen, J. Enhancement effect of gold nanoparticles on biohydrogen production from artificial wastewater. Int. J. Hydrogen Energy 2007, 32, 17–23.
  44. Ramsurn, H.; Gupta, R.B. Nanotechnology in solar and biofuels. ACS Sustain. Chem. Eng. 2013, 1, 779–797.
  45. Gordon, R.; Seckbach, J. (Eds.) The Science of Algal Fuels: Phycology, Geology, Biophotonics, Genomics and Nanotechnology; Springer Science & Business Media: Berlin/Heidelberg, Germany, 2012; ISBN 978-94-007-5110-1.
  46. Yang, G.; Wang, J. Improving mechanisms of biohydrogen production from grass using zero- valent iron nanoparticles. Bioresour. Technol. 2018, 266, 413–420.
  47. Beckers, L.; Hiligsmann, S.; Lambert, S.D.; Heinrichs, B.; Thonart, P. Improving effect of metal and oxide nanoparticles encapsulated in porous silica on fermentative biohydrogen production by Clostridium butyricum. Bioresour. Technol. 2013, 133, 109–117.
  48. Elreedy, A.; Ibrahim, E.; Hassan, N.; El-Dissouky, A.; Fujii, M.; Yoshimura, C.; Tawfik, A. Nickel-graphene nanocomposite as a novel supplement for enhancement of biohydrogen production from industrial wastewater containing mono-ethylene glycol. Energy Convers. Manag. 2017, 140, 133–144.
  49. Raliya, R.; Biswas, P.; Tarafdar, J.C. TiO2 nanoparticle biosynthesis and its physiological effect on mung bean (Vigna radiata L.). Biotechnol. Rep. 2015, 5, 22–26.
  50. Pádrová, K.; Lukavský, J.; Nedbalová, L.; Čejková, A.; Cajthaml, T.; Sigler, K.; Vítová, M.; Řezanka, T. Trace concentrations of iron nanoparticles cause overproduction of biomass and lipids during cultivation of cyanobacteria and microalgae. J. Appl. Phycol. 2015, 27, 1443–1451.
  51. Giannelli, L.; Torzillo, G. Hydrogen production with the microalga Chlamydomonas reinhardtii grown in a compact tubular photobioreactor immersed in a scattering light nanoparticle suspension. Int. J. Hydrogen Energy 2012, 37, 16951–16961.
  52. Eroglu, E.; Eggers, P.K.; Winslade, M.; Smith, S.M.; Raston, C.L. Enhanced accumulation of microalgal pigments using metal nanoparticle solutions as light filtering devices. Green Chem. 2013, 15, 3155–3159.
  53. Pandey, A.; Gupta, K.; Pandey, A. Effect of nanosized TiO2 on photofermentation by Rhodobacter sphaeroides NMBL-02. Biomass Bioenergy 2015, 72, 273–279.
  54. Yang, F.; Hong, F.; You, W.; Liu, C.; Gao, F.; Wu, C.; Yang, P. Influences of nano-anatase TiO2 on the nitrogen metabolism of growing spinach. Biol. Trace Elem. Res. 2006, 110, 179–190.
  55. Mishra, A.; Kumari, M.; Pandey, S.; Chaudhry, V.; Gupta, K.C.; Nautiyal, C.S. Biocatalytic and antimicrobial activities of gold nanoparticles synthesized by Trichoderma sp. Bioresour. Technol. 2014, 166, 235–242.
  56. Abraham, R.E.; Verma, M.L.; Barrow, C.J.; Puri, M. Suitability of magnetic nanoparticle immobilised cellulases in enhancing enzymatic saccharification of pretreated hemp biomass. Biotechnol. Biofuels 2014, 7, 90.
  57. Yates, M.D.; Cusick, R.D.; Logan, B.E. Extracellular palladium nanoparticle production using geobacter sulfurreducens. ACS Sustain. Chem. Eng. 2013, 1, 1165–1171.
  58. Hakamizadeh, M.; Afshar, S.; Tadjarodi, A.; Khajavian, R.; Fadaie, M.R.; Bozorgi, B. Improving hydrogen production via water splitting over Pt/TiO2/activated carbon nanocomposite. Int. J. Hydrogen Energy 2014, 39, 7262–7269.
  59. Markowska-Szczupak, A.; Wang, K.; Rokicka, P.; Endo, M.; Wei, Z.; Ohtani, B.; Morawski, A.W.; Kowalska, E. The effect of anatase and rutile crystallites isolated from titania P25 photocatalyst on growth of selected mould fungi. J. Photochem. Photobiol. B Biol. 2015, 151, 54–62.
  60. Cheng, P.; Yang, Z.; Wang, H.; Cheng, W.; Chen, M.; Shangguan, W.; Ding, G. TiO2-graphene nanocomposites for photocatalytic hydrogen production from splitting water. Int. J. Hydrogen Energy 2012, 37, 2224–2230.
  61. Sekoai, P.T.; Ouma, C.N.M.; du Preez, S.P.; Modisha, P.; Engelbrecht, N.; Bessarabov, D.G.; Ghimire, A. Application of nanoparticles in biofuels: An overview. Fuel 2019, 237, 380–397.
  62. Zhao, W.; Zhang, Y.; Du, B.; Wei, D.; Wei, Q.; Zhao, Y. Enhancement effect of silver nanoparticles on fermentative biohydrogen production using mixed bacteria. Bioresour. Technol. 2013, 142, 240–245.
  63. Mohanraj, S.; Anbalagan, K.; Kodhaiyolii, S.; Pugalenthi, V. Comparative evaluation of fermentative hydrogen production using Enterobacter cloacae and mixed culture: Effect of Pd (II) ion and phytogenic palladium nanoparticles. J. Biotechnol. 2014, 192, 87–95.
  64. Mullai, P.; Yogeswari, M.K.; Sridevi, K. Optimisation and enhancement of biohydrogen production using nickel nanoparticles—A novel approach. Bioresour. Technol. 2013, 141, 212–219.
  65. Mohanraj, S.; Anbalagan, K.; Rajaguru, P.; Pugalenthi, V. Effects of phytogenic copper nanoparticles on fermentative hydrogen production by Enterobacter cloacae and Clostridium acetobutylicum. Int. J. Hydrogen Energy 2016, 41, 10639–10645.
  66. Nath, D.; Manhar, A.K.; Gupta, K.; Saikia, D.; Das, S.K.; Mandal, M. Phytosynthesized iron nanoparticles: Effects on fermentative hydrogen production by Enterobacter cloacae DH-89. Bull. Mater. Sci. 2015, 38, 1533–1538.
  67. Dolly, S.; Pandey, A.; Pandey, B.K.; Gopal, R. Process parameter optimization and enhancement of photo-biohydrogen production by mixed culture of Rhodobacter sphaeroides NMBL-02 and Escherichia coli NMBL-04 using Fe-nanoparticle. Int. J. Hydrogen Energy 2015, 40, 16010–16020.
  68. Lin, R.; Cheng, J.; Ding, L.; Song, W.; Liu, M.; Zhou, J.; Cen, K. Enhanced dark hydrogen fermentation by addition of ferric oxide nanoparticles using Enterobacter aerogenes. Bioresour. Technol. 2016, 207, 213–219.
  69. Malik, S.N.; Pugalenthi, V.; Vaidya, A.N.; Ghosh, P.C.; Mudliar, S.N. Kinetics of nano-catalysed dark fermentative hydrogen production from distillery wastewater. Energy Procedia 2014, 54, 417–430.
  70. Mohanraj, S.; Kodhaiyolii, S.; Rengasamy, M.; Pugalenthi, V. Green synthesized iron oxide nanoparticles effect on fermentative hydrogen production by Clostridium acetobutylicum. Appl. Biochem. Biotechnol. 2014, 173, 318–331.
  71. Engliman, N.S.; Abdul, P.M.; Wu, S.Y.; Jahim, J.M. Influence of iron (II) oxide nanoparticle on biohydrogen production in thermophilic mixed fermentation. Int. J. Hydrogen Energy 2017, 42, 27482–27493.
  72. Zhao, Y.; Chen, Y. Nano-TiO2 enhanced photofermentative hydrogen produced from the dark fermentation liquid of waste activated sludge. Environ. Sci. Technol. 2011, 45, 8589–8595.
  73. Liu, Z.; Lv, F.; Zheng, H.; Zhang, C.; Wei, F.; Xing, X.H. Enhanced hydrogen production in a UASB reactor by retaining microbial consortium onto carbon nanotubes (CNTs). Int. J. Hydrogen Energy 2012, 37, 10619–10626.
  74. Hsieh, P.H.; Lai, Y.C.; Chen, K.Y.; Hung, C.H. Explore the possible effect of TiO2 and magnetic hematite nanoparticle addition on biohydrogen production by Clostridium pasteurianum based on gene expression measurements. Int. J. Hydrogen Energy 2016, 41, 21685–21691.
  75. Saeed, S.; Samer, M.; Mohamed, M.S.M.; Abdelsalam, E.; Mohamed, Y.M.A.; Abdel-Hafez, S.H.; Attia, Y.A. Implementation of graphitic carbon nitride nanomaterials and laser irradiation for increasing bioethanol production from potato processing wastes. Environ. Sci. Pollut. Res. 2022, 29, 34887–34897.
  76. Gupta, K.; Chundawat, T.S. Zinc oxide nanoparticles synthesized using Fusarium oxysporum to enhance bioethanol production from rice-straw. Biomass Bioenergy 2020, 143, 105840.
  77. Ivanova, V.; Petrova, P.; Hristov, J. Application in the Ethanol Fermentation of Immobilized Yeast Cells in Matrix of Alginate/Magnetic Nanoparticles, on Chitosan-Magnetite Microparticles and Cellulose-coated Magnetic Nanoparticles. Int. Rev. Chem. Eng. 2011, 3, 289–299.
  78. Kim, Y.K.; Park, S.E.; Lee, H.; Yun, J.Y. Enhancement of bioethanol production in syngas fermentation with Clostridium ljungdahlii using nanoparticles. Bioresour. Technol. 2014, 159, 446–450.
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