Nonsterile Process for Biohydrogen Production: Recent Updates, Challenges, and Opportunities.

Hydrogen (H2), a clean and versatile energy carrier, has recently gained significant attention as a potential solution for reducing carbon emissions and promoting sustainable energy systems. The yield and efficiency of the biological H2 production process primarily depend on sterilization conditions. Various strategies, such as heat inactivation and membrane-based sterilization, have been used to achieve desirable yields via microbial fermentation. Almost every failed biotransformation process is linked to nonsterile conditions at any reaction stage. Therefore, the production of renewable biofuels as alternatives to fossil fuels is more attractive. Pure sugars have been widely documented as a costly feedstock for H2 production under sterile conditions. Biotransformation under nonsterile conditions is more desirable for stable and sustainable operation. Low-cost feeds, such as biowaste, are considered suitable alternatives, but they require appropriate sterilization to overcome the limitations of inherited or contaminating microbes during H2 production. This article describes the status of microbial fermentative processes for H2 production under nonsterile conditions and discusses strategies to improve such processes for sustainable, cleaner production.

Food waste generation and its industrial utilization: An overview.

Food waste is produced for intended human consumption and is normally lost, discharged, contaminated, or finally degraded. The rising problem of food waste is increasing rapidly, so every sector is involved in minimizing food waste generation as well as waste management from collection to disposal, and scientists are developing the best eco-friendly and sustainable solutions for all sectors in the food supply chain, from the agricultural sector to the industrial sector and even up to the retailer to human consumption. Sustainable management is needed for the food wastes in the agricultural and industrial sectors, which are a major burning headache for environmentalists, health departments, and the government all over the earth. Various strategies can be employed to effectively control food waste, and these strategies can be ranked in a manner similar to the waste management hierarchy. The most desirable options involve the act of avoiding and donating edible portions to social agencies. Food waste is utilized in industrial operations to produce biofuels or biopolymers. The next stages involve the retrieval of nutrients and the sequestration of carbon through composting. The government implements appropriate management practices, laws, and orders to minimize food waste generation. Different contemporary methods are utilized to produce biofuel utilizing various types of food waste. In order for composting techniques to recover nutrients and fix carbon, food waste must be processed. Both the management of food waste and the creation of outgrowths utilizing biomaterials require additional study. This review aims to present a comprehensive analysis of the ongoing discourse surrounding the definitions of food waste, the production and implementation of methods to reduce it, the emergence of conversion technologies, and the most recent trends.

Green nanobiocatalysts: enhancing enzyme immobilization for industrial and biomedical applications.

Nanobiocatalysts (NBCs), which merge enzymes with nanomaterials, provide a potent method for improving enzyme durability, efficiency, and recyclability. This review highlights the use of eco-friendly synthesis methods to create sustainable nanomaterials for enzyme transport. We investigate different methods of immobilization, such as adsorption, ionic and covalent bonding, entrapment, and cross-linking, examining their pros and cons. The decreased environmental impact of green-synthesized nanomaterials from plants, bacteria, and fungi is emphasized. The review exhibits the various uses of NBCs in food industry, biofuel production, and bioremediation, showing how they can enhance effectiveness and eco-friendliness. Furthermore, we explore the potential impact of NBCs in biomedicine. In general, green nanobiocatalysts are a notable progression in enzyme technology, leading to environmentally-friendly and effective biocatalytic methods that have important impacts on industrial and biomedical fields.

One-pot, microwave (MW)-assisted production of furfural from almond-, oil-, and wine-derived co-products through biorefinery-based approaches.

This work outlines the first microwave (MW)-assisted protocol for the production of biofuel precursor furfural (FF) from the raw agricultural waste almond hull (AH), olive stone (OS), and the winemaking-derived grape stalk (GS), grape marc (GM) and exhausted grape marc (EGM) through a one-pot synthesis process. To enhance the overall yield, a catalytic process was firstly developed from xylose, major constituent of hemicellulose present in lignocellulosic biomass. This method afforded FF with 100 % selectivity, yielding over 85 % in isolated product when using H2SO4, as opposed to a 37 % yield with AlCl3·6H2O, at 150 °C in only 10 min. For both catalysts, the developed methodology was further validated, proving adaptable and efficient in producing the targeted FF from the aforementioned lignocellulosic raw materials. More specifically, the employment of AlCl3·6H2O resulted in the highest selectivity (up to 89 % from GM) and FF yield (42 % and 39 % molar from OS and AH, respectively), maintaining notable selectivity for the latter (61 and 48 % from AH and OS). At this regard, and considering the environmental factor of sustainability, it is important to point out the role of AlCl3·6H2O in contrast to H2SO4, thus mitigating detrimental substances. This study provides an important management of agricultural waste through sustainable practises for the development of potential bio-based chemicals, aligning with Green Chemistry and process intensification principles.

Mechanistic Insights into the Direct Deoxygenation of Phenolic Compounds over Novel Heusler Alloy Catalysts.

The catalytic deoxygenation of phenolic compounds is a crucial step in the valorization of biomass resources, which can effectively enhance the heating value and stability of primary biofuel. In this study, the catalytic mechanism of four Heusler alloy catalysts for the direct deoxidation pathway of phenol was studied through electronic structure regulation by element occupation. We found that Heusler alloys catalysts exhibit excellent catalytic activity in the dissociation activation of H2 and the cleavage of aryl hydroxyl bond (CAr-OH) bonds. The energy barriers for the direct cleavage of the CAr-OH bond in phenol on Ni2MoAl, Co2MoAl, Ni2NbAl and Ni2MoGa catalysts are 0.86, 0.95, 1.09, and 1.28 eV, respectively. And Y element of the X2YZ catalyst has a significant impact on this reaction, while the X element has a complex influence on the hydrogenation step of the unsaturated benzene ring. Microkinetic analysis further substantiates that the phenol (CAr-OH) bond cleavage step in the reaction exhibits a fast reaction rate and high extent of reaction. The reaction of hydroxyl hydrogenation to produce water exhibits the highest energy barrier, serving as the rate-determining step of the entire reaction. This issue could potentially be addressed by further fine-tuning the electronic structure.

Real biofuel and fossil-fuel soot combustion activities in active and passive regeneration of diesel/gasoline particulate filters under different O2/NOx concentrations.

In this work, we aim to investigate and compare the combustion reactivities of real biofuel soot and fossil-fuel soot in the active and passive regeneration conditions of DPF and GPF through temperature-programmed oxidation (TPO). Higher reactivity of biofuel soot is achieved even under GPF conditions with extremely low oxygen concentration (~ 1%), which provides a great potential for low-temperature regeneration of GPF. Such a result is mainly attributed to the low graphitization and less surface C = C groups of biofuel soot. Unfortunately, the presence of high-content ashes (~ 47%) and P impurity in real biofuel soot hinder its combustion reactivity. TPO evidences that the O2/NOX-lacking conditions in GPF are key factors to impact the combustion of soot, especially fossil-fuel soot. This work provides some useful information for understanding real biofuel and fossil-fuel soot combustion in GPF and DPF regeneration and further improvement in filter regeneration process.

Sustainable Production of Biofuels from Biomass Feedstocks Using Modified Montmorillonite Catalysts.

The rampant exploitation of fossil fuels has led to the significant energy scarcity and environmental disruption, affecting the sound momentum of development and progress of human civilization. To build a closed-loop anthropogenic carbon cycle, development of biofuels employing sustainable biomass feedstocks stands at the forefront of advancing carbon neutrality, yet its widespread adoption is mainly hampered by the high production costs. Montmorillonite, however, has garnered considerable attention serving as an efficient heterogeneous catalyst of ideal economic feasibility for biofuel production, primarily due to its affordability, accessibility, stability, and excellent plasticity. Up to now, nevertheless, it has merely received finite concerns and interests in production of various biofuels using montmorillonite-based catalysts. There is no timely and comprehensive review that addresses this latest relevant progress. This review fills the gap by providing a systematically review and summary in controllable synthesis, performance enhancement, and applications related to different kinds of biofuels including biodiesel, biohydrogenated diesel, levulinate, γ-valerolactone, 5-ethoxymethylfurfural, gaseous biofuels (CO, H2), and cycloalkane, by using montmorillonite catalysts and its modified forms. Particularly, this review critically depicts the design strategies for montmorillonite, illustrates the relevant reaction mechanisms, and assesses their economic viability, realizing sustainable biofuels production via efficient biomass valorization.

Vinasse treated with charcoal as a molasses diluent for ethanol fermentation.

The demand for new products derived from agro-industrial residues has increased recently. Furthermore, vinasse, a wastewater from ethanol production, needs treatment to be reused in the sugarcane industry, reducing industrial water consumption. This study performed vinasse filtration with charcoal from industrial sugarcane residues and used filtered molasses dilution in ethanolic fermentation. There were five treatments in randomized blocks with three repetitions. The treatments included deionized water and natural vinasse as positive and negative controls, respectively, and filtered vinasse from charcoal made from bamboo, sugarcane bagasse, and straw. Hence, fermentation for ethanol production was performed. Compared with natural vinasse, filtered vinasse with all types of charcoal showed lower soluble solids, total residual reducing sugars, higher ethanol concentrations, and greater fermentative efficiency. Filtered vinasse from bagasse and straw charcoals had efficiencies of 81.14% and 77.98%, respectively, in terms of ethanol production, which are close to those of deionized water (81.49%). In a hypothetical industry, vinasse charcoal filtration and charcoal regeneration should prevent 84.12% of water consumption from environmental resources. This process is feasible because it uses a product of sugarcane residue to treat wastewater and reduce industrial water consumption and vinasse disposal.

Ultrasensitive self-powered biosensor with facile chemical signal amplification strategy using hydrogen peroxide-triggered silver oxidation reaction.

The amplification strategies used for self-powered biosensor based on biofuel cell (BFC-SPB) need to be further developed. Because the currently developed strategies utilized the complicated hybridization of DNA or poorly readable current signal of capacitors for amplification, which limits the practical application in public health emergencies. Here, we present a facile chemical amplification strategy for BFC-SPB. The 5-min amplification was triggered by simply adding H2O2 solution dropwise to the sensing cathode after the formation of the immune sandwich. The Ag NP of immunoprobe were oxidized to Ag(I), which can be served as the electron acceptor of the cathode. The amount of immunoprobe was positively correlated with that of the antigen, resulting in corresponding and high concentration of Ag(I) after the amplification, which enhanced the ability of the cathode as the electron acceptor. Meanwhile the glucose oxidation reaction (GOR) was performed on the bioanode modified with glucose oxidase (GOx). After assembling the bioanode and sensing cathode, the open circuit voltage of the BFC-SPB, measured by digital multimeter, distinctly rised with the elevated concentration of the antigen. To demonstrate the proof of concept, immunoglobulin G (IgG), selecting as a model analyte, was sensitively detected using this method. Result indicated that the limit of detection was 4.4 fg mL-1 (0.03 amol mL-1) in the linear range of 1 pg mL-1-10 µg mL-1. This work initiates a brand-new way of chemical amplification strategy for BFC-SPB, and offers a promising platform for practical applications.

Bacterial isolate collection from switchgrass rhizosphere.

We provide a collection of 78 bacterial isolates from the rhizosphere of switchgrass (Panicum virgatum L.) at the Lux Arbor Reserve in Delton, MI, a site of the Great Lakes Bioenergy Research Center (GLBRC), Michigan State University, MI, USA. We include information on isolation conditions and full-length 16S rRNA sequences.

Phytomanagement of a metal-contaminated agricultural soil with Sorghum bicolor, humic / fulvic acids and arbuscular mycorrhizal fungi near the former Pb/Zn metaleurop Nord smelter.

As many contaminated agricultural soils can no longer be used for food crops, lignocellulosic energy crops matter due to their ability to grow on such soils and to produce biomass for biosourced materials and biofuels, thereby reducing the pressure on the limited arable lands. Sorghum bicolor (L.) Moench, can potentially produce a high biomass suitable for producing bioethanol, renewable gasoline, diesel, and sustainable aircraft fuel, despite adverse environmental conditions (e.g. drought, contaminated soils). A 2-year field trial was carried out for the first time in the northern France for assessing sorghum growth on a Cd, Pb and Zn-contaminated agricultural soil amended with humic/fulvic acid, alone and paired with arbuscular mycorrhizal fungi. Sorghum produced on average (in t DW ha-1): 12.4 in year 1 despite experiencing a severe drought season and 15.3 in year 2. Humic/fulvic acids (Lonite 80SP®) and arbuscular mycorrhizal fungi did not significantly act as biostimulants regarding the shoot DW yield and metal uptake of sorghum. The annual shoot Cd, Pb and Zn removals averaged 0.14, 0.20 and 1.97 kg ha-1, respectively. Sorghum cultivation and its metal uptake induced a significant decrease in 0.01 M Ca(NO3)2-extractable soil Cd, Pb and Zn concentrations by 95%, 73% and 95%, respectively, in year 2. Soluble and exchangeable soil Cd, Pb and Zn would be progressively depleted in subsequent crops, which should result in lower pollutant linkages and enhanced ecosystem services. This evidenced sorghum as a relevant plant species for phytomanaging the large area (750 ha) with metal-contaminated soil near the former Pb/Zn Metaleurop Nord smelter, amidst ongoing climate change. The potential bioethanol yield of the harvested sorghum biomass was 5589 L ha-1. Thus sorghum would be a promising candidate for bioethanol production, even in this northern French region.

Investigating fouling deposition during combustion of hydrothermally treated palm empty fruit Bunch: Pilot-Scale study for industrial hydrothermal reactor.

Inorganic elements in palm empty fruit bunch (EFB) are problematic in boiler operation, causing slagging and fouling deposits. The first pilot-scale hydrothermal treatment (HTT) system was commenced in a palm oil mill to remove undesirable elements. Fuel properties, combustion behavior, and fouling deposition of HTT-EFB were investigated. Liquid temperatures and treatment times in the HTT system significantly altered EFB-fuel properties. At ≥ 60 °C, potassium removals of at least 78 % were achieved, generating EFB-fuel containing potassium below 0.5 %wt. Later, a series of EFB combustion experiments were conducted in a specially designed fixed-bed reactor to simulate the tube surface of industrial boilers. Fouling deposition from HTT-EFB combustion reduced to below half of untreated EFB at all HTT conditions and combustion temperatures studied. The deposit-to-fuel ratio of HTT-EFB combusted at 1,000 °C was 37.3 % lower than untreated EFB combusted at a typical EFB boiler at 800 °C. Results demonstrated great potential for HTT-EFB in industrial applications.

Enhancing anaerobic digestion of lignocellulosic biomass by mechanical cotreatment.

BACKGROUND: The aim of this study was to increase the accessibility and accelerate the breakdown of lignocellulosic biomass to methane in an anaerobic fermentation system by mechanical cotreatment: milling during fermentation, as an alternative to conventional pretreatment prior to biological deconstruction. Effluent from a mesophilic anaerobic digester running with unpretreated senescent switchgrass as the predominant carbon source was collected and subjected to ball milling for 0.5, 2, 5 and 10 min. Following this, a batch fermentation test was conducted with this material in triplicate for an additional 18 days with unmilled effluent as the 'status quo' control. RESULTS: The results indicate 0.5 - 10 min of cotreatment increased sugar solubilization by 5- 13% when compared to the unmilled control, with greater solubilization correlated with increased milling duration. Biogas concentrations ranged from 44% to 55.5% methane with the balance carbon dioxide. The total biogas production was statistically higher than the unmilled control for all treatments with 2 or more minutes of milling (α = 0.1). Cotreatment also decreased mean particle size. Energy consumption measurements of a lab-scale mill indicate that longer durations of milling offer diminishing benefits with respect to additional methane production. CONCLUSIONS: Cotreatment in anaerobic digestion systems, as demonstrated in this study, provides an alternative approach to conventional pretreatments to increase biogas production from lignocellulosic grassy material.

Tailored Engineering of Layered Double Hydroxide Catalysts for Biomass Valorization: A Way Towards Waste to Wealth.

Layered double hydroxides (LDH) have significant attention in recent times due to their unique characteristic properties, including layered structure, variable compositions, tunable acidity and basicity, memory effect, and their ability to transform into various kinds of catalysts, which make them desirable for various types of catalytic applications, such as electrocatalysis, photocatalysis, and thermocatalysis. In addition, the upcycling of lignocellulose biomass and its derived compounds has emerged as a promising strategy for the synthesis of valuable products and fine chemicals. The current review focuses on recent advancements in LDH-based catalysts for biomass conversion reactions. Specifically, this review highlights the structural features and advantages of LDH and LDH-derived catalysts for biomass conversion reactions, followed by a detailed summary of the different synthesis methods and different strategies used to tailor their properties. Subsequently, LDH-based catalysts for hydrogenation, oxidation, coupling, and isomerization reactions of biomass-derived molecules are critically summarized in a very detailed manner. The review concludes with a discussion on future research directions in this field which anticipates that further exploration of LDH-based catalysts and integration of cutting-edge technologies into biomass conversion reactions hold promise for addressing future energy challenges, potentially leading to a carbon-neutral or carbon-positive future.

Self-Powered Engineering of Cell Membrane Receptors to On-Demand Regulate Cellular Behaviors.

On-demand engineering of cell membrane receptors to nongenetically intervene in cellular behaviors is still a challenge. Herein, a membraneless enzyme biofuel cell-based self-powered biosensor (EBFC-SPB) was developed for autonomously and precisely releasing Zn2+ to initiate DNAzyme-based reprogramming of cell membrane receptors, which further mediates signal transduction to regulate cellular behaviors. The critical component of EBFC-SPB is a hydrogel film on a biocathode which is prepared using a Fe3+-cross-linked alginate hydrogel film loaded with Zn2+ ions. In the working mode in the presence of glucose/O2, the hydrogel is decomposed due to the reduction of Fe3+ to Fe2+, accompanied by rapid release of Zn2+ to specifically activate a Zn2+-responsive DNAzyme nanodevice on the cell surface, leading to the dimerization of homologous or nonhomologous receptors to promote or inhibit cell proliferation and migration. This EBFC-SPB platform provides a powerful "sensing-actuating-treating" tool for chemically regulating cellular behaviors, which holds great promise in precision biomedicine.

Functional studies on tandem carbohydrate-binding modules of a multimodular enzyme possessing two catalytic domains.

Although functional studies on carbohydrate-binding module (CBM) have been carried out extensively, the role of tandem CBMs in the enzyme containing multiple catalytic domains (CDs) is unclear. Here, we identified a multidomain enzyme (Lc25986) with a novel modular structure from lignocellulolytic bacterial consortium. It consists of a mannanase domain, two CBM65 domains (LcCBM65-1/LcCBM65-2), and an esterase domain. To investigate CBM function and domain interactions, full-length Lc25986 and its variants were constructed and used for enzymatic activity, binding, and bioinformatic analyses. The results showed that LcCBM65-1 and LcCBM65-2 both bind mannan and xyloglucan but not cellulose or ß-1,3-1,4-glucan, which differs from the ligand specificity of reported CBM65s. Compared to LcCBM65-2, LcCBM65-1 showed a stronger ligand affinity and a preference for acetylation sites. Both CBM65s stimulated the enzymatic activities of their respective neighboring CDs against acetylated mannan, but did not contribute to the activities of the distal CDs. The time course of mannan hydrolysis indicated that the full-length Lc25986 was more effective in the complete degradation of mixed acetyl/non-acetyl substrates than the mixture of single-CD mutants. When acting on complex substrates, LcCBM65-1 not only improved the enzymatic activity of the mannanase domain, but also directed the esterase domain to the acetylated polysaccharides. LcCBM65-2 adopted a low affinity to reduce interference with the catalysis of the mannanase domain. These results demonstrate the importance of CBMs for the synergism between the two CDs of a multidomain enzyme and suggest that they contribute to the adequate degradation of complex substrates such as plant cell walls. IMPORTANCE: Lignocellulolytic enzymes, particularly those of bacterial origin, often harbor multiple carbohydrate-binding modules (CBMs). However, the function of CBM multivalency remains poorly understood. This is especially true for enzymes that contain more than one catalytic domain (CD), as the interactions between CDs, CBMs, and CDs and CBMs can be complex. Our research demonstrates that homogeneous CBMs can have distinct functions in a multimodular enzyme. The tandem CBMs coordinate the CDs in catalytic conflict through their differences in binding affinity, ligand preference, and arrangement within the full-length enzyme. Additionally, although the synergism between mannanase and esterase is widely acknowledged, our study highlights the benefits of integrating the two enzymes into a single entity for the degradation of complex substrates. In summary, these findings enhance our understanding of the intra-synergism of a multimodular enzyme and emphasize the significance of multiple CBMs in this context.

Mesoporous SO42- / kit-6-catalyzed hydrocracking of waste chicken oil.

In this study, we studied the hydrocracking of waste chicken oil (WCO) catalyzed by mesoporous SO42-/KIT-6. The study included WCO extraction, SO42-/KIT-6 catalyst synthesis, hydrocracking, and catalytic characterization. XRD patterns revealed intense peaks in the low-angle region, with shoulder peaks showing an increase in sulphate loading from 10% to 30%. The BET-specific surface area for the pure KIT-6 supports measured at 1003 m2/g, indicative of a well-defined mesoporous structure. Thermogravimetric analysis (TGA) showed a two-stage weight loss, attributed to the elimination of hydrated water (about 200 °C) and decomposition of sulphate ions (400-450 °C). SEM analysis highlighted the surface morphology of the active SK-2 catalyst. Hydrocatalytic and catalytic cracking reactions were performed, and about 99.8% conversion was achieved with 20 mL/H H2 flow, whereas higher production of bioliquids was observed at a flow of 15 mL/h. The hydrocracking mechanism was also studied to understand the formation of lower hydrocarbons. GC analyses of simulated distilled gasoline, kerosene, and diesel showed diverse hydrocarbon compositions. For engine testing, non-hydrocracked fuel rose to 28 kW at 3000 rpm and declined to 21 kW at 3500 rpm. Emission analysis revealed decreasing trends in NOX emissions of hydrogen-rich blends, with values of 65 ppm, 54 ppm, and 48 ppm for petrol, NHBL, and HBL, respectively. Similarly, SO2 emissions reduced from petrol to NHBL and HBL at 910 ppm, 800 ppm, and 600 ppm, respectively, suggesting reduced environmental impact. CO emissions exhibited a substantial reduction in NHBL (0.90%) and HBL (0.54%) compared to petrol (2.70%), emphasizing the cleaner combustion characteristics. Our results provide a comprehensive exploration of waste chicken oil hydrocracking, emphasizing catalyst synthesis, fuel characterization, engine performance, and environmental impact, thereby contributing valuable insights to the field of sustainable bioenergy.

Plasmonics nanorod biosensor for in situ intracellular detection of gene expression biomarkers in intact plant systems.

The intracellular developmental processes in plants, particularly concerning lignin polymer formation and biomass production are regulated by microRNAs (miRNAs). MiRNAs including miR397b are important for developing efficient and cost-effective biofuels. However, traditional methods of monitoring miRNA expression, like PCR, are time-consuming, require sample extraction, and lack spatial and temporal resolution, especially in real-world conditions. We present a novel approach using plasmonics nanosensing to monitor miRNA activity within living plant cells without sample extraction. Plasmonic biosensors using surface-enhanced Raman scattering (SERS) detection offer high sensitivity and precise molecular information. We used the Inverse Molecular Sentinel (iMS) biosensor on unique silver-coated gold nanorods (AuNR@Ag) with a high-aspect ratio to penetrate plant cell walls for detecting miR397b within intact living plant cells. MiR397b overexpression has shown promise in reducing lignin content. Thus, monitoring miR397b is essential for cost-effective biofuel generation. This study demonstrates the infiltration of nanorod iMS biosensors and detection of non-native miRNA 397b within plant cells for the first time. The investigation successfully demonstrates the localization of nanorod iMS biosensors through TEM and XRF-based elemental mapping for miRNA detection within plant cells of Nicotiana benthamiana. The study integrates shifted-excitation Raman difference spectroscopy (SERDS) to decrease background interference and enhance target signal extraction. In vivo SERDS testing confirms the dynamic detection of miR397b in Arabidopsis thaliana leaves after infiltration with iMS nanorods and miR397b target. This proof-of-concept study is an important stepping stone towards spatially resolved, intracellular miRNA mapping to monitor biomarkers and biological pathways for developing efficient renewable biofuel sources.

Experimental investigation of performance, emissions, combustion characteristics, cyclic variations, and exergy efficiency of CI engine fueled with Karanja-camphor oil blends and diesel-camphor oil blends.

This article compares the influence of blending the low-viscous oxygenated camphor oil with hydrocarbon diesel fuel and high-viscous oxygenated Karanja oil. The experiment is conducted in a four-stroke one-cylinder naturally aspirated Kirloskar compression ignition (CI) engine coupled with an eddy current dynamometer. The three types of fuel blends are prepared by blending the camphor oil with Karanja oil on the volume ratio of 30:70 (C30K70), 50:50 (C50K50), and 70:30 (C70K30), and the other three types of fuels are prepared by blending the camphor oil with diesel on the volume ratio of 30:70 (C30D70), 50:50 (C50D50), and 70:30 (C70D30). The experimental efficiency results show higher thermal efficiency of 31.86% and 30.84% for C70D30 and C70K30 at rated operating conditions. The brake-specific energy consumptions of C70D30 and C70K30 were found to be 11.29 and 11.67 MJ/kWh, respectively, at rated operating conditions. The lowest CO, CO2, HC, and smoke emissions are found for C70D30 at rated operating conditions, which are 96.58%, 6.15%, 34.20%, and 7.59% lower than diesel. However, the NO emissions were found to be 27.62% higher for C70D30 than diesel at full load. The rate of pressure rise, net heat release rate, and cyclic variations were found to increase with increase in proportion of the camphor oil. The P-v diagram also confirms the lower heat addition period for the C70D30 and C70K30 with an increase in brake thermal efficiency. The actual compression ratio and the actual cutoff ratio are found to have a reasonable correlation with the thermal efficiency of the engine. The exergy efficiency of C30K70 is found higher which is 2.11% higher than diesel fuel at rated power. Second-order polynomial equations were obtained for the engine characteristics using the curve fitting method, and the characteristic equations confirmed the confidence level of 95%.

Microalgae to bioenergy production: Recent advances, influencing parameters, utilization of wastewater - A critical review.

Fossil fuel limitations and their influence on climate change through atmospheric greenhouse gas emissions have made the excessive use of fossil fuels widely recognized as unsustainable. The high lipid content, carbon-neutral nature and potential as a biofuel source have made microalgae a subject of global study. Microalgae are a promising supply of biomass for third-generation biofuels production since they are renewable. They have the potential to produce significant amounts of biofuel and are considered a sustainable alternative to non-renewable energy sources. Microalgae are currently incapable to synthesize algal biofuel on an extensive basis in a sustainable manner, despite their significance in the global production of biofuels. Wastewater contains nutrients (both organic and inorganic) which is essential for the development of microalgae. Microalgae and wastewater can be combined to remediate waste effectively. Wastewater of various kinds such as industrial, agricultural, domestic, and municipal can be used as a substrate for microalgal growth. This process helps reduce carbon dioxide emissions and makes the production of biofuels more cost-effective. This critical review provides a detailed analysis of the utilization of wastewater as a growth medium for microalgal - biofuel production. The review also highlights potential future strategies to improve the commercial production of biofuels from microalgae.