Bento, ArturTome, Ana S.Robertson, MichaelGaugler, Evamaria C....
11页
查看更多>>摘要：The bark of Pinus radiata is an under-utilized forest residue that is renewable, abundant and has the potential to become a source of sustainable high-value chemicals. However, the use of this bark within a biorefinery for advanced applications is hindered by its intractable characteristics: high integrity, complex composition, and high heterogeneity. Most of the bark is burnt to provide energy and heat. The bark contains a high portion of phenolic extractives, constituting a potential source of valuable compounds. It also contains the heteropolymer suberin, a source of unique building blocks for developing innovative materials with potential broad bactericidal properties. Removal of phenolic extractives and suberin from bark simplifies down-streaming pulping processing of bark's lignocellulosic part. Herein, we describe an effective green strategy to sequentially extract the lipophilic bark constituents and suberin, exploring scCO2 (40, 50 or 60 degrees C / 200, 350 or 500 bar) and a biocompatible ionic liquid catalyst. The obtained scCO2 extracts had similar diversity of lipophilic compounds and predominantly contained resin acids. Further extraction of the scCO2 extracted bark yielded suberin amounts of 2.25% wt. The bark's suberin structure shows archetypal chemical features yet has an idiosyncratic high abundance of alkanoic acids, which is not common in most sources. The findings of this opening bark biorefinery study deserve further development and complementary techno-economic analyses to secure new value chains for the bark's major lipophilic compounds consisting of resin acids and bark suberin.
Aini, Nor Anizah MohamadOthman, NadrasHussin, M. HazwanSahakaro, Kannika...
11页
查看更多>>摘要：This study reports the effect of two different types of compatibilizer, namely epoxidized natural rubber with 50 mol% of epoxide group (ENR-50) and liquid butadiene rubber (LBR-352) for carbon black/lignin-filled natural rubber/polybutadiene rubber (NR/BR) composites in the range of 5-15 parts per hundred rubber (phr). The presence of ENR at concentrations up to 10 phr in carbon black/lignin-filled NR/BR composites reduced cure and scorch time by 33.7% and 21.1% respectively, compared to composites without ENR. This contributed to a better dispersion of the filler and an increase of the 300% modulus by 28.1%. Scanning electron microscopy results (SEM) showed better interaction between carbon black/lignin-filled NR/BR with ENR. Meanwhile, the composites with LBR showed the lowest filler-filler interaction, indicated by a decrease in storage modulus with an increase in strain in the filled compound i.e., Payne effect. Moreover, the utilization of LBR was increased by 168.8% compared to 18.3% with the addition of ENR. It can be concluded that the presence of ENR can enhance the mechanical, flexibility and dynamical properties, while the use of LBR can improve the process-ability and flexibility of rubber composites.
查看更多>>摘要：Flowers of tuberose (Polianthes tuberosa L.) are usually fragrant and are cultivated commercially to meet the demand of both loose and cut flower applications. This in turn generates huge floral wastes after their utilization in decoration and rituals. In this work we aim to explore waste flowers to isolate floral concrete as by-product for possible utility in skincare products. Such attempt of converting floral waste into commodity product remained apparently unexplored with cultivated flowers including tuberose. Further, no information is apparently available on the phytoconstituent of the tuberose floral concrete that constitute its waxy nature. Here we extracted floral concrete from waste flowers of two popular tuberose cultivars namely, Calcutta Single (CS) and Calcutta Double (CD) using n-hexane as solvent. Floral concrete extracts after derivatization were subjected to GC-MS analysis which revealed the presence of several fatty acid and fatty acid ester compounds. Presence of higher content of fatty acids in floral concrete of CD was detected. In contrast, ester components were found to be higher in CS, suggestive of its fragrant nature. Extracted floral concretes from both the cultivars exhibited comparable antioxidant capacities and DNA protection abilities. Further, floral concrete from CS cultivar showed higher inhibition of tyrosinase activity than CD, while elastase and hyalumnidase activities were greatly inhibited by the extracted concrete from CD cultivar suggesting their possible utility in skin-care product.
查看更多>>摘要：Acetone-butanol-ethanol (ABE) and lipids were produced from sugarcane molasses via coupled fermentation by Clostridium acetobutylicum and oleaginous yeasts. ABE fermentation of sugarcane molasses with varying sugar concentrations (50-100 g/L) was investigated, and the wastewaters were analyzed and classified into two types based on their carbon source content and structure. Then, four oleaginous yeasts were cultured on the two types of ABE fermentation wastewaters respectively, and their lipid productions, removals of COD and ammonia were investigated and evaluated. It was found that via coupling with lipid-producing fermentation process, the ABE fermentation wastewaters rich in organic acids could be effectively treated, the added value of the products obtained could be increased, meanwhile, the sugar load and treatment efficiency of the whole system could be improved. Specifically, ABE fermentation by C. acetobutylicum CH012 could be carried out normally on 50-80 g/ L of total sugars. The maximum solvents production, which was 19.640 g/L (5.580 g/L acetone, 13.159 g/L butanol and 0.901 g/L ethanol) with a corresponding yield of 0.335 g/g, was obtained at 70 g/L sugars. Wastewater (from the ABE fermentations performed at 50-60 g/L sugars) containing low concentrations (<3 g/ L) of sugars and taking organic acids as dominant carbon source was defined as Type-1, while wastewater (from the ABE fermentations performed at 70-80 g/L sugars) containing high concentrations (10-20 g/L) of sugars and taking sugars as dominant carbon source was defined as Type-2. Trichosporon dermatis could performed well on both Type-1 and Type-2 wastewaters in terms of lipids production and removals of COD and ammonia. Lipomyces starkeyi did not adapt to Type-1 wastewater, but when culturing on Type-2 wastewater, it achieved the highest lipid production of 2.37 g/L with COD and ammonia nitrogen removal rate of 64.62 % and 57.09 % respectively.
查看更多>>摘要：Traditional hemp degumming creates large volumes of effluent. Chemical treatment and discharge of the degumming solution is still a challenging task. In this work, ethanol-water solution was reused for hemp degumming and gum recovery was explored to reduce effluent volume and improve resource recovery. The influences of recycling times on fiber color, morphology, mechanical properties, thermal properties and dimensional properties were investigated. Also, the characterizations of the extracted lignin were conducted. The results indicated that pectin could be removed in every degumming cycle. Above 86% of cellulose could be achieved in the five degumming cycles and fiber tenacity increased with each consecutive cycle from 35.6 to 43.6 cN/tex. Most importantly, spherical lignin particles could be extracted from the solution of the last degumming cycle with an average diameter of 249.7 nm. This work contributes to green degumming of bast fibers, reducing degumming cost and value-adding of the lignin-rich residues.
Genisheva, Z. A.Flores-Lopez, M. L.Jasso de Rodriguez, D.Victorino-Jasso, M. C....
7页
查看更多>>摘要：Urinary tract infections (UTIs) represent a serious health problem worldwide and are the third most common infectious disease in Mexico. With the excessive use of antibiotics, bacterial species are becoming resistant to drugs prescribed to treat UTIs. These factors have attracted the attention of researchers toward identifying natural antibiotic compounds obtained from plants that provide similar antibacterial activity. Flourensia retinophylla S.F. Blake is an endemic plant from the semi-arid zones of Mexico that has been reported to produce bioactive compounds. Therefore, the aims of this study were to evaluate the in vitro antibacterial activity of the F. retinophylla extract against six bacterial species that cause UTIs: Enterobacter aerogenes, Escherichia coli, Proteus hauseri, Proteus mirabilis, Proteus vulgaris, and Staphylococus epidermidis, and identify the chemical compounds in the extract. The extract was obtained using procedures such as agitating with ethanol, evaluating phytochemicals for total phenolic and flavonoid contents (TPC and TFC, respectively), determining antioxidant activity, and analyzing chemical composition using gas chromatography-mass spectrometry. Antibacterial activity was evaluated in vitro for the six bacterial species. The results showed a TPC of 78.6 mg of gallic acid equivalent/100 mg of extract and a TFC of 47.1 mg of (+)-catechin equivalent/100 mg of extract with antioxidant activity of 86.8%. Moreover, the extract exhibited remarkable antibacterial activity, with a range of minimal inhibitory concentrations for 90% bacteria (MICs90) from 50 to 156.2 mg/L, with values lower than those obtained with penicillin G on E. aerogenes, P. hauseri, P. mirabilis, and S. epidermidis. F. retinophylla leaf extract showed noteworthy bactericidal activity by inhibiting the growth of all six pathogenic bacterial species causing UTIs, mainly E. aerogenes, P. hauseri, and P. mirabilis.
查看更多>>摘要：Formaldehyde attacks the ortho phenolic hydroxyl groups on the p-hydroxyphenyl and guaiac-based structures in the lignin, shedding the hydrogen atom on the ortho-position carbon and grafting hydroxymethyl group to obtain the hydroxymethylated modified lignin (HMKL). The infrared spectroscopy, hydrogen NMR spectroscopy, thermogravimetric (TG), and derivative thermogravimetric (DTG) analysis show that the hydroxymethylation modification of alkali lignin is successful. Then, lignin nanoparticles (LNPs) are prepared by the acid precipitation self-assembly method in ethylene glycol solution of hydroxymethylated modified lignin. The particle size and shape of lignin nanoparticles are determined by scanning electron microscopy and dynamic light scattering (DLS) analysis. In the liquefaction agent prepared from polyethylene glycol 400 and glycerol, the graft polyol is liquefied under methanesulfonic acid. The Fourier transform infrared spectroscopy, hydrogen NMR, and thermogravimetric analysis indicate the successful formation of nano-lignin polyols. In addition, epoxy resin is synthesized by two-step epoxidation of nano-lignin polyols including ring-opening and closed-loop epoxidation in an alkaline environment. The prepared epoxy resin from nano-lignin polyol exhibits excellent performance and wide application prospects. The optimum process conditions are the mass fraction of LNP-P is 19.98 %, the amount of catalyst (NaOH) is 20.10 %, the reaction time is 6.99 h, the solid content of the epoxy resin is 57.05 %, the viscosity is 615.58 mPa.s, the tensile strength is 44.80 MPa, the elastic modulus is 2.77 GPa.
查看更多>>摘要：Exploring new aldehydes with non-volatility and non-toxicity to replace formaldehyde (FA) for the fabrication of melamine resins (MRs) with eco-friendliness is a topical challenge worldwide. Herein, we report on a novel and facile way to synthesize an eco-friendly MR using a green crop-oriented saccharide-derived aldehyde (SDA) instead of FA. FTIR, NMR and XPS spectra demonstrated that a biomass-derived aldehyde bonded melamine resin (BMR) was synthesized. GPC test showed that the weight average molecular weight of BMR could be up to 4849 g/mol when the mole ratio between SDA and melamine (MA) was 1:1, which decreased as the SDA dosage increased. The application of BMR as a filling agent for leather processing indicated that BMR could improve the hydrothermal stability of filled leather and exhibited reasonable thickening capability. Meanwhile, the BMRtreated crust leather had higher mechanical strengths than melamine FA resin (MFR)-treated crust leather, and it contained almost no FA while the FA content of the MFR-treated crust leather was up to 86.4 mg/kg, indicating the favorable eco-friendliness of BMRs. This work presents a significant step forward for synthesizing environmentally-friendly BMR used in eco-leather production and other MR-involved industries.
查看更多>>摘要：In this work, alpha-etherification of lignin in diol pretreatment was selectively enhanced at mild temperature for lignin isolation and subsequent valorisation. More than 90 % of lignin was removed from Eucalyptus at 120 degrees C in diol (ethylene glycol and 1,4-butanediol) pretreatment, resulting in > 90 % cellulose conversion in 24 h at 7.5 FPU/g glucan cellulase loading. Subsequent catalytic transfer hydrogenolysis of the isolated lignins with Ru/C in ethanol gave 15 % monomer yield on native lignin basis, 5 times of that from the technical ethanol process (170 degrees C). HSQC NMR analysis revealed that diol pretreated lignin (120 degrees C) contained ~23 % alpha-etherified beta-O-4 interunit bonds, indicating that lignin degradation (i.e. cleavage of beta-O-4 bonds) was suppressed via etherification by grafting a hydroxyl group at the alpha position of lignin. This finding was consistent with the isolated lignin (120 degrees C) had less number of phenolic OH and higher molecular weight via P-31 NMR and GPC analysis. 31P NMR analysis also revealed that diol isolated lignin contained more number of aliphatic OH than ethanol-isolated lignin, which increased lignin solubility and maintained the high yield (> 80 %) of isolated lignin from Eucalyptus at 120 degrees C as expected. In summary, diol pretreatment of woody biomass can effectively isolate more lignin for hydrogenolysis to valued-added monomers without compromising the isolated yield of lignin and hydrolysis yield of remained cellulose.
NSTL
Elsevier