Alkyl Glucosides Research Articles

Adsorption, Aggregation, and Application Properties of Green Pluronic Aliphatic Alcohol Ether Carboxylic Acids and Nonionic/Amphoteric Surfactants in Water.

In the realm of colloid and interface science, new types of green surfactants, including anionic Pluronic alcohol ether carboxylate (AEC), branched alkyl glucoside (IG), and zwitterionic coconut oil amide propyl betaine (CAB), have been identified and merit further exploration. AEC, characterized by its inclusion of 5 EO and 3.5 PO units, was synthesized, and its behavior in aqueous solutions with IG and CAB was meticulously examined. Their performance in applications such as foam generation, wetting, and the dispersion and stabilization of graphene was also evaluated. At αAE5P3C = 0.5, AE5P3C/CAB exhibited superior surface and interfacial properties compared to AE5P3C/IG. In these hybrid systems, the self-assembly of micelles is predominantly influenced by hydrogen bonding, electrostatic interactions, and hydrophobic forces. Kinetic analysis further confirmed that the driving force for micelle formation in these hybrid systems is enthalpy, with the adsorption process involving a mixed diffusion-kinetic adsorption mechanism. AE5P3C/CAB demonstrated enhanced foaming ability, foam stability, and wetting properties compared to AE5P3C/IG. Intriguingly, the optimal dispersion and stabilization of graphene were achieved with AE5P3C/IG at αAE5P3C = 0.2, providing a foundational basis for its potential application in graphene-based systems. A thorough examination of the synergistic mechanisms and application potential of these three distinct surfactants in aqueous solutions was presented, taking into account various charged ions and the specific hydrophilic and hydrophobic groups of EO and PO. This study not only provides fundamental insights into their intrinsic properties but also offers a fresh perspective for the ongoing exploration of green surfactants.

Stimulation of cytochrome c oxidase activity by detergents

Cytochrome c oxidase (CytcO) is an integral membrane protein, which catalyzes four-electron reduction of oxygen linked to proton uptake and pumping. Amphipathic molecules bind in sites near the so-called K proton pathway of CytcO to reversibly modulate its activity. However, purification of CytcO for mechanistic studies typically involves the use of detergents, which may interfere with binding of these regulatory molecules. Here, we investigated the CytcO enzymatic activity as well as intramolecular electron transfer linked to proton transfer upon addition of different detergents to bovine heart mitoplasts. The CytcO activity increased upon addition of alkyl glucosides (DDM and DM) and the steroid analog GDN. The maximum stimulating effect was observed for DDM and DM, and the half-stimulating effect correlated with their CMC values. With GDN the stimulation effect was smaller and occurred at a concentration higher than CMC. A kinetic analysis suggests that the stimulation of activity is due to removal of a ligand bound near the K proton pathway, which indicates that in the native membrane this site is occupied to yield a lower than maximal possible CytcO activity. Possible functional consequences are discussed.

Insights into the preparation and mechanism of Non-Alkali viscosity reducer for enhancing heavy oil recovery under Low-Shear condition

Viscosity reducer flooding technology has been applied for enhanced oil recovery (EOR) in ordinary heavy oil reservoirs. However, the non-alkali viscosity reducer for heavy oil reservoir under low-shear condition has not been systematic studied. Thus, in terms of emulsifying ability and stability, oil–water interfacial tension and viscosity reduction performance, the non-alkali viscosity reducer was prepared under low-shear condition by the bottle inversion test method and shaker shaking method. Then the enhanced oil recovery ability of the non-alkali viscosity reducer was evaluated and the pore-scale EOR mechanism was investigated via microscopic visual flooding experiments. Results show that the non-alkali viscosity reducer consisting of C12-14 alkyl glucoside (APG1214) surfactant and sodium linear-dodecyl benzenesulfonate (LAS-30) surfactant was prepared with the oil–water interfacial tension of 0.15mN·m−1 and viscosity reduction rate of 97.9%. Compared with water flooding, the non-alkali viscosity reducer can significantly increase the sweep efficiency and the oil displacement efficiency and enhance oil recovery by 8.94% by the mechanism of emulsification, reducing interfacial tension and changing wettability.

Effect of alkyl glucoside concentration on functional group structure and adsorption characteristics of anthracite.

To investigate the influence of different concentrations of surfactants on the adsorption of anthracite, the nonionic surfactant alkyl polyglucoside (APG) was selected. The study examined the adsorption characteristics of different concentrations of APG on the surface of anthracite. The results revealed the existence of two modes of APG adsorption on anthracite. Under the action of 0.06 wt% APG, APG was found to adsorb in a monolayer state on the anthracite surface, with a saturation adsorption capacity of 20.06mg/g. When the solution concentration exceeded 0.14 wt%, APG exhibited a double-layer saturation adsorption state on anthracite, with a saturation adsorption capacity of 71.71mg/g. Molecular dynamics simulations complemented these findings, demonstrating that low concentrations of APG could reduce the mobility of water molecules and enhance the hydrophilicity of anthracite. With an increase in the number of APG molecules, multi-layer adsorption occurred on the anthracite surface, making it more hydrophobic. Therefore, the differences in wettability of anthracite induced by different concentrations of APG were primarily attributed to the spatial distribution of the surfactant at the water/coal interface. This study analyzed the adsorption capacity of the surfactant through adsorption experiments and Fourier-transform infrared spectroscopy (FTIR) experiments. Molecular dynamics simulations were conducted to construct six concentration levels of water/APG/anthracite systems. Various aspects, including APG adsorption configurations, interaction energies, relative concentrations of each component, and the diffusion coefficient of water molecules, were discussed to elucidate the reasons for the differential wettability of anthracite induced by different concentrations of APG.

Occurrence of alkyl glucosides in rinse-off cosmetics marketed as hypoallergenic or for sensitive skin.

Rinse-off cosmetic products, primarily shampoos, are frequently implicated in the onset of allergic contact dermatitis (ACD) caused by alkyl glucosides (AGs). AGs are increasingly popular surfactants and known contact allergens. Glucoside-induced ACD was most frequently observed with shampoos and skin-cleansing products in both consumer and occupational settings. Thereby, studies have shown that atopic individuals are the most susceptible to ACD. Also, several investigations have indicated that individuals with sensitive skin might be more prone to skin allergies. This is why the presence of AGs was investigated in shampoos and body cleansers marketed as hypoallergenic or for sensitive skin. For this purpose, the website of Amazon.com was surveyed. Four groups of cosmetics were obtained by using the following keywords: "hypoallergenic shampoo for adults," "sensitive skin shampoo for adults," "hypoallergenic body cleanser for adults," and "sensitive skin body cleanser for adults." The first 30 best-selling cosmetics in each group were investigated for the presence of AGs, by analyzing the product information pages. The results showed that as much as 56.7% of hypoallergenic shampoos contained AGs, as ingredients, whereas the percentage was somewhat lower for other product categories. Even though decyl and lauryl glucoside were nearly ubiquitously used AGs in cosmetics over the past decade, the most commonly present AG in our analysis was coco-glucoside. The results of this study indicated a necessity to include coco-glucoside in the baseline series of patch testing allergens. Industry, regulators, and healthcare providers should be made aware of the frequent presence of AGs in rinse-off cosmetic products marketed as hypoallergenic or for sensitive skin to ensure the safety and well-being of consumers and patients.

New withanolides from leaves along with alkyl glucoside from roots and stem as well as variations in withanolide contents in leaves of accessions of Withania somnifera, Ashwagandha- the Indian ginseng$

Based on the major components in the leaves, the ashwagandha has been found to exist in several chemotypic forms in India. From the leaves of various accessions of Withania somnifera, which were maintained in our institute, three new steroids namely, 4-acetoxy-20β-hydroxy-1-oxo-witha-2,5,24-trienolide (7), 24,25-dihydro-14α-hydroxy withanolide D (9), 5α,6β,17α,27-tetrahydroxy-1-oxo-witha-2,24-dienolide (12) together with thirteen known withanolides were identified by spectroscopic methods. From the roots and stem of one accession and leaves of another, a new alkyl ester glucoside (4) has also been isolated. The new withanolides 7, 9 and 12 have been tentatively named as withanolide 135 A, withanolide 135B and withanolide 108, respectively.

Preparation of porous sulfated zirconia with deep eutectic solvents for improved catalytic efficiency in the synthesis of biodegradable alkyl glucosides

In this study, a deep eutectic solvent (DES) system, comprising choline chloride and urea, was employed to synthesize sulfated zirconia (SZ) solid acid catalysts. The characteristics and efficacy of the SZ catalysts synthesized using this DES system were meticulously evaluated using a suite of analytical techniques, including nitrogen sorption, X-ray diffraction (XRD), pyridine adsorption infrared spectroscopy (Py-IR), X-ray photoelectron spectroscopy (XPS), and ammonia temperature-programmed desorption (NH3-TPD). The research also focused on analyzing the distinctive role and characteristics of the DES in the preparation of SZ. When compared with conventional aqueous phase precipitation methods, the SZ catalysts synthesized in the DES environment exhibited enhanced properties, such as an increased specific surface area, a higher density of acidic sites, and a larger proportion of potent acid centers. These improvements led to augmented catalytic activity in the reaction between alkyl alcohols and glucose. Moreover, the SZ catalysts prepared with DES demonstrated superior reaction stability and reusability, which can be attributed to the well-dispersed strong acid centers. The study uncovered that the components of the DES significantly contribute as microporous templating agents during the formation of SZ, assisting in the stabilization of the defect sites in the zirconia precursor. These components eventually evolved into prominently exposed surface strong acid centers during the stages of acidification and calcination, enhancing mass transfer efficiency and the acidic catalytic properties of the catalysts.

Enzymatic and selective production of alkyl α-d-glucopyranosides by the α-glucosyl transfer enzyme derived from Xanthomonas campestris WU-9701

Several alkyl glucosides exhibit various bioactivities. 1-Octyl β-d-glucopyranoside produced by organic synthesis is used as a nonionic surfactant. However, no convenient method has been developed for the selective production of alkyl α-glucosides (α-AGs), such as 1-octyl α-d-glucopyranoside (α-OG). Therefore, we developed a simple method for selective production of α-AGs using the glucosyl transfer enzyme XgtA, (E.C. 3.2.1.20), derived from Xanthomonas campestris WU-9701. When 0.80M alkyl alcohol and 2.5 units XgtA were incubated in 2.0mL of 30mM HEPES-NaOH buffer (pH 8.0) containing 1.2M maltose at 45°C, a specific α-AG corresponding to each alkyl alcohol (C2-C10) was detected. Under the standard conditions, we examined the selective production of α-OG from 1-octanol and maltose using XgtA. The reaction product was isolated and identified as α-OG via 1H nuclear magnetic resonance and nuclear overhauser effect spectroscopy analyses. No other glucosylated products, such as maltotriose, were detected in the reaction mixture. Under the standard conditions at 45°C for 96h, 243mM α-OG (71g/L) was produced in one batch production. Moreover, the addition of glucose isomerase to the reaction mixture decreased the concentration of glucose released via the reaction and increased the amount of α-OG produced; 359mM α-OG (105g/L) was maximally produced at 96h. In conclusion, this study demonstrates the selective production of α-AGs using a simple enzymatic reaction, and XgtA has the potential to selectively produce various α-AGs.

Systematic Identification of Copositivity Groups in Standard Series Patch Testing Through Hierarchical Clustering

Patients are frequently copositive for multiple allergens simultaneously, either due to chemical similarity or simultaneous sensitization. A better understanding of copositivity groups would help guide contact avoidance. To use patient data to systematically determine copositivity groups in the Mayo Clinic Standard Series. In this retrospective cross-sectional analysis, the Mayo Clinic patch test database was queried for pairwise copositivity rates in the 80 allergen Mayo Clinic Standard Series between 2012 and 2021. Data were collected from 3 tertiary care sites of the Mayo Clinic Contact Dermatitis Group and a total of 5943 patients were included, comprising all patients undergoing patch testing to the Mayo Clinic Standard Series allergens. Copositivity rates between every 2 allergens in the 80-allergen Mayo Clinic Standard Series were estimated. After background correction, copositivity rates were analyzed using unsupervised hierarchical clustering to systematically identify copositivity groups in an unbiased manner. Overall, 394 921 total patches were applied to 5943 patients (4164 [70.1%] women, 1776 [29.9%] men, with a mean [SD] age of 52.3 [18.8] years ), comprising 9545 positive reactions. After background correction based on overall positivity rates, hierarchical clustering revealed distinct copositivity groups. Many were supported by prior literature, including formaldehyde releasers, cobalt-nickel-potassium dichromate, acrylates, 3-dimethylaminopropylamine-amidoamine-oleamidopropyl dimethylamine, alkyl glucosides, budesonide-hydrocortisone-17-butyrate, certain fragrances, compositae-sesquiterpene lactone mix, mercapto mix-mercaptobenzothiazole, carba mix-thiuram mix, and disperse orange-p-phenylenediamine. However, novel associations were also found, including glutaraldehyde-sorbitan sesquioleate, benzalkonium chloride-neomycin-bacitracin, bronopol-methylchloroisothiazolinone-methylisothiazolinone, and benzoic acid-iodopropynyl butylcarbamate. This retrospective cross-sectional analysis found that copositivity rates varied between allergens; allergens with extremely high positivity rates demonstrated nonspecific copositivity to multiple other allergens. Background correction based on positivity rates followed by hierarchical clustering confirmed prior known copositivity groups, contaminants and/or excipients leading to copositivity, and novel associations to guide contact avoidance.

Alkil glükozid szenzibilizáció – a környezetbarát termékek veszélyei Ajánlás a magyar környezeti standard sorba történő beemelésre

Alkyl glucosides are compounds with cleaning, foaming, and emulsifying properties. They have become increasingly popular in recent years due to their environmentally- friendly features. They are mainly used in products for environmentally conscious consumers. Alkyl glucosides are present in 10% of products according to the Contact Allergen Management Program (CAMP) database. They are present in shower gels, soaps, shampoos, sunscreens, detergents, hair dyes, perfumes, and deodorants. They are also found in wipes for newborns and infants, so there is a risk of early sensitization. Their presence has also been described in foam wound dressings and antimicrobial foam dressings. Their importance is highlighted by the fact that in 2017, the American Contact Dermatitis Society (ACDS) named alkyl glucosides as „allergens of the year”. The present article describes the frequency and characteristics of decyl glucoside and lauryl glucoside sensitization in patients patch tested between 2018 and 2021 at the Department of Dermatology, Venereology, and Dermatooncology of the Semmelweis University. From January 2018 to December 2021, a total of 1160 patients were patch tested and 30 patients (2,59%) had a positive reaction to at least one of the alkyl glucosides. 7 patients were sensitized only to decyl glucoside, 10 patients only to a lauryl glucoside, and 13 patients to both alkyl glucosides. 56.67% of the alkyl glucoside sensitized patients were female, and 26.67 - 26.67% were in the age group 20- 29 years and 60-69 years. Patients sensitized with alkyl glucoside most commonly had allergic contact dermatitis symptoms all over the body, on the face, and hands. The positive patch test reactions occurred mainly in the 72. hour. The most common co-sensitizations were methylisothiazolinone (MI) and nickel (II) sulfate. 30% of the alkyl glucoside sensitized patients had a history of atopic dermatitis. According to our results, we recommend the inclusion of decyl glucoside and lauryl glucoside in the Hungarian standard patch test series.

Simulation of surfactant adsorption at liquid-liquid interface: What we may expect from soft-core models?

The present work attempts to systematically explore the surfactant sorption at liquid-liquid interfaces with coarse-grained models targeting thermodynamic properties of reference liquid solutions. We employ dissipative particle dynamics with soft-core forcefield tested against experimental data on micellization of surfactants in water, and the previous results are reproduced in this work. We consider three different nonionic surfactants: hexaethylene glycol monododecyl ether (C12E6), 2-[4-(2,4,4-trimethylpentan-2-yl)phenoxy]ethanol) known as Triton X-100 (TX-100), and two alkyl glucoside surfactants (CnG1) with n-alkane tail fragments and a saccharide hydrophilic head at decane-water and toluene-water interfaces. For TX-100, we composed a model based on the literature forcefield and found good agreement with the experimental critical micelle concentrations (CMCs). The head-head interactions are of different origins for different surfactant groups: entropic repulsion between ethylene oxide chains of C12E6 and TX-100, and more chemically specific and complex interactions between the maltose heads of alkyl glucosides. We interpret our results with the Redlich-Peterson equation of monolayer adsorption in order to relate the adsorption to the bulk concentration of the surfactant and the interfacial tension. The densities of the adsorbed monolayer at CMC mostly agree with the experimental data, and a reasonable agreement was obtained for the interfacial tension at CMC. At the same time, we found significant discrepancies between the simulated and experimental adsorption isotherms. We explain them by the oversimplified forcefield: when the parameters are fitted to the free energies of bulk solutions, they may not correctly reproduce the interfacial free energies.

Biotechnological production of sialylated solid lipid microparticles as inhibitors of influenza A virus infection.

Influenza viruses bind to their target through a multivalent interaction of their hemagglutinins (HAs) with sialosides at the host cell surface. To fight the virus, one therapeutic approach consists in developing sialylated multivalent structures that can saturate the virus HAs and prevent the binding to host cells. We describe herein the biotechnological production of sialylated solid lipid microparticles (SSLMs) in 3 steps: (i) a microbiological step leading to the large-scale production of sialylated maltodextrins by metabolic engineering of an Escherichia coli strain, (ii) a new in vitro glycosylation process using the amylomaltase MalQ, based on the transglycosylation of the terminal sialoside ligand of the sialylated maltodextrin onto a long-chain alkyl glucoside, and (iii) the formulation of the final SSLMs presenting a multivalent sialic acid. We also describe the morphology and structure of the SSLMs and demonstrate their very promising properties as influenza virus inhibitors using hemagglutination inhibition and microneutralization assays on the human A/H1N1 pdm09 virus.

Chemical synthesis and tyrosinase inhibitory activity of resorcinol alkyl glucosides, hydroxyalkyl resorcinols, and alkyl resorcinols

To develop novel tyrosinase inhibitors, resorcinol alkyl glucosides 7–12 were synthesized via the Wittig and/or Horner-Wadsworth-Emmons reactions with Koenigs-Knorr glycosylation as the key step. Half maximal inhibitory concentrations (IC50) of 35.9–0.39 µM were observed for 7–12 for the tyrosinase-catalyzed oxidation. Tyrosinase inhibitory activity of hydroxyalkyl resorcinols 13–18 and alkyl resorcinols 19–24 were also evaluated to investigate the effect of sugar in their structures. As a result, the IC50s of 13–18 and 19–24 were 9.27–0.32 µM and 1.58–0.53 µM, respectively. Most of the derivatives became more potent with the increasing length of the alkyl chain. The gap in the activities between the C2 and C3 analogs was decreased in the order: resorcinol alkyl glucosides>hydroxyalkyl resorcinols>alkyl resorcinols. It indicates that the sugar and hydroxy groups interfered in the functions when they were adjacent to the resorcinol ring. C14 analog 22 (IC50 = 0.81 µM) with the poor water solubility showed slightly weak activity compared with the C10 analog 21 (IC50 = 0.53 µM). Thus, the modification of a prescribed distance, at least, the C3 alkyl spacer, between the resorcinol ring and sugar or hydroxy group is a requisite to effectively design a potent, hydrophilic tyrosinase inhibitor.

Natural Is Not Always Better: The Prevalence of Allergenic Ingredients in "Clean" Beauty Products.

Consumers seek "clean" and "natural" products based on their perception of safety. However, there is no standard, scientific basis, or regulatory oversight in the marketing or ingredient use for "clean" products. The aim of this study was to determine the prevalence of allergenic ingredients in "clean" products. Target and Walgreens Web sites were queried for "clean" products with inclusion of 1470 products. Ingredient lists were analyzed for potential allergens. Analysis included descriptive statistics and χ2 test. The most common allergens were fragrances/botanicals (1218/1470, 82.9%), phenoxyethanol (591/1470, 40.2%), tocopherol (545/1470, 40.2%), benzoic acid and benzoates (434/1470, 29.5%), propylene glycol (369/1470, 25.1%), alkyl glucosides (305/1470, 20.7%), ethylhexylglycerin (304/1470, 20.7%), cetyl alcohol (282/1470, 19.2%), cocamidopropyl betaine (258/1470, 17.6%), and benzyl alcohol (232/1470, 15.8%). Among fragrances/botanicals, the most common ingredients found were fragrance/perfume/aroma (911/1470, 68.2%), citrus derivatives (375/1470, 25.5%), linalool (305/1470, 20.7%), limonene (279/1470, 19.0%), and benzyl alcohol (231/1470, 15.7%). A total of 93.8% of the products (1379/1470) contained at least 1 potential allergen. Most "clean" products contain a potential allergen, predominately fragrances and botanicals.

Dynamic Tuning in Synthetic Glycosidase for Selective Hydrolysis of Alkyl and Aryl Glycosides.

Enzymes use sophisticated conformational control to optimize the dynamics of their protein framework for efficient catalysis. Although it is difficult to employ a similar strategy to improve catalysis in a synthetic enzyme, we here report that modulation of the dynamics of the substrate in the active site is readily achievable in a complex between a molecularly imprinted nanoparticle and its acid cofactor, through tuning of the size and shape of the imprinted site. As the alkyl glucoside substrate is bound with increasing strength and held in a more tightly fitted pocket, the acid-catalyzed glycan hydrolysis becomes more difficult. A larger, wider active site, although less able to bind the substrate, affords a higher catalytic activity, likely due to easier alignment of the substrate and the acid cofactor for a general acid catalysis. The substrate selectivity is controlled by both the tightness of the aglycon-binding site and the orientation of the glycan-binding boroxole group.

Green technology for production of potent antioxidants and alkyl glucosides by Aspergillus niger β-glucosidase: prospects for broad application in the food industry

Green technology for production of potent antioxidants and alkyl glucosides by Aspergillus niger β-glucosidase: prospects for broad application in the food industry

Eco-friendly surfactants in glyphosate formulation

Weeds affect various crops worldwide, causing low yields and, therefore, significant economic losses. These losses can be minimized by the use of herbicides such as glyphosate. However, the efficiency of glyphosate depends on the type of agrochemical formulations. The most widely used surfactant is polyethoxylated tallow amine. Nevertheless, the disadvantage of these compounds is that their toxicity is greater than that of glyphosate itself. Thus, this study aimed to develop an environmentally-friendly combination of surfactants that can increase the performance of glyphosate compared to other currently used formulations. Saponin (S) is environmentally friendly and has a unique ability to go through the waxy cuticle of the weed leaf. However, its interfacial properties are very poor. In contrast, the alkyl glucoside (AG) mixture has shown excellent interfacial properties, being an environmentally safe surfactant, but cannot pass through the cuticle. In the present study, we mixed both surfactants. Two formulations were made with 20% (F1) and 2% (F2) of S with 4% AG. To verify the usefulness of our formulations, they were compared against a commercial product. The results showed that the commercial product had better CMC 0.3±0.1% and pC20 1.155±0.099 than our formulations F1 and F2. Formulations F1 and F2 showed better gCMC than the commercial product 36.5±4.1 mN/m and 30.9±1.4 mN/m, respectively. Field tests showed that F2 was more effective than the commercial product in eliminating weeds at the end of the test at 30 days. Our results allowed confirming that the use of saponin improves the efficiency of glyphosate. The work showed that structures similar to cyclopentaneperhydrophenanthrene are very effective for introducing drugs into plants through the leaves. This is an advance in general and in particular for the increase of the yield in certain crops.

Enzymatic Synthesis of Alkyl Glucosides byβ‐Glucosidases in a 2‐in‐1 Deep Eutectic Solvent System

AbstractAlkyl glycosides are biodegradable surfactants with excellent physico‐chemical properties. Although their wide‐range application is considered ecofriendly, their synthesis is not due to the need for toxic organic solvents and corrosive acids as catalysts. Moreover, chemical synthesis results in complex mixtures rather than defined compounds. To overcome both disadvantages as well as the limited solubility of sugars in organic solvents, a highly selective enzymatic synthesis was set up with aβ‐glucosidase condensing D‐glucose and different fatty alcohols in a deep eutectic solvent.

β-glucosidase from Streptomyces griseus: Ester hydrolysis and alkyl glucoside synthesis in the presence of Deep Eutectic Solvents

Deep Eutectic Solvents (DES) are ionic liquid analogs that have attracted considerable attention as green solvents for biocatalytic transformations. The use of DES as part of a ‘solvent engineering’ approach to enhance enzyme stability holds great promise since they are biodegradable, relatively inexpensive and environmentally safe media for enzyme reactions. However, the behaviour of specific enzymes in such solvents is complex; some enzymes are inhibited in DES, while others appear to be activated.Glucosidases are among the most widely used enzymes for commercial chemoenzymatic synthesis. In particular, their application in the synthesis of biodegradable alkyl glucosides by reverse hydrolysis is of great interest. Previous work in this laboratory identified Streptomyces griseus glucosidase (Sgβgl) as an interesting enzyme for biotechnological applications. In this study, we examined its behaviour in the presence of DES as a co-solvent using choline chloride as hydrogen bond donor and using glycerol, glucose and urea as hydrogen bond acceptors. We show that Sgβgl activity depends on both the nature of DES components, and their ratio in the eutectic mixture, as well as the water content of the reaction medium. A choline chloride/glycerol DES mixture at a level of 40% (v/v) caused activation of Sgβgl and increased its optimum temperature from 70 to 80 ​°C: it also led to a striking increase in its thermostability, doubling its half-life at 60 ​°C and almost tripling its half-life at 80 ​°C.The synthesis of alkyl glucosides was explored using DES as a co-solvent. In the presence of DES, Sgβgl catalysed the formation of a range of alkyl glucosides. The presence of DES resulted in enhanced product yield, which was observed to increase with increasing temperature, up to 60 ​°C.These studies show that the application of DES at relatively low % (v/v) levels can dramatically effect enzyme activity and stability. Specifically, enhanced thermostability can significantly increase the operating range for glucosidases for biocatalytic applications. Solvent engineering offers a simple and effective way to enhance glucosidase stability and will be useful as an alternative and/or adjunct to more complex methods such as immobilisation or protein engineering.

Bamboo Tar as a Novel Fungicide: Its Chemical Components, Laboratory Evaluation, and Field Efficacy Against False Smut and Sheath Blight of Rice and Powdery Mildew and Fusarium Wilt of Cucumber.

The application of agricultural and forest residues can benefit the environment and the economy; however, they also generate a large amount of byproducts. In this study, bamboo tar (BT), a waste product of bamboo charcoal production, was dissolved in natural ethanol and the surfactant alkyl glucoside to manufacture a 50% (wt/wt) BT emulsifiable concentrate (BTEC) biopesticide. BTEC was screened for fungicidal activity against pathogens. The greatest activity was seen against Ustilaginoidea virens with a half-maximal effective concentration (EC50) value of 6 mg/liter. Four phytopathogenic fungi, Podosphaera xanthii, Rhizoctonia solani, Fusarium oxysporum, and Botrytis cinerea, showed EC50 values of <60 mg/liter. Greenhouse tests in vivo showed 2,000 mg/liter BTEC had a 78.4% protective effect against U. virens, and replicated treatments had an 80.6% protective effect. In addition, replicated 2-year field trials were conducted in two geographic locations with four plant diseases: false smut (U. virens), rice sheath blight (Thanatephorus cucumeris [Frank] Donk), cucumber powdery mildew (P. xanthii), and cucumber Fusarium wilt (F. oxysporum). Results showed that 1,000 to 2,000 mg/liter BTEC significantly inhibited these diseases. Gas chromatography-mass spectrometry analysis showed that the total phenolic mass fractions of two BT samples were 45.39 and 48.26%. Eleven components were detected, and their percentage content was as follows (from high to low): 2,6-dimethoxyphenol > 2- or 4-ethylphenol > 2- or 4-methylphenol > phenol > 4-ethylguaiacol > dimethoxyphenol > 4-methylguaiacol > 4-propenyl-2,6-dimethoxyphenol > 2,4-dimethylphenol. Some of the phenolic compounds identified from the tar might be fungicidally active components. BT is a biochar waste, which has potential as a biofungicide and has promise in organic agriculture. The value of this tar may not be because of any fundamental physical differences from other synthetic fungicides but rather caused by reduced production expenses and more efficient use of waste products.