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Biomass conversion to value added chemicals to be used as industrial platform molecules for further synthesis of commodity chemicals has opened new window for scientists. Biomass is a lignocellulosic compound and it requires technological development since biomass is a complex molecule of linear, cyclic and aromatic hydrocarbons. Lignin being aromatic in nature can beneficial for the production of phenolic hydrocarbons. In this work conversion of Guaiacol, a model lignin compound to different aromatic hydrocarbon is performed over pure silica and alumina silica catalysts e.g. SBA-15and ZSM-5 in a fixed bed catalytic reactor. SBA-15 material was synthesized at different aging time leading to improvement in surface area and pore diameter whereas ZSM-5 was pre-treated with H3PO4 and KOH to modify their acidic strength. Maximum Guaiacol conversion in absence of catalyst was obtained aa 90.1 % at 550oC, 97.33 % at 550 °c in presence of SBA-15 (C) and 95.33 % in presence of P/ZSM-5, indicating the catalyst helps in enhancing the conversion, however depends on the type of catalysts and its properties like surface area, pore diameter and Lews/Bronsted acid strength. Similarly the selectivity of catechol was observed to be maximum with SBA-15 (C) as compared to other catalyst owing to its high surface area and large pore diameter. The GCMS analysis of the liquid product obtained includes Dimethyl phenol, 2-dimethoxy benzene, 2-ethyl,5-methyl phenol, catechol, Ethynylanisole and O-cresol

Abstract Background Lignin is a highly abundant but strongly underutilized natural resource that could serve as a sustainable feedstock for producing chemicals by microbial cell factories. Because of the heterogeneous nature of the lignin feedstocks, the biological upgrading of lignin relying on the metabolic routes of aerobic bacteria is currently considered as the most promising approach. However, the limited substrate range and the inefficient catabolism of the production hosts hinder the upgrading of lignin-related aromatics. Particularly, the aerobic O-demethylation of the methoxyl groups in aromatic substrates is energy-limited, inhibits growth, and results in carbon loss in the form of CO2. Results In this study, we present a novel approach for carbon-wise utilization of lignin-related aromatics by the integration of anaerobic and aerobic metabolisms. In practice, we employed an acetogenic bacterium Acetobacterium woodii for anaerobic O-demethylation of aromatic compounds, which distinctively differs from the aerobic O-demethylation; in the process, the carbon from the methoxyl groups is fixed together with CO2 to form acetate, while the aromatic ring remains unchanged. These accessible end-metabolites were then utilized by an aerobic bacterium Acinetobacter baylyi ADP1. By utilizing this cocultivation approach, we demonstrated an upgrading of guaiacol, an abundant but inaccessible substrate to most microbes, into a plastic precursor muconate, with a nearly equimolar yields (0.9 mol/mol in a small-scale cultivation and 1.0 mol/mol in a one-pot bioreactor cultivation). The process required only a minor genetic engineering, namely a single gene knock-out. Noticeably, by employing a metabolic integration of the two bacteria, it was possible to produce biomass and muconate by utilizing only CO2 and guaiacol as carbon sources. Conclusions By the novel approach, we were able to overcome the issues related to aerobic O-demethylation of methoxylated aromatic substrates and demonstrated carbon-wise conversion of lignin-related aromatics to products with yields unattainable by aerobic processes. This study highlights the power of synergistic integration of distinctive metabolic features of bacteria, thus unlocking new opportunities for harnessing microbial cocultures in upgrading challenging feedstocks.

In a bushfire burning of plant material generates volatile phenolics that may be absorbed by berries and leaves of grapes in nearby vineyards. In grapes these phenolics form glycoconjugates and the undesirable sensory attributes of smoke-exposed grapes only develop post-fermentation in the wine making process, when the free phenolics are released. To reduce the financial losses from producing smoke-tainted wines, phenolic glycosides associated with smoke-taint in grapes are currently monitored in analytical laboratories. Here, we performed LC-MS analysis on extracts of diverse grape varieties of various geographic sites and with varying levels of smoke taint exposure. Discovery of smoke-taint biomarkers, based on untargeted analysis led to the identification of additional phenolic compounds that could contribute significantly to the smoke-tainted flavour of wine. A total of 73 differentially expressed metabolites were detected and LCMSMS analysis resulted in the structural assignment of 15 compounds, including guaiacol and syringol derivatives and novel glycoconguate intermediaries.

Bio-crude oil is known to be sustainable, eco-environmentally, and an alternative energy source produced by biomass pyrolysis. However, its quality remains relatively low due to a higher oxygen concentration compared to liquid fuels from fossils. Therefore, an upgrading process is necessary through the catalytic hydrodeoxygenation (HDO) process. This work synthesized pillared bentonite using Al and Ti metals as the pillaring agent to produce Al-PILC and Ti-PILC as catalyst support for sulfided NiMo. Their catalytic activity in HDO reaction using guaiacol as a model compound of bio-crude oil were also evaluated. Characterization of the bentonite-pillared materials, including Al-PILC, Mo/Al-PILC, NiMo/Al-PILC, Ti-PILC, Mo/Ti-PILC, and NiMo/Ti-PILC, was performed using Surface Area Analyzer, X-ray Diffractometer (XRD), Temperature-Programmed Desorption of ammonia (NH3-TPD), X-Ray Fluorescence (XRF), and Scanning Electron Microscope (SEM) techniques. The characterization results confirm the pillarization process of bentonite using Al and Ti metals as the pillaring agent, and the preparation of the NiMo catalyst using the stepwise impregnation method was successfully prepared. The NiMo/Ti-PILC catalyst performs a superior conversion value on the HDO guaiacol reaction than other catalysts. A well dispersion of Mo and Ni metals on the surface support (NiMo/Ti-PILC), thus creating numerous active sites of the catalyst after the sulfidation. Variations in time and temperature during the HDO guaiacol reaction significantly affected the conversion.

Vanillin (4-hydroxy-3-methoxybenzaldehyde) is an important platform chemical compound that is invariably produced from pyrolysis of various categories of biomass. Hydrodeoxygenation (HDO) of vanillin has been a thematic topic in catalysis with the underlying aim to devise processes and reactions for catalytic upgrading of bio-oil and in the production of value-added products. Herein, we investigate the HDO of an evaporated stream of vanillin over a 4 % load of palladium supported on ceria; a Pd/CeO2 catalyst. The synthesized catalyst was characterized by various techniques including XRD, XPS, EDX-SEM, HR-TEM, and TPR. The HDO reaction (carried out at temperatures from 100 °C to 300 °C at 10 °C/min ramp rate with a 5 % H2 feed ratio) resulted in a 95 % conversion of vanillin with an 85 % yield of guaiacol (2-methoxyphenol). Minute loads of alkylbenzene compounds (mainly xylene and ethylbenzene) also emerged. DFT computations elucidate pathways for the observed formation of guaiacol where synergistic effects of both Pd and vacant oxygen sites are highlighted. Overall, we presented a viable HDO route for an oxygenated biomass model compound at mild operational conditions (intermediate temperatures, ambient pressure, and moderate H2/Feed ratio).

A series of six composites was prepared from the reaction of lignin-derived guaiacol, fatty acids, and sulfur. In this preparation, the organic comonomers undergo C–S bond-forming reactions to establish a highly crosslinked network material in which some non-covalently incorporated sulfur species are also entrapped. Both monounsaturated oleic acid and diunsaturated linoleic acid were used as fatty acid components to assess the influence of their unsaturation levels on composite properties. The ratio of organics and the proportion of sulfur (70 or 80 wt%) was also varied to assess the effect on thermal, morphological, and mechanical properties. Thermogravimetric analysis showed that composites exhibited good thermal stability up to ~220 °C. Differential scanning calorimetry revealed that the materials generally exhibit melting features for entrapped cyclo-S8, cold crystallization features for some materials, and a composition-dependent glass transition temperature. The flexural and compressive strengths of the composites revealed that some of the composites exhibit strengths significantly higher than those required of Portland cements used in residential housing fabrication and may be more sustainable structural materials. The thermal and mechanical properties could be tailored by changing the degree of unsaturation of the fatty acid comonomer or by altering the percentage of fatty acid in the monomer feed. The highest mechanical strength was achieved with greater amounts of monounsaturated oleic acid comonomer.

The potential for grapes and wine to be tainted following vineyard exposure to wildfire smoke is well established, with recent studies suggesting hops and apples (and thus beer and cider) can be similarly affected. However, the susceptibility of other crops to ‘smoke taint’ has not yet been investigated. Smoke was applied to a selection of fruits and vegetables, as well as potted lavender plants, and their volatile phenol composition determined by gas chromatography–mass spectrometry to evaluate their susceptibility to contamination by smoke. Volatile phenols were observed in control (unsmoked) capsicum, cherry, lavender, lemon, spinach and tomato samples, typically at ≤18 µg/kg, but 52 µg/kg of guaiacol and 83–416 µg/kg of o- and m-cresol and 4-methylsyringol were detected in tomato and lavender samples, respectively. However, significant increases in volatile phenol concentrations were observed as a consequence of smoke exposure; with the highest volatile phenol levels occurring in smoke-exposed strawberry and lavender samples. Variation in the uptake of volatile phenols by different crops was attributed to differences in their physical properties, i.e., their surface area, texture and/or cuticle composition, while the peel of banana, lemon, and to a lesser extent apple samples, mitigated the permeation of smoke-derived volatile phenols into pulp. Results provide valuable insight into the susceptibility of different crops to smoke contamination.

Bio-oils derived from the pyrolysis of lignin-based biomass often contain a variety of oxygenated compounds, which can compromise their usefulness as a fuel. To improve the quality of bio-oil, catalytic hydrodeoxygenation (HDO) is a crucial step that removes oxygen from the oil in the form of water. In this study, we showed that MFI nanosheets are excellent supports for Ru-catalysts. We synthesized highly crystalline MFI nanosheets using a simple hydrothermal seeding procedure; the final material was obtained in 56 h of crystallization. We investigated the activity of Ru supported on different materials. Our findings indicated that Ru supported on hierarchical MFI demonstrated excellent activity in HDO of guaiacol. Our results demonstrated that Ru/ZNS-56 achieved nearly 100% selectivity towards cyclohexane under mild conditions (200 °C, 50 bar H2, 1 h).

Laccase is a fungal enzyme that play a crucial role in bioremediation. The purified laccase from Ganoderma multipileum and its effectiveness in bioremediation of Cr (VI) was determined in this study. Two strains of G. multipileum were identified by ITS sequences and their phylogeny was compared with G. multipileum taken from GenBank (KF494997, LC149613, MG739453, MG739455). The fungi were grown on guaiacol substrate for laccase optimization using different environmental and nutritional conditions. Laccase Glacc113 (75 kDa) was partially purified and characterized under different parameters. Glacc113 (GIAPTAD) was confirmed by using a Precise Protein Sequencing System to analyze sequence of N-terminal amino acid. Laccase exhibited maximum optimal activity (1355.5 ± 8.8 U/L) at pH 3.0 and can tolerate the maximum temperature upto 70 °C. During submerged fermentation, on 7th day after inoculum of 3 fungal discs at 100 rpm yielded maximum laccase. The production of laccase increased by optimization of inorganic and organic nitrogen and carbon sources. The purified laccase from G. multipileum was used to reduce (>94%) 100 μg/mL of Cr (VI) into less toxic chromium Cr (III). The catalytic kinetic parameters Vmax and Km for guaiacol were 1.817 (mM min−1) and 1.4617 (mM), respectively. This study determined the conditions that enhance production and an ecofriendly approach to bio remediate the Cr (VI) to Cr (III). The purified enzyme exerted maximum durability and reliability for industrial usage also.

Abstract Pholcodine and guaiacol are widely used together in pharmaceutical syrups for cough treatment. On the other hand, the Ultra Performance Liquid Chromatographic technique is characterized by having the power of increasing chromatographic efficiency and decreasing run time compared to the traditional High Performance Liquid Chromatographic one. In this work, this power was exploited for the simultaneous determination of pholcodine, guaiacol along with three guaiacol impurities, namely; guaiacol impurity A, guaiacol impurity B, and guaiacol impurity E. Good separation was achieved by employing Agilent Zorbax C8 column (50 × 2.1 mm) as the stationary phase, and acetonitrile: phosphate buffer pH 3.5 (40: 60, by volume) as a mobile phase. The proposed method was validated as per International Council for Harmonisation guidelines. Linear relationships, at ranges of 50–1000 µg mL−1 for pholcodine and 5–100 µg mL−1 for guaiacol and the three related impurities, were established. Finally, the proposed method was applied for pholcodine and guaiacol determination in Coughpent® syrup and compared favorably to the reported one.

Abstract Alicyclobacillus acidoterrestris (A. acidoterrestris), a kind of spore‐forming bacterium, could causes spoilage of fruit juices, which results in pecuniary losses to the industry. Unfortunately, the conventional methods used to identify this bacterium are laborious and complex. In this work, copper‐based metal‐organic frameworks (Cu‐MOFs) with intrinsic peroxidase‐like activity were fabricated by a self‐assembly method. Based on the properties of Cu‐MOFs, a colorimetric assay was developed for the detection of guaiacol, a characteristic metabolite of A. acidoterrestris and chromogenic substrate of peroxidase. Under optimal conditions, an excellent linear relationship was achieved over a range of guaiacol (0.01–0.4 mM), with a limit of detection (LOD) as low as 0.003 mM. This biosensor also showed a satisfactory sensing performance towards guaiacol, allowing the identification of A. acidoterrestris with high selectivity in a real sample. This present study provides a new perspective for the exploration of more sensitive and convenient methods for A. acidoterrestris detection.

In order to contribute to the shift from petro-based chemistry to biobased chemistry, necessary to minimize the environmental impacts of the chemical industry, 2-methoxy-4-vinylphenol (4-vinyl guaiacol, 4VG) was used to synthesize a platform of biobased monomers. Thus, nine biobased monomers were successfully prepared. The synthesis procedures were investigated through the green metrics calculations in order to quantify the sustainability of our approaches. Their radical homopolymerization in toluene solution initiated by 2,2′-azobis(2-methylpropionitrile) (AIBN) was studied and the effect of residual 4VG as a radical inhibitor on the kinetics of polymerization was also explored. The new homopolymers were characterized by proton nuclear magnetic resonance (1H-NMR) spectroscopy, size exclusion chromatography and thermal analyses (dynamical scanning calorimetry DSC, thermal gravimetric analysis TGA). By varying the length of the alkyl ester or ether group of the 4VG derivatives, homopolymers with Tg ranging from 117 °C down to 5 °C were obtained. These new biobased monomers could be implemented in radical copolymerization as substitutes to petro-based monomers to decrease the carbon footprint of the resulting copolymers for various applications.

Fruit juice spoilage that caused by contaminated Alicyclobacillus has brought huge losses to beverage industry worldwide. Thus, it is very essential to understand the growth and metabolism processing of Alicyclobacillus acidoterrestris (A. acidoterrestris) in controlling juice spoilage caused by Alicyclobacillus. In this work, simulative models for the growth and metabolism of A. acidoterrestris were systematically conducted in the medium and fruit juice. The results showed that low temperature (4 ℃) and strong acidic environment (pH 3.0–2.0) of medium inhibited the growth and reproduction of A. acidoterrestris. In addition, with decreasing temperature, the color, smell and turbidity of commercially available juice supplemented with A. acidoterrestris significantly improved. This work provided a clear exploration of growth characteristics of A. acidoterrestris by applying theory (medium) to reality (fruit juices), and pave fundamental for exploring the zero additives of controlling juice spoilage.

Here, we report a Ru/TS-1 catalyst for selective hydrogenolysis of guaiacol to benzene in the aqueous phase at conditions of 240 °C and 0.2 MPa H2, achieving a benzene yield of 86% with a hydrogenolysis rate of 103.1 mmol g−1 h−1. It was found that Silicalite-1 (MFI type) with suitable pore sizes supported Ru nanoparticles (NPs) favored for hydrogenolysis of guaiacol, whereas de-aluminated Ru/HBEA, Ru/HY and Ru/MWW (without acidic sites) accelerated the parallel reactions of hydrogenation of aromatics. In addition, Ru NPs located at the orifice of Silicalite-1 was proved to be more electron-deficient and active than Ru NPs on the outer surface, as evidenced by CO-IR characterization and activity tests on Ru/Silicalite-1 (with and without templates). Moreover, Brønsted acid sites (BAS) on Ru/MFI highly promoted the hydrogenation rates of aromatics, while Lewis acid sites (LAS) on Ru/TS-1 and Ru/MFI led to a linear increase of guaiacol hydrogenolysis rate to benzene, probably due to the enhanced absorbance capability of guaiacol and phenol on the LAS of MFI. Thus, pore structure properties of MFI coupled with abundant LAS (TS-1) as well as Ru NPs on the orifice of pores of TS-1 construct a promising catalyst for achieving efficient aromatic hydrocarbons from selective hydrogenolysis of lignin.

Some species of Alicyclobacillus spoil beverages by producing guaiacol. Current culture-based methods detect the presence of Alicyclobacillus spp. and a subsequent peroxidase assay determines if the isolate can produce guaiacol. However, these methods are time-consuming and can yield false negatives due to differences in growth optima among species. The purpose of this study was to compare a RT-PCR-based method, the GENE-UP® PRO ACB assay, to the IFU Method No. 12 Enumeration and Enrichment methods. Ten species of Alicyclobacillus were detected using the tested RT-PCR assay, while A. dauci and A. kakegewensis were not detected using either IFU protocol. Low concentrations (1–10, 10–100, and 100–1,000 CFU/10 mL) of A. acidoterrestris, A. suci, and A. acidocaldarius were tested in five matrices. The proportion of positive samples identified using the tested RT-PCR assay (62/84) or the IFU Enrichment protocol (62/84) did not differ significantly from the proportion of inoculated samples (63/84). However, the IFU Enumeration method (32/84) detected statistically fewer positives. Additionally, methods identifying guaiacol production were compared. The proportion of correctly identified guaiacol producers using the tested RT-PCR assay (51/63) was not significantly different than those identified using the 3 h Cosmo Bio assay (54/63). Finally, four commercial samples of orange juice and sucrose solution were tested. Alicyclobacillus spp. were identified in all four samples using the IFU Enrichment method and in two samples using the tested RT-PCR assay. However, Alicyclobacillus was not detected in any sample using the IFU Enumeration method. Overall, this study showed consistent detection of Alicyclobacillus spp. using either the IFU Enrichment protocol or the tested RT-PCR assay, which both outperformed the IFU Enumeration protocol. Both the 3 h guaiacol bioassay and the tested RT-PCR assays consistently differentiated guaiacol-producing and nonproducing strains.

The investigation of the low-cost deoxygenation of guaiacol (GUA, a model bio-oil compound) is of importance for upgrading bio-oil. At present, common sulfide catalysts for GUA deoxygenation reactions cause contamination of the liquid product, and noble metal catalysts are economically disadvantageous. In this study, four reduced Fe-based oxides with different Ce doping ratios were prepared and their effects on the in-situ deoxygenation performance of GUA in aqueous/methanol hydrogen donor solvents were explored. The results based on the deoxygenation degree, conversion degree, and higher heating value (HHV) of the products showed that the oxide catalyst with a Fe/Ce molar ratio of 2:1 in the methanol solvent performed very well. After selecting an excellent catalyst and a better hydrogen donor solvent, four factors (reaction temperature, reaction time, volume ratio of GUA dosage and methanol dosage, and the ratio of catalyst dosage at the bottom of the reactor to that at the top) in the deoxygenation degree of GUA were investigated using an orthogonal experimental method to further explore the performance of the catalyst. The results showed that the reaction temperature and time greatly influenced GUA deoxygenation. Under optimal experimental conditions, the deoxygenation degree and conversion degree of GUA could reach 34.36% and 92.56%, respectively, based on the relative peak area of gas chromatography–mass spectrometry, and the HHV of the liquid product was 32.27 MJ/kg. Although Fe/Ce catalysts mainly promote demethoxylation, demethylation, and methylation, the stability and quality of the liquid products were improved compared with GUA owing to the reduction in phenolic hydroxyl and ether content. The reduced catalyst in the process of GUA in-situ deoxygenation reactions in methanol maintained a steady performance, as revealed by X-ray diffraction and X-ray fluorescence.

Metarhizium robertsii microsclerotia are fungal aggregates composed of compacted, pigmented hyphae. As they are highly tolerant to desiccation and produce infective conidia, they are promising candidates to be formulated as bioinsecticides. Despite this potential, the nature of the pigments within these structures remains unclear. In this study, routine culture media used for the differentiation of M. robertsii microsclerotia were supplemented with four melanin inhibitors, and the resulting propagules were characterized. Inhibitors of the 1,8-dihydroxynaphthalene (DHN)-melanin biosynthetic pathway such as tricyclazole and guaiacol induced significant phenotypic and molecular modifications in the obtained M. robertsii propagules, which exhibited a more spherical shape, reduced size, and increased susceptibility to desiccation, heat, and oxidative stress than microsclerotia obtained without inhibitors. Additionally, genes encoding for a polyketide synthase (Mrpks2) and a putative 1,3,6,8-tetrahydroxynaphthalene reductase (Mrthnr), potentially involved in the DHN-melanin biosynthetic pathway, were upregulated in fungi grown in the inhibitor-added media. In conclusion, M. robertsii microsclerotia contain melanins of type DHN that might play a role in both microsclerotia differentiation and environmental stress tolerance.

Diabetes is a metabolic disease of global concern, causing death due to triggered oxidative and inflammatory complications. Alpha-glucosidase has become a popular drug target for managing diabetes. This study, therefore, investigated the potential of Curcuma longa (Tumeric) rhizome methanolic extract (MECL) to inhibit alpha-glucosidase and screened its phytochemical library through molecular biology docking for potential new drug candidates. Quantitative phytochemical analysis of MECL showed that the plant extract was abundant with phenols (790.32 ± 129.20 mg/100 g), alkaloids (494.99 ± 1.27 mg/100 g), flavonoids (171.08 ± 0.04 mg/100 g), and terpenoids (131.99 ± 6.59 mg/100 g). Moreover, in vitro inhibitory studies showed a dose-dependent increase in the inhibition of alpha-glucosidase by MECL, and the maximum inhibition (37.01%) was observed at 30 µg/mL, possibly a better inhibition with increased concentration. Further scrutiny was performed using molecular docking to screen for Turmeric phytochemicals (retrieved from PubChem) with alpha-glucosidase (PDB ID: 3W37) inhibitory potentials. Based on their binding affinity, the top three compounds [Guaiacol (−7.422), Eriodictyol (−5.266), and p-Tolyl-MethylCarbinol (−3.939)] were analyzed for their intermolecular interactions in the binding pocket of alpha-glucosidase and ADMET properties; and compared to the standard drug, acarbose (−9.522). Interestingly, strong and weak interactions, such as hydrogen bonding, pi-pi stacking, and charged and hydrophobic interactions, were observed with Guaiacol in the binding pocket of alpha-glucosidase. Although acarbose had a better docking score, Guaiacol showed better ADMET (including physicochemical, drug-likeness, and pharmacokinetic) properties. Future studies could evaluate those potential anti-diabetes drug candidates against other targets and analyze them through in vivo experiments.

Lignocellulosic nanofibres (LCNF) are nanometer additives that can be used to improve the mechanical, esthetical, optical and thermal properties of polymers in composites, packages, or coatings. Surface modification of these hydrophilic nanometer additives is needed to improve their properties and applicability in hydrophobic polymers matrix. In this work, two phenolic monomers, guaiacol and syringaldehyde were for the first time, efficiently grafted onto the exposed residual lignin of lignocellulosic nanofibres surface by a laccase from Trametes versicolor mediated reaction. Guaiacol grafted (LCNFG) and syringaldehyde grafted (LCNFS) lignocellulosic nanofibres were characterized with Fourier Transform Infra-Red (FTIR) and UV–visible techniques. Thermal and hydrophobic properties were analyzed by thermogravimetric analysis (TGA) and Water contact angle (WCA) measurements. FTIR analyzes confirmed the laccase mediated grafting of guaiacol and syringaldehyde onto lignocellulosic nanofibres. UV–visible gave evidence for the grafting of phenolic entities onto lignocellulosic nanofibres by factual data supporting experimental observations, leading to brown and orange colored grafted lignocellulosic nanofibres (LCNFG and LCNFS, respectively). TGA has shown that grafting of phenolic compounds endowed LCNF better thermal stability. WCA angle and wettability measurements showed that the surface hydrophobicity of LCNFG and LCNFS was increased after the enzymatic grafting modification.

Herein, RuMn/Al2O3-SiO2 multifunctional catalyst was prepared and efficiently converted lignin-derived phenols into cyclohexanol by aqueous partial hydrodeoxygenation (HDO). The optimal RuMn/Al2O3-SiO2 (Ru/Mn = 2) catalyst achieved 96.8% of cyclohexanol yield with 100% guaiacol conversion under mild reaction conditions (180 °C and 2.0 MPa H2) for 4 h, with a turnover frequency (TOF) of 861.1 h−1, which is better than most results reported. The high performance of RuMn/Al2O3-SiO2 was attributed to the synergic effect of highly dispersed Ru nanoparticles with small size (1.25 nm), the microsphere structure, the appropriate acid sites from Al2O3-SiO2 and acid-base sites from MnOx.

Lignins are the most abundant biopolymers that consist of aromatic units. Lignins are obtained by fractionation of lignocellulose in the form of “technical lignins”. The depolymerization (conversion) of lignin and the treatment of depolymerized lignin are challenging processes due to the complexity and resistance of lignins. Progress toward mild work-up of lignins has been discussed in numerous reviews. The next step in the valorization of lignin is the conversion of lignin-based monomers, which are limited in number, into a wider range of bulk and fine chemicals. These reactions may need chemicals, catalysts, solvents, or energy from fossil resources. This is counterintuitive to green, sustainable chemistry. Therefore, in this review, we focus on biocatalyzed reactions of lignin monomers, e.g., vanillin, vanillic acid, syringaldehyde, guaiacols, (iso)eugenol, ferulic acid, p-coumaric acid, and alkylphenols. For each monomer, its production from lignin or lignocellulose is summarized, and, mainly, its biotransformations that provide useful chemicals are discussed. The technological maturity of these processes is characterized based on, e.g., scale, volumetric productivities, or isolated yields. The biocatalyzed reactions are compared with their chemically catalyzed counterparts if the latter are available.

Understanding the mechanisms of guaiacol’s catalytic hydrodeoxygenation (HDO) is essential to remove the oxygen excess in bio-oils. The present work systematically examines guaiacol’s HDO mechanisms to form benzene on six transition metal (TM) catalysts using density functional theory calculations. The results suggested a preferable Caryl−O bond scission on Ni (111) and Co (0001), whereas on Fe (110), the Caryl–OH bond scission is the most likely pathway. The C−O scission on Pd (111) and Pt (111) is not energetically feasible due to their high activation barriers and endothermic behaviour. Fe (110) also demonstrated its high oxophilic character by challenging the desorption of oxygenated products. A detailed analysis concludes that Co (0001) and Ni (111) are the most favourable in breaking phenolic compounds’ C−O type bonds. Brønsted-Evans-Polanyi (BEP) and transition state scaling (TSS) models were implemented on the catalytic results to derive trends and accelerate the catalyst design and innovation. TSS demonstrated a reliable trend in defining dissociation and association reaction energies. The phenyl ring-oxo-group and the metal-molecule distances complement the catalysts’ oxophilicity as selectivity descriptors in the HDO process.

Laccase-mediator-oxidized lignin offers replacement for conventional chemical binders to produce fiberboards. Compared to the previously reported laccase–mediator system (LMS), a lignin-laccase-mediator-system (LLMS) has an advantage in that it requires much shorter fiber-enzyme incubation time due to significantly increased redox reactions. However, the cost of regularly applying laccase on an industrial scale is currently too high. We have employed CcLcc5 from cultures of the basidiomycete Coprinopsis cinerea as a novel basi-laccase (a CAZy subfamily AA1_1 laccase) in medium-density fiberboard (MDF) production, in comparison to the commercial formulation Novozym 51003 with recombinantly produced asco-laccase MtL (a CAZy subfamily AA1_3 laccase-like multicopper oxidase from the ascomycete Myceliophthora thermophila). With the best-performing natural mediator 2,6-dimethoxyphenol (DMP), unpurified CcLcc5 was almost as good as formulated Novozym 51003 in increasing the molecular weight (MW) of the technical lignins tested, the hydrophilic high-MW Ca-lignosulfonate and the hydrophobic low-MW kraft lignin (Indulin AT). Oxygen consumption rates of the two distantly related, poorly conserved enzymes (31% sequence identity) with different mediators and lignosulfonate were also comparable, but Indulin AT significantly reduced the oxidative activity of Novozym 51003 unlike CcLcc5, regardless of the mediator used, either DMP or guaiacol. Oxygen uptake by both laccases was much faster with both technical lignins with DMP than with guaiacol. In case of lignosulfonate and DMP, 20–30 min of incubation was sufficient for full oxygen consumption, which fits in well in time with the usual binder application steps in industrial MDF production processes. LLMS-bonded MDF was thus produced on a pilot-plant scale with either crude CcLcc5 or Novozym 51003 at reduced enzyme levels of 5 kU/kg absolutely dry wood fiber with lignosulfonate and mediator DMP. Boards produced with CcLcc5 were comparably good as those made with Novozym 51003. Boards reached nearly standard specifications in internal bond strength (IB) and modulus of rupture (MOR), while thickness swelling (TS) was less good based on the hydrophilic character of lignosulfonate. LLMS-bonded MDF with Indulin AT and DMP performed better in TS but showed reduced IB and MOR values.

Bio-oil is a reliable renewable alternative to petroleum for wide range of applications such as transportation fuels, power generation and source of many value-added chemicals for petrochemical industry. However, compared to petroleum, the physical and chemical properties of bio-oil such as high oxygen content, high moisture content and low pH are some limiting factors for its real-life applications. Thus, requires upgrading to improve its quality and catalytic hydrodeoxygenation (HDO) is one of the best available bio-oil upgrading techniques. Further, bio-oil is a complex mixture of various organic compounds such as acids, ketones, aldehydes, esters, acids and many phenolic compounds thus difficult to study as a whole mixture. Accordingly, it is often followed by researchers to select a model compound under a given compound catalogue for HDO study; and the same is followed in this work by selecting guaiacol of phenolic catalogue. This HDO study in a fluidized bed reactor has been carried out using computational fluid dynamics (CFD) based solver, ANSYS Fluent 14.5. The operating conditions includes bio-oil mass rate per unit mass of catalyst (WHSV) ​= ​1, 3 and 5 h−1; fluidizing medium velocity (u) ​= ​0.075, 0.15 and 0.25 ​m/s; catalyst load ​= ​0.06 ​kg and temperature (T) ​= ​548, 573, and 598 ​K. From the results, it is understood that the phenol is a primary product with approximately 66% while the cyclopentanone (≈22%) and methanol (≈11%) are other products. The cyclopentanone production by HDO of guaiacol is favourable at high temperature whereas low temperature conditions favour production of methanol and phenol by HDO of guaiacol.

Because of the global necessity to decrease CO2 emissions, biomass-based fuels have become an interesting option to explore; although, bio-oils need to be upgraded, for example, by catalytic hydrodeoxygenation (HDO), to reduce oxygen content. This reaction generally requires bifunctional catalysts with both metal and acid sites. For that purpose, Pt-Al2O3 and Ni-Al2O3 catalysts containing heteropolyacids (HPA) were prepared. HPAs were added by two different methods: the impregnation of a H3PW12O40 solution onto the support and a physical mixture of the support with Cs2.5H0.5PW12O40. The catalysts were characterized by powder X-ray diffraction, Infrared, UV-Vis, Raman, X-ray photoelectron spectroscopy and NH3-TPD experiments. The presence of H3PW12O40 was confirmed by Raman, UV-Vis and X-ray photoelectron spectroscopy, while the presence of Cs2.5H0.5PW12O40 was confirmed by all of the techniques. However, HPW was shown to strongly interact with the supports, especially in the case of Pt-Al2O3. These catalysts were tested in the HDO of guaiacol, at 300 °C, under H2 and at atmospheric pressure. Ni-based catalysts led to higher conversion and selectivity to deoxygenated compound values, such as benzene. This is attributed to both a higher metal and acidic contents of these catalysts. Among all tested catalysts, HPW/Ni-Al2O3 was shown to be the most promising, although it suffered a more severe deactivation with time-on-stream.

The main component of creosote obtained from dry wood distillation—guaiacol—is a natural antioxidant that has been widely used in pharmaceutical and food preservation applications. However, the antifungal mechanism of guaiacol against phytopathogens remains unclear. In this study, we found that guaiacol exerts inhibitory effects against mycelial growth, conidial formation and germination, and deoxynivalenol (DON) biosynthesis in Fusarium graminearum in a dose-dependent manner. The median effective concentration (EC50) value of guaiacol for the standard F. graminearum strain PH-1 was 1.838 mM. Guaiacol strongly inhibited conidial production and germination. The antifungal effects of guaiacol may be attributed to its capability to cause damage to the cell membrane by disrupting Ca2+ transport channels. In addition, the decreased malondialdehyde (MDA) levels and catalase (CAT), peroxidase (POD), and superoxide dismutase (SOD) activity by guaiacol treatment indicate that guaiacol displays activity against DON production by modulating the oxidative response in F. graminearum. Taken together, this study revealed the potentials of antioxidant in inhibiting mycotoxins in F. graminearum.

In this study, the impact of NaOH on the hydrothermal oxidation of guaiacol was investigated. It was found that NaOH significantly accelerated the production of formic acid and acetic acid with H2O2 or CuO as the oxidant. With the strong oxidant, H2O2, the highest acetic acid yield (15.73%) and formic acid (5.64%) were obtained at 300 °C for 90 s with NaOH 1.0 mol·L−1 and a 100% H2O2 oxygen supply. In comparison, with CuO as the oxidant, the highest values of acetic acid (13.42%) and formic acid (4.21%) were acquired at 250 °C for 6 h with NaOH 1.0 mol·L−1. Formic acid and acetic acid were generated through the oxidation of intermediates, such as levulinic acid, fumaric acid, maleic acid, etc. These results demonstrated that NaOH catalytic hydrothermal oxidation has potential for the production of value-added chemicals from biomass materials. When CuO is used as the oxidant, this process could also be used as a green method for copper smelting along with the utilization of lignin biomass.

The 4-allyl guaiacol is a natural phenolic molecule that has been widely studied for its antioxidant capacity against reactive-oxygen-species-mediated cellular damage. Therefore, we hypothesized that concomitant use of an antioxidant and NSAID may decrease the risk of gastrointestinal toxicity and make the therapy safer. To address the gastrointestinal toxicity of conventional NSAIDs, a new S-naproxen-4-allyl guaiacol chimera (MAS-1696) was computationally developed, chemically synthesized, and tested for anti-inflammatory effectiveness and gastrointestinal safety. The inhibitory potency of MAS-1696 tested against cyclooxygenase-2 (COX2), 15-lipoxygenase-2 (15-LOX2), and lipoxygenase-5 (5-LOX) in vitro revealed a stronger inhibition of COX2. Furthermore, the MAS-1696 chimera increased the COX selectivity index by 23% as compared to the parent compound naproxen, implying higher efficacy and gastric safety. In vivo data showed that MAS-1696 was less likely to cause gastrointestinal harm than naproxen while also exerting anti-inflammatory and analgesic effects equivalent to or superior to naproxen. In conclusion, MAS-1696 is orally active, bio-labile, and crystalline, making it a medication that may be administered orally.

Herein, cobalt-reduced graphene oxide (rGO) catalyst was synthesized with a practical impregnation–calcination approach for the selective hydrodeoxygenation (HDO) of guaiacol to cyclohexanol. The synthesized Co/rGO was characterized by transmission electron microscopy (TEM), high-angle annular dark-field scanning TEM (HAADF-STEM), X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, X-ray diffraction (XRD), and H2 temperature-programmed reduction (H2-TPR) analysis. According to the comprehensive characterization results, the catalyst contains single Co atoms in the graphene matrix and Co oxide nanoparticles (CoOx) on the graphene surface. The isolated Co atoms embedded in the rGO matrix form stable metal carbides (CoCx), which constitute catalytically active sites for hydrogenation. The rGO material with proper amounts of N heteroatoms and lattice defects becomes a suitable graphene material for fabricating the catalyst. The Co/rGO catalyst without prereduction treatment leads to the complete conversion of guaiacol with 93.2% selectivity to cyclohexanol under mild conditions. The remarkable HDO capability of the Co/rGO catalyst is attributed to the unique metal–acid synergy between the CoCx sites and the acid sites of the CoOx nanoparticles. The CoCx sites provide H while the acid sites of CoOx nanoparticles bind the C-O group of reactants to the surface, allowing easier C-O scission. The reaction pathways were characterized based on the observed reaction–product distributions. The effects of the process parameters on catalyst preparation and the HDO reaction, as well as the reusability of the catalyst, were systematically investigated.

The kinetics of the liquid-phase alkylation of guaiacol (G) with cyclohexene (CH) over Amberlyst 36 resin was studied using Langmuir–Hinshelwood–Hougen–Watson (LHHW) heterogeneous kinetic models. Catalytic tests were performed in a batch reactor, in solvent-less conditions, at 363 K, 1 bar, 600 RPM, using a G:CH molar ratio equal to 5 with a total volume of 30 ml and 1.5 g of solid catalyst. The alkylation of G with CH formed cyclohexyl-2-methoxyphenylether (CHMPE) by O-alkylation and cyclohexyl-2-methoxyphenol isomers (CHMP) by C-alkylation. Furthermore, CHMPE isomerizated into CHMP. A negligible amount of cyclohexylcyclohexene (CHC) was observed by dimerization of CH. Among these products, CHMP are important intermediaries for the production of resins, antioxidants, drugs, polymeric additives, agrochemicals, etc.Several LHHW kinetic models, varying the rate limiting step of reactions, were proposed in order to elucidate a reaction mechanism. The fitting of experimental data was performed consecutively by: (1) a stochastic optimization method and (2) by nonlinear regression, using the Levenberg–Marquardt algorithm, reducing the probability of reaching local minima in the objective function. The selected kinetic model considers that: (a) the rate limiting step for both the O-alkylation and C-alkylation is the surface chemical reaction between adsorbed G and adsorbed CH; (b) the adsorption of the O-alkylated products is the rate limiting step for the isomerization into C-alkylated products. Finally, this kinetic model that fits experimental data appreciably well from both physical and statistical point of view, suggests that CH adsorbs stronger than G over Amberlyst 36 catalyst.

Laccases have vast prospective for biotechnological applications due to their outstanding bioremediation potential. These include abundant applications in effluent detoxification, enzymatic conversion of chemical intermediates, wine clarification degradation of textile dyes etc. In the present study, two potential microbes were isolated on solid medium containing guaiacol and ABTS for laccase activity out of 10 microbes. Two cultures PHP7 and PKD5 were selected for molecular characterization was carried out using 16S rRNA gene technology of PHP7 revealed as Bacillus cereus (KU878970.1).Partial amplification of laccase gene contain conserved domain of multicopper oxidase family. The biomass produced by PHP7 was 0.053 mg/5 mL, while PKD5 was 0.058 mg/5 mL. While dye degradation of PHP7dye of 64.28% after incubation of 6 days at pH7 whereas PKD5 shows highest degradation of dye i.e. 61.90% after incubation of 8 days at pH8. PHP7 showed highest Laccase activity of 0.489 U/L at pH 7 while PKD5 showed 0.404 U/L Laccase activity at pH 8 at 8th day of incubation. Using laccase from PHP7 and PKD5 isolates, explored at industrial level for decolorization of coloured effluents that significance in environmentally friendly and play critical role as bioremediation at commercial scale.

Abstract Background Lignin is a potential feedstock for microbial conversion into various chemicals. However, the microbial degradation rate of native or technical lignin is low, and chemical depolymerization is needed to obtain reasonable conversion rates. In the current study, nine bacterial strains belonging to the Pseudomonas and Rhodococcus genera were evaluated for their ability to grow on alkaline-treated softwood lignin as a sole carbon source. Results Pseudomonas fluorescens DSM 50090 and Rhodococcus opacus DSM1069 showed the best growth of the tested species on plates with lignin. Further evaluation of P. fluorescens and R. opacus was made in liquid cultivations with depolymerized softwood Kraft lignin (DL) at a concentration of 1 g/L. Size-exclusion chromatography (SEC) showed that R. opacus consumed most of the available lower-molecular weight compounds (approximately 0.1–0.4 kDa) in the DL, but the weight distribution of larger fractions was almost unaffected. Importantly, the consumed compounds included guaiacol—one of the main monomers in the DL. SEC analysis of P. fluorescens culture broth, in contrast, did not show a large conversion of low-molecular weight compounds, and guaiacol remained unconsumed. However, a significant shift in molecular weight distribution towards lower average weights was seen after cultivation with P. fluorescens. Conclusions Rhodococcus opacus and P. fluorescens were identified as two potential microbial candidates for the conversion/consumption of base-catalyzed depolymerized lignin, acting on low- and high-molecular weight lignin fragments, respectively. These findings will be of relevance for designing bioconversion of softwood Kraft lignin.

The proper consumption of plant wastes could not only provide a possible source of natural products, but it also is an environmental friendly research. The aim of this study was to use grape wastes as a source of peroxidase. In practice, one isoenzyme of peroxidase (POD1) was partially purified from Vitis vinifera wastes, the plant which is widely harvested in Iran. The activity of this novel peroxidase was determined using guaiacol as its substrate. The new peroxidase was partially purified and its kinetic parameters determined. The values of Km and Vmax of peroxidase for guaiacol were 83.2 mM and 0.35 M/min respectively. Optimum pH and temperature were determined for guaiacol to be 6.2 and 60°C respectively. According to SDS-PAGE results, the molecular weight of isozymes was 38-40 KD. The results indicate that agricultural leftovers from Vitis vinifera are a considerable source for a peroxidase with reliable kinetic behaviors.

The article provides the results of studies on the identification of Alicyclobacillus genus bacteria in apple juice concentrates produced at the processing enterprises of the Southern Federal District of the Russian Federation. Microorganisms of the genus Alicyclobacillus are acid resistant, thermophilic, spore-forming bacteria that can cause juice products spoilage. Spoilage mainly appears as the formation of a phenolic (medicinal or smoky) smell. An alien odor is the result of the formation of guaiacol (2-methoxyphenol), the product of the vital activity of separate strains (guaiacol-forming) bacteria of Alicyclobacillus genus. Microbiological studies of 49 samples of sterilized apple juice concentrates and 10 samples of washing water from the equipment, selected in the process of apple juice concentrate producing were carried out. The studies have shown that spores of Alicyclobacillus genus bacteria can remain viable in juice concentrates after the heat treatment commonly used in the food processing industry for microbiological stability. Microbiological analysis of 49 samples of apple juice concentrates showed that 30 samples (61% of the total number of examined samples) contained bacteria of the genus Alicyclobacillus. When identifying bacteria of Alycyclobacillus genus in 30 samples of apple juice concentrates containing these bacteria, 25 samples (83%) contained guaiacol-positive bacteria and, accordingly, 5 samples (17%) contained guaiacol-negative bacteria. The number of bacteria in 1 cm3 of apple juice concentrates did not exceed 400 CFU/cm3. The results of the research can serve as the basis for the development of standards concerning the allowable content of Alicyclobacillus bacteria in apple juice concentrate.

This study is focused on understanding the hydrodeoxygenation (HDO) kinetics of pyrolysates from lignin such as phenol, guaiacol and syringol over H-ZSM-5 catalyst. The major products from syringol were guaiacol, phenol, anisole, cresol, benzene, and toluene. A reaction network was proposed to capture the transformations of syringol in which the transformations of guaiacol and phenol were included. A kinetic model comprising nine reactions of seven species was developed. The simulated yields of a majority of the HDO products matched well with experiments in the temperature range of 350-500 °C, substantiating that the obtained rate parameters reasonably represent the HDO kinetics.

When bushfires occur near wine regions, grapevine exposure to smoke can taint grapes due to the uptake of smoke-derived volatile compounds that can subsequently impart unpleasant smoky, medicinal, burnt rubber and ashy characters to wine. Whereas early research sought to understand the effects of smoke on grapevine physiology, and grape and wine chemistry, research efforts have shifted towards the strategic imperative for effective mitigation strategies. This study evaluated the extent to which excised grape bunches could be reproducibly tainted during smoke exposure in a purpose-built ‘smoke box’. The volatile phenol composition of grapes exposed to smoke for 30 min was similar to that of smoke-affected grapes from field trials involving grapevine exposure to smoke. Some variation was observed between replicate smoke treatments, but implementing appropriate controls and experimental replication enabled the smoke box to be used to successfully evaluate the efficacy of several agrochemical sprays and protective coverings as methods for mitigating the smoke exposure of grapes. Whereas the agrochemical sprays did not provide effective protection from smoke, enclosing grape bunches in activated carbon fabric prevented the uptake of up to 98% of the smoke-derived volatile phenols observed in smoke-affected grapes. As such, the study demonstrated not only a convenient, efficient approach to smoke taint research that overcomes the constraints associated with vineyard-based field trials, but also a promising new strategy for preventing smoke taint.

Abstract Background Lignin is a potential feedstock for microbial conversion into various chemicals. However, the degradation rate of native or technical lignin is low, and depolymerization is needed to obtain reasonable conversion rates. In the current study, base-catalyzed depolymerization—using NaOH (5 wt%)—of softwood Kraft lignin was conducted in a continuous-flow reactor system at temperatures in the range 190–240 °C and residence times of 1 or 2 min. The ability of growth of nine bacterial strains belonging to the genera Pseudomonas and Rhodococcus was tested using the alkaline-treated lignin as a sole carbon source. Results Pseudomonas fluorescens and Rhodococcus opacus showed the best growth of the tested species on plates with lignin. Further evaluation of P. fluorescens and R. opacus was made in liquid cultivations with depolymerized lignin (DL) at a concentration of 1 g/L. Size exclusion chromatography (SEC) showed that R. opacus consumed most of the available lower molecular weight compounds (approximately 0.1–0.4 kDa) in the DL, but the weight distribution of larger fractions was almost unaffected. Importantly, the consumed compounds included guaiacol—one of the main monomers in the DL. SEC analysis of P. fluorescens culture broth, in contrast, did not show a large conversion of low molecular weight compounds, and guaiacol remained unconsumed. However, a significant shift in molecular weight distribution towards lower average weights was seen. Conclusions Rhodococcus opacus and P. fluorescens were identified as two potential microbial candidates for the conversion/consumption of base-catalyzed depolymerized lignin, acting on low and high molecular weight lignin fragments, respectively. These findings will be of relevance for designing bioconversion of softwood Kraft lignin.

in this study was tried Different tomato varieties based on phytochemical and morphological traits as well as antioxidant properties of leaf In the form of two germination experiments in laboratory and pot plants in a greenhouse, completely randomized in three replications. Totally two experiments, different varieties of tomatoes were different (P

Taint in grapes and wine following vineyard exposure to bushfire smoke continues to challenge the financial viability of grape and wine producers worldwide. In response, researchers are studying the chemical, sensory and physiological consequences of grapevine smoke exposure. However, studies involving winemaking trials are often limited by the availability of suitable quantities of smoke-affected grapes, either from vineyards exposed to smoke or from field trials involving the application of smoke to grapevines. This study compared the accumulation of volatile phenol glycosides (as compositional markers of smoke taint) in Viognier and Cabernet Sauvignon grapes exposed to smoke pre- vs. post-harvest, and found post-harvest smoke exposure of fruit gave similar levels of volatile phenol glycosides to fruit exposed to smoke pre-harvest. Furthermore, wines made from smoke-affected fruit contained similar levels of smoke-derived volatile phenols and their glycosides, irrespective of whether smoke exposure occurred pre- vs. post-harvest. Post-harvest smoke exposure therefore provides a valid approach to generating smoke-affected grapes in the quantities needed for winemaking trials and/or trials that employ both chemical and sensory analysis of wine.

When wine grapes are exposed to smoke, there is a risk that the resulting wines may possess smoky, ashy, or burnt aromas, a wine flaw known as smoke taint. Smoke taint occurs when the volatile phenols (VPs) largely responsible for the aroma of smoke are transformed in grape into a range of glycosides that are imperceptible by smell. The majority of VP-glycosides described to date are disaccharides possessing a reducing β-d-glucopyranosyl moiety. Here, a two-part experiment was performed to (1) assess the stability of 11 synthesized VP-glycosides towards general acid-catalyzed hydrolysis during aging, and (2) to examine whether yeast strains differed in their capacity to produce free VPs both from these model glycosides as well as from grapes that had been deliberately exposed to smoke. When fortified into both model and real wine matrices at 200 ng/g, all VP-disaccharides were stable over 12 weeks, while (42–50 ng/g) increases in free 4-ethylphenol and p-cresol were detected when these were added to wine as their monoglucosides. Guaiacol and phenol were the most abundantly produced VPs during fermentation, whether originating from natural VP-precursors in smoked-exposed Pinot Noir must, or due to fortification with synthetic VP-glycosides. Significant yeast strain-specific differences in glycolytic activities were observed for phenyl-β-d-glycopyranoside, with two strains (RC212 and BM45) being unable to hydrolyze this model VP, albeit both were active on the guaiacyl analogue. Thus, differences in Saccharomyces cerevisiae β-glucosidase activity appear to be influenced by the VP moiety.

Strategies that mitigate the negative effects of vineyard exposure to smoke on wine composition and sensory properties are needed to address the recurring incidence of bushfires in or near wine regions. Recent research demonstrated the potential for post-harvest ozonation of moderately smoke-exposed grapes to reduce both the concentration of smoke taint marker compounds (i.e., volatile phenols and their glycosides) and the perceived intensity of smoke taint in wine, depending on the dose and duration of ozone treatment. The current study further evaluated the efficacy of ozonation as a method for the amelioration of smoke taint in wine by comparing the chemical and sensory consequences of post-harvest ozonation (at 1 ppm for 24 h) of Cabernet Sauvignon grapes following grapevine exposure to dense smoke, i.e., ozone treatment of more heavily tainted grapes. Ozonation again yielded significant reductions in the concentration of free and glycosylated volatile phenols—up to 25% and 30%, respectively. However, although the intensities of smoke-related sensory attributes were generally lower in wines made with smoke-exposed grapes that were ozonated (compared to wines made with smoke-exposed grapes that were not ozonated), the results were not statistically significant. This suggests that the efficacy of ozone treatment depends on the extent to which grapes have been tainted by smoke.

The aim of this study was isolation and molecular identification of laccase-producing saprophytic/phytopathogen Basidiomycetes species from different geographic regions with dominant vegetation of Pinus, Abies, and Quercus spp. in the state of Michoacán, Mexico. Soil samples and visible mycelial aggregates were collected for fungal isolations. Soil samples were processed using a soil particle washing technique, where a selective Ascomycetes inhibitor and guaiacol, as an indicator of saprophytic Basidiomycetes growth, were used. Most of the isolates were obtained from samples collected in Parque Nacional, José Ma. Morelos (Km 23), Charo, Michoacán, Mexico. Based on sequence comparisons and phylogenetic analysis of internal transcribed spacer regions (ITS1-5.8S-ITS4) with respect to reference taxa, identification of saprophytic/phytopathogen Basidiomycetes species was carried out. In total, 15 isolates from 12 genera (i.e., Bjerkandera, Coriolopsis, Ganoderma, Hexagonia, Irpex, Limonomyces, Psathyrella, Peniophora, Phlebia, Phlebiopsis, Trametes, and Trichaptum) and one species from family Corticiaceae were identified. This study will be useful for further investigations on biodiversity of soil Basidiomycetes in different ecosystems. At present, these isolates are being used in our various lab experiments and can be useful in different industrial and bioremediation applications.

Herein, Pt/HZSM-5 zeolite catalysts with different crystallite sizes ranging from nanosheet (~2 nm) to bulk crystals (~1.5 μm) have been prepared for the hydrodeoxygenation of guaiacol, and their effects on the reaction pathway and product selectivity were explored. HZSM-5 zeolites prepared by seeding (Pt/Z-40: ~40 nm) or templating (Pt/NS-2: ~2 nm) fabricated intra-crystalline mesopores and thus enhanced the reaction rate by promoting the diffusion of various molecules, especially the bulky ones such as guaiacol and 2-methoxycyclohexanol, leading to a higher cyclohexane selectivity of up to 80 wt % (both for Pt/Z-40 and Pt/NS-2) compared to 70 wt % for bulky HZSM-5 (Pt/CZ: ~1.5 μm) at 250 °C and 120 min. Furthermore, decreased crystallite sizes more effectively promoted the dispersion of Pt particles than bulky HZSM-5 (Pt/Z-400: ~400 nm and Pt/CZ). The relatively low distance between Pt and acidic sites on the Pt/Z-40 catalyst enhanced the metal/support interaction and induced the reaction between the guaiacol molecules adsorbed on the acidic sites and the metal-activated hydrogen species, which was found more favorable for deoxygenation than for hydrogenation of oxygen-containing molecules. In addition, Pt/NS-2 catalyst with a highly exposed surface facilitated more diverse reaction pathways such as alkyl transfer and isomerization.

Wine made from grapes exposed to bushfire smoke can exhibit unpleasant smoky, ashy characters, which have been attributed to the presence of smoke-derived volatile phenols, in free or glycosylated forms. Here we report the uptake and glycosylation of volatile phenols by grapes following exposure of Cabernet Sauvignon vines to smoke, and their fate during winemaking. A significant delay was observed in the conversion of volatile phenols to their corresponding glycoconjugates, which suggests sequestration, the presence of intermediates within the glycosylation pathway and/or other volatile phenol storage forms. This finding has implications for industry in terms of detecting smoke-affected grapes following vineyard smoke exposure. The potential for an in-canopy sprinkler system to mitigate the uptake of smoke-derived volatile phenols by grapes, by spraying grapevines with water during smoke exposure, was also evaluated. While “misting” appeared to partially mitigate the uptake of volatile phenols by grapes during grapevine exposure to smoke, it did not readily influence the concentration of volatile phenols or the sensory perception of smoke taint in wine. Commercial sensors were used to monitor the concentration of smoke particulate matter (PM) during grapevine exposure to low and high density smoke. Similar PM profiles were observed, irrespective of smoke density, such that PM concentrations did not reflect the extent of smoke exposure by grapes or risk of taint in wine. The sensors could nevertheless be used to monitor the presence of smoke in vineyards during bushfires, and hence, the need for compositional analysis of grapes to quantify smoke taint marker compounds.

Biomass-derived liquids, such as bio-oil obtained by fast pyrolysis, can be a valuable source of fuels and chemicals. However, these liquids have high oxygen and water content, needing further upgrading typically involving hydrotreating using H2 at high pressure and temperature. The harsh reaction conditions and use of expensive H2 have hindered the progress of this technology and led to the search for alternative processes. In this work, hydrogenation in aqueous phase is investigated using in-situ produced hydrogen from reforming of glycerol, a low-value by-product from biodiesel production, over Ni-based catalysts. Guaiacol was selected as a bio-oil model compound and high conversion (95%) to phenol and aromatic ring hydrogenation products was obtained over Ni/γ-Al2O3 at 250 °C and 2-h reaction time. Seventy percent selectivity to cyclohexanol and cyclohexanone was achieved at this condition. Hydrogenation capacity of P and Mo modified Ni/γ-Al2O3 was inhibited because more hydrogen undergoes methanation, while Cu showed a good performance in suppressing methane formation. These results demonstrate the feasibility of coupling aqueous phase reforming of glycerol with bio-oil hydrogenation, enabling the reaction to be carried out at lower temperatures and pressures and without the need for molecular H2.

The present work concerns with the development of stability indicating the RP-HPLC method for simultaneous determination of guaifenesin (GUF) and pseudoephedrine hydrochloride (PSH) in the presence of guaifenesin related substance (Guaiacol). GUC, and in the presence of syrup excepients with minimum sample pre-treatment. In the developed RP-HPLC method efficient chromatographic separation was achieved for GUF, PSH, GUC and syrup excepients using ODS column as a stationary phase and methanol: water (50:50, v/v, pH = 4 with orthophosphoric acid) as a mobile phase with a flow rate of 1 mL min−1 and UV detection at 210 nm. The chromatographic run time was approximately 10 min. Calibration curves were drawn relating the integrated area under peak to the corresponding concentrations of PSH, GUF and GUC in the range of 1–8, 1–20, 0.4–8 μg mL−1, respectively. The developed method has been validated and met the requirements delineated by ICH guidelines with respect to linearity, accuracy, precision, specificity and robustness. The validated method was successfully applied for determination of the studied drugs in triaminic chest congestion® syrup; moreover its results were statistically compared with those obtained by the official method and no significant difference was found between them.

The unprocessed bio-oil obtained by the pyrolysis of lignocellulosic biomass comprises hundreds of oxy-components which vitiate its quality in terms of low heating value, low stability, low pH, etc. Therefore, it has to be upgraded prior to its use as transportation fuel. In this work, guaiacol, a promising compound of the phenolic fraction of unprocessed bio-oil, is considered as a model component for studying its hydrodeoxygenation over a Pt3 catalyst cluster. The production of catechol, 3-methylcatechol, m-cresol and o-cresol from guaiacol over a Pt3 cluster is numerically investigated using density functional theory. Further, the kinetic parameters are obtained over a wide range of temperature, i.e. 473–673 K at an interval of 50 K. Briefly, results indicate that O─H and C─H bond scissions determine the reaction rates of ‘guaiacol to catechol’ and ‘catechol to 3-methylcatechol’ reactions with activation energies of 30.32 and 41.3 kcal mol−1, respectively. On the other hand, C─O bond scissions determine the rates of 3-methylcatechol to m- and o-cresol production reactions, respectively. The kinetics of all reactions indicate that ln k versus 1/T plots are linear over the entire range of temperature considered herein.

Guaiacol, a phenolic compound is known as an anticancer. Dimerization of guaiacol has been done by biotransformation using peroxidase enzyme as biocatalyst. This enzyme was isolated from Indonesian plant, kailan (Brassica oleraceae var. alboglabra). Analysis of dimerization product was carried out by TLC, IR, LC-MS, and NMR. Whilst analysis of in-vitro cytotoxic activity was carried out by MTT method against breast cancer T47D and MCF7 cells. The result showed that the dimerization reaction gave O-para dehydroguaiacol. The in-vitro cytotoxic activity analysis showed that O-para dehydroguaiacol compound has potency as anti-breast cancer.

Hollow Silicalite-1 and ZSM-5 zeolites with hierarchical porous shells have been synthesized by using a dissolution-recrystallization method. The morphology, structure, and acidity of these zeolites supported Pt catalysts were characterized by XRD, FT-IR, MAS-SSNMR, FE-SEM, FE-TEM, N2-BET, XPS, NH3-TPD, and CO pulse chemisorption. Compared to the conventional ZSM-5 supported Pt catalyst, the special structure in hollow ZSM-5 zeolite significantly promotes the dispersion of metallic Pt and the synergistic effect between metal active sites and acid sites. These boost the catalytic activity, selectivity of guaiacol hydrodeoxygenation toward cycloalkanes and long-term stability over the Pt/hollow ZSM-5 catalyst combined with improved mass transfer of products and reactants derived from the hierarchical hollow porous structure. Moreover, the Pt/hollow ZSM-5 catalyst exhibits excellent low temperature catalytic activity to completely transform guaiacol into cycloalkanes with the cyclohexane selectivity of more than 93% at 220 °C, suggesting that hollow ZSM-5 zeolite is a promising support for upgrading of bio-oils.

Microorganisms producing laccases may be used for the pretreatment of lignocellulosic biomass to recover fermentable sugar. Very few fungi and other microbes growing in high altitudes have been tested for this purpose. As part of this study, we have collected soil samples from different parts of the Kathmandu Valley and the Rautah at district of Nepal (1600 to 2303 m above sea level) and successfully cultured 53 different isolates of microorganisms. Among the 53 isolates obtained 30 were Actinomycetes, 20 were Streptomycetes, and three were fungi). These isolates were tested for laccase expression using guaiacol, tannic acid, and 1-naphthol as substrates. Twelve of the 53 isolates tested positive for the expression of laccase. Among the laccase- positive isolates, a fungal species designated as CDBT-F-G1was found to produce high levels of laccase. This isolate was identified as Pestalotiopsis species based on 18S rRNA sequencing. Pestalotiopsis spp. CDBT-F-G1 isolate grows efficiently in PDB media containing 1% Kraft lignin at pH 5 and 30 °C and secretes 20 ± 2 U/mL laccase in culture medium. Further optimization of growth conditions reveled that addition of (i) metal salts, e.g., 1 mM magnesium sulfate (51 ± 25 U/mL); (ii) agitation of cultures at 200 rpm (51 ± 9U/mL); (iii) surfactants, e.g., 0.75 mM Tween 80 (54 ± 14 U/mL); (iv) 40% dissolved O2 (57 ± 2 U/mL) and inducers, e.g., 1 mM gallic acid (69 ± 11 U/mL), further promote laccase production by Pestalotiopsis spp. CDBT-F-G1 isolate. On the other hand, 0.1 mM cysteine inhibited laccase production. The secretory laccase obtained from fermentation broth of CDBT-F-G1 was partially purified by ammonium sulfate (13-fold purification with specific activity 26,200 U/mg) and acetone (14-fold purification with specific activity 31,700 U/mg) precipitation methods. The enzyme has an approximate molecular mass of 43 kDa, pH and temperature optima werepH6 and 60 °C, respectively. Vmax and Km were 100 μmol/min and 0.10 mM, respectively, with ABTS as the substrate. Given the above characteristics, we believe Pestalotiopsis spp. CDBT-F-G1 strain native to high altitudes of Nepal could be used to pretreat lignocellulosic biomass to efficiently recover fermentable sugars.