Biofuels Bioproducts & Biorefining-Biofpr最新文献

Significant progress has recently been made in the biosynthesis of germacrene A using microbial cell factories. Germacrene A is a crucial precursor for the synthesis of anti-cancer active compounds. However, its hydrophobic characteristics lead to its aggregation in cell membranes and cause severe cytotoxicity. In the present study, we found that rhamnolipids (RLs), as toxicity antidotes, could promote the production of germacrene A. An optimal RLs concentration of 1.25 g L⁻¹ resulted in an increase of over 30% in the germacrene A titer at both shake flask and bioreactor scales. Mechanistic analysis showed that the addition of RLs could dramatically reduce aqueous-phase surface tension and cell surface hydrophobicity (CSH), and increase the cell membrane permeability. This, in turn, promoted an efficient transfer of germacrene A from cell membrane to extraction phases. The addition of RLs also increased the adenosine triphosphate (ATP) concentration and the nicotinamide adenine dinucleotide (NAD⁺/NADH) ratio, while reducing reactive oxygen species (ROS) levels. Correspondingly, gene transcripts for key enzymes associated with germacrene A biosynthesis, the respiratory chain, and ROS scavenging were upregulated significantly. This study provides an effective RLs-regulated fermentation method for the biosynthesis of hydrophobic natural products.

Recurring environmental challenges and the global energy crisis have led to intensified research on alternative energy sources. Hydrogen has emerged as a promising solution, produced through electrochemical, thermochemical, and biological methods. This study presents the advantages and disadvantages of these technologies. It also provides pertinent data on hydrogen production, identifying world-leading countries in hydrogen production, such as the USA, Japan, and China, and the government policies that they have adopted. It reports market trends such as hydrogen synthesis by water electrolysis, the high cost of the electrolyzers used, and incentives for the carbon market to become competitive with other alternative energy sources. It also highlights startups from around the world that are developing innovative methodologies for producing hydrogen. The study concludes that integrating hydrogen production concepts with social, environmental, and industry interests is essential.

The efficient use of vinasse, the primary byproduct of sugarcane ethanol production, is important for the economic and environmental sustainability of the industry. Few studies have quantified the soil health response to long-term vinasse application, even though this byproduct is generally applied as a potassium (K) source in sugarcane fields. The Soil Management Assessment Framework (SMAF) was used to assess the integrated soil health response in soils with contrasting textures. Chemical, physical, and biological indicators were selected, measured, and integrated into a soil health index for clay- and sandy-textured soils in Brazil. Overall, the application of vinasse improved soil health components in both soils. The results showed that the benefits of vinasse go beyond increasing the K content. Vinasse application showed increased soil organic carbon content, nutrient recycling, and soil physical quality. The long-term application of vinasse increased the soil health from 49% to 62% in the clayey soil and from 43% to 61% in the sandy clay soil. The findings therefore revealed the potential of vinasse application to reduce the need for synthetic fertilizer and promote the circular economy and soil health regardless of soil type. This study verifies that the long-term application of vinasse to sandy- and clay-texture soils in Brazil has both economic and environmental benefits because it recycles an important ethanol byproduct and enhances soil health.

Sugarcane wax is a co-product with strong potential. It contains several bioactive components that can be used for pharmaceutical and cosmetic purposes. It is also considered a substitute for leading vegetable waxes in the international market. The extraction and refining technologies that have been reported in Cuba do not always manage to deliver a wax that meets the quality demanded by the market. This problem can be solved with the development of innovative technologies that allow increasing yields, higher quality, and the reduction of costs. The main objective of this work was to achieve a validated model of the Cuban sugarcane wax-refining process using the SuperPro Designer simulator, and to evaluate the alternatives in order to reduce consumption rates and increase stability in the final product quality, as customers demand. The model successfully replicated 39 out of 44 variables used for process validation, with values falling within the historical range of the process. Deviations from historical values were less than 4 percentage points. Among the proposed modifications, the second of the two alternatives proposed resulted in lower consumption rates and more consistent quality of refined wax.

Cyanobacteria, renowned for their nitrogen-fixing characteristics, are important for sustainable biomanufacturing and agricultural innovation. This review explores the synergy between cyanobacteria and nitrogen fixation, highlighting their potential to revolutionize biobased compound production and reduce the ecological impact of traditional nitrogen sources. It focuses on genetic enhancements and synthetic biology techniques, which transform these microorganisms into sustainable nitrogen providers. Current applications range from agricultural enhancement to cutting-edge biotechnology, highlighting the important consequences of cyanobacterial nitrogen fixation. Challenges persist, however, requiring a meticulous analysis of ecological, regulatory, and scalability concerns. The untapped potential of cyanobacteria in nitrogen fixation promises a significant shift in biomanufacturing and environmental stewardship. The aim of this article is to inspire high-impact research and transformative applications in biotechnology and sustainability.

The use of agricultural biomass fibers, specifically palm kernel shell (PKS), has significant potential to enhance biodiesel production. This approach overcomes economic barriers and contributes to sustainability by repurposing agricultural biomass. This study explores the effectiveness of PKS as a cost-effective and sustainable catalyst support. Palm kernel shell was chosen due to its high carbon content, low ash presence, and abundance as a byproduct in the palm oil industry, making it an economically viable and environmentally friendly option. In this study, an optimized activated carbon from PKS biomass was fabricated as catalyst support to enhance biodiesel production efficiency. Using response surface methodology (RSM), the PKS was impregnated with phosphoric acid and synthesized at various acid concentrations, impregnation times, and activation times to enhance porosity for catalytic support capabilities. The experimental design included a central composite design (CCD) to vary these factors systematically and determine their optimal levels. Scanning electron microscopy (SEM) and Brunauer–Emmett–Teller (BET) analysis revealed significant development of porosity, affirming the efficient activation process. Energy dispersive X-ray (EDX) analysis confirmed phosphorus incorporation during activation, indicating the formation of an intricate pore structure. Fourier transform infrared (FTIR) spectroscopy highlighted the presence of functional groups pertinent to the biodiesel reaction process. The transesterification process employing PKS as a catalyst with different biobased feedstocks, such as waste frying oils from corn, palm, and sunflower, led to biodiesel yields of varying efficiencies. Notably, corn oil had the highest yield at 94.92%. This study highlights the potential of PKS as a biobased catalyst support and contributes to the broader biorefinery concept by integrating biomass utilization into renewable fuel production.

Biochar, a carbon-rich material derived from organic biomass under low-O₂ conditions, has gained importance due to its role in mitigating climate change by sequestering carbon. It can be used as an alternative energy source and has applications in nutrient cycling, improving soil properties, and removing heavy metals and organic pollutants, thus contributing to sustainable agriculture and environmental remediation. In the face of alarming climate change, rising energy demand, and increasing pollution, the integration of biochar production into biorefineries is an important strategy to promote a sustainable and circular economy. Adopting a holistic approach to biomass utilization by developing strategies to maximize biochar production along with the production of other value-added products while improving its quality can increase biorefineries' overall sustainability and efficiency. Fine-tuning the biorefinery process from feedstock selection to co-production, optimizing pyrolysis conditions, and integrating it with other technologies can help to achieve this goal while generating zero waste and diversified revenues. With the biochar market growing exponentially, further research into the long-term impact of biochar on carbon sequestration and its application in the environment is the next step.

This study reports the use of deep-eutectic-solvent- (DES-) assisted hydrothermal carbonization (HTC) to disrupt the floc structure of sewage sludge (SS) for deep carbonization, with the resulting hydrochars employed in the preparation of formaldehyde-free plywood bioadhesives. Sewage-sludge-based bioadhesive exhibits an excellent wet shear strength, complying with the requirements of Chinese national standard GB/T 9846–2015 (≥0.7 MPa). The molecular weight of proteins and the formation of covalent bonds via dehydration have a notable role in improving adhesive performance (wet shear strength). The Maillard reaction is a key reaction during HTC to destroy the secondary structure of proteins, resulting in the release of more OH and NH₂. The main reaction during hot-press treatment is dehydration. High ash content in bioadhesives improves flame resistance potential, particularly on addition of DES. A plausible mechanism is proposed for this. This work provides a new method for the valorization of SS-derived hydrochars and contributes to the development of greener formaldehyde-free wood bioadhesives.

Shell-derived materials are promising heterogeneous catalysts for biodiesel production due to their nontoxic and renewable nature, but they have the disadvantage of being highly leachable. To overcome this issue, Ca(OCH₃)₂ formed through the reaction of CaO with methanol, and supported in turn on Al₂O₃ is proposed as a catalytic system for the transesterification of fresh soybean oil and waste cooking oil (WCO). First, catalysts with several Al/Ca molar ratios (0.2, 0.5, and 0.8-AC), as well as their precursors (CaO and Al₂O₃) alone, were tested at 60 °C, catalyst loading 6% wt, methanol-to-oil molar ratio (MOR) 10, for 1 h for fresh oil, and 3 h for WCO. The 0.2-AC catalyst generated the highest biodiesel yield for both oils. The optimum operating conditions for WCO transesterification, determined by using a univariable approach, were 60 °C, 9 wt% catalyst loading, MOR of 12.5, and a reaction time of 3 h. These improved conditions led to yields higher than 90% for pure CaO and the 0.2, 0.5, and 0.8-AC catalysts. The density, kinematic viscosity, and refractive index of the biodiesel obtained were measured.

Lignin, the main source of renewable aromatics, has a complex structure, high polydispersity, and low reactivity, which hinders its large-scale use. This study aims to improve lignin reactivity through heat treatment combined with fractionation by organic solvents or the pH effect. Heat treatment of commercial hardwood black liquor was performed at 225 °C for 150 min. The samples were then fractionated either by using organic solvents (ethyl acetate, ethanol, methanol, and acetone) or by lowering pH using hydrochloric acid (HCl) (pH values 1, 3, 5, 7, and 9). The fractionation was carried out in one step and in sequential mode. The fractionated samples were characterized chemically by the content of acid-soluble and acid-insoluble lignin, carbohydrates, ash, inorganic compounds (metals), elemental analysis, and by pyrolysis-gas chromatography–mass spectrometry (Py-GC–MS). The highest mass yields were obtained using the one-step mode for both fractionations, with yields as high as 53.3% for organic solvents and 47.8% for the pH effect. Solvent fractionation reduced ash content by up to 75.4% and increased calorific value, carbon content, and total lignin content. Fractionation by pH effect showed an ash reduction of up to 55.9% and an increase in calorific value and carbon content of up to 8.7 MJ kg⁻¹ and 49.7%, respectively. The Hansen solubility parameters were also calculated to address lignin's solubility in each of the tested solvents. These findings indicate that combining heat treatment and fractionation techniques improves lignin's chemical properties significantly, making it a more viable raw material for industrial use. This approach supports the circular economy by transforming lignin into a high-value product, thereby promoting sustainable and efficient resource utilization across industries.