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Antibiotic Microbial Resistance (AMR) is a major global challenge as it constitutes a severe threat to global public health if not addressed. To fight against AMR bacteria, new antimicrobial agents are continually needed, and their efficacy must be tested. Historically, many transition metals have been employed, but their cytotoxicity is an issue and hence must be reduced, typically by combination with organic polymers. Cellulose of natural origin, especially those derived from unavoidable residues in the food supply chain, appears to be a good capping agent for the green synthesis of silver nanoparticles. Herein, we describe a green synthesis method to produce a novel biocomposite, using ascorbic acid as reducing agent and microfibrillated cellulose as a capping agent and demonstrate this material to be an efficient antimicrobial agent. Silver nanoparticles were obtained in the cellulose matrix with an average size of 140 nm and with antimicrobial activity against both sensitive and resistant Gram positive (using 1500 ppm) as well as sensitive and resistant Gram negative (using 125 ppm) bacteria. Also, an inverted disk-diffusion methodology was applied to overcome the low-solubility of cellulose compounds. This novel silver nanoparticle-cellulose biocomposite synthesized by a green methodology shows the potential to be applied in the future development of biomedical instruments and therapeutics.

Blackcurrant pomace (BCP) is an example of an annual, high-volume, under-utilized renewable resource with potential to generate chemicals, materials and bioenergy within the context of a zero-waste biorefinery. Herein, the microwave-assisted isolation, characterization and potential application of defibrillated lignocelluloses from depectinated blackcurrant pomace are reported. Depectination was achieved using citric acid (0.2–0.8 M, 80 °C, 2 h, conventional heating) and compared with acid-free hydrothermal microwave-assisted processing (1500 W, 100–160 °C, 30 min). The resultant depectinated residues were subjected to microwave-assisted hydrothermal defibrillation to afford two classes of materials: namely, (i) hydrothermal acid-free microwave-assisted (1500 W, 160 °C, 30 min; DFC-M1-M4), and (ii) hydrothermal citric acid microwave-assisted (1500 W, 160 °C, 30 min; DFC-C1–C4). Thermogravimetric analysis (TGA) revealed that the thermal stability with respect to native BCP (Td = 330 °C) was higher for DFC-M1-M4 (Td = 345–348 °C) and lower for DFC-C1–C4 (322–325 °C). Both classes of material showed good propensity to hold water but failed to form stable hydrogels (5–7.5 wt% in water) unless they underwent bleaching which removed residual lignin and hemicellulosic matter, as evidenced by 13C solid-state NMR spectroscopy. The hydrogels made from bleached DFC-C1–C4 (7.5 wt%) and bleached DFC-M1-M4 (5 wt%) exhibited rheological viscoelastic, shear thinning, and time-dependent behaviour, which highlights the potential opportunity afforded by microwave-assisted defibrillation of BCP for food applications.

Planet Earth is under severe stress from several inter-linked factors mainly associated with rising global population, linear resource consumption, security of resources, unsurmountable waste generation, and social inequality, which unabated will lead to an unsustainable 21st Century. The traditional way products are designed promotes a linear economy that discards recoverable resources and creates negative environmental and social impacts. Here, we suggest multi-disciplinary approaches encompassing chemistry, process engineering and sustainability science, and sustainable solutions in “game changer” challenges in three intersecting arenas of food: Sustainable diet, valorisation of unavoidable food supply chain wastes, and circularity of food value chain systems aligning with the United Nations’ seventeen Sustainable Development Goals. In the arena of sustainable diet, comprehensive life cycle assessment using the global life cycle inventory datasets and recommended daily servings is conducted to rank food choices, covering all food groups from fresh fruits/vegetables, lentils/pulses and grains to livestock, with regard to health and the environment, to emphasise the essence of plant-based diet, especially plant-based sources of protein, for holistic systemic sustainability and stability of the earth system. In the arena of unavoidable food supply chain wastes, economically feasible and synergistically (energy and material) integrated innovative biorefinery systems are suggested to transform unavoidable food waste into functional and platform chemical productions alongside energy vectors: Fuel or combined heat and power generation. In the arena of circularity of food value chain systems, novel materials and methods for plant-based protein functionalisation for food/nutraceutical applications are investigated using regenerative bio-surfactants from unavoidable food waste. This circular economy or industrial symbiosis example thus combines the other two arenas, i.e., plant-based protein sourcing and unavoidable food waste valorisation. The multi-disciplinary analysis here will eventually impact on policies for dietary change, but also contribute knowledge needed by industry and policy makers and raise awareness amongst the population at large for making a better approach to the circular economy of food.

The exploitation of unavoidable food supply chain wastes resulting from primary and secondary processing for chemicals, materials, and bioenergy is an important concept in the drive towards circular-based, resource-efficient biorefineries rather than petroleum refineries. The potential production of hydrogels (materials) from unavoidable food supply chain wastes, which are naturally rich in biopolymers such as cellulose, hemicellulose, pectin, and lignin, represents an interesting opportunity. However, these intertwined and interconnected biopolymers require separation and deconstruction prior to any useful application. Thus, this study aims to explore the formation of hydrogels from defibrillated celluloses (MW-DFCs) produced via acid-free stepwise microwave hydrothermal processing of blackcurrant pomace residues. Initially, pectin was removed from blackcurrant pomace residues (MW, 100–160 °C), and the resultant depectinated residues were reprocessed at 160 °C. The pectin yield increased from 2.36 wt.% (MW, 100 °C) to 3.07 wt.% (MW, 140 °C) and then decreased to 2.05 wt.% (MW, 160 °C). The isolated pectins were characterized by attenuated total reflectance infrared spectroscopy (ATR-IR), thermogravimetric analysis (TGA), and 13C NMR (D2O). The cellulosic-rich residues were reprocessed (MW, 160 °C) and further characterized by ATR-IR, TGA, and Klason lignin analysis. All the MW-DFCs contained significant lignin content, which prevented hydrogel formation. However, subsequent bleaching (H2O2/OH−) afforded off-white samples with improved gelling ability at the concentration of 5% w/v. Confocal laser microscopy (CLSM) revealed the removal of lignin and a more pronounced cellulosic-rich material. In conclusion, the microwave-assisted defibrillation of blackcurrant pomace, an exploitable unavoidable food supply chain waste, affords cellulosic-rich materials with the propensity to form hydrogels which may serve useful applications when put back into food products, pharmaceuticals, cosmetics, and home and personal care products.

Lignocellulose based nanomaterials are emerging green biosolids commonly obtained from wood pulp. Alternative feedstocks, such as as unavoidable food waste, are interesting resources for nano/microfibers. This research reports the production and characterization of microfibrillated lignocellulose (MFLC) from cassava peel (CP) and almond hull (AH) via acid-free microwave-assisted hydrothermal treatment (MHT) at different temperatures (120–220 °C). During processing, the structural changes were tracked by ATR-IR, TGA, XRD, 13C CPMAS NMR, zeta potential, HPLC, elemental analysis (CHN; carbon, hydrogen and nitrogen), TEM and SEM analyses. The microwave processing temperature and nature of feedstock exerted a significant influence on the yields and properties of the MFLCs produced. The MFLC yields from CP and AH shifted by 15–49% and 31–73%, respectively. Increasing the MHT temperature substantially affected the crystallinity index (13–66% for CP and 36–62% for AH) and thermal stability (300–374 °C for CP and 300–364 °C for AH) of the MFLCs produced. This suggested that the MFLC from CP is more fragile and brittle than that produced from AH. These phenomena influenced the gelation capabilities of the fibers. AH MFLC pretreated with ethanol at low temperature gave better film-forming capabilities, while untreated and heptane pretreated materials formed stable hydrogels at solid concentration (2% w/v). At high processing temperatures, the microfibrils were separated into elementary fibers, regardless of pretreatment or feedstock type. Given these data, this work demonstrates that the acid-free MHT processing of CP and AH is a facile method for producing MFLC with potential applications, including adsorption, packaging and the production of nanocomposites and personal care rheology modifiers.Graphic abstract

There is increasing evidence to suggest that arctic cultures and ecosystems have followed non-linear responses to climate change. Norse Scandinavian farmers introduced agriculture to sub-arctic Greenland in the late tenth century, creating synanthropic landscapes and utilising seasonally abundant marine and terrestrial resources. Using a niche-construction framework and data from recent survey work, studies of diet, and regional-scale climate proxies we examine the potential mismatch between this imported agricultural niche and the constraints of the environment from the tenth to the fifteenth centuries. We argue that landscape modification conformed the Norse to a Scandinavian style of agriculture throughout settlement, structuring and limiting the efficacy of seasonal hunting strategies. Recent climate data provide evidence of sustained cooling from the mid thirteenth century and climate variation from the early fifteenth century. Archaeological evidence suggests that the Norse made incremental adjustments to the changing sub-arctic environment, but were limited by cultural adaptations made in past environments.

We present palaeoenvironmental, geomorphological, archaeological, and place-name data which allow a holistic assessment of the history of landscape change on Sandoy, Faroe Islands, especially in terms of the changes that occurred in response to the colonization of the island by humans. In contrast to other situations in the North Atlantic region, there is considerable continuity in the patterns and processes of landscape evolution across the initial settlement horizon. Many of the characteristic features of post-settlement North Atlantic landscapes--absence of trees, widespread blanket mires, high rates of soil erosion--were already in place when the first people arrived. Although human impact on Sandoy appears to have been light, conversely, the unusual environment forced major alterations of the subsistence economy imported by the colonists. Settlement-era archaeological records suggest that, from the start, patterns of resource use differed substantially from the regional norm, and these differences became amplified over time as the Faroese economy created a locally sustainable cultural landscape.