Journal of Bioresources and Bioproducts最新文献

Passive cooling strategy shows great potential in mitigating global warming and reducing energy consumption. Because of the high emissivity in the atmospheric transparency window (λ ≈ 8–13 µm), cellulose is considered as a good candidate for radiative cooling. However, traditional cellulose coolers generally show poor solar reflection and can be polluted by dust outside, thereby resulting in poor daytime cooling efficiency. To address these drawbacks, we developed sustainable cellulose nanowhiskers (CNWs)/ZnO composite aerogel films with favorable optical performance, mechanical robustness, and self-cleaning function for efficient daytime radiative cooling, which can be achieved via freeze casting and hot-pressing process. Due to formation of multi-level porous structure and chemical bonds (Si-O-C/Si-O-Si), such aerogel film exhibited high solar reflectance (97%) and high infrared emittance (92.5%). It achieved a sub-ambient temperature drop of 6.9 °C under direct sunlight in hot weather. Most importantly, the surface roughness and low surface energy enable cellulose aerogel film hydrophobicity (contact angle = 133°), thereby resulting in an anti-dust function. This work provides insight into the design of sustainable thermal regulating materials to realize carbon neutrality.

Conventional plastics exacerbate climate change by generating substantial amounts of greenhouse gases and solid wastes throughout their lifecycle. To address the environmental and economic challenges associated with petroleum-based plastics, bioplastics have emerged as a viable alternative. Bioplastics are a type of plastic that are either biobased, biodegradable, or both. Due to their biodegradability and renewability, bioplastics are established as earth-friendly materials that can replace nonrenewable plastics. However, early bioplastic development has been hindered by higher production costs and inferior mechanical and barrier properties compared to conventional plastics. Nevertheless, studies have shown that the addition of additives and fillers can enhance bioplastic properties. Recent advancements in bioplastics have incorporated special additives like antibacterial, antifungal, and antioxidant agents, offering added values and unique properties for specific applications in various sectors. For instance, integrating antibacterial additives into bioplastics enables the creation of active food packaging, extending the shelf-life of food by inhibiting spoilage-causing bacteria and microorganisms. Moreover, bioplastics with antioxidant additives can be applied in wound dressings, accelerating wound healing by preventing oxidative damage to cells and tissues. These innovative bioplastic developments offer promising opportunities for developing sustainable and practical solutions in various fields. Within this review are two main focuses: an outline of the bioplastic classifications to understand how they fit in as the coveted conventional plastics substitute and an overview of the recent bioplastic innovations in the antibacterial, antifungal, and antioxidant applications. We cover the use of different polymers and additives, presenting the findings and potential applications within the last decade. Although current research primarily focuses on food packaging and biomedicine, the exploration of bioplastics with specialized properties is still in its early stages, offering a wide range of undiscovered opportunities.

Carbothermal reduction using biochar (BC) is a green and effective method of synthesizing BC-supported nanoscale zero-valent iron (nanoFe⁰) composites. However, the effect of BC surface area on the structure, distribution, and performance such as the heavy metal uptake capacity of nanoFe⁰ particles remains unclear. Soybean stover-based BCs with different surface areas (1.7 − 1 472 m²/g) were prepared in this study. They have been used for in-situ synthesis BCs-supported nanoFe⁰ particles through carbothermal reduction of ferrous chloride. The BCs-supported nanoFe⁰ particles were found to be covered with graphene shells and dispersed onto BC surfaces, forming the BC-supported graphene-encapsulated nanoFe⁰ (BC-G@Fe⁰) composite. These graphene shells covering the nanoFe⁰ particles were formed because of gaseous carbon evolved from biomass carbonization reacting with iron oxides/iron salts. Increasing BC surface area decreased the average diameters of nanoFe⁰ particles, indicating a higher BC surface area alleviated the aggregation of nanoFe⁰ particles, which resulted in higher heavy metal uptake capacity. At the optimized condition, BC-G@Fe⁰ composite exhibited uptake capacities of 124.4, 121.8, 254.5, and 48.0 mg/g for Cu²⁺, Pb²⁺, Ag⁺, and As³⁺, respectively (pH 5, 25 °C). Moreover, the BC-G@Fe⁰ composite also demonstrated high stability for Cu²⁺ removal from the fixed-bed continuous flow, in which 1 g of BC-G@Fe⁰ can work for 120 h in a 4 mg/L Cu²⁺ flow continually and clean 28.6 L Cu²⁺ contaminated water. Furthermore, the BC-G@Fe⁰ composite can effectively immobilize the bioavailable As³⁺ from the contaminated soil, i.e., 5% (w) of BC-G@Fe⁰ composite addition can immobilize up to 92.2% bioavailable As³⁺ from the contaminated soil.

Hydrogen as a clean energy carrier has attracted great interests world-wide for substitution of fossil fuels and for abatement of the climate change concerns. However, green hydrogen from renewable resources is less than 0.1% at present in the world hydrogen production and this is largely from water electrolysis which is beneficial only when renewable electricity is used. Hydrogen production from diverse renewable resources is desirable. This review presents recent advances in hydrogen production from woody biomass through biomass steam gasification, producer gas processing and H₂/CO₂ separation. The producer gas processing includes steam-methane reforming (SMR) and water-gas shift (WGS) reactions to convert CH₄ and CO in the producer gas to H₂ and CO₂. The H₂ storage discussed using liquid carrier through hydrogenation is also discussed. The CO₂ capture prior to the SMR is investigated to enhance H₂ yield in the SMR and the WGS reactions.

Carbon dots (CDs) have gained unprecedented attention as a novel luminescent zero-dimensional carbon nanomaterial owing to their diverse industrial applications. Herein, we reported the sustainable synthesis of fluorescent CDs from papaya peel waste, acting as a natural carbon originator. As-prepared CDs and reduced graphene oxide (RGO) were fabricated in the composites through a facile one-step hydrothermal method. Synthesized RGO/CDs (RC) nanocomposites were characterized using spectroscopic, diffraction, and electron-microscopic techniques. Nanocomposites with variable RGO to CD mass ratios were tested for photodegradation of textile dye methylene blue (MB). The highest photocatalytic activity (degradation efficiency of 87% in 135 min) was obtained in the nanocomposite containing a 2꞉1 mass ratio (RC2). The RGO sheets in the nanocomposite acted as media for electron acceptors, promoting the fast transfer and separation of photoinduced electrons during CDs excitation, thus preventing the recombination of the electron and holes. Based on the agar well diffusion assay, the nanocomposites exhibited excellent antibacterial activity than other tested materials against Bacillus subtilis (Gram-positive) and Pseudomonas aeruginosa (Gram-negative) bacterium. The largest inhibition zone area (22 mm), i.e., the highest antimicrobial activity, was obtained in the nanocomposite tested against Gram-positive strains. Taken together, the synergistic effect of RGO and CDs enhanced the photocatalytic and antibacterial performance of synthesized nanocomposite material.

Yeast has been used as a cell factory for thousands of years to produce a wide variety of complex biofuels, bioproducts, biochemicals, food ingredients, and pharmaceuticals. For a variety of biotechnological production hosts, a few specific genera of yeast have proven themselves. Rapid developments in metabolic engineering and synthetic biology provide a workable long-term supply solution for these substances. In this review, we have covered recent advances in the design of yeast cell factories for the synthesis of terpenoids, alkaloids, phenylpropanoids, and other natural chemicals, primarily focusing on Pichia species. Cutting-edge solutions involving genetic and process engineering have also been discussed. Overall, the review summarized recent advancements and challenges in synthetic and systems biology, as well as initiatives in metabolic engineering aimed at commercializing non-conventional yeasts like Pichia. The processes used in non-traditional yeasts to produce enzymes, therapeutic proteins, lipids, and metabolic products for industrial applications were thoroughly elaborated.

Hydrogels are highly porous three-dimensional crosslinked polymer networks consisting of hydrophilic polymers, employed most practically in medicine and industry, often as biosensors. Simple hydrogels suffer limitations in their mechanical properties, such as tensile and compression, and freeze at sub-zero temperatures, which compromise their ability as useful biosensors. In this study, the incorporation of L-ornithine-based zwitterionic monomer (OZM), titanium carbide (MXene), and glycerol within polyacrylamide hydrogels was used to prepare a novel polyacrylamide/polyL-ornithine-based zwitterion/MXene (PAM/Porn/MXene) hydrogel to improve the mechanical, adhesion, and anti-freezing properties of pure polyacrylamide hydrogels. This study also analyzed the mechanical strength (tensile and compression), adhesion, and anti-freezing properties of a novel PAM/Porn/MXene hydrogel at 1%, 4%, and 10% MXene concentrations to establish to what extent the conductive MXene material enhanced these properties and concluded that the tensile and compressive properties improved linearly with the increase in the concentrations of MXene, adhesion decreased with the increased MXene concentrations, and synergistic interaction between MXene and OZM significantly improved the anti-freezing properties up to –80 °C.

In this study, sulfonic acid functionalized polystyrene coated coal fly ash catalyst (CFA@PS-SO₃H) was designed and prepared by the post-synthesis method, which exhibited excellent catalytic performance for esterification of levulinic acid (LA) to afford alkyl levulinates. Four significant factors, including reaction time, catalyst dosage, alcohol-to-acid molar ratio and reaction temperature were evaluated systematically. Response surface methodology based on Box-Behnken design (BBD) was carried out to determine the optimal parameters. The maximum yield could reach 99.6% under the mild conditions. Furthermore, kinetics of the esterification reaction between levulinic acid and n-butanol were analyzed and the activation energies of the first and second step of esterification reaction were found to 52.18 and 59.81 kJ/mol, respectively. The CFA@PS-SO₃H also showed high catalytic activity for the esterification of levulinic acid with other linear alcohols, which made it a low cost, environmentally friendly and promising solid catalyst for the synthesis of alkyl levulinates.

Raw materials availability needed for commercial bioethanol production is one of the challenges against its global adoption. Identifying rich, cheap, underused, and readily available starch sources for bioethanol production could help address the problem. Thus, this current study investigated the bioconversion of underutilized Artocarpus altilis (breadfruit) starch to bioethanol using Saccharomyces cerevisiae. The effects of the essential fermentation conditions (fermentation time, breadfruit starch hydrolysate (BSH) concentration, pH, and inoculum size) and their interactions on bioethanol production were investigated. The central composite design was used to generate twenty-one experiments conducted under batch fermentation conditions in the laboratory. The breadfruit starch hydrolysis led to a BSH concentration of 108.9 g/L under a starch concentration of 122 g/L, microwave output of 720 W, and an incubation time of 6 min. For the fermentation of BSH, maximum bioethanol production of 4.99% (V) was reached under the cultivation conditions of BSH concentration of 80 g/L, medium pH of 4.7, inoculum size of 2% (V), and fermentation time of 20.41 h. Except for pH, the impact of each parameter on the bioethanol production was in this order: BSH concentration, inoculum size, and fermentation time. While for the interactions amongst the parameters, the impact is in this order: BSH concentration and inoculum size; BSH concentration and fermentation time; and fermentation time and inoculum size. The results of this study indicated breadfruit starch could be hydrolyzed using acid hydrolysis and microwave irradiation in a relatively short time. The BSH obtained could potentially add to other substrates for bioethanol production.