Utilization of lignocellulosic biomass: A practical journey towards the development of emulsifying agent

Minimizing Energy Demand in the Conversion of Levulinic Acid to γ‑Valerolactone via Photothermal Catalysis Using Raney Ni

The valorization of lignocellulosic wastes emerges as a prime strategy to mitigate the global carbon footprint. Among the multiple biomass derivatives, γ-valerolactone is particularly attractive as precursor of high-value chemicals, biofuel, green solvent or perfumery. γ-Valerolactone can be synthesized through a hydrogenation reaction from levulinic acid, obtained from cellulose. However, the high energy requirements of this synthetic pathway have hindered its industrial viability. To drastically reduce the reaction energy requirements, here a novel synthetic strategy, based on solvothermal-photothermal processes using cost-effective Raney-Ni as photothermal catalyst, is proposed. First, the use of hydrogen gas is avoided by selecting isopropanol as a safer and greener H-source. Second, a photothermocatalytic process is used to minimize the reaction temperature and time with respect to conventional reactions. This approach exploits the broadband optical absorption of the Raney®-Ni, due to its highly damped plasmonic behavior, to achieve fast and efficient catalyst heating inside the reactor. The photothermal reaction required less than 2 h and just 132 °C to reach over 95% conversion, thereby drastically reducing the reaction time and energy consumption compared to conventional reactions. Importantly, these conditions granted high catalyst reusability. This solvothermal-photothermal approach could offer a sustainable alternative for the industrial production of γ-valerolactone.

Enhancing Lignin-Carbohydrate Complexes Production and Properties With Machine Learning

Lignin-carbohydrate complexes (LCCs) present a unique opportunity for harnessing the synergy between lignin and carbohydrates for high-value product development. However, producing LCCs in high yields remains a significant challenge. In this study, we address this challenge with a novel approach for the targeted production of LCCs. We optimized the AquaSolv Omni (AqSO) biorefinery for the synthesis of LCCs with high carbohydrate content (up to 60/100 Ar) and high yields (up to 15 wt %) by employing machine learning (ML). Our method significantly improves the yield of LCCs compared to conventional procedures, such as ball milling and enzymatic hydrolysis. The ML approach was pivotal in tuning the biorefinery to achieve the best performance with a limited number of experimental trials. Specifically, we utilized Bayesian Optimization to iteratively gather data and examine the effects of key processing conditions-temperature, process severity, and liquid-to-solid ratio-on yield and carbohydrate content. Through Pareto front analysis, we identified optimal trade-offs between LCC yield and carbohydrate content, discovering extensive regions of processing conditions that produce LCCs with yields of 8-15 wt % and carbohydrate contents ranging from 10-40/100 Ar. To assess the potential of these LCCs for high-value applications, we measured their glass transition temperature (Tg), surface tension, and antioxidant activity. Notably, we found that LCCs with high carbohydrate content generally exhibit low Tg and surface tension. Our biorefinery concept, augmented by ML-guided optimization, represents a significant step toward scalable production of LCCs with tailored properties.

Facile Fabrication of Sandalwood Oil-Based Nanoemulsion to Intensify the Fatty Acid Composition in Burned and Rough Skin

The restoration process of burned and rough skin takes a long time and remains a critical challenge. It can be repaired through a combination of proper care, hydration, and topical therapies. In this study, a novel nanoemulsion was synthesized through the high-energy ultrasonication method. A total of five nanoemulsions (NE1-5) were prepared with varying concentrations of sandalwood oil, a nonionic surfactant (polysorbate 80), and water. Among them, NE3 had a number of appropriate physicochemical characteristics, such as physiological pH (5.58 ± 0.09), refractive index (∼1.34), electrical conductivity (115 ± 0.23 mS cm-1), and transmittance (∼96.5%), which were suitable for skin care applications. The NE3 had a strong surface potential of -18.5 ± 0.15 mV and a hydrodynamic size of 61.99 ± 0.22 nm with a polydispersity index of 0.204. The structural integrity and a distinct droplet size range between 50 and 100 nm were confirmed by transmission electron microscopic analysis. The skin regeneration and restoration abilities of synthesized nanoemulsions were examined by conducting an in vivo study on Sprague-Dawley rats. Exposure to NE3 significantly increased the healing process in burned skin as compared to untreated control and nonemulsified sandalwood oil. In another set of experiments, the NE3-treated rough skin became softer, smoother, and less scaly than all other treatments. Enhanced fatty acids, i.e., palmitic acid, stearic acid, and cholesterol, were recorded in NE3-supplemented burned and rough skin compared to the untreated control. The NE3 had outstanding compatibility with key components of skincare products without any stability issues. Its biocompatibility with the cellular system was established by the negligible generation of reactive oxygen species (ROS) and a lack of genotoxicity. Considering these results, NE3 can be used in cosmetic products such as creams, lotions, and serums, allowing industries to achieve improved product formulations and provide better healthcare benefits to humanity.

Exploitation of lignocellulosic-based biomass biorefinery: A critical review of renewable bioresource, sustainability and economic views

Urbanization has driven the demand for fossil fuels, however, the overly exploited resource has caused severe damage on environmental pollution. Biorefining using abundant lignocellulosic biomass is an emerging strategy to replace traditional fossil fuels. Value-added lignin biomass reduces the waste pollution in the environment and provides a green path of conversion to obtain renewable resources. The technology is designed to produce biofuels, biomaterials and value-added products from lignocellulosic biomass. In the biorefinery process, the pretreatment step is required to reduce the recalcitrant structure of lignocellulose biomass and improve the enzymatic digestion. There is still a gap in the full and deep understanding of the biorefinery process including the pretreatment process, thus it is necessary to provide optimized and adapted biorefinery solutions to cope with the conversion process in different biorefineries to further provide efficiency in industrial applications. Current research progress on value-added applications of lignocellulosic biomass still stagnates at the biofuel phase, and there is a lack of comprehensive discussion of emerging potential applications. This review article explores the advantages, disadvantages and properties of pretreatment methods including physical, chemical, physico-chemical and biological pretreatment methods. Value-added bioproducts produced from lignocellulosic biomass were comprehensively evaluated in terms of encompassing biochemical products , cosmetics, pharmaceuticals, potent functional materials from cellulose and lignin, waste management alternatives, multifunctional carbon materials and eco-friendly products. This review article critically identifies research-related to sustainability of lignocellulosic biomass to promote the development of green chemistry and to facilitate the refinement of high-value, environmentally-friendly materials. In addition, to align commercialized practice of lignocellulosic biomass application towards the 21st century, this paper provides a comprehensive analysis of lignocellulosic biomass biorefining and the utilization of biorefinery green technologies is further analyzed as being considered sustainable, including having potential benefits in terms of environmental, economic and social impacts. This facilitates sustainability options for biorefinery processes by providing policy makers with intuitive evaluation and guidance.

Polyaniline Composites Containing Eco-Friendly Biomass Carbon from Agricultural-Waste Coconut Husk for Enhancing Gas Sensor Performance in Hydrogen Sulfide Detection

Hydrogen sulfide, a colorless, flammable gas with a distinct rotten egg odor, poses severe health risks in industrial settings. Sensing hydrogen sulfide is crucial for safeguarding worker safety and preventing potential accidents. This study investigated the gas-sensing performance of an electroactive polymer (i.e., polyaniline, PANI) and its composites with active carbon (AC) (i.e., PANI-AC1 and PANI-AC3) toward H2S at room temperature. PANI-AC composites-coated IDE gas sensors were fabricated and their capability of detecting H2S at concentrations ranging from 1 ppm to 30 ppm was tested. The superior gas-sensing performance of the PANI-AC composites can be attributed to the increased surface area of the materials, which provided increased active sites for doping processes and enhanced the sensing capability of the composites. Specifically, the incorporation of AC in the PANI matrix resulted in a substantial improvement in the doping process, which led to stronger gas-sensing responses with higher repeatability and higher stability toward H2S compared to the neat PANI-coated IDE sensor. Furthermore, the as-prepared IDE gas sensor exhibited the best sensing response toward H2S at 60% RH. The use of agricultural-waste coconut husk for the synthesis of these high-performance gas-sensing materials promotes sustainable and eco-friendly practices while improving the detection and monitoring of H2S gas in industrial settings.

Toxicity evaluation of Pinus radiata D.Don bark wax for potential cosmetic application

Radiata pine bark is a widely available organic waste, requiring alternative uses due to its environmental impact on soil, fauna, and forest fires. Pine bark waxes could be used as cosmetic substitutes, but their toxicity requires evaluation since pine bark may contain toxic substances or xenobiotics, depending on the extraction process. This study evaluates the toxicity of radiata pine bark waxes obtained through various extraction methods on human skin cells grown in vitro. The assessment includes using XTT to evaluate mitochondrial activity, violet crystal dye to assess cell membrane integrity, and ApoTox-Glo triple assay to measure cytotoxicity, viability, and apoptosis signals. Pine bark waxes extracted via T3 (acid hydrolysis and petroleum ether incubation) and T9 (saturated steam cycle, alkaline hydrolysis, and petroleum ether incubation) exhibit non-toxicity up to 2% concentration, making them a potential substitute for petroleum-based cosmetic materials. Integrating the forestry and cosmetic industries through pine bark wax production under circular economy principles could promote development while replacing petroleum-based materials. Extraction methodology affects pine bark wax toxicity in human skin cells due to the retention of xenobiotic compounds including methyl 4-ketohex-5-enoate; 1-naphthalenol; dioctyl adipate; eicosanebioic acid dimethyl ester; among others. Future research will investigate whether the extraction methodology alters the molecular structure of the bark, affecting the release of toxic compounds in the wax mixture.

Lignin-Based Admixtures: A Scientometric Analysis and Qualitative Discussion Applied to Cement-Based Composites

The development of lignin-based admixtures (LBAs) for cement-based composites is an alternative to valorizing residual lignins generated in biorefineries and pulp and paper mills. Consequently, LBAs have become an emerging research domain in the past decade. This study examined the bibliographic data on LBAs through a scientometric analysis and in-depth qualitative discussion. For this purpose, 161 articles were selected for the scientometric approach. After analyzing the articles' abstracts, 37 papers on developing new LBAs were selected and critically reviewed. Significant publication sources, frequent keywords, influential scholars, and contributing countries in LBAs research were identified during the science mapping. The LBAs developed so far were classified as plasticizers, superplasticizers, set retarders, grinding aids, and air-entraining admixtures. The qualitative discussion revealed that most studies have focused on developing LBAs using Kraft lignins from pulp and paper mills. Thus, residual lignins from biorefineries need more attention since their valorization is a relevant strategy for emerging economies with high biomass availability. Most studies focused on production processes, chemical characterizations, and primary fresh-state analyses of LBA-containing cement-based composites. However, to better assess the feasibility of using different LBAs and encompass the multidisciplinarity of this subject, it is mandatory that future studies also evaluate hardened-sate properties. This holistic review offers a helpful reference point to early-stage researchers, industry professionals, and funding authorities on the research progress in LBAs. It also contributes to understanding the role of lignin in sustainable construction.