Search

Zeolites are a group of crystalline aluminosilicates with exchangeable cations and molecular-dimensioned micropores, which have successfully been applied to transform biomass and waste into biofuels. Herein, the effectiveness of acidic H-zeolites in biomass transformation and chemical valorization is demonstrated. In this process, the Brønsted/Lewis acid sites in zeolites catalyze the transition of carbohydrates into valuable chemicals. β-glucan polymer extracted from the lichen Usnea was catalytically converted into value-added molecules, such as glucose monomers. Particular challenges to elucidate the zeolite-catalyzed β-glucan conversion to glucose were addressed, namely: (i) water as the solvent, ii) hydrolysis of the biopolymer in an ionic liquid of 1-Butyl-3-vinylimidazolium bromide ([BVinIm]Br), and iii) reaction time of 30, 60, 120, and 240 min. Effective hydrolysis of β-glucan was achieved by H-zeolites (H-Beta, H-Mordenite, and H-ZSM-5), and the formed glucose was quantified through the dinitrosalicylic acid (DNS) method. Finally, applying H-zeolites as heterogeneous catalysts to prove the chemical recyclability of flexible films based on β-glucan was demonstrated as a step forward in integrating biopolymer-based materials into the circular economy., (© 2025 Wiley-VCH GmbH.)

Fungal mycelium is emerging as a source for sustainable bio-based materials. Fungal biomass of Aspergillus oryzae was prepared by cultivation on bread waste hydrolysate to valorize this abundant food waste. Chitin-glucan-rich alkali-insoluble material (AIM) was isolated from fungal biomass, formed into hydrogels, and wet spun into monofilaments. AIM in the form of fungal microfibers containing 0.09 g polymer of glucosamine (GlcN)/g AIM was subjected to freeze-thaw and deacetylation treatments to increase the amount of GlcN. The GlcN fraction was 0.19 and 0.34 g polymer of GlcN/g AIM, for AIM subjected to deacetylation (AIM-DAC) and freeze-thaw cycles and deacetylation (AIM-FRTH-DAC), respectively. The increased GlcN fraction enabled the formation of hydrogels via the protonation of amino groups after the addition of lactic acid. Morphological differences in the hydrogels included aggregation of the fungal microfibers in the AIM-DAC hydrogel, whereas the microfibers in the AIM-FRTH-DAC hydrogel had a porous and interconnected network. Rheological assessment revealed shear thinning behavior and gel properties of the produced hydrogels. Wet spinning of the hydrogels resulted in monofilaments with tensile strengths of up to 70 MPa and 12 % elongation at break. This demonstrates promising avenues for biomaterial development from fungal cell walls containing chitin-glucan via food waste valorization., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier B.V. All rights reserved.)

A green strategy that significantly accelerates the biodegradation rate of cellulose acetate (CA) by triggering deacetylation was demonstrated. Lipase isolated from Candida rugosa was immobilized on CA particles (immobilized lipase (IL)) by a physical entrapment method and further incorporated in CA films. After 40 days of aging in contact with external enzymes (lipase and cellulase), the number-average molecular weight ( M n ) of CA/IL 5% decreased by 88%, while the M n of CA only exhibited a 48% reduction. Fourier transform infrared and nuclear magnetic resonance spectroscopy of CA/IL 5% indicated significant deacetylation, which was further supported by the decrease of the water contact angle from 59 to 16°. These drastic changes were not observed for CA. Similar differences in the degradation rate were observed during aging under simulated composting conditions. After 180 days of simulated composting, traces of CA/IL 5% were barely observable, while large pieces of CA still remained. This could open the door to modified lignocellulose materials with retained biodegradability, also reducing the requirements for the degradation environment as the process is initiated from inside of the material.

An environmentally friendly non-woven nanotextile has been prepared using enantiomeric pairs of poly (lactic acid) PLA by electrospinning technique. Solution blending of synthesized high molecular weight (⁓10 5  Da) poly (L-lactic acid) PLLA and poly (D-lactic acid), PDLA for prolonged time stirring produce solely stereocrystallites (sc). The high crosslinking effect of sc-PLA has played an important role, with multifunctional behaviour on the addition of anatase-TiO 2 (a-TiO 2 ) in three different ways (Case-I-III). The high crystallinity of a-TiO 2 (~7.14 nm), has been confirmed from XRD and TEM studies as 98 %. The nanofinish as studied in (Case -III) by dipping and drying has decreased the water contact angle for the electrospun sc-PLA nanotextile from highly hydrophobic (132°) to superhydrophilicity after 8 min. An easy demonstration of high temperature treated nanofabric (at 100 °C) has proven to obtain an anti-shrinkage sc-PLA nanofabric. Even, the presence of a-TiO 2 has improved the colour strength ability of sc-PLA as a dark dyed nanofabric. The loading of as-synthesized a-TiO 2 nanoparticle has enhanced adsorbent dosages for 5T dip scPLA up to 1.44 mg/g of MB dosage, at contact time (8 h), and 68 % methylene blue (MB) removal efficiency under UV irradiation. Thereby, this a-TiO 2 impregnated sc-PLA nanofabric tends to dye removal., (Copyright © 2022. Published by Elsevier B.V.)

This study endeavoured to explore and fabricate antiviral and antibacterial facemasks using zinc (oligo-lactate) (ZL), developed through a microwave synthesis technique. The prepared nano-fabric layer has excellent antiviral and antibacterial properties against Newcastle Disease Virus (NDV) and E. coli and S. aureus , respectively. Thermogravimetric analysis (TGA) of ZL shows a two-step thermal degradation, which confirms the formation of low molecular weight end group lactyl units with zinc ions. Another investigation using varying ZL concentration and silk nanocrystal (SNC) with poly(lactic acid) (PLA) and electrospinning them into nanofibres led to the fabrication of a facile and sustainable nanofabric that can be utilized as a protective layer for facemasks. Morphological analysis revealed the successful preparation of the nanofabric with proper distribution and uniformity in fibre diameter. Hydrophobicity of the prepared nanofabric confirmed excellent protection from water droplets that may transpire during coughing or sneezing by an infected individual. Breathability and reusability tests confirmed that the prepared facemask could be reused by ethanol washing without compromising its surface properties till 4 cycles. The PLA/ZL nanofabric layer demonstrated 97% antiviral efficacy against NDV in 10 minutes. In conclusion, the electrospun nanofabric layer can be used as a facemask having high hydrophobicity, good breathability, antibacterial, and antiviral properties to control the spread of contagious diseases., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

The present study evaluates biodegradation of the polyblends of poly(lactic acid) (PLA), polycaprolactone (PCL) and microcrystalline cellulose (MCC) in different compositions and comparison of the properties of those blends with that of neat PLA and neat PCL. The samples were melt extruded and blended to evaluate the environmental fate of the polyblends under simulated composting conditions following the standard ASTM International D5338-15 protocol. It was seen that blends with a higher concentration of PCL and MCC in the PLA matrix showed higher carbon mineralization percentage in comparison to the blends having low PCL and MCC components. Molecular weight analysis of the samples showed a decrease in their weight due to chain scission mechanism leading to the formation of intermediates. Analytical techniques revealed the formation of microbial biofilms on the blended biopolymeric surfaces. Field emission scanning electron microscopy showed the formation of fibril-like structures by PLA, and the formation of rough patches on the PCL surface re-confirmed biodegradation of the samples. This work fuels interest in the material characterization of PLA/PCL/MCC based polyblends and helps in tuning the biodegradability of the studied samples according to the demands., (Copyright © 2020. Published by Elsevier Ltd.)

The current study evaluates aerobic biodegradation of melt extruded poly(lactic acid) PLA based blends under composting conditions. Samples of neat PLA (NPLA) and bio-based polyblend composites of PLA/LLDPE (linear low-density polyethylene) having different concentration of MCC (microcrystalline cellulose crystal) were analyzed to understand the biodegradation behavior of these blends under simulated composting conditions. Biodegradation kinetics revealed that higher content of MCC and PLA accelerated the biodegradation process of the polymeric blends. Increase in the spherulite growth size and decrease in the spherulite density of the biodegraded samples confirmed the decline in amorphous portion of the test samples due to microbial assimilation, leaving behind the crystalline portion. Surface morphological analysis revealed that the samples of PLA/LLDPE/MCC blends underwent surface erosion prior to bulk biodegradation (50-80%) until the 90th day and the PLA formed fibril-like structures after degradation. This study would help in the design and preparation of biodegradable bio-based commercial blends in the future., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Background: To evaluate the role of sonography (US) in assessing hypopharyngeal carcinoma when compared with CT., Methods: A randomized prospective study was performed on 40 biopsy-proven cases of hypopharyngeal carcinoma.Contrast-enhanced CT of the neck was performed in all patients, followed by US. Sonographic identification of any tumor extension into the extralaryngeal soft tissues, postcricoid space, subglottis, thyroid gland, esophagus, and across the midline was recorded. US observations and CT findings were compared and then correlated with the histopathologic findings in 14 operative cases. In the remaining 26 inoperable cases, US was compared only with CT., Results: Our cohort was composed of 38 men and 2 women ranging in age from 36 to 59 years. In a subset of 14 operative patients, US had a sensitivity of 71.4% (10/14), while CT achieved a sensitivity of 92.8% (13/14), and the difference was not statistically significant (p > 0.05). US and CT findings concurred in 67.5% (27/40) of cases., Conclusions: Even though small tumors are difficult to visualize, US can play a significant role in the assessment of tumor extension within and beyond the larynx, especially when cross-sectional imaging is either unavailable or unaffordable., (Copyright © 2014 Wiley Periodicals, Inc.)