Catalytic Fast Pyrolysis of Kraft Lignin With Conventional, Mesoporous and Nanosized ZSM-5 Zeolite for the Production of Alkyl-Phenols and Aromatics

The valorization of lignin that derives as by product in various biomass conversion processes has become a major research and technological objective. The potential of the production of valuable mono-aromatics (BTX and others) and (alkyl)phenols by catalytic fast pyrolysis of lignin is investigated in this work by the use of ZSM-5 zeolites with different acidic and porosity characteristics. More specifically, conventional microporous ZSM-5 (Si/Al = 11.5, 25, 40), nano-sized (≤20 nm, by direct synthesis) and mesoporous (9 nm, by mild alkaline treatment) ZSM-5 zeolites were tested in the fast pyrolysis of a softwood kraft lignin at 400–600°C on a Py/GC-MS system and a fixed-bed reactor unit. The composition of lignin (FT-IR, 2D HSQC NMR) was correlated with the composition of the thermal (non-catalytic) pyrolysis oil, while the effect of pyrolysis temperature and catalyst-to-lignin (C/L) ratio, as well as of the Si/Al ratio, acidity, micro/mesoporosity and nano-size of ZSM-5, on bio-oil composition was thoroughly investigated. It was shown that the conventional microporous ZSM-5 zeolites are more selective toward mono-aromatics while the nano-sized and mesoporous ZSM-5 exhibited also high selectivity for (alkyl)phenols. However, the nano-sized ZSM-5 zeolite exhibited the lowest yield of organic bio-oil and highest production of water, coke and non-condensable gases compared to the conventional microporous and mesoporous ZSM-5 zeolites

Medium-chain triglycerides may improve memory in non-demented older adults: a systematic review of randomized controlled trials

Background: Ketosis has been exploited for its neuroprotective impact and treatment of neurological conditions via ketone production. Exogenous medium-chain triglyceride (MCT) supplementation may induce nutritional ketosis. The aim of this systematic review is to explore the effects of MCTs on memory function in older adults without cognitive impairment. Methods: A systematic literature search of PubMed, Cochrane Library, Scopus, and Web of Science was employed from inception until April 2022 for randomized controlled trials (RCTs) in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, investigating the impact of MCT oils on components of memory. Risk of bias (RoB2) tool was utilized for quality assessment. Results: Six trials were included for qualitative synthesis, in which two studies examined the effect of MCTs through a ketogenic meal. MCT supplementation compared to controls was associated with improved indices of memory function in 4 out of 6 studies, particularly working memory. A meta-analysis was not employed due to the low number of studies, therefore, a true effect measure of MCT supplementation was not explored. Conclusions: MCT supplementation may enhance working memory in non-demented older adults. These effects may be more prominent in individuals with lower baseline scores, from short and long-term supplementation. Further studies are warranted to confirm these findings in terms of optimal dose and MCTs composition, which may protect from memory decline during aging

Medium-chain triglycerides may improve memory in non-demented older adults: a systematic review of randomized controlled trials

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The impact of branched-chain amino acid supplementation on measures of glucose homeostasis in individuals with hepatic disorders: A systematic review of clinical studies.

BackgroundBranched chain amino acid (BCAA) supplementation may influence glucose metabolism in individuals with impaired glycemic profile. This systematic review investigated the effects of isolated BCAA supplementation on measures of glucose homeostasis in individuals with hepatic disorders.MethodsWe searched PubMed, Web of Science, Cochrane Library, and Scopus for published clinical trials that investigated the effects of isolated BCAA supplementation on measures of glucose homeostasis, including serum glucose and insulin, glycated hemoglobin (HbA1c) levels, and Homeostatic Model Assessment for Insulin Resistance (HOMA-IR) scores.ResultsEleven trials met the inclusion criteria. Only one study revealed a decrease in serum glucose from BCAA supplementation compared to three studies that showed increases. Five studies demonstrated no significant changes in serum glucose, and two studies displayed no changes in HbA1c following BCAA supplementation. Serum levels of insulin were decreased in three studies, remained unchanged in one, whilst increased in the remaining three studies. BCAA supplementation reduced HOMA-IR scores in two studies, increased HOMA-IR scores in another two or resulted in no changes in two other studies.ConclusionsBCAA supplementation in isolation had no effect on overall glucose homeostasis in individuals with hepatic disorders, although some improvements on serum insulin levels and HOMA-IR scores were observed. Overall, there is little evidence to support the utilization of BCAA supplementation as a potential nutritional strategy for improving measures of glucose homeostasis in individuals with hepatic disorders. This article is protected by copyright. All rights reserved

Techno-economic optimization of a process superstructure for lignin valorization

Lignin, the most abundant aromatic biopolymer on Earth, is often considered a biorefinery by-product, despite its potential to be valorized into high-added-value chemicals and fuels. In this work, an integrated superstructure-based optimization model was set up and optimized using mixed-integer non-linear programming for the conversion of technical lignin to three main biobased products: aromatic monomers, phenol-formaldehyde resins, and aromatic aldehydes/acids. Several alternative conversion pathways were simultaneously compared to assess the profitability of lignins-based processes by predicting the performance of technologies with different TRL. Upon employing key technologies such as hydrothermal liquefaction, dissolution in solvent, or high-temperature electrolysis, the technical lignins could have a market value of 200 €/t when the market price for aromatic monomers, resins, and vanillin is at least 2.0, 0.8, and 15.0 €/kg, respectively. When lower product selling prices were considered, the aromatic monomers and the resins were not profitable as target products

Medium-chain triglycerides may improve memory in non-demented older adults: a systematic review of randomized controlled trials.

BackgroundKetosis has been exploited for its neuroprotective impact and treatment of neurological conditions via ketone production. Exogenous medium-chain triglyceride (MCT) supplementation may induce nutritional ketosis. The aim of this systematic review is to explore the effects of MCTs on memory function in older adults without cognitive impairment.MethodsA systematic literature search of PubMed, Cochrane Library, Scopus, and Web of Science was employed from inception until April 2022 for randomized controlled trials (RCTs) in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, investigating the impact of MCT oils on components of memory. Risk of bias (RoB2) tool was utilized for quality assessment.ResultsSix trials were included for qualitative synthesis, in which two studies examined the effect of MCTs through a ketogenic meal. MCT supplementation compared to controls was associated with improved indices of memory function in 4 out of 6 studies, particularly working memory. A meta-analysis was not employed due to the low number of studies, therefore, a true effect measure of MCT supplementation was not explored.ConclusionsMCT supplementation may enhance working memory in non-demented older adults. These effects may be more prominent in individuals with lower baseline scores, from short and long-term supplementation. Further studies are warranted to confirm these findings in terms of optimal dose and MCTs composition, which may protect from memory decline during aging

The key role of pretreatment for the one-step and multi-step conversions of European lignocellulosic materials into furan compounds.

peer reviewedNowadays, an increased interest from the chemical industry towards the furanic compounds production, renewable molecules alternatives to fossil molecules, which can be transformed into a wide range of chemicals and biopolymers. These molecules are produced following hexose and pentose dehydration. In this context, lignocellulosic biomass, owing to its richness in carbohydrates, notably cellulose and hemicellulose, can be the starting material for monosaccharide supply to be converted into bio-based products. Nevertheless, processing biomass is essential to overcome the recalcitrance of biomass, cellulose crystallinity, and lignin crosslinked structure. The previous reports describe only the furanic compound production from monosaccharides, without considering the starting raw material from which they would be extracted, and without paying attention to raw material pretreatment for the furan production pathway, nor the mass balance of the whole process. Taking account of these shortcomings, this review focuses, firstly, on the conversion potential of different European abundant lignocellulosic matrices into 5-hydroxymethyl furfural and 2-furfural based on their chemical composition. The second line of discussion is focused on the many technological approaches reported so far for the conversion of feedstocks into furan intermediates for polymer technology but highlighting those adopting the minimum possible steps and with the lowest possible environmental impact. The focus of this review is to providing an updated discussion of the important issues relevant to bringing chemically furan derivatives into a market context within a green European context