ACS Sustainable Resource Management最新文献

Non-isothermal kinetic assessment of seaweed biomass (e.g., Solieria filiformis) was studied using three different iso-conversional kinetic methods to calculate activation energy. S. filiformis biomass decomposed in three stages: Zone I (300–457 K), Zone II (458–845 K), and Zone III (846–1150 K), respectively. Average activation energies for Zone I, Zone II, and Zone III were observed in the ranges of 73–77, 281–366, and 441–448 kJ/mol with Kissinger–Akahira–Sunose (KAS), Flynn–Wall–Ozawa (FWO), and Starink methods, respectively. In this study, three blends of S. filiformis biomass with poly(vinyl chloride) (PVC) waste in 30:70 w/w, 50:50 w/w, and 70:30 w/w were prepared and screened based on thermal decomposition temperature to understand the effect of co-pyrolysis. Co-pyrolysis has shifted the decomposition temperature of PVC from 572 to 560 K (12 K) in a 70:30 w/w (biomass/PVC) blend and found suitable for the co-pyrolysis. In this co-pyrolysis blend, mass fragments of hydrocarbons and volatile components of waste PVC were monitored by a thermogravimetric analysis-mass spectrometry (TGA-MS) instrument. Results of this study revealed that emission of hazardous (HCl, m/z = 36; benzene, m/z = 78) components was decreased significantly in the presence of biomass, while commercially important hydrogen (H₂) and methane (CH₄) gas evolution was enhanced.

Investigating avenues for sustainable energy, this study assesses the role of deep eutectic solvents (DES) in the pretreatment of corn straw to boost hydrogen output through dark fermentation. We systematically applied six DES formulations to modify the structural and compositional characteristics of corn straw. The treatments aimed to optimize enzymatic accessibility by increasing the biomass’s surface area and crystallinity and decreasing its lignin and hemicellulose contents. The enzymatic hydrolysis efficiencies for choline chloride (ChCl)/oxalic acid (OA) and ChCl/monoethanolamine (MEA), under pretreatment conditions of 100 °C for 2 h, reached 0.375 and 0.289 g/g, respectively─over four and three times higher than that of the untreated corn straw. Correspondingly, these treatments also led to significantly enhanced hydrogen yields of 123.52 and 117.06 mL/g, compared to only 0.62 mL/g from the untreated sample. This study explores the impact of different functional groups of hydrogen bond donors (HBD) in DES on the effectiveness of corn straw pretreatment. It elucidates the changes in the composition and morphology of biomass during the process and investigates the mechanisms by which these alterations influence enzymatic hydrolysis and H₂ production.

Sugarcane bagasse (SCB), the solid residue produced by the sugar industry, is a potential substrate for the fermentative synthesis of value-added products. The present study has reported statistical optimization of the enzymatic saccharification of SCB and its intensification using 35 kHz ultrasound. Initial dilute acid and alkali pretreatment of 100 g of raw SCB yielded 43.7 g of cellulose-rich SCB (or ApSCB). Statistical optimization of enzymatic saccharification resulted in a total reducing sugar (TRS) yield of 388 mg/g ApSCB (16.9 g) with a glucose content of 330 mg/g ApSCB (14.4 g). In ultrasound-assisted saccharification with a 10% duty cycle, the TRS yield was enhanced by 1.7× to 660 mg/g ApSCB (28.9 g) with 85% (24.5 g) glucose content. Analysis of the changes induced by sonication in the secondary structure of enzymes revealed the unfolding of the enzyme structure with the rise in random coil content. The random coil content of enzymes increased from 35.72 to 45.16, with a reduction in the α-helix content from 43.71 to 34.16%. Simultaneously, the molecular docking of the enzyme–ligand complex was carried out for both enzymes, viz., the combinations of endoglucanase–cellulose (binding energy = −4.16 kcal/mol) and β-glucosidase–cellobiose (binding energy = −7.42 kcal/mol). The molecular docking revealed that residues involved in the cellulose and cellobiose binding sites were in random coil regions. Thus, sonication resulted in opening the binding sites of enzymes with easier access to the substrate, which enhanced the enzyme activities with a higher TRS yield.

Agave residues from the tequila industry contain branched inulin (agavin), and this structure limits its efficient utilization. Hence, inulin hydrolysis has been proposed as a strategy for valorizing agave residues. This contribution describes the utilization of recombinant inulinase (rInu-ISO3), an enzyme, to degrade agavin derived from agave residues. The hydrolysis products are used by Cupriavidus necator H16 to simultaneously produce polyhydroxybutyrate (PHB). Within this approach and in line with process intensification principles to increase energy and cost efficiency, two strategies were assessed for the saccharification and fermentation stages, namely, Simultaneous Saccharification and Fermentation (SSF) and Hybrid Hydrolysis and Fermentation (HHF). A maximum biomass titter of 6.5 g L^–1 with a PHB accumulation of 58 wt % was achieved after 5 min of hydrolysis reaction using an HHF strategy, whereas the SSF method yielded 5.1 g L^–1 of biomass with a polymer content of 55 wt %. The obtained materials were characterized by using proton nuclear magnetic resonance (¹H NMR) and size exclusion chromatography (SEC), which confirms the presence of PHB with a number-average molar mass (M_n) of 537 kDa and a dispersity (D̵) value of 2.4. In comparison with similar reported systems focusing on the valorization of inulin, the results of these current research efforts may represent a milestone to demonstrate the feasibility of using the rInu-ISO3 enzyme to produce chemicals of added value from waste biomass while offering an alternative to alleviate the ongoing environmental crisis derived from petroleum.

Agavin, a complex carbohydrate, is hydrolyzed with an in-house enzyme, rInu-ISO3, to produce bioplastics. This process provides a sustainable alternative to petroleum-based plastics, while valorizing agave residues and contributing to reduced environmental pollution.

The use of biowaste in three-dimensional (3D) printing for pharmaceutical and biomedical applications provides a promising approach for waste valorization and sustainable manufacturing. Biowaste consists mainly of organic materials from municipal, agricultural, and industrial sources and offers a diverse range of resources for developing alternatives that are more eco-friendly than traditional materials. The potential of biowaste-derived materials in 3D printing technologies is discussed, highlighting their applications in drug delivery systems, tissue engineering scaffolds, and medical devices. Different types of biowastes, such as eggshells, marine eel fish skin, sheep wool, and lignocellulosic agricultural waste, have been successfully processed and incorporated into 3D printing processes, demonstrating their feasibility as sustainable raw materials. The unique properties of biowaste-derived materials, such as biocompatibility, biodegradability, and renewability, make them attractive candidates for pharmaceutical and biomedical applications. However, challenges such as mechanical properties, material consistency, and regulatory hurdles must be addressed to use biowaste in 3D printing. Future perspectives highlight the integration of biowaste-derived materials with advanced technologies, such as four-dimensional (4D) printing and smart materials, which open new avenues for personalized healthcare solutions. Comprehensive exploration of biowaste valorization has been carried out for 3D printing applications, especially in the pharmaceutical and biomedical fields, highlighting an innovative approach to sustainable materials development in these fields. Continued research and collaboration between engineers, materials scientists, and biological scientists are crucial for overcoming the current limitations and realizing the full potential of biowaste use in 3D printing for pharmaceutical and biomedical applications.

Holocellulose, a key biomass material, holds broad potential in the energy, materials, and chemical industries. Here, we developed a novel method for its extraction by selectively removing lignin using Gemini imidazole salts and surfactants [C_n-m-C_nim]Br₂ (m = 1, 2, 4, 6; n = 1, 2, 4, 8, 12, 14, 16) in ethylene glycol (EG). Key factors, such as reagent concentration, alkyl/spacer chain length, pretreatment time/temperature, solid–liquid ratio, and straw particle size, were optimized. Under optimal conditions ([C₁-2-C₁im]Br₂/EG, 100 °C, 3 h), cellulose and hemicellulose retention reached 94.2 and 88.4%, respectively, with 73.1% lignin removal. The pretreatment solution remained effective for five reuse cycles. FT-IR, ¹³CNMR, TG, XRD, and SEM analyses confirmed the holocellulose’s composition and morphology, and the delignification mechanism was elucidated.

After a period of sealing the cellar for Maotai-flavor liquor brewing, the sealing mud can no longer be used due to the accumulation of organics and nitrogen. In this study, a method for restoring waste mud driven by the cycle of indigenous iron was proposed, in which Fe(II) was oxidized to Fe(OH)₃ after short-term aeration, and then dissimilatory Fe(OH)₃ reduction coupled with organics and ammonium oxidation (Feammox) occurred under anoxic conditions. The results showed that the aeration group achieved 60.0% organic matter removal and 53.6% nitrogen removal, which were significantly higher than those of the control group (p < 0.05). Microbial analysis showed that intermittent aeration enriched iron-reducing bacteria, removing ammonium via Feammox as well as microorganisms degrading organics, while ammonium-oxidizing bacteria and anaerobic ammonium oxidation (Anammox) microorganisms were undetected, ruling out the contribution of nitrification and Anammox to nitrogen removal. Metagenomic analysis further demonstrated that the genes related to the iron cycle, organic degradation, and nitrogen removal were significantly increased in the aeration group. After the treatment, the mud had no odor, and the viscosity was recovered, achieving a remediation effect. This method provides an economical and efficient solution for waste containing organics and nitrogen.

Low carbon fuel policies such as the U.S. Renewable Fuel Standard (RFS), Canada Clean Fuel Regulations (CFR), and California Low Carbon Fuel Standard (LCFS) as well as the 45Z tax credit are intended to reduce greenhouse gas (GHG) emissions from transportation. Cellulosic feedstocks, optimized biorefineries, and favorable farming locations can significantly reduce biofuel carbon intensity (CI). Despite advances in field-to-fuel GHG monitoring and flexibility in resource allocation within biorefineries (e.g., governing net electricity production), rigid CI accounting procedures in current policies may limit CI responsiveness across candidate sites and processing facilities. This work examines a hypothetical biomass-to-sustainable aviation fuel (SAF) pathway using miscanthus and alcohol-to-jet (i) to demonstrate how GHG accounting requirements drive estimates of biofuel CIs and (ii) to explore potential CI and financial implications of scenario-specific life cycle assessment (LCA). Results demonstrate that GHG accounting using the CFR/LCFS can reasonably account for distinct levels of net electricity production by a biorefinery, but only the CFR yields similar CI sensitivity to spatially explicit factors (feedstock CI, grid electricity CI) as scenario-specific LCA: most GHG accounting frameworks do not capture CI variation across candidate sites in the United States. Ultimately, this work demonstrates the importance of LCA methodological specifications in low carbon fuel policies and tax credits.

Lignin, a promising precursor of low-cost carbon fibers, faces a significant challenge for environmentally friendly processing: Kraft lignin’s insolubility in water. To address this issue, the enzyme Bilirubin oxidase from Bacillus pumilus has been employed to modify lignin’s solubility. This treatment results in aqueous solubilization and condensation, evidenced by a nearly 5-fold increase in molecular weight. Crucially, the carbon content after pyrolysis remains intact, which is essential for carbon fiber production. Consequently, this modified lignin is well-suited for carbon fiber manufacturing. In this study, a solution of the treated lignin and alginate, acting as a plasticizer, was wet-spun into calcium chloride and ammonium persulfate baths, producing fibers composed entirely of biopolymers. Following carbonization, without the need for a stabilization step, the resulting fibers exhibited mechanical properties that compared with the properties of fibers produced in organic solvents or with oil-based plasticizers. The optimal mechanical properties were achieved with 67% lignin content, yielding a Young’s modulus of 39 ± 6 GPa and a tensile strength of 457 ± 54 MPa. These findings demonstrate the successful development of 100% bio-sourced fibers under environmentally friendly conditions.

Chitosan films are emerging as a magnificent alternative to powdered photocatalysts but suffer from issues such as poor mechanical stability and loss of photocatalytic activity. These issues hinder the aspired green rationale for choosing these films over powdered materials. Herein, we have demonstrated how a simple and green Deep Eutectic Solvent (DES) based modification can resolve these problems. The DES, composed of ZnCl₂ and urea, induced significant structural and morphological changes on the CN surface, which led to a massive rise in the mechanical strength of the films. Particularly in the CN-6.6 formulation, DES adhered to a unique dendrite arrangement, which enhanced the adsorption capacity of the surface towards pollutants. Besides, DES also affected the electronic properties of the CN surface, which enabled the latter to showcase significant photocatalytic activity. The combined impact of enhanced adsorption and excellent charge transfer with the help of electronic coordination between CN-6.6 film surface and g-C₃N₄ ensured that CN-g-C₃N₄-6.6 film not just retains but also exceeds the efficiency of g-C₃N₄ for all the target pollutants, i.e., methylene blue, tetracycline hydrochloride, and rhodamine B. Mechanistically, the enhanced photocatalytic activity after DES inclusion was a consequence of the direct coordination between DES and photocatalyst due to in situ formation of semiconducting entities, which enhanced the charge separation. Hence, for the first time, we are reporting the application of the solvent as a direct and functional constituent of the photocatalytic pathway. These remarkable structural, morphological, and electronic effects embarked by DES have resolved two of the most notorious problems persisting with CN films in an entirely green framework.