α-Ketoglutarate, a key intermediate in the TCA cycle, is crucial for amino acid synthesis and nitrogen transport. However, microbial engineering for α-ketoglutarate production is hindered by the intrinsic inefficiency of the metabolic network. In this study, transcription factor engineering was performed for the reconstruction of the metabolic network to boost α-ketoglutarate biosynthesis in Candida glabrata. Transcription factors GCR2 and RTG1 were first reinstalled to kick-start the glycolytic pathway and the TCA cycle, respectively, and then optimized to redistribute carbon flux between the two pathways. In addition, pyruvate carriers, MPC1 and MPC2, were introduced to facilitate the transport of cytoplasmic pyruvate to mitochondria, thereby feeding it into the TCA cycle for α-ketoglutarate biosynthesis. Next, transcription factor HAP4 was utilized to rewire the electron transport chain for improving redox balance and reducing overflow metabolism, thereby channeling more carbon flux to α-ketoglutarate production. Finally, the engineered strain C. glabrata KGA17 was capable of producing 210.4 g/L α-ketoglutarate in a 5-L bioreactor. This approach showed significant promise for developing efficient microbial cell factories for high-value chemical production.

Exploring the potential of advanced distillable solvents as efficient biomass pretreatment agents is critical for biorefineries, enhancing fermentable sugar yields while enabling solvent recovery and recycling without suffering significant losses. Here, we employ distillable amine-based solvents for pretreating a wide range of lignocellulosic feedstocks, aiming to facilitate the industrial release of fermentable sugars from diverse feedstocks through enzymatic hydrolysis. Twenty-two diverse feedstocks, sourced from different geographical regions and representing various biomass categories, were surveyed for chemical (mainly carbohydrates and lignin) and lignin (S, G, and H units) profiles. Several solvents, including ethanolamine, ethanolammonium acetate, butylamine, butylammonium acetate, and triethylamine, were tested for the pretreatment of eight selected biomasses. Among these solvents, butylamine emerged as the most effective due to its favorable sugar release, excellent solvent removal rate, and low boiling point, facilitating solvent recovery and recycling. Extending butylamine pretreatment to all 22 feedstocks demonstrated desirable sugar yields and highly efficient solvent removal in the majority of the biomass sources tested. Agricultural residues and their mixtures showed particularly favorable sugar release. Despite minimal changes in cellulose crystallinity, XRD characterization of sorghum, poplar, and pine before and after butylamine pretreatment showed a decrease in intensity and a slight shift of certain peaks, indicating alterations in cellulose structure. Fourier-transform infrared spectroscopy and thermogravimetric analysis analyses suggested disruption of biomass linkages in hemicellulose and lignin, enhancing enzymatic digestibility. Scale-up experiments of the mixed agricultural feedstocks in a 1 L Parr reactor achieved over 90% glucose liberation and more than 99% butylamine removal, highlighting the scalability of the method. The resulting hydrolysates supported the growth of diverse bacterial and fungal strains, indicating downstream compatibility with commercial fermentation processes. This study presents butylamine as an effective, recoverable pretreatment solvent for a wide range of lignocellulosic feedstocks, offering a promising solution to key biorefinery challenges. The demonstrated scalability and compatibility with various biomass types and blends underscore its potential for industrial application, advancing sustainable biofuel and biochemical production.

Anaerobic digestion (AD) is a key waste-to-energy technology that transforms organic waste into biogas, contributing to renewable energy generation and environmental protection. However, AD systems are vulnerable to the accumulation of volatile fatty acids (VFAs), which disrupt methanogenesis and reduce system stability. Using batch tests to determine methanation kinetics, followed by long-term semi-continuous operations with stepwise butyrate and propionate additions, this study assessed both short- and long-term impacts of nano magnetite (magnetic nanoparticles, MNPs; specifically Fe₃O₄ nanoparticles) supplementation. Results demonstrated that MNPs facilitated VFA degradation within the VFA-stressed systems by promoting direct interspecies electron transfer (DIET), reducing oxidative stress, and enhancing enzymatic activity. The supplementation of MNPs improved methane production under VFA-induced stress, increasing yields by up to 7.9% and 8.7% in butyrate- and propionate-stressed systems, respectively. Moreover, MNP additions shortened the lag phases of butyrate and propionate methanation by over 24% while stabilised microbial viability above 85% compared to 70.7% in untreated systems during long-term operations. Smaller MNPs (20 nm) improved solid reduction rates by 4.01–6.82% within the stressed systems, reducing slurry disposal costs. Economic and environmental analysis demonstrated potential electricity revenue increases of 8.78–12.79%, while environmental assessments showed reduced carbon emissions. These findings suggest that MNPs provide a scalable and effective solution for industrial AD plants, particularly those treating cellulose-rich waste and substrates leading to rapid VFA production (e.g., food waste). Importantly, this study bridges lab-scale experimentation with practical applications, using batch-derived thresholds to inform semi-continuous operations. Future research should focus on long-term environmental impacts and MNP recovery strategies to ensure sustainable deployment.

Livestock manure is a significant source of methane and nitrous oxide emissions, posing serious environmental challenges. While conventional management often exacerbates these impacts, thermochemical technologies such as pyrolysis, gasification, and hydrothermal processing offer promising pathways to convert manure into energy, biochar, and other valuable products within a circular bioeconomy. However, these processes can still emit carbon, limiting their environmental benefits. Integrating carbon capture technologies can mitigate these emissions, enabling net-negative outcomes and enhancing overall energy efficiency. This review explores the technical, economic, and environmental aspects of thermochemical manure valorization and emphasizes the transformative potential of coupling these processes with carbon capture. Combustion and co-firing reduce greenhouse gas emissions compared to fossil fuels, but are hindered by manure’s high ash and moisture content. Advanced thermochemical methods such as pyrolysis and gasification yield biochar, bio-oil, and syngas, yet face similar limitations. Hydrothermal processing, especially hydrothermal liquefaction and carbonization, effectively addresses moisture-related challenges and is particularly effective for pig manure. Catalytic gasification further improves conversion efficiency and product quality but remains costly due to expensive catalysts and process complexity. Evidence suggests that integrating carbon capture with thermochemical conversion offers a viable solution for achieving net-negative emissions. However, the widespread deployment of these integrated systems is constrained by high capital costs and infrastructure requirements. Realizing their full potential requires targeted investment, technological innovation, and robust policy support to overcome existing barriers and drive scalable, sustainable implementation.

Diesel fuels and jet fuels will dominate the future liquid fuel market. Biodiesel, renewable diesel, and sustainable aviation fuel are alternatives for carbon sequestration in the transportation sector. However, biodiesel and renewable diesel are unsuitable for use during cold winter seasons or as jet fuel. Moreover, renewable diesel and sustainable aviation fuel face challenges such as harsh operating conditions and high energy consumption. A groundbreaking production process was investigated to synthesize biokerosene using nonanoic acid, a major compound from lipid ozone cracking. Various alcohols can be used to tune the physicochemical properties of biokerosene. The synthesized biokerosene exhibited excellent low-temperature performance, characterized by cloud points ranging from −35 to −67 °C, making it suitable for winter-season diesel, kerosene, and jet fuels. In addition, the products showed several superior qualities, such as long oxidation stability for extended storage, high flash points for safe handling, and high cetane numbers. Emission analysis indicated that the presence of oxygen in the fuel molecules facilitates combustion and reduces hydrocarbon and CO emissions. Moreover, nitrogen oxide emissions, associated with a global warming potential about 300 times that of CO₂, were significantly lower than those of biodiesel and jet fuel. Preliminary techno-economic analysis showed that the production cost of biokerosene was approximately USD 0.97/kg. Preliminary life cycle assessment showed CO₂ emissions of about 20.6 g CO₂-eq/MJ, representing a 77% reduction in greenhouse gas emissions. These emissions can be further reduced to about 6 g CO₂-eq/MJ with clean electricity and low-carbon alcohol. In summary, the biokerosene synthesis presented in this study offers a sustainable and economical route for producing winter-season diesel and jet fuel.

The increasing reliance on commercial inorganic fertilizers has raised significant environmental and economic concerns, including soil degradation, nutrient leaching, water pollution, and greenhouse gas emissions. This review critically evaluates biomass-derived chars produced via thermochemical processes, i.e., pyrolysis, gasification, and hydrothermal carbonization, as potential alternatives to synthetic fertilizers. Among the three biomass-derived chars, biochar stands out as the most viable option for soil amendment due to its high stability, nutrient retention capacity, and long-term carbon sequestration benefits. Gasification char, despite its high porosity and adsorption capacity, often lacks bioavailable nutrients, whereas hydrochar, though rich in organic compounds, poses challenges related to stability and phytotoxicity. Biochar application has been shown to significantly reduce N2O emissions, enhance soil water retention, and mitigate nutrient runoff, offering clear environmental advantages over conventional fertilizers. Moreover, biochar has transitioned from an experimental soil amendment to a commercially available product with increasing adoption in agriculture worldwide, further reinforcing its practical viability. However, large-scale implementation still faces economic and logistical constraints, including high production costs, transportation inefficiencies, and regulatory uncertainties. Addressing these challenges through policy incentives such as subsidies and carbon credits can enhance the economic feasibility of biochar production and application. Given these findings, this review focuses on biochar as the most practical and sustainable alternative to commercial inorganic fertilizers.

Adipic acid (ADA) is a highly valuable industrial dicarboxylic acid used largely as a precursor of nylon 6,6 production. It is currently synthesized via a petrochemical process that accounts for over 80% of the global industrial N2O emissions. Biobased ADA offers a cleaner alternative but requires technological advancements in microbe and bioprocess performance to be commercially relevant. An in-depth feasibility analysis was conducted to evaluate two biobased pathways for the production of ADA, modeled as integrated sugarcane biorefineries in Aspen Plus®. The pathways examined were: (1) direct fermentation of sugars to ADA (S1-ADA) and (2) hydrogenation of biobased cis,cis-muconic acid to ADA (S2-ccMA-ADA). The impact of improvements to key bioprocess metrics (product yield, titer, and volumetric productivity) on the minimum selling price and greenhouse gas (GHG) emissions for both pathways was also evaluated in a full-factorial study. S1-ADA demonstrated the highest feasibility potential, achieving minimum selling prices and GHG emissions that were 33.3% and 78.7% lower, respectively, than those of fossil-based production. These results were obtained under conditions of optimal strain performance and bioprocess efficiencies. However, under comparable technological advancements, the best-achievable results for S2-ccMA-ADA indicated a green premium of 13.4% alongside a 68.4% reduction in emissions compared to the fossil-based product. Consequently, the direct biobased pathway (S1-ADA) shows greater potential to compete with and eventually replace its fossil-based counterpart once optimized. This finding highlights the need to prioritize S1-ADA for further biotechnological development.

Bio-based plastics, primarily polyhydroxyalkanoates (PHAs), offer a hopeful alternative to petroleum-derived plastics. Third-generation (3G; microalgae/cyanobacteria) biomass has gained significant importance due to its rapid biomass productivity and metabolic versatility. Microalgae can produce PHAs by utilizing CO2 and wastewater, establishing them as highly promising and eco-friendly systems for bioplastic production. This comprehensive review presents comprehensive insights into microalgae-PHA production, from optimization of physicochemical and cultural conditions to effective PHA purification processes. The critical review also examines the latest advancements in cultivation strategies, metabolic engineering, and bioreactor developments, which may lead to more sustainable and progressive microalgal-based bioplastic accumulation. The effectiveness of algae biomass generation for PHA accumulation through integrated wastewater treatment has been addressed. This review examines the role of mathematical modeling and emerging artificial intelligence in advancing algae-based PHA production processes. Finally, the review concludes with a discussion of the economic and social challenges, life cycle analysis, and prospects for research and development of advanced microalgal-derived bioplastics production and predictions of potential solutions for economically feasible and sustainable microalgae-based PHA production at the industrial scale.

We explore here, through reactive force field (ReaxFF) molecular dynamics simulations, oleic acid upgrading on beta zeolite (BEA) regulated with nine silica-to-aluminium ratios (SARs) to investigate their acid-catalyzed deoxygenation and coking susceptibility. The selected computational descriptors involved conversion, hydrodeoxygenation, and decarboxylation/decarbonylation selectivity, biofuels yield, and coke deposition characteristics. Simulations were validated by 20.3 SAR available experimental data and used for the systematic study. High deoxygenation selectivity was found to be related to the structural sensitivity of BEA(100) on the upgrading mechanism. ReaxFF simulations revealed that altering the Al-substitution could greatly promote biofuel formation. Specifically, SARs towards the mid-region (SAR 47) favored gasoline production, while 31 SAR exploited diesel-like hydrocarbons. An optimum ratio of 37.4 SAR achieved maximum oleic acid conversion (69.8%), with high yields of gasoline and diesel fuels (15.6 and 20.4 wt%, respectively) and moderate coking (8.6 wt%). Density functional theory screening of metallic dopants allowed investigating of their deoxygenation and coke susceptibility, obtaining that Cu-BEA structure favored the optimal carbon and O-moiety adsorption (-3.89 and -1.8 eV, respectively). Furthermore, the economic and environmental analysis showed that Cu-dopped BEA displayed the lowest market price and global warming potential (71 USD/kg and 2.8 kg CO2-eq/kg).

Biofuel Research Journal (BRJ) is a leading, peer-reviewed academic journal dedicated to publishing high-quality research on biofuels, bioproducts, and related biomass-derived materials and technologies.BRJ is an open-access online journal and completely free-of-charge,