Feedstock Availability Research Articles

Analysis of location, feedstock availability, and economic impacts of potential mass timber processing facilities in Michigan

Mass timber, an engineered wood product, offers exceptional strength and versatility as a building material, is lightweight, which makes it easy to transport and assemble, is aesthetically appealing, and offers the potential to reduce GHG emissions. This study attempts to identify the potential locations for mass timber production in Michigan, estimate the available feedstock, and evaluate the economic impacts of mass timber production on the state's economy. Procurement zones for all softwood lumber producers in Michigan were identified and overlaid to create competition hotspots for the softwood sawtimber industry. Two potential locations were identified for mass timber production within the state. Forest Inventory and Analysis (FIA) data was used to estimate the annual sustainable availability of softwood (ASAW) for mass timber production. Finally, IMPLAN was used to assess the economic impacts associated with mass timber production in Michigan. We identified two sawmills for mass timber production and concluded that there is sufficient ASAW for mass timber production in these facilities. Producing 12,429 m3 of mass timber supports at least 93 total jobs (35 direct, 29 indirect, and 29 induced) with a total output of $12.52 million in Michigan's economy. Similarly, upgrading the capacity of existing sawmills to supply lumber for mass timber production will result in 34 additional jobs with a total output of $5.63 million.

Efficiency of engineered/modified biochars-based adsorbents for removal of pollutants from aquatic environment: A critical review

<p>Biochar shows substantial potential to contribute as a globally applicable adsorbent to decontaminate the water system due to the ample availability of feedstocks and valuable physio-chemical surface properties. This review aims to highlight the modification technologies of biochar, the alteration of characteristics after modification, and the eliminating of organic, inorganic, antibiotics and other pollutants from water systems by modified biochar. Alkali-acid modified and metal-loaded biochar possesses the superior surface functionality; these modifications are greatly favorable for improving the removal of different pollutants from water systems. Acidic- alkaline and metal treatment provides more diverse functional groups on biochar surfaces e.g. produces ample oxygenated functional groups, improve the surface attributes, generates high ratios of surface aromaticity and N/C, these changes provide the more adsorption sites and increase the removal of pollutants. This review also demonstrates the existing problems and future research direction related to modified biochars by acidic and alkaline agents as well as metal loaded composite in the remediation of the pollutants.</p>

A Review of Catalyst Modification and Process Factors in the Production of Light Olefins from Direct Crude Oil Catalytic Cracking

Petrochemical feedstocks are experiencing a fast growth in demand, which will further expand their market in the coming years. This is due to an increase in the demand for petrochemical-based materials that are used in households, hospitals, transportation, electronics, and telecommunications. Consequently, petrochemical industries rely heavily on olefins, namely propylene, ethylene, and butene, as fundamental components for their manufacturing processes. Presently, there is a growing interest among refineries in prioritising their operations towards the production of fuels, specifically gasoline, diesel, and light olefins. The cost-effectiveness and availability of petrochemical primary feedstocks, such as propylene and butene, can be enhanced through the direct conversion of crude oil into light olefins using fluid catalytic cracking (FCC). To achieve this objective, the FCC technology, process optimisation, and catalyst modifications may need to be redesigned. It is helpful to know that there are several documented methods of modifying traditional FCC catalysts’ physicochemical characteristics to enhance their selectivity toward light olefins’ production, since the direct cracking of crude oil to olefins is still in its infancy. Based on a review of the existing zeolite catalysts, this work focuses on the factors that need to be optimized and the approaches to modifying FCC catalysts to maximize light olefin production from crude oil conversion via FCC. Several viewpoints have been combined as a result of this research, and recommendations have been made for future work in the areas of optimising the yield of light olefins by engineering the pore structure of zeolite catalysts, reducing deactivation by adding dopants, and conducting technoeconomic analyses of direct crude oil cracking to produce light olefins.

Spatio-temporal feedstock availability and techno-economic constraints in the design and optimization of supply chains: The case of domestic woody biomass for biorefining

A future bio-based economy envisions the transformation of the petrochemical industry into using biomass such as wood (waste) as a major resource. The early-stage evaluation of a biorefinery project requires the optimization of the lay-out of the supply chain considering the spatio-temporal variability of the availability of feedstock and the techno-economical characteristics of the biorefinery process. Therefore, the presented methodology was developed combining three models: (1) a forest management and planning tool providing a detailed prediction on the wood resource availability as well as the harvested feedstock quantity and cost with respect to location and time, (2) a techno-economic assessment model of the biorefinery process (e.g., species-specific conditions, capacity, CAPEX, OPEX), and (3) a strategic supply chain optimization model combining the insights of (1) and (2) into a spatio-temporal explicit supply chain analysis.The developed methodology has been evaluated through a case-study on the emerging reductive catalytic fractionation (RCF) biorefining in the Flanders region (EU) and shows that the most economically interesting configuration is one large biorefinery with a yearly wood chip intake of 150 kton. The biorefinery location reflects the available feedstock distribution in Flanders and is suggested to be situated best in the most forested region. The proposed methodology proved to be dynamic and robust: (1) input data and technical calculations can easily be adapted or updated; (2) the methodology can be applied to a broad range of applications beyond the scope of the biorefinery, to different feedstock choices; (3) the impact of the biorefinery location on e.g. energy balance, CO2 emissions, and financial balance can be assessed.

Life cycle analysis (cost and environmental) of different renewable natural gas from waste procedures based on a multivariate decision-making approach: a comprehensive comparative analysis

Abstract This article presents a framework that focuses on structural considerations within gas networks to evaluate and rank various feasibility options for renewable natural gas (RNG) cases. Specifically, the analysis examines and compares a range of methods for producing RNG using natural gas from waste (NGFW), considering different types of waste as feedstock. To analyze and evaluate the different methodologies, the article uses a decision architecture based on life cycle analysis (cost and environmental). These tools are used to determine the most favorable path for the NGFW process. The preferred pathway is identified by considering a range of decision scenarios that take into account variables such as geographical conditions, the availability of various feedstocks and the different stakeholders’ priorities. The results show that according to the economically neutral scenarios and those that favor economic considerations, the pathway involving RNG generation from landfill gas coupled with a pressure swing adsorption (PSA) upgrading technology emerges as the optimum choice. Conversely, in a scenario where environmental sustainability is a priority, the process that emerges as most advantageous is the use of animal manure with the addition of a PSA upgrading unit. The designed structure can be adapted to different regions, each with its own unique geographical features and feedstock resources, and can be customized to meet the varying interests of stakeholders. Based on both parametric assessments and analytical interpretations, this article not only identifies optimal pathways but also provides a set of recommendations and strategies aimed at improving economic behavior.

Continuous reciprocating plate and packed bed multiphase reactors in biodiesel production: Advancements and challenges

Biodiesel, a renewable and environmentally friendly alternative to conventional fossil fuels, has gained significant attention over the last two decades. Continuous production of biodiesel offers efficiency, productivity, and scalability advantages. This paper provides a concise overview of continuous reactor systems for biodiesel production, focusing on two specific systems-the reciprocating plate reactor and the packed bed reactor-subjects of the authors' extensive research. A thorough comparison of these reactors, spanning biodiesel yield, reaction kinetics, and conversion efficiency, underscores their advantages. The reciprocating plate reactor demonstrates superior mixing characteristics, which improve mass transfer and reaction kinetics. Conversely, the packed bed reactor offers a higher catalyst-to-feedstock ratio and longer residence time, enhancing conversion efficiency. Both reactors exhibit favourable performance for continuous biodiesel production. This research can contribute to understanding continuous biodiesel production using innovative reactor designs. The comparative analysis between the reciprocating plate and packed bed reactors offers valuable insights for process optimization and reactor selection based on specific requirements such as feedstock availability, reaction kinetics, and economic considerations. These insights pave the way for the implementation of sustainable and efficient biodiesel production processes in the future.

Bio-Nanoparticles Mediated Transesterification of Algal Biomass for Biodiesel Production

Immense use of fossil fuels leads to various environmental issues, including greenhouse gas emissions, reduced oil reserves, increased energy costs, global climate changes, etc. These challenges can be tackled by using alternative renewable fuels such as biodiesel. Many studies reported that biodiesel production from microalgae biomass is an environment-friendly and energy-efficient approach, with significantly improved fuel quality in terms of density, calorific value and viscosity. Biodiesel is produced using the transesterification process and the most sustainable method is utilizing enzymes for transesterification. Lipase is an enzyme with excellent catalytic activity, specificity, enantio-selectivity, compatibility and stability and hence it is applied in microalgae biodiesel production. But, difficulty in enzymatic recovery, high enzyme cost and minimal reaction rate are some of its drawbacks that have to be addressed. In this aspect, the nanotechnological approach of lipase immobilization in producing microalgae biodiesel is a promising way to increase production yield and it is due to the adsorption efficiency, economic benefit, recyclability, crystallinity, durability, stability, environmental friendliness and catalytic performance of the bio-nanoparticles used. Through increasing post-harvest biomass yield, absorption of CO2 and photosynthesis in the photobioreactor, the use of nanoparticle immobilized lipase during the generation of biodiesel from microalgae has the potential to also remove feedstock availability constraints. This review article discusses the production of microalgae biodiesel, and effect of nanoparticles and immobilized lipase nanoparticles on biodiesel production. The advantages of using lipase nanoparticles and the challenges in introducing the immobilized lipase on nanoparticles in large-scale microalgae biodiesel production are also discussed. Reducing the water and land use, energy and nutrient footprints of integrated algae-based operations must be the main goal of larger-scale experiments as well as ongoing research and development in order to expedite the adoption of microalgae-based biodiesel production. Also, the cost-effectiveness and large-scale availability of nanoparticles and the impact of lipase nanoparticles on engine performance should be analyzed for commercialization of microalgae biodiesel.

A bibliometric analysis on sustainable aviation fuels: core technologies, challenges and trends

International initiatives such as the Carbon Offsetting and Reduction Scheme for International Aviation (CORSIA) have set goals for the complete de-carbonization of international aviation in this century. It motivated increasing numbers of Sustainable Aviation Fuel (SAF) research projects. The objective of this paper is to provide an overview on SAF research to point one to its foundations and recent advances. Data from the Web of Science database was collected and investigated. Important papers, cooperation networks, textual, productivity and trends analysis is provided. The most productive countries are in the global north, led by the United States and China. Big developing nations such as India and Brazil need to improve. The future of a sustainable aviation sector is heading in the direction of replacement of conventional jet fuel by synthetic hydrocarbon fuels by the end of the century. But there are still doubts about its viability both from the environmental and practical aspects, as there are concerns about feedstock availability and life cycle emissions. Fischer-Tropsch Synthesis, Alcohol-to-Jet and Hydroprocessing of Esters and Fatty Acids appear as the main SAF technologies for drop-in replacements. Longer term prospects are for the development of more efficient aircraft designed for renewables and non-hydrocarbon energy sources.

Synthesis and Optimisation of an Integrated Renewable Energy and Greenhouse Network

This paper presents a study on the synthesis and optimisation of a renewable energy and resource supply chain network (SCN) to satisfy agricultural greenhouse resource and energy demands. This is motivated by the high costs and emissions to run greenhouses due to the resources and energy required for optimal growth conditions. The investigation aims to contribute to the growing area of research on circular practices in the agricultural sector. The SCN includes biomass from agricultural waste transported to a utility hub, consisting of water and carbon dioxide (CO2) as resource supplies, as well as a boiler and steam turbine-generator and solar photovoltaic (PV), as energy conversion technologies. The resources and energy are distributed to greenhouses. The objectives are to minimise both the total annualised costs (TAC) and environmental impact (EI), calculated as CO2 emissions of the integrated network. Multi-periodicity accounts for the monthly and daily variation in constraints on the system, such as feedstock and solar radiation availability and energy limitations. The model is applied to a case study of an agro-industrial zone in Kwa-Zulu Natal (KZN) province, South Africa. The network meets greenhouse demands at a minimum TAC and EI of 8.052 ×106\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\ imes {10}^{6}$$\\end{document} R/y and 14,370 tCO2e/y, respectively. The biomass supply chain (BSC) contributes most significantly to the TAC at 43.7% while biomass combustion makes up 99.8% of the EI. Additional key results include bagasse and corn stover being selected as the only feedstocks and rail as the transport mode. The 26,560 MWh/y of electricity supplied to the greenhouses is made up by 71.4% from the boiler and turbine-generator with the remainder from solar PV. The potential of solar PV as a clean and low-cost energy source is demonstrated by the model selection at its full capacity. The study confirms that holistic modelling and optimisation of renewable energy SCNs for greenhouses is necessary to meet a trade-off between the network costs and CO2 emissions.

Life‐cycle analysis of sustainable aviation fuel production through catalytic hydrothermolysis

AbstractCatalytic hydrothermolysis (CH) is a sustainable aviation fuel (SAF) pathway that has been recently approved for use in aircraft fuel production. In alignment with broader sustainable aviation goals, SAF production through CH requires a quantitative assessment of carbon intensity (CI) impacts. In this study, a current‐day life‐cycle analysis (LCA) was performed on SAF produced via CH to determine the CI. Various oily feedstocks were considered, including vegetable oils (soybean, carinata, camelina and canola) and low‐burden oils and greases (corn oil, yellow grease and brown grease). Life‐cycle inventory data were collected on all processes within the CH LCA boundary: feedstock cultivation and/or collection, preprocessing, hydrothermal cleanup and CH, biocrude refining, fuel transportation and end use through combustion. Baseline results show that the CH‐produced SAF can be generated with CI reductions ranging from 48 to 82% compared with conventional jet fuel. Modest improvements to CI can be achieved through incremental changes to the brown grease CH process, such as relaxing the dewatering specification and implementing renewable natural gas and electricity, which could decrease the CI from 22.9 to 7.9 g CO2e/MJ. Total CH fuel production potential was also assessed on the basis of current or near‐future feedstock availability and CI. The total biofuel production potential of CH (SAF and renewable fuel co‐products) in the US sums to approximately 3487 million gallons per year, with 97% of these volumes having a CI below 50% of that for petroleum jet fuel. The study shows that from an LCA perspective, CH offers a viable SAF pathway that is comparable with existing SAF pathways like hydroprocessed esters and fatty acids.

Brønsted Acid-Mediated Multicomponent One-Pot Approach to Direct Construction of 4-Aryl-hydrocoumarin Derivatives.

The facile and efficient synthesis of a unique class of 4-aryl-hydrocoumarins having enormous applications in medicinal chemistry and natural products is presented. We have for the first time developed a Brønsted acid-catalyzed, multicomponent, one-pot approach for producing various 4-aryl-coumarin derivatives. The feedstock availability of these precursors allowed access to a wide range of 2-chromanone derivatives in good to excellent yields under mild conditions. The practicality of this protocol was justified by the synthesis of bioactive compounds, late-stage functionalization of natural products, and gram-scale synthesis.

Comparative techno-economic and life cycle analyses of synthetic “drop-in” fuel production from UK wet biomass

Renewable synthetic hydrocarbon “drop-in” fuels can help mitigate greenhouse gas emissions from transport, particularly in hard-to-abate sectors like freight and aviation. However, no study has extensively addressed the concerns over biomass availability, cost viability, and CO2 reduction feasibility that are associated with diverse production configurations and feedstocks. Here, we report detailed techno-economics and life cycle greenhouse gas emission assessments of drop-in fuel productions via hydrothermal liquefaction to assess their economic viabilities, CO2 mitigation potentials, and prospects for scale-up specifically within the UK context. Our approach integrates key production factors which include regional availability of main feedstocks (digestates, food waste, biodegradable municipal waste, and sewage sludge), plant configurations (centralised vs decentralised) and hydrogen sources (grey, blue, green). We demonstrated the economic trade-off between economy-of-scale and feedstock transport distances in the centralised/decentralised configurations, and also the economic and emissions trade-offs associated with the use of different hydrogen sources. We find that co-processing of different waste feedstocks is an important strategy to minimise fuel selling price by enabling better economy of scale and feedstock transport, resulting in a fuel selling price of £14.76 – 20.30 per GJ. The corresponding greenhouse gas emissions from the co-processing case vary from 11.4 to 24.9 kgCO2eqperGJ for 2021, based on the consequential life cycle assessment approach. Furthermore, we estimated that the utilisation of key UK wet feedstocks could only provide 4.5 % of current fuel consumptions and reduce emissions by 4.5–5.4 Mt CO2eq/year, which translates to 3.4–4.0 % reduction in the UK’s 2021 transport emissions.

Carbon-neutral aviation in Nigeria: Assessing the feasibility and impacts of sustainable aviation fuel adoption

This study investigates the feasibility and potential impacts of transitioning Nigeria's aviation industry towards carbon-neutral operations through the adoption of Sustainable Aviation Fuel (SAF). By examining Nigeria's aviation landscape, international efforts for carbon-neutral aviation, and factors such as feedstock availability, infrastructure, and economic considerations, the paper assesses the viability of SAF adoption. Environmental and economic benefits, including reduced carbon emissions, improved air quality, job creation, and economic diversification, are explored. Challenges such as regulatory hurdles, investment requirements, and public awareness are analyzed, with recommendations provided for policy support, industry collaboration, research and development, and public education campaigns. Despite the absence of specific SAF adoption case studies in Nigeria, insights from international experiences inform the recommendations. The findings suggest Nigeria's potential to lead in SAF adoption regionally, contributing to environmental sustainability and economic growth in the aviation sector, while also offering broader implications for the global industry's transition towards a more sustainable future.

Diverse sustainable methods for future jet engine

With global concerns over CO2 emissions and climate change, the aviation industry is investing in renewable fuels and sustainable engines. Bio-Synthetic Paraffinic Kerosene (Bio-SPK) and hydrogen are two significant biofuels that can replace fossil fuels in jet engines. Biofuel is considered a sustainable fuel; it is possible to replace fossil fuel in jet engines. Bio-SPK is an aviation fuel made from plant-derived lipids and processed to have similar properties to traditional jet fuel. It offers significant emissions savings compared to Jet-A1 but is not widely available due to high production costs and limited feedstock availability. While it can improve fuel efficiency and reduce emissions, it has lower energy density than conventional aviation fuels, potentially reducing aircraft range or payload capacity. Hydrogen produces only water but requires careful extraction or manufacturing. Green hydrogen is carbon-neutral, grey hydrogen generates carbon, and blue hydrogen captures and stores carbon. However, most hydrogen is currently generated as grey hydrogen, which offers less environmental benefit than directly burning fossil fuels. This work provides an overview of current and future sustainable jet engine technologies.

Electrochemical Wastewater Refining: A Vision for Circular Chemical Manufacturing.

Wastewater is an underleveraged resource; it contains pollutants that can be transformed into valuable high-purity products. Innovations in chemistry and chemical engineering will play critical roles in valorizing wastewater to remediate environmental pollution, provide equitable access to chemical resources and services, and secure critical materials from diminishing feedstock availability. This perspective envisions electrochemical wastewater refining─the use of electrochemical processes to tune and recover specific products from wastewaters─as the necessary framework to accelerate wastewater-based electrochemistry to widespread practice. We define and prescribe a use-informed approach that simultaneously serves specific wastewater-pollutant-product triads and uncovers a mechanistic understanding generalizable to broad use cases. We use this approach to evaluate research needs in specific case studies of electrocatalysis, stoichiometric electrochemical conversions, and electrochemical separations. Finally, we provide rationale and guidance for intentionally expanding the electrochemical wastewater refining product portfolio. Wastewater refining will require a coordinated effort from multiple expertise areas to meet the urgent need of extracting maximal value from complex, variable, diverse, and abundant wastewater resources.

Valorization of tropical fruit‐processing wastes and byproducts for biofuel production

AbstractGlobal energy demand is expanding due to an increasing population and the use of energy‐intensive technologies. Fossil‐based energy and transportation sectors have been blamed for greenhouse gas emissions and price fluctuations. Biofuel production has been suggested as a possible solution to this problem, despite the cost of production and difficulties with the availability of feedstocks, and the food versus energy debate, which is still a challenging issue. For many decades, researchers have been investigating how to valorize low‐cost and non‐edible biomass resources, including fruit‐processing waste and its byproducts, to produce various biofuels using innovative, cost‐effective, and green technologies to overcome these challenges. However, exhaustive studies and comprehensive and structured knowledge related to the biofuel production potential of fruit waste and byproducts are lacking because most of the research that has been done so far was specific to a single fruit, location, and method. As a result, this review paper emphasizes the evaluation of the physicochemical compositions of the wastes and byproducts derived from tropical fruit production and processing to determine their suitability in the production of different biofuels via various valorization techniques. The results of the review showed that fruit waste is a potential alternative raw material for producing different biofuels, like biodiesel, biogas, biohydrogen, and fuel pellets.

Biofuel technologies: Lessons learned and pathways to decarbonization

AbstractThis Opinion highlights several successful cases of biofuel technologies recently described by the IEA Bioenergy Intertask Report on Lessons Learned. The report discussed the potential of biofuels to contribute to a significant market supply, thus replacing fossil fuels and mitigating global warming, and it underscores the challenges in expanding biofuel production and replicating successful models between countries and regions. Based on the lessons learned from conventional, established technologies, the authors analyzed policies, feedstocks, products, technologies, economics, environmental concerns, social aspects, scalability, and ease of implementation and replication in different countries or regions. There are blending mandates in place around the world to foster the use of biofuels. Dependence on the availability and price fluctuations of crop feedstocks may limit biofuel production in certain circumstances. Legal restrictions on using food crops as feedstocks present obstacles to scaling up production. Temporary constraints related to feedstock costs and availability, as evidenced by changes and postponements of biofuel blending mandates in various countries (particularly during the COVID‐19 pandemic) also pose challenges. Technological hurdles exist for advanced biofuels that implicate premium pricing. Still, 2G ethanol from sugarcane meets very strict feedstock requirements with a carbon footprint so low that only electric vehicles charged in Norway could have life‐cycle GHG emissions at the same level as a 2G ethanol‐fueled combustion engine car. The authors evaluate whether and how much electrification could contribute to advance the decarbonization efforts in different countries. Drawing from these observations, the authors express their viewpoints to assist researchers and policymakers in the energy sector in formulating viable approaches to combat the climate crisis.

Industries Based on the Petrochemical Industry in Iraq-Plastics Industry as a Model

This study came to discuss the subject of industries dependent on petrochemical industries in Iraq (plastic as a model) during the period 2005–2020, and the study concluded that the plastic industries contribute to areas of advancement and progress and opportunities to deal efficiently with the challenges posed by the new variables, the most important of which is the information revolution. communications and trade liberalization, and this is what contributes to the competitiveness of these industries. And because the petrochemical industry in Iraq has an active role in establishing plastic industrial clusters and clusters of micro, small, and medium industries by providing the necessary feedstock for these industries in various fields and industrial sectors, such as plastic packaging industries and building, And the industries feeding the automobile industry, textiles, machinery and equipment manufacturing, and other industries, depending on the availability of various petrochemical products and feedstocks. The study recommended developing strategies and approving medium and long-term development plans through which results can be benefited from in the field of developing small, medium, and micro industries, as well as coordination and cooperation between agencies. , and the bodies concerned with the development of small and medium enterprises in the Arab countries, encouraging the establishment of projects for small and medium industries, reviewing policies and legislation, and updating them to ensure facilitating financing procedures and encouraging and stimulating the participation of the private sector in the development of small and medium enterprises in addition to the government sector.
 
 Paper type: Research paper

Introduction of sustainable food waste-derived biochar for phase change material assembly to enhance energy storage capacity and enable circular economy

Production and utilization of renewable materials receive considerable attention to achieve the goals of carbon neutrality and carbon peaking and create a sustainable society. Phase-change materials (PCMs) have emerged as a novel energy storage technology but usually suffer inherent insufficient thermal stability and liquid leakage, thereby requiring solid supporting materials. However, there are complications in the synthesis of PCM-supporting materials, including environmental issues. In this regard, upcycling biowaste into higher value carbon materials, inspired by the low cost and availability of feedstocks, is a promising strategy for dealing with challenges caused by waste and global climate change. Thus, we designed food waste-derived biochar-supported PCMs using a facile vacuum impregnation method to overcome these limitations. Porous biochar materials with a certain degree of graphitization, high specific surface area (SSA), (up to 1195 m2 g−1), and micro-/mesopore distribution were prepared from sustainable and commercially available food waste through carbonization and activation. They displayed greater carbon lattice expansion after undergoing KOH activation and being washed than that shown by carbon materials synthesized without activation. Thereby, the graphitic carbon materials presented high loading ratios and corresponding enthalpy values that were 243.9, 302, 346.9, and 251.4 % higher than those of the composites prepared without activation, encapsulated only 15 wt% of octadecane. Additionally, the composite PCMs exhibited high thermal stability without leakage above the melting temperature of pristine PCM. Textural properties, including the SSA, interconnected pores, activation, graphite-like characteristics, and intermolecular interactions between the composite constituents, were integral to the enhanced thermal performance of the as-synthesized composite PCMs. Furthermore, the composite demonstrated high durability, showing potential for thermal management, sustainable management of food waste, and mitigation of climate change.

Engineered Escherichia coli platforms for tyrosine-derivative production from phenylalanine using phenylalanine hydroxylase and tetrahydrobiopterin-regeneration system

BackgroundAromatic compounds derived from tyrosine are important and diverse chemicals that have industrial and commercial applications. Although these aromatic compounds can be obtained by extraction from natural producers, their growth is slow, and their content is low. To overcome these problems, many of them have been chemically synthesized from petroleum-based feedstocks. However, because of the environmental burden and depleting availability of feedstock, microbial cell factories are attracting much attention as sustainable and environmentally friendly processes.ResultsTo facilitate development of microbial cell factories for producing tyrosine derivatives, we developed simple and convenient tyrosine-producing Escherichia coli platforms with a bacterial phenylalanine hydroxylase, which converted phenylalanine to tyrosine with tetrahydromonapterin as a cofactor, using a synthetic biology approach. By introducing a tetrahydrobiopterin-regeneration system, the tyrosine titer of the plasmid-based engineered strain was 4.63 g/L in a medium supplemented with 5.00 g/L phenylalanine with a test tube. The strains were successfully used to produce industrially attractive compounds, such as tyrosol with a yield of 1.58 g/L by installing a tyrosol-producing module consisting of genes encoding tyrosine decarboxylase and tyramine oxidase on a plasmid. Gene integration into E. coli chromosomes has an advantage over the use of plasmids because it increases genetic stability without antibiotic feeding to the culture media and enables more flexible pathway engineering by accepting more plasmids with artificial pathway genes. Therefore, we constructed a plasmid-free tyrosine-producing platform by integrating five modules, comprising genes encoding the phenylalanine hydroxylase and tetrahydrobiopterin-regeneration system, into the chromosome. The platform strain could produce 1.04 g/L of 3,4-dihydroxyphenylalanine, a drug medicine, by installing a gene encoding tyrosine hydroxylase and the tetrahydrobiopterin-regeneration system on a plasmid. Moreover, by installing the tyrosol-producing module, tyrosol was produced with a yield of 1.28 g/L.ConclusionsWe developed novel E. coli platforms for producing tyrosine from phenylalanine at multi-gram-per-liter levels in test-tube cultivation. The platforms allowed development and evaluation of microbial cell factories installing various designed tyrosine-derivative biosynthetic pathways at multi-grams-per-liter levels in test tubes.