The lack of proper waste management of health care facilities can have a significant negative health impact on the global population. This study provides a critical view on the current state of the existing healthcare waste management practices used in healthcare facilities around the world during the Coronavirus disease 2019 (COVID-19) pandemic outbreak. The increasing amount of COVID-related healthcare waste was analyzed and classified to provide justification for the urgent need to develop waste management standards that ensure safe containment and diversion of hazardous and non-hazardous wastes through recycling, reuse and repurposing. The waste handling, treatment, and disposal management of healthcare waste from various COVID-infected locations such as homes, quarantine centers, camps, and hospitals have been reviewed. A total of 100 documents on COVID-19 related healthcare waste were published on the Web of Science database over the 2020-2022 period. Innovative solutions for effective waste treatment and disposal, related government policies and regulations, and literature survey supported by VOSviewer-aided detailed bibliographic analysis are presented and critically discussed. Thus, the present research output advocates for a paradigm shift towards circular economy principles in healthcare waste management, emphasizing waste reduction, recycling, and recovery, and encourages global cooperation to develop resilient, crisis-responsive waste management systems.

Due to the population growth, there is an urgent need for sustainable technologies and products to address the imbalance between the availability of arable land and growing food needs. Increasing crop productivity in a cost-efficient and environmentally-friendly pathway is one approach to address this issue. In this study, lignin, a low-cost and underutilized by-product of the pulping industry, was converted to a fertilizer via oxidation in the presence of KOH. The oxidation of lignin in water (15 wt%) under the conditions of 195 degrees C temperature, 300 psi pressure, and KOH dosage of 30 wt% (based on dried lignin) generated water-soluble lignin enriched with carboxylate groups. The X-ray photoelectron spectroscopy (XPS) and proton nuclear magnetic resonance (1H NMR) analyses confirmed the introduction of carboxylate groups to lignin, while 31P NMR and heteronuclear single quantum coherence (HSQC) NMR studies confirmed the alterations in the aliphatic and aromatic struc-tures of lignin. The fertilizing effects of oxidized lignin were investigated on Zea mays (maize) plants. The results confirmed that the average length and dry weight of the plants grown in the presence of oxidized kraft lignin were 27% and 92% greater than those produced without lignin, and they were 12% and 81% higher than those grown in the presence of humic acid, respectively. After 30 days, the plants grown in the presence of oxidized kraft lignin contained 14% and 32% more chlorophyll than those generated in the presence of humic acid and control samples, respectively. Finally, the ash content analysis of the plants shows that applying oxidized kraft lignin as a fertilizer can reduce the ash content and increase the organic content of plants. These results confirmed that the oxidation of kraft lignin in the presence of KOH could be a strategy to induce a green fertilizer for crop cultivation.

Lichens produce a large variety of secondary metabolites with diverse bioactivities, chemical structures, and physicochemical properties. For this reason, there is a growing interest in the use of lichen-derived bioactive molecules for drug discovery and development. Here, we report on the isolation, identification, and cytotoxic evaluation of gyrophoric acid (GA) from the lichen Umbilicaria muhlenbergii, a largely unexplored and scantly described lichen species. A simple purification protocol was developed for the fractionation of lichen crude extracts with silica gel column chromatography using solvents with changing polarity. GA was identified in one of the fractions with Fourier transform infrared spectroscopy (FTIR), ion trap mass spectrometry (MS), and nuclear magnetic resonance spectroscopy (1H-NMR and 13C-NMR). The FTIR spectra demonstrated the presence of aromatic and ester functional groups C=C, C-H, and C=O bonds, with the most remarkable signals recorded at 1400 cm−1 for the aromatic region, at 1400 cm−1 for the CH3 groups, and at 1650 cm−1 for the carbonyl groups in GA. The MS spectra showed a molecular ion [M-1]− at (m/z) 467 with a molecular weight of 468.4 and the molecular formula C24H20O10. that correspond to GA. The 1H-NMR and 13C-NMR spectra verified the chemical shifts that are typical for GA. GA reduced the cell viability of breast cancer cells from the MCF-7 cell line by 98%, which is indicative of the strong cytotoxic properties of GA and its significant potential to serve as a potent anticancer drug.

Biodiesel is a biodegradable, renewable, and carbon-neutral alternative to petroleum diesel that can contribute to the global effort of minimizing the use of fossil fuels and meeting the ever-growing energy demands and stringent environmental constraints. The aim of this work was to (1) review the recent progress in feedstock development, including first, second, third, and fourth-generation feedstocks for biodiesel production; (2) discuss recent progress in lipase research and development as one of the key factors for establishing a cost-competitive biodiesel process in terms of enzyme sources, properties, immobilization, and transesterification efficiency; and (3) provide an update of the current challenges and opportunities for biodiesel commercialization from techno-economic and social perspectives. Related biodiesel producers, markets, challenges, and opportunities for biodiesel commercialization, including environmental considerations, are critically discussed.

Biodiesel is a promising renewable energy source that can be used together with other biofuels to help meet the growing energy needs of the rapidly increasing global population in an environmentally friendly way. In search for new and more efficient biodiesel production methods, this work reports on the synthesis and use of a novel biocatalyst that can function in a broader range of pH and temperature conditions, while producing high biodiesel yields from vegetable oils. Biodiesel was synthesized by transesterification of non-edible Eruca sativa oil using a lipase from Aspergillus niger that was immobilized on cerium oxide bismuth oxide nanoparticles. The synthesized nanoparticles were first grafted with polydopamine which facilitated the subsequent anchoring of the enzyme on the nanoparticle support. The enzyme activity, pH and temperature stability, and reusability of the immobilized lipase were superior to those of the free enzyme. Following response surface methodology optimization, the highest biodiesel yield of 90.6% was attained using 5 wt% biocatalyst, methanol to oil ratio of 6:1, reaction temperature of 40 °C, pH of 7, and reaction time of 60 h. The produced biodiesel was characterized by Fourier transform infrared spectroscopy and its fatty acid methyl ester composition was determined by gas chromatography-mass spectrometry. Erucic acid methyl ester was identified as the major component in biodiesel, with 47.7 wt% of the total fatty acid methyl esters content. The novel nanobiocatalyst (Bi2O3·CeO2@PDA@A.niger.Lipase) has the potential to produce high biodiesel yields from a variety of vegetable oils.

The objective of this work was to examine opportunities for reducing the overall cost of lignocellulose hydrolysis to fermentable sugars. Primary sludge (PS), a negative cost lignocellulosic feedstock, was hydrolyzed sludge using a commercial cellulase preparation (Cellic (R) CTec2) in presence of non-ionic surfactants. Polyethylene glycol (PEG) 4000 facilitated the highest hydrolysis yield of 74.4% which represented a 2-fold increase over the control without surfactant. Response surface methodological analysis at four variables (hydrolysis time, solids, enzyme, and surfactant loadings) revealed that enzymatic hydrolysis was significantly enhanced by the interactive effect of all factors with solids and enzyme loadings as the most significant parameters (p < 0.05). Using ultrafiltration, 40% of the cellulase enzyme was recovered from the enzymatic hydrolysate and reused on fresh PS substrate. The hydrolysate fermentabilty was evaluated in production of 9.7 g/L bioethanol at 92% ethanol yield using Saccharomyces cerevisiae, and in production of 37.8% biolipids by the oleaginous yeast Cutaneotrichosporon oleaginosum at a carbon to nitrogen ratio of 40. The compression load of a sample prepared from the unhydrolyzed PS solids was 102% higher than Portland cement. The potential for valorization of the unhydrolyzed solids as reinforcement material warrants further investigations. (C) 2020 Elsevier Ltd. All rights reserved.

OBJECTIVE:Lichens are emerging as a promising natural source of bioactivities of pharmaceutical interest. The present study aims to contribute to the knowledge of the lichen Umbilicaria muhlenbergii as a potential source of pharmaceutically relevant anticancer and antibiotic lichen chemicals.METHODS:The crude acetone extract of U. muhlenbergii exhibited 13.3 μg mL-1 cytotoxic activity (EC50) against breast cancer cells (MCF-7), as compared to a cisplatin positive control with EC50 of 5.8 μg mL-1. The antibiotic activity of the crude extract against a gram-positive Staphylococcus aureus was 22.5 μg mL-1 as MIC. Using silica gel 60 (SG60) column chromatography, the crude extract was then separated into eight fractions, which were further evaluated for their anticancer activities against MCF-7 cells. By means of propidium iodide flow cytometry, two of the eight SG60 fractions were found to cause cell cycle arrest in MCF-7 cells (73.14% of cells) at the G2 phase, which is indicative of apoptosis and inhibition of cellular proliferation.RESULTS:Identification of chemical constituents present in these two SG60 fractions was carried out with Thin-Layer Chromatography (TLC) and a lichen metabolite database (Wintabolites). The two fractions (SG60-5 and SG60-6) were found to contain compounds belonging to the chemical families depsides, depsidones, anthraquinones, and xanthones.DISCUSSION:The SG60-5 and SG60-6 fractions were further fractionated with Sephadex LH-20. Over 15% of the 46 LH-20 fractions obtained from the SG60-5 fraction caused 100% cell death, whereas 32% of the LH-20 fractions derived from SG60 6 fraction reduced cell survival to below 20%.CONCLUSION:This work extends the evaluation of the cytotoxic and antibiotic activities of lichen secondary metabolites to the species U. muhlenbergii. It presents encouraging results of pharmaceutical interest that set up lichens as an effective source of new bioactive natural products. Further investigations are underway to reveal the full biopharmaceutical potential of U. muhlenbergii.

Crude tall oil (CTO) is the third largest by-product at kraft pulp and paper mills. Due the large presence of value-added fatty and resin acids, CTO has a huge valorization potential as a biobased, readily available, non-food, and low-cost biorefinery feedstock. The objective of this work was to present a method for the isolation of high-value linoleic acid (LA), an omega (ω)-6 essential fatty acid, from CTO using a combination of pretreatment, fractionation, and purification techniques. Following the distillation of CTO to separate the tall oil fatty acids (TOFAs) from CTO, LA was isolated and purified from TOFAs by urea complexation (UC) and low-temperature crystallization (LTC) in the temperature range between −7 and −15 °C. The crystallization yield of LA from CTO in that range was 7.8 w/w at 95.2% purity, with 3.8% w/w of ω-6 γ-linolenic acid (GLA) and 1.0% w/w of ω-3 α-linolenic (ALA) present as contaminants. This is the first report on the isolation of LA from CTO. The approach presented here can be applied to recover other valuable fatty acids. Furthermore, once the targeted fatty acid(s) are isolated, the rest of the TOFAs can be utilized for the production of biodiesel, biobased surfactants, or other valuable bioproducts.

Introduction: To date, over 1,000 lichen secondary metabolites have been identified. Despite their promising cytotoxic properties, the number of literature reports on anticancer evaluation of lichenochemicals is limited. As cancer prevalence among the human population increases, there is growing interest in lichens as a natural source of secondary metabolites for anti-cancer drug discovery and development. Areas covered: The lack of significant progress in lichen anticancer research is due to the low levels of cytotoxic compounds contained in lichens, the technical difficulties associated with their isolation and characterization, and the insufficient understanding of their mechanism of action on different cancer cell lines. In this review, the authors discuss these challenges and provide systematically organized information on the limitations and advantages of commonly used and newly developed methods for lichen exploration and screening of lichen secondary metabolites for their anticancer potential. Expert opinion: Recent research activities have demonstrated that lichen secondary metabolites possess chemotherapeutic properties. A systematic and multidisciplinary approach is required to advance lichen research and improve our understanding of the mechanisms responsible for the potent cytotoxic properties of lichenochemicals. More efforts need to focus on screening and discovery of new lichen-derived compounds with unique anticancer properties.

Nowadays, most of the commonly used superabsorbent polymers (SAPs) are derived from synthetic polymers, particularly acrylic acid and its copolymers made with acrylamide. Here, we describe a novel and environmentally friendly aqueous-based process for fabrication of a new, natural, cellulose-based SAP (hydrogel). In this two-step process, cellulose was first reacted with sodium monochloroacetate (MCA) to obtain carboxymethyl cellulose (CMC) and then cross-linked with epichlorohydrin (ECH). In distilled water (d-water), the water retention value (WRV) of the newly fabricated hydrogels reached 725 g d-water/g gel, which is significantly greater than any other commercially available superabsorbent cellulose-based material (WRV of 10-100 g/g) and comparable to the commercial synthetic (polyacrylate) SAP gels (WRV of up to 1000 g/g). In saline water (s-water; 0.9% NaCl), the maximum WRV attained was 118 g s-water/g gel, which exceeds more than 2-fold the WRV of commercial gels (40-50 g/g). Compositional analysis was carried out to determine the amount of carboxyl groups and average molecular mass, and the parameters for hydrogel preparation were optimized. The natural SAP was characterized using scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), and X-ray diffraction (XRD). The hydrogels showed good re-swelling properties losing only 5-10% of their capabilities to reabsorb d-water when reused in four consecutive cycles. Because of their superior swelling properties in physiological saline, the new hydrogels can compete with their synthetic counterparts in applications such as high-value hygiene and biomedical products.

A novel process for the production of superabsorbent materials (hydrogels) from bacterial cellulose (BC) was developed. Prior to crosslinking with a water-soluble polyethylene glycol diacrylate (PEGDA), BC was first carboxymethylated and functionalized with glycidyl methacrylate. The degree of crosslinking influenced the swelling properties of the hydrogels. The use of greater amounts of PEGDA enhanced the formation of a thicker macromolecular network containing fewer capillary spaces in the crosslinked gel. The maximum water retention value of the hydrogels containing 2.5-3.5 mmol of carboxyl groups per gram of gel reached 125 g g(-1) in distilled water, and 29 g g(-1) in saline (0.9% NaCl solution). The highly porous hydrogel architecture with a pore size of 350-600 mu m created a high specific surface area. This enables rapid mass penetration in superabsorbent applications. The superabsorbent hydrogels reached 80% of their maximum water absorption capacity in 30 min. (c) 2018 Society of Chemical Industry

We have developed a new, aqueous-based process for production of superabsorbent materials that is catalyst-free and eco-friendly as the superabsorbent was derived from two completely biodegradable polymers with water as the only byproduct. The new hydrogels were obtained by cross-linking partially oxidized bleached kraft pulp fibers with carboxymethylated chitosan. In distilled water, the maximum water retention value (WRV) of the cross-linked hydrogels reached 610 (g/g gel), which is several times higher than any neat cellulose-based superabsorbent material reported in the literature. In saline water, the WRV of the new hydrogels (85 g/g) doubled that of commercial gels (40-50 g/g). In the presence of potassium or ammonium cations, the WRV increased further to reach 91 and 96 g/g, respectively. Gels only lost 5-10% of their reswelling capacity when reused four consecutive times. The hydrogels had high porous architecture and specific surface area that facilitates rapid mass penetration in superabsorbent applications. Due to their superior swelling properties, reusability, and biodegradable nature, the new hydrogels could serve as strong candidates to replace synthetic petroleum-derived polymers and find uses in high-value hygiene, food, agricultural, and pharmaCeutical products.

The green bacterial cellulose (BC)-based hydrogel materials have successfully prepared by modification and crosslink BC. BC was derived from acetic acid bacteria isolated and selected from ripe fruits. The production of BC was performed by fermentation in various media. It was found that using liquid potato medium represented the highest thickness of BC film (0.80 cm) with 2 wt% solid content covered the media. To reduce the crystallization of BC, carboxyl group was introduced onto BC chains using a carboxymethylation reaction giving carboxymethyl BC (CMBC) and subsequently crosslinked with divinyl sulfone (DVS). The extent of crosslinking influenced on the swelling properties of the hydrogels. Using large DVS amounts (>30 wt%-of CMBC), dense macromolecular network with less capacity spaces in the hydrogel was formed. The maximum water retention value of green hydrogels containing ~3.0 mmol carboxyl groups/g CMBC reached 27 (g/g).

Addition of surfactants to enzymatic hydrolysis has been reported to enhance the hydrolytic potential of enzymes in the bioconversion of lignocellulosic biomass to fermentable sugars. The objective of this investigation was to evaluate the effects of four non-ionic surfactants (PEG4000, PEG8000, TitronX-100, and Tween80) on the efficiency of enzymatic hydrolysis of steam-pretreated poplar using a commercial cellulase preparation (Cellic® CTec2). Statistical discriminant analysis at four variable factors (surfactant type, surfactant concentration, hydrolysis time, and substrate consistency) revealed that enzymatic hydrolysis was significantly enhanced in the presence of PEG4000, with 19.2% increase in glucose yield over control without surfactant, whereas ANOVA test indicated substrate consistency and hydrolysis time as the most significant factors (P < 0.05). Hydrolysis of poplar pulp at 5% w/w pulp consistency with CTec2 in presence of 1% w/w PEG4000 produced the highest glucose yield of 58.5% after 96 h reaction time.

Although cellulosic fibers are increasingly used in textile products, current methods for production of cellulose-based textiles suffer certain economic and/or environmental drawbacks. We have developed a new, cost-effective and environmentally-friendly (CS2-free) process that overcomes some of the shortcomings of existing technologies. The process is based on a modified method for periodate oxidation of cellulose that is then cross-linked with chitosan and extruded to obtain cellulosic fibers in the form of textile fibers. The produced fibers have low content of aldehyde groups (∼2mmol/g cellulose) and water retention values of 1.5-2.0g/g fibers. The new process makes use of both hardwood and softwood pulps, and offers significant yield advantages over the use of dissolving pulp as a raw material. The mechanical, water absorbency and morphological properties of the new textile fibers and their potential applications are discussed. The potential techno-economic and environmental benefits of the process are summarized.

The primary objective of this work was to investigate the thermal and rheological properties of crude tall oil (CTO), a low-cost by-product from the Kraft pulping process, as a potential feedstock for biodiesel production. Adequate knowledge of CTO properties is a prerequisite for the optimal design of a cost-effective biodiesel process and related processing equipment. The study revealed the correlation between the physicochemical properties, thermal, and rheological behavior of CTO. It was established that the trans/esterification temperature for CTO was greater than the temperature at which viscosity of CTO entered a steady-state. This information is useful in the selection of appropriate agitation conditions for optimal biodiesel production from CTO. The point of interception of storage modulus (G′) and loss modulus (G′′) determined the glass transition temperature (40 °C) of CTO that strongly correlated with its melting point (35.3 °C). The flow pattern of CTO was modeled as a non-Newtonian fluid. Furthermore, due to the high content of fatty acids (FA) in CTO, it is recommended to first reduce the FA level by acid catalyzed methanolysis prior to alkali treatment, or alternatively apply a one-step heterogeneous or enzymatic trans/esterification of CTO for high-yield biodiesel production.

BACKGROUND:Lichens provide a large array of compounds with the potential for pharmaceutical development. In the present study, extracts from three previously undescribed North American lichen species were examined for antioxidant, antibacterial and anticancer activities. RESULTS:The results from this study demonstrated the following: (i) Acarospora socialis ethanol extract exhibited significant DPPH antioxidant scavenging activities, which were concentration dependent; (ii) acetone and ethyl acetate extracts of Xanthoparmelia mexicana inhibited Gram-positive bacteria but had no effect on Gram-negative bacteria; X. mexicana acetone extract yielded a minimum inhibitory concentration (MIC) of 20.9 µg mL-1 against Staphylococcus aureus, and 41.9 µg mL-1 against Enterococcus faecalis; (iii) acetone extract of Lobothallia alphoplaca inhibited growth of cultured breast cancer MCF-7 cells with an effective concentration (EC50 ) of 87 µg mL-1 ; the MCF-7 cell cycle appears arrested in the G2 phase, whereas the DNA synthesis cell cycle (S) may be inhibited. CONCLUSION:New lichen species that possess strong biological activities have been identified. These lichens comprise secondary metabolites that possess antioxidant, antibacterial and anticancer properties. © 2017 Society of Chemical Industry.

This work provides a critical overview of the recent trends toward the development of modern, dissolving pulp production technologies that respond to the current challenges and opportunities for the emerging low-carbon bioresource economy. Special attention is paid to recent advancements in prehydrolysis kraft pulping and conversion of paper grade pulp to dissolving pulp, with emphasis on the valorization of hemicellulose to value-added products. A comprehensive analysis of the current and future developmental opportunities for novel bioprocessing technologies and new products from dissolving pulp that aim to improve the process economics and enhance the industry competitiveness is presented and discussed.

Inhibitors generated during biomass pretreatment negatively affect fermentability of biomass hydrolysates and need to be removed prior to fermentation. In this study, four different polymeric resins were evaluated for their abilities to remove acid soluble lignin (ASL) from poplar hydrolysate. The ASL removal capabilities of Amberlite IRA-400 (OH-) and XAD-4 were similar (96.7% and 97.3%, respectively), however 88% of xylo-saccharides (XS) were lost with XAD-4 treatment as compared to 21% with IRA-400 (OH-) treatment. IRA-400 (OH-) was also efficient in adsorption of aromatic-based inhibitors such as benzoic acid, vanillin and 4-hydroxybenzoic acid. The consecutive resin IRA-400 (OH-) -> enzyme (HTec2) treatment removed 79.5% of ASL from the hydrolysate at a loss of only 9.5% of xylo-based carbohydrates (XBC). This improved the hydrolysate fermentability to ethanol attaining 41.5 g/L ethanol titer and 89.6% ethanol yield at a sugar utilization efficiency of 95.3% after 72 h of fermentation. (C) 2017 Elsevier Ltd. All rights reserved.