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28 pages, 6229 KB

Open AccessReview

Mechanical Pretreatment of Plant Biomass: Mechanisms, Energy Efficiency, Technologies, and Life Cycle Assessment

by Ekaterina Podgorbunskikh, Tatiana Skripkina and Aleksey Bychkov

Polysaccharides 2026, 7(2), 38; https://doi.org/10.3390/polysaccharides7020038 - 24 Mar 2026

Cited by 3 | Viewed by 1961

Mechanical pretreatment techniques are essential for overcoming lignocellulosic biomass recalcitrance in emerging biorefineries. This review critically synthesizes advances from 2020 to 2025 across fundamental mechanisms, hybrid technologies, energy efficiency, Life Cycle Assessment, and industrial scalability. The analysis reveals that effective pretreatment targets supramolecular modification—defect generation in cellulose crystallites and the creation of reactive sites—beyond simple particle size reduction. Impact–shear regimes prove most effective for fibrous materials. Hybrid approaches are examined: mechanocatalysis enables solvent-free depolymerization, while mechanoenzymatic technologies achieve hydrolysis without bulk water, though enzyme denaturation under mechanical stress remains unresolved. Energy consumption is the primary upscaling barrier, with Life Cycle Assessment identifying electricity use as the dominant environmental hotspot and emphasizing burden per unit of final product as the critical metric. Technology Readiness Level assessment provides a strategic framework: continuous extruders and mills are industrially mature for bulk applications, while high-intensity batch devices are suited for high-value coproducts. A research agenda prioritizing mechanistic understanding, hybrid process engineering, feedstock diversification, and embedded sustainability assessment is proposed. Full article

(This article belongs to the Special Issue Recent Progress on Lignocellulosic-Based Materials)

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13 pages, 3909 KB

Open AccessArticle

Sustainable and Green Production of Nanostructured Cellulose by a 2-Step Mechano-Enzymatic Process

by Martina Aulitto, Rachele Castaldo, Roberto Avolio, Maria Emanuela Errico, Yong-Quan Xu, Gennaro Gentile and Patrizia Contursi

Polymers 2023, 15(5), 1115; https://doi.org/10.3390/polym15051115 - 23 Feb 2023

Cited by 9 | Viewed by 3130

Abstract

Nanostructured cellulose (NC) represents an emerging sustainable biomaterial for diverse biotechnological applications; however, its production requires hazardous chemicals that render the process ecologically unfriendly. Using commercial plant-derived cellulose, an innovative strategy for NC production based on the combination of mechanical and enzymatic approaches was proposed as a sustainable alternative to conventional chemical procedures. After ball milling, the average length of the fibers was reduced by one order of magnitude (down to 10–20 μm) and the crystallinity index decreased from 0.54 to 0.07–0.18. Moreover, a 60 min ball milling pre-treatment followed by 3 h Cellic Ctec2 enzymatic hydrolysis led to NC production (15% yield). Analysis of the structural features of NC obtained by the mechano-enzymatic process revealed that the diameters of the obtained cellulose fibrils and particles were in the range of 200–500 nm and approximately 50 nm, respectively. Interestingly, the film-forming property on polyethylene (coating ≅ 2 μm thickness) was successfully demonstrated and a significant reduction (18%) of the oxygen transmission rate was obtained. Altogether, these findings demonstrated that nanostructured cellulose could be successfully produced using a novel, cheap, and rapid 2-step physico-enzymatic process that provides a potential green and sustainable route that could be exploitable in future biorefineries. Full article

(This article belongs to the Special Issue Chemical and Mechano-Chemical Modification of Polymers and Organic Materials)

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14 pages, 3353 KB

Open AccessArticle

Calcium Binds to Transthyretin with Low Affinity

by Cristina Cantarutti, Maria Chiara Mimmi, Guglielmo Verona, Walter Mandaliti, Graham W. Taylor, P. Patrizia Mangione, Sofia Giorgetti, Vittorio Bellotti and Alessandra Corazza

Biomolecules 2022, 12(8), 1066; https://doi.org/10.3390/biom12081066 - 2 Aug 2022

Cited by 10 | Viewed by 3515

Abstract

The plasma protein transthyretin (TTR), a transporter for thyroid hormones and retinol in plasma and cerebrospinal fluid, is responsible for the second most common type of systemic (ATTR) amyloidosis either in its wild type form or as a result of destabilizing genetic mutations that increase its aggregation propensity. The association between free calcium ions (Ca²⁺) and TTR is still debated, although recent work seems to suggest that calcium induces structural destabilization of TTR and promotes its aggregation at non-physiological low pH in vitro. We apply high-resolution NMR spectroscopy to investigate calcium binding to TTR showing the formation of labile interactions, which leave the native structure of TTR substantially unaltered. The effect of calcium binding on TTR-enhanced aggregation is also assessed at physiological pH through the mechano-enzymatic mechanism. Our results indicate that, even if the binding is weak, about 7% of TTR is likely to be Ca²⁺-bound in vivo and therefore more aggregation prone as we have shown that this interaction is able to increase the protein susceptibility to the proteolytic cleavage that leads to aggregation at physiological pH. These events, even if involving a minority of circulating TTR, may be relevant for ATTR, a pathology that takes several decades to develop. Full article

(This article belongs to the Section Molecular Biophysics: Structure, Dynamics, and Function)

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1 pages, 160 KB

Open AccessAbstract

Enhanced Biodegradation of Polyethylene Terephthalate (PET) via Microwave-Assisted Green Bio-Based Deep Eutectic Solvent Pre-Treatment Technique

by Muhammad Azeem, Olivia Adly Attallah and Margaret Brennan Fournet

Chem. Proc. 2022, 6(1), 9; https://doi.org/10.3390/ECCS2021-11181 - 15 Oct 2021

Viewed by 2016

Abstract

Most plastic degradation methods are currently inefficient and are limited by processing difficulties, quality loss, and diminished value. This research focuses on the development of novel mechano-chemical disintegration processes for the breakdown of waste plastics. The outputs will be biocatalyzed and used as building blocks for new polymers or other bioproducts. For the purpose of this research, microwave pre-treatment technology was used. Microwave technology is an ideal pre-treatment process for the degradation of plastics due to its lower treatment times under lower energy inputs. In the previous work, extensive research has been carried out utilizing different solvents and catalysts to develop efficient degradation mechanisms under microwave irradiations. A new class of ionic liquids (deep eutectic solvents) were used as catalysts to make a suspension with poly(ethylene terephthalate) (PET) and develop an alcoholysis reaction. Certain degradation parameters like crystallinity index, weight loss, and carbonyl index were depicted using differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and Fourier-transform infrared spectroscopy (FTIR) characterization techniques. Furthermore, enhanced enzymatic degradation using LCC variant ICCG proved that microwave technology is an efficient process for the alcoholysis reaction and degradation of PET under mild conditions into its monomers. Full article

(This article belongs to the Proceedings of The 2nd International Electronic Conference on Catalysis Sciences—A Celebration of Catalysts 10th Anniversary)

25 pages, 1415 KB

Open AccessReview

Unconventional Myosins: How Regulation Meets Function

by Natalia Fili and Christopher P. Toseland

Int. J. Mol. Sci. 2020, 21(1), 67; https://doi.org/10.3390/ijms21010067 - 20 Dec 2019

Cited by 44 | Viewed by 12507

Abstract

Unconventional myosins are multi-potent molecular motors that are assigned important roles in fundamental cellular processes. Depending on their mechano-enzymatic properties and structural features, myosins fulfil their roles by acting as cargo transporters along the actin cytoskeleton, molecular anchors or tension sensors. In order to perform such a wide range of roles and modes of action, myosins need to be under tight regulation in time and space. This is achieved at multiple levels through diverse regulatory mechanisms: the alternative splicing of various isoforms, the interaction with their binding partners, their phosphorylation, their applied load and the composition of their local environment, such as ions and lipids. This review summarizes our current knowledge of how unconventional myosins are regulated, how these regulatory mechanisms can adapt to the specific features of a myosin and how they can converge with each other in order to ensure the required tight control of their function. Full article

(This article belongs to the Special Issue Motile Function of Myosins in Cells and Tissues)

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