Self-Formation of Lignin Particles Through Melt-Extrusion for Active Biodegradable Food Packaging.

This study presents a method for the self-formation of lignin particles within a polylactic acid (PLA) matrix during melt-extrusion, eliminating the need for separation and drying steps typically associated with submicro-size lignin particles. This method effectively mitigates the problem of agglomeration often associated with the drying step. Softwood kraft lignin, guaiacyl lignin (GL-lignin), was dissolved in low-molecular-weight poly(ethylene glycol) (PEG) and was introduced into a twin-screw extruder using a liquid feeder. Lignin particles within a particle size range of 200-500 nm were observed in the extrudate of the PLA/PEG/GL-lignin composites. PLA/PEG/GL-lignin composite films were produced through blown film extrusion. These composite films demonstrated superior ultraviolet (UV)-barrier and antioxidant properties compared to neat PLA films, with optical and mechanical characteristics comparable to those of neat PLA. Moreover, migration values of the composite films in various food simulants were below regulatory limits, suggesting their potential for food packaging applications. This self-formation process offers a promising approach for utilizing lignin for PLA applications.

Pebax/Modified Cellulose Nanofiber Composite Membranes for Highly Enhanced CO2/CH4 Separation.

This work explored the use of biomass-derived cellulose nanofibers as an additive to enhance the separation performance of Pebax membranes for the removal of CO2 from biogas. Succinate functional groups were modified on the cellulose nanofiber (SCNF) to incorporate more CO2-attracting functional groups before they were added to the polymer matrix. A small addition of SCNF up to 0.5 wt % had no significant impact on the polymer chain packing of Pebax but significantly enhanced the tensile strength and separation performance in both CO2 permeability and CO2/CH4 selectivity. On the other hand, increasing the SCNF addition amount above 1 wt % resulted in a slight alternation of membrane microstructure, i.e., lowering crystallinity, stiffer structure, and reduced tensile strength. At high loading, the CO2 permeability and CO2/CH4 selectivity of the composite membrane were, however, found to decline. This behavior is explained by a greater propensity for interaction among the CO2-attracting functional groups of SCNF and Pebax at elevated SCNF loadings, leading to fewer functional groups available for CO2 sorption. The optimal 0.5% SCNF loading (Pebax/SCNF-0.5) demonstrated a CO2 permeability of 263.8 Barrer and selectivity of 19.9 under 4 bar pressure and an operating temperature of 30 °C. These separation performances increased by 29.69% permeability and 39.04% selectivity compared with those of pure Pebax. These highly impressive results corresponded to the increases in the levels of CO2 dissolution and diffusion via hydrophilic SCNF nanofillers in Pebax. This work could strongly advance the research and development of gas separation technology based on polymeric membranes with the utilization of biobased nanofillers for energy and environmental sectors.

Development of Photothermal Catalyst from Biomass Ash (Bagasse) for Hydrogen Production via Dry Reforming of Methane (DRM): An Experimental Study.

Conventional hydrogen production, as an alternative energy resource, has relied on fossil fuels to produce hydrogen, releasing CO2 into the atmosphere. Hydrogen production via the dry forming of methane (DRM) process is a lucrative solution to utilize greenhouse gases, such as carbon dioxide and methane, by using them as raw materials in the DRM process. However, there are a few DRM processing issues, with one being the need to operate at a high temperature to gain high conversion of hydrogen, which is energy intensive. In this study, bagasse ash, which contains a high percentage of silicon dioxide, was designed and modified for catalytic support. Modification of silicon dioxide from bagasse ash was utilized as a waste material, and the performance of bagasse ash-derived catalysts interacting with light irradiation and reducing the amount of energy used in the DRM process was explored. The results showed that the performance of 3%Ni/SiO2 bagasse ash WI was higher than that of 3%Ni/SiO2 commercial SiO2 in terms of the hydrogen product yield, with hydrogen generation initiated in the reaction at 300 °C. Using the same synthesis method, the current results suggested that bagasse ash-derived catalysts had better performance than commercial SiO2-derived catalysts when exposed to an Hg-Xe lamp. This indicated that silicon dioxide from bagasse ash as a catalyst support could help improve the hydrogen yield while lowering the temperature in the DRM reaction, resulting in less energy consumption in hydrogen production.

Physicochemical properties of lignin nanoparticles from softwood and their potential application in sustainable pre-harvest bagging as transparent UV-shielding films.

Technical lignin can be mainly obtained as a waste by-product from pulp industry, and it exhibits unique properties including ultraviolet adsorption, biodegradable, antibacterial, and antioxidant which can be utilized for bioplastic applications. However, common limitations of technical lignin for plastic applications are compatibility mainly due to poor interfacial adhesion, relatively large particle size and impurity. In this study lignin nanoparticles from softwood (S-LNPs) were successfully produced through a continuous-green-scalable antisolvent precipitation and the suitability of S-LNPs for fabrication of bio-composite polybutylene succinate (PBS) films using conventional blown film extrusion was examined. The attained S-LNPs showed lower ash content, higher phenolic content and higher lignin content compared to pristine softwood kraft lignin (S-lignin). Rheological property including shear viscosity and melt-flow index was determined. The obtained PBS/S-LNP composite films showed improved tensile modulus, higher water vapor transmission rate and excellent UV-shielding ability compared to neat PBS and PBS/S-lignin films. Accelerated weathering testing was conducted to replicate outdoor conditions. Degradation indices including carbonyl, vinyl and hydroxyl of the weathered PBS/lignin composites were evaluated for photo-oxidative stability. The S-LNPs as multifunctional bio-additives in biodegradable composite film exhibited superior performances of transparency, UV-absorption and stiffness with high photo-oxidative stability suitable for outdoor applications.

Development of tailor-made synergistic cellulolytic enzyme system for saccharification of steam exploded sugarcane bagasse.

Designing a tailor-made synergistic system is a promising strategy for developing an effective enzyme for saccharification of lignocellulosic materials. In this study, a cellulolytic enzyme mixture comprising selected core recombinant enzymes for hydrolysis of sugarcane bagasse pretreated by alkaline-catalyzed steam explosion was optimized using a mixture design approach. The optimized enzyme system comprised a cellobiohydrolase (Cel7A) from Talaromyces cellulolyticus, an endo-glucanase (Cel7B) from Thielavia terrestris, a ß-glucosidase (BGL) and an endo-ß1,4-xylanase (XYN) from Aspergillus aculeatus at the ratio of 0.34:0.27:0.14:0.25. The maximum reducing sugar yield of 797 mg/g biomass, comprising 543 and 96.8 mg/g glucose and xylose, respectively were achieved, equivalent to 92.44% and 47.50% recoveries, respectively from the pretreated substrate at the enzyme dosage of 20 mg/g biomass. The sugar yield from the quaternary enzyme mixture was 17.37% higher than that obtained with Accellerase 1500.