Biofuel Production Process Research Articles

Thermobifida fusca Cel6B moves bidirectionally while processively degrading cellulose

BackgroundCellulose, an abundant biopolymer, has great potential to be utilized as a renewable fuel feedstock through its enzymatic degradation into soluble sugars followed by sugar fermentation into liquid biofuels. However, crystalline cellulose is highly resistant to hydrolysis, thus industrial-scale production of cellulosic biofuels has been cost-prohibitive to date. Mechanistic studies of enzymes that break down cellulose, called cellulases, are necessary to improve and adapt such biocatalysts for implementation in biofuel production processes. Thermobifida fusca Cel6B (TfCel6B) is a promising candidate for industrial use due to its thermostability and insensitivity to pH changes. However, mechanistic studies probing TfCel6B hydrolytic activity have been limited to ensemble-scale measurements.ResultsWe utilized optical tweezers to perform single-molecule, nanometer-scale measurements of enzyme displacement during cellulose hydrolysis by TfCel6B. Records featured forward motility on the order of 0.17 nm s−1 interrupted by backward motions and long pauses. Processive run lengths were on the order of 5 nm in both forward and backward directions. Motility records also showed rapid bidirectional displacements greater than 5 nm. Single-enzyme velocity and bulk ensemble activity were assayed on multiple crystalline cellulose allomorphs revealing that the degree of crystallinity and hydrogen bonding have disparate effects on the single-molecule level compared to the bulk scale. Additionally, we isolated and monitored the catalytic domain of TfCel6B and observed a reduction in velocity compared to the full-length enzyme that includes the carbohydrate-binding module. Applied force has little impact on enzyme velocity yet it readily facilitates dissociation from cellulose. Preliminary measurements at elevated temperatures indicated enzyme velocity strongly increases with temperature.ConclusionsThe unexpected motility patterns of TfCel6B are likely due to previously unknown mechanisms of processive cellulase motility implicating irregularities in cellulose substrate ultrastructure. While TfCel6B is processive, it has low motility at room temperature. Factors that most dramatically impact enzyme velocity are temperature and the presence of its native carbohydrate-binding module and linker. In contrast, substrate ultrastructure and applied force did not greatly impact velocity. These findings motivate further study of TfCel6B for its engineering and potential implementation in industrial processes.

Conversion of Spirulina platensis into Methanol via Gasification: Process Simulation Modeling and Economic Evaluation

The conversion of bioresources like Spirulina platensis (SP) into value-added chemicals, such as methanol, offers a sustainable replacement of fossil fuels and contributes to greenhouse gas mitigation. This study presents an integrated process simulation model, developed using Aspen Plus v10®, for the steam gasification of SP and subsequent methanol production. Process parameters, including temperature range from 650-950°C, steam/feed ratio from 0.5-2, and recycle ratio from 0-9, were investigated to optimize syngas composition and methanol yield. Results demonstrated that increasing temperature enhances H2 and CO production while reducing CO2 and CH4, significantly increasing methanol production from 6500 to 9500 kg/h. The steam/feed ratio also influences syngas composition and methanol yield, with higher ratios promoting H2 and CO2 production and reducing CO and CH4. The economic evaluation of two scenarios, a base case and an optimum case, shows that the capital expenditure (Capex) and operating expenditure (Opex) are 19.3M$ and 9.07M$ for the base case, and 20.018M$ and 10.21M$ for the optimum case. The analysis also reveals that the optimum case, with higher methanol production (7.2 tonnes/h compared to 6.7 tonnes/h in the base case), generates a higher net income (9.76 M$/y) and reduces CO2 emissions (4.918 tonnes CO2-e/y compared to 5.72 tonnes CO2-e/y). The energy flow indicates the input energy requirement, the energy carried by methanol, and the surplus energy, totalling 26740 kW to meet the major system's energy demands. This study provides valuable insights for researchers, policymakers, and commercial entities seeking to develop sustainable and economically viable biofuel production processes.

Pyrolysis of açai stems (Euterpe oleracea Mart.) and cocoa husks (Theobroma cacao L.) residues for the generation of added-value products in rural areas

AbstractGenerally, agriculture activities represent the main economic income of rural areas, and during these, huge amounts of biomass are generated. This biomass is considered as garbage due to its high storage cost. However, energy and added-value products can be recovered from biomass. Within this context, açai stems and cocoa husks were collected from different rural areas of Bolivia due to their high importance in the local and international markets as two of the most available products of the country. The preliminary study will contribute in the field of green energy recovery and resource management. Thus, in this study, both residues were tested as renewable feedstocks for the generation of added-value products from pyrolysis at 500 °C for 30 min. Açai stems were found to be more suitable to biochar based with yields up to 49.1% ± 2.4%, but also for biogas production (33.9% ± 2.0%). Cocoa husk was also found to be more suitable for biochar production (38.1% ± 1.7%) but also for bio-oils (33.6% ± 17.6%). Both resulting biochars had basic pH (between 10 and 12) and low density (287.2 kg/m3 and 401.7 kg/m3). Additionally, the lack of heavy metals on the surface makes both biochar products good candidates for soil amendment applications. Furthermore, the bio-oil composition is complex and varied, and products such as Maltol, 2-methyl furane, and D-allose have direct applications in the food industry. Moreover, the presence of phenolic compounds and hydrocarbons with more than five carbons in the structure makes the obtained bio-oils suitable for upgrading processes for biofuel production. Finally, the obtained biogases can be applied for local electricity generation, or to reduce the energy requirements for the pyrolysis reactor. Graphical Abstract

Global processes of solid biofuel production: Trends and prospects of its development in Ukraine

The article highlights current global energy problems concerning the consumption of fossil fuels, their negative consequences, and trends in the growth of the consumption of renewable energy resources. It has been established that one of the most promising alternative energy sources in the world and Europe is solid biomass of plant origin, an environmentally friendly and rapidly renewable energy resource. An intensive process of growth in production and consumption of fuel briquettes and pellets, which in 2014–2020 made up averagely 27.2 %, can be observed in Ukraine. The constructed trend line of fuel briquettes and pellets production and consumption in Ukraine from 2014 to 2025 has a high level of reliability with a 0.92 coefficient of determination. Based on the analysis of the consumption of fuel briquettes and pellets in the regions of Ukraine, they were divided into low, medium, high, and very high levels of consumption. The developed miscanthus cultivation technology ensures: 20–25 t/ha dry biomass yield; 25–28 t/ha solid fuel yield; 500–520 GJ/ha solid fuel energy output; 160–190 % production profitability. The developed switchgrass growing technology provides: 15–20 t/ha dry biomass yield; 8.5–12.0 t/ha solid fuel yield; 150–220 GJ/ha solid fuel energy output; 160–230 % production profitability. The further development of solid biofuel production will ensure the expansion of technologies for the combined generation of electrical and thermal energy, which will be obtained due to the cheap biological resources processing. Development of domestic bioenergy engineering can be considered as an additional socio-economic effect.

Heterogeneous catalysts for sustainable biofuel production: A paradigm shift towards renewable energy

In a globalized world, energy remains a critical driver of development. The reliance on non-renewable fossil fuels has led to pollution, health concerns, and accelerated climate change due to greenhouse gas emissions. As fossil fuel reserves diminish, biofuels derived from biomass present a promising and sustainable alternative. Biomass, being abundant and renewable, has the potential to replace fossil fuels, with advances in technology and a focus on green synthesis enabling more efficient and environmentally friendly production processes. Heterogeneous catalysts play a crucial role in biofuel production, significantly impacting the development of more sustainable energy solutions. These catalysts, which operate in a different phase from the reactants, are crucial for achieving high conversion efficiency, recyclability, and minimal environmental impact in biofuel production. Specifically designed to break down lignocellulosic biomass, these catalysts are essential for a carbon-neutral biofuel production process and for driving sustainable development. This article explores the historical development and evolving role of these catalysts in biofuel technology along with a categorization of various catalysts used in biofuel production. The discussion includes an examination of biomass sources and its structural and chemical compositions vital for conversion processes. The application of heterogeneous catalysts in producing diverse biofuels—such as bioethanol, biobutanol, biogas, biodiesel and biohydrogen are analyzed, highlighting recent advancements and improvements in efficiency. Insights and recommendations for future research underscore the indispensable role of heterogeneous catalysts in advancing sustainable energy practices and securing our energy future.

Water hyacinth biorefinery: Improved biofuel production using Trichoderma atroviride pretreatment

AbstractThe pyrolysis of water hyacinth is gaining attention and acceptance as a resource recovery technique due to its availability and economic viability. However, the presence of lignin, one of the three major biomass fractions, presents significant challenges for profitable water hyacinth processing for biofuel production. Fungal pretreatment of water hyacinth for lignin breakdown has been explored but the application of Trichoderma atroviride as a pretreatment for pyrolysis is relatively novel. The efficacy of T. atroviride pretreatment in improving water hyacinth's pyrolytic products using a fixed‐bed reactor was therefore investigated in this study. The optimization process was studied using a central composite design in response surface methodology with Design Expert 13. Delignification of the biomass was established because the elemental analysis showed a 25.42% increase in cellulose content and a 23.40% and 3.37% decrease in lignin and hemicellulose content, respectively. The biomass pretreatment applied influenced the physical and chemical characteristics of the pyrolytic products. The highest pyrolysis oil yield increased by 25.81% at 575 °C and particle size 2290 μm, and the highest char yield decreased by 4.23% at 273 °C and particle size 1500 μm. This research is crucial for policy and research conversations as it offers a scientific basis for the application of T. atroviride pretreatment in biomass pyrolysis technology and emphasizes the optimal utilization of water hyacinths to obtain socio‐environmental benefits.

Applications of Machine Learning Technologies for Feedstock Yield Estimation of Ethanol Production

Biofuel has received worldwide attention as one of the most promising renewable energy sources. Particularly, in many countries such as the U.S. and Brazil, first-generation ethanol from corn and sugar cane has been used as automobile fuel after blending with gasoline. Nevertheless, in order to continuously increase the use of biofuels, efforts are needed to reduce the cost of biofuel production and increase its profitability. This can be achieved by increasing the efficiency of a sequential biofuel production process consisting of multiple operations such as feedstock supply, pretreatment, fermentation, distillation, and biofuel transportation. This study aims at investigating methodologies for predicting feedstock yields, which is the earliest step for stable and sustainable biofuel production. Particularly, this study reviews feedstock yield estimation approaches using machine learning technologies that focus on gradually improving estimation accuracy by using big data and computer algorithms from traditional statistical approaches. Given that it is becoming increasingly difficult to stably produce biofuel feedstocks as climate change worsens, research on developing predictive modeling for raw material supply using the latest ML techniques is very important. As a result, this study will help researchers and engineers predict feedstock yields using various machine learning techniques, and contribute to efficient and stable biofuel production and supply chain design based on accurate predictions of feedstocks.

Machine learning-enabled techno-economic uncertainty analysis of sustainable aviation fuel production pathways

Stochastic techno-economic analysis (TEA) is pivotal in assessing the financial viability and risks inherent in biofuel production processes. In this method, the Monte Carlo approach entails the random sampling of input variables and multiple runs of the TEA model to create probability distributions of economic metrics. However, traditional Monte Carlo TEA, reliant on iterative calls to process simulation, is resource-intensive and time-consuming, hindering widespread adoption. To address these challenges, we present an accessible framework that harnesses machine learning methods to estimate techno-economic uncertainty in biofuel production pathways. Our approach streamlines the conventional simulation process by automating dataset generation and machine learning model training. These trained models enable rapid predictions of minimum fuel selling prices at any scale, accommodating randomized input variables based on their defined distributions. We illustrate the efficacy of our framework through examples from sustainable aviation fuel production pathways. Our research entails identifying the primary factors influencing uncertainties in minimum selling prices, exploring the synergistic effects of pathway inputs, and assessing how price variability is impacted by financial, technical, and supply chain factors. These examples underscore the framework's effectiveness in addressing breakeven price uncertainties in biofuel production across diverse input scenarios.

Sustainable Biofuel Production Utilizing Nanotechnology: Challenges and Potential Solutions

ABSTRACTThe transition to biofuels as viable alternatives to fossil fuels is increasingly critical, given the rising demand for sustainable energy. However, biofuel production is hindered by challenges such as feedstock scarcity, elevated production costs, and environmental impacts. Nanotechnology has the potential to significantly improve the efficiency and durability of biofuel production processes, thereby overcoming these challenges. Although there has been significant research on using nanomaterials in biofuel production, there needs to be more emphasis on understanding and addressing the difficulties of integrating these materials and developing strategies to overcome them. This review systematically examines the role of nanotechnology in various biofuel production pathways, including biodiesel, biogas, bioethanol, biohydrogen, hydrotreated vegetable oils, and Fischer–Tropsch synthesis. We discuss how nanomaterials improve key aspects of biofuel production, such as catalysis, microbial conversion, biomass pretreatment, and separation. Despite these advancements, nanotechnology has challenges, including nanoparticle toxicity, increased operational costs, and technical limitations. We propose potential solutions to these issues, emphasizing the need for interdisciplinary collaboration and innovative approaches. By effectively integrating nanotechnology into biofuel production, the energy sector can move toward a more sustainable and environmentally friendly future.

Disposal of used oils as a prospective method of production of biodiesel

The article is devoted to the improvement of the production technology of diesel biofuel from waste oils, which are a significant source of environmental pollution. Environmental pollution is one of the biggest environmental problems of our time. Used oils that are not properly disposed of cause serious environmental problems, including water and soil pollution. The use of waste oils for the production of biofuel is a promising technology that allows reducing the amount of pollution and reducing dependence on fossil fuels. Biodiesel from waste oils has significant environmental, economic and sustainable advantages. The main goal of the article is a detailed analysis of modern technologies for the production of diesel biofuel from waste oils and an assessment of their improvements and impact on ecology, economy and society. The article discusses innovative approaches to the processing of used oils, their purification and preparation for further use. An analysis of the main methods of transesterification, hydrogenation, esterification and enzyme catalysis, as well as the latest technologies, such as ultrasonic and microwave intensification of biofuel production, was carried out. New technological solutions for the preliminary preparation of used oils with a high content of free fatty acids using a combination of acid catalysts are proposed, and a technological scheme of the full production cycle is developed. The rational parameters of the equipment for the preliminary preparation of used oils with a high content of free fatty acids have been determined. Recommended conditions include hydrogenation temperature not higher than 80°С, duration of the process not less than 40 minutes; separation of the water-protein part by centrifugation at a rotation frequency of the centrifuge rotor of 3000 rpm for 20 minutes; the esterification reaction temperature is no more than 60°C; molar ratio of alcohol to oil 9:1; acid catalyst concentration within 1-15%; the intensity of mixing in the reactor is 31.42 s-1; the duration of the process is not less than 120 minutes. It was established that it is advisable to use potassium hydroxide for the transesterification reaction. The use of potassium hydroxide is beneficial because the potassium salts formed during the technological process of diesel biofuel production can be used as mineral fertilizers. According to the results of the research, the optimal parameters for the transesterification reaction were chosen: the amount of methanol - 20% by mass. from the weight of the oil, the KOH 1 catalyst is 1.5%, the temperature of the process is 60°C and the duration is 60-70 minutes. Examples of successful implementation of these technologies in various countries of the world, in particular in Europe, the USA and Asia, are presented. Additionally, recommendations are provided for further research and technology development, including the need to improve waste oil purification methods, optimize transesterification processes, and integrate renewable energy sources. The prospects and challenges of the industry of biofuel production from waste oils are considered, in particular the issues of regulatory support, financial incentives and investment attraction.

Induction of lipid production through controlled acidification: A transcriptional insight into the metabolism of Scenedesmus obtusiusculus AT-UAM

Scenedesmus obtusiusculus AT-UAM was able to accumulate up to 62 % of lipids when controlled acidification was applied to a nitrogen-deplete culture. Under these conditions, up-regulation of genes related to lipid synthesis and central carbon metabolism (glycolysis, the tricarboxylic acid cycle, and the pentose phosphate pathway) was recorded. Additionally, genes related to photosynthesis were up-regulated in the nitrogen depletion and nitrogen depletion with controlled acidification conditions with respect to the control samples analyzed under nutritional sufficiency. The Pyani program was used to establish pairwise ANI values between reported and annotated NCBI genomes to uphold genomics similarity. ANI analysis confirms the previously observed identity of S. obtusiusculus AT-UAM with the 18S rRNA and ITS2 regions, and also provides a solid framework for understanding the genetic stability and lineage of the strain. Results obtained are encouraging for integrating biofuel production processes and carbon capture technologies. Specifically, the up-regulation of genes related to both lipid synthesis and photosynthesis under controlled conditions indicates the potential of S. obtusiusculus AT-UAM for efficient biofuel production while simultaneously sequestering carbon. These biochemical properties make this strain a promising candidate for sustainable energy solutions and environmental mitigation strategies.

Brazilian Biofuel Policy: Challenges to Incorporating Socio-Environmental Criteria

Objective: Biofuels have been receiving increasing attention around the world as a result of growing concerns about the security of oil supplies and global climate change. Considering this context, the article aims to analyze the Brazilian biofuels policy (RenovaBio program) in order to propose a summary table of gaps in the consideration of socio-environmental criteria. Method: Qualitative, descriptive research was carried out, supported by secondary data obtained through bibliographical research. Results and Discussion: We found that gaps in the incorporation of socio-environmental criteria in RenovaBio are related to the following topics: traceability of inputs and raw materials; sugarcane agroecological zoning (ZAE Cana), measurement of water footprint consumption associated with traceability of raw materials, measurement of emissions resulting from I-MUT and criteria encouraging E2G. Research Implications: We found that RenovaBio could include the adoption of instruments and practices aimed at agricultural production that are more appropriate to the Brazilian scenario, considering the characteristics of each biome, aiming to include socio-environmental criteria. Originality/Value: The analysis of socio-environmental criteria that are absent or insufficiently included in public policy contributes to clarify the challenges to be overcome in the biofuels production process marked by the agricultural, industrial and distribution phases.

Optimizing bioethanol production from sweet sorghum stem juice under very high gravity fermentation and temperature stress conditions

This study optimized ethanol production from sweet sorghum stem juice (SSJ) by Saccharomyces cerevisiae NP01 under very high gravity (VHG) fermentation in 500-mL air–locked flasks at 30 °C. Response surface methodology based on a Box-Behnken design was employed to optimize initial sugar (267 g/L), urea (3.24 g/L), and cell concentration (1.32 × 108cells/mL) for maximization of ethanol concentration (PE), productivity (QP), and sugar consumption (%SC). The experimental values (PE, 119.29 g/L; QP, 2.49 g/L.h and %SC,91.83 %) under optimal conditions were close to the predicted values, verifying the optimization process. Aeration (2.5 vvm for 4 h) increased viable cell counts and decreased glycerol production (a by-product), but not fermentation efficiency. An osmoprotectant (40 mM potassium chloride combined with 10 mM potassium hydroxide, KCl/KOH) at 30 °C had no positive effect on ethanol fermentation efficiency. However, at 25 °C, the osmoprotectant increased PE from 106 to 116 g/L and ethanol yield from 0.46 to 0.49 g/g. At 35–37 °C, it prolonged cell viability, increasing PE by 5–12 g/L and %SC by 3–8 % without affecting ethanol yield. However, at 39 °C, no positive impact occurred on ethanol fermentation efficiency. The findings from this study, particularly the optimized fermentation conditions and stress tolerance strategies, could guide the scale-up to an industrial level of bioethanol production from sweet sorghum stem juice or other feedstocks using VHG fermentation, contributing to the development of more efficient and sustainable biofuel production processes.

Microbial Induced Biotechnological Processes for Biofuel Production from Waste Organics Conversion

In the current era there are huge quantities of waste organic matter available, creating a big burden to the environment. To address these issues, researchers started to apply effective and microbial induced biotechnological processes that can mitigate these waste matters. In this context, different nature of microbial systems are involved in hydrolysing the waste organic material into fermentable sugar. These can be easily consumed by specific microbial systems like Saccharomyces cerevisiae MTCC 3821 and Clostridium acetobutylicum that produced bioethanol and biobutanol, respectively. Saccharomyces cerevisiae was cultured in specific media and incubated at rotary shaker with 150 rpm at 30°C for 72 to 96 hours. Ethanol concentrations from different waste matters were found in the range of 1.2-1.5 g.L-1. Ethanol synthesis was done by shake flask experiment with addition of glucose (50 g.L-1) to waste organic hydrolyzed solution. Non-glucose media produced less than 3 g.L-1 ethanol but glucose media produced 4.5 g.L-1. Next, Clostridium acetobutylicum was grown in culture media containing waste organics as sole carbon substrate with pH 7 and then was incubated in anaerobic conditions at 35°C for 72 hours, produced butanol (0.7 to 1.25 g.L-1). This research work promoted biofuels synthesis by keeping a waste mitigation strategy.

Advancements in biofuel research: Understanding the physical and chemical characteristics of green diesel

Green diesel is a potential biofuel that offers certain advantages over traditional fossil diesel, such as low environmental pollution and no sulfur. However, there is little information available regarding the density and viscosity of green diesel, which is crucial for the quality control of biofuels and their performance in engines. In this study, the properties of green diesel produced from palm and soybean oils hydrotreatment were investigated, and models were developed to predict the physical properties of green diesel and n-alkanes. The experimental measurements had uncertainties of 1×10-4 g/cm3 and 1×10-2 mPa s in density and viscosity, respectively. The models were found to be in good agreement with the experimental values. The study highlights the importance of density and viscosity for quality control and engine performance of biofuels. The developed models for predicting the physical properties of green diesel and n-alkanes can be useful for quality control and optimization of biofuel production processes. The findings can be useful for researchers, engineers, and policymakers working in the field of biofuels and renewable energy. Further research is needed to explore the applicability of the developed models to other types of biofuels and to investigate the environmental and economic sustainability of green diesel production.

POTENSI LIPID MIKROALGA AURANTIOCHYTRIUM DARI HUTAN BAKAU INDONESIA SEBAGAI BAHAN BAKU PRODUKSI BIOFUEL

Microalgae's high lipid content makes them an alternative raw material for the generation of biofuel. This research examines the potential of Aurantiochytrium microalgae sourced from mangrove forests. The capacity to create omega-3 polyunsaturated fatty acids, such DHA, which have a high economic value, is one benefit of Aurantiochytrium microalgae and makes integrated production with biofuel production feasible. The possible biofuel products from Aurantiochytrium microalgae, including biodiesel and bioviation fuel, are reviewed in this research. These microalgae go through multiple steps in the biofuel production process, including isolation, cultivation, lipid extraction, and hydroprocessing and transesterification to turn the algae into biodiesel or biojet fuel. The first steps toward producing biofuel from Aurantiochytrium microalgae obtained from Indonesian mangrove forests are expected to be laid by this research.

Fast screening of catalyst performances in hydrothermal processes for biofuel production using differential scanning calorimetry

Catalysts are usually employed in hydrothermal processes for different purposes, such as enhancing quality and yield of produced biofuels. However, assessing catalyst performances can be time consuming and expensive. For this reason, in this work, a technique based on high pressure differential scanning calorimetry was applied to study heterogeneous catalyst behavior under hydrothermal conditions at the micro-scale. Heterogeneous catalysts were mixed with distilled water and cellulose, selected as substrate, and tested at 250 °C. The heat release profiles obtained were deconvoluted in three Gaussian peaks, each associated with a set of reactions. Siralox and iron chloride showed the highest catalytic activities impacting the development and the enthalpy of the reactions. Selected samples were further characterized to investigate synergies among acid and basic sites and emphasize the importance of the spatial distribution of the components inside the catalysts. This study highlights the crucial role of advanced techniques in optimizing catalyst performance for more efficient biofuel production.

Environmental impact assessment of biohydrogen production from orange peel waste by lab-scale dark and photofermentation processes

Orange peel waste (OPW), as a relevant and recoverable residue, is composed of peel, internal tissue, pulp, and seeds. This organic residue is rich in carbohydrates useful for biofuel production processes. Biohydrogen is obtained from dark fermentation (DF) and photofermentation (PF), which are complementary in the bioprocessing chain. The objective of this work was to compare the environmental impact assessment of a sequential dark–photofermentation process (Scenario DF-PF) and the individual fermentation processes: dark fermentation (Scenario DF) and photofermentation (Scenario PF). The assessment was performed at a laboratory scale, and the functional unit (FU) was defined as the production of 1 kg H2. Scenario DF showed the lowest environmental impacts regarding global warming and fossil resource scarcity indicators, with 375.5 kg CO2-eq/FU and 108.8 kg oil-eq/FU, respectively, followed by Scenario DF-PF and Scenario PF. Scenario DF-PF presented the lowest impact regarding the water consumption indicator (7.6 m3/FU), followed by Scenario DF, which had 46.6% more impact. Additionally, Scenario DF-PF required 3.3 times less substrate than Scenario DF due to more efficient substrate conversion. The high share of fossil fuels in the Mexican electricity mix directly impacts the processes that require electric energy, such as the PF process. Therefore, eco-friendly light sources should be used to minimize effects. Valorization of OPW could follow two routes depending on whether the aim is to reduce a specific environmental impact indicator or biowaste conversion efficiency.

An in-depth exploration of recent advances and promising outlooks in biogas production

Biogas is a product composed of a mixture of gases resulting from the biological decomposition of organic material, consisting primarily of methane gas and carbon dioxide, besides smaller amounts of other gases. The current study aims to comprehensively analyze waste-based biogas production to ensure sustainability in the biofuel production process. An advanced systematic bibliometric analysis using keywords, co-citations, and bibliographic coupling analysis was performed on 641 peer-reviewed articles from Web of Science to conclude this goal further. This analysis covers the period from 2000 to 2022, a little more than 20 years. The methodology used reveals several themes that have been identified and addressed in the articles: (1) the importance of the topic in academia by country in which they were analyzed; (2) sectors contributing to biofuel production; (3) equipment used in biofuel production; (4) the most cited waste sources in the database; (5) application purpose of biogas; (6) relevance of other energy sources; (7) areas of interest where biofuels are used; and (8) a comparison between the energy production capacity and the number of publications on the topic by country. Furthermore, the potentials, limitations, perspectives, and future trends highlighted to improve the production process are also considered. Therefore, the conclusion is that organic waste can be used in the sustainable production of goods with added value for society.

Graphene and its derivatives fabrication from paddy straw for improved and sustainable application in biofuels production: New Insight

One of the most sustainable processes for producing green fuels for industrial use is biomass to biofuels production. However, the high production cost of enzymes, the low functional stability of microbes and enzymes with low sugar, and fuel production are key challenges. Nanocatalyst implementation can be a potential strategy to resolve the technical hurdles of biomass-based biofuel production. Due to its distinct physicochemical features, graphene and its derivatives have recently attracted a lot of interest in microbial interaction and microbial based biomass to biofuels production technologies. The diverse physicochemical properties of graphene have created new prospects for biomass to biofuels manufacturing technology to become more cost-effective at the pilot stage. However, sustainable fabrication methods and scale-up process optimization are still not well explored for mass application trials. Therefore, the present review is based on developing a sustainable approach towards the green synthesis of graphene and its derivatives from paddy straw waste. Furthermore, potential opportunities for low-cost synthesis approaches of graphene and its derivatives from paddy straw and their sustainable application in economical biomass to biofuel production processes using paddy straw as a substrate itself, as well as current challenges and feasible future applications, have been discussed.