Immobilization Of Alcohol Dehydrogenase Research Articles

Opting for polyamines with specific structural traits as a strategy to boost performance of enzymatic membrane reactors

Enzymatic membrane reactor (EMR) is a type of continuous-flow bioreactor offering easy separation and reuse of biocatalyst while giving opportunities to improve its performance. However, simultaneous enhancement of activity and stability of enzyme while retaining high membrane permeability poses a challenge for a single reactor. Herein, we propose a new method to optimize EMR system − by employing cationic polyelectrolytes with selected molecular weight, backbone, and amino group type for modification of membrane surface; after we have evaluated the effect of polyamine chemistry and membrane properties on each aspect of EMR performance. Polydopamine (PDA)-assisted co-deposition of polyamines (polyethyleneimine (PEI), PEI-graft-poly(ethylene glycol) (PEI-g-PEG), poly(allylamine hydrochloride) (PAH), and poly(diallyldimethylammonium chloride) (PDADMAC)) was used as the modification method; the membranes were characterized by water permeability, water contact angle (WCA), zeta potential (ZP), FTIR spectra, and SEM/EDX; and EMRs were assessed by biocatalytic activity at various pH, flux, immobilization yield and efficiency (activity recovery), enzyme leakage, pH/storage and thermal stability, and reusability. In this work, EMRs with immobilized alcohol dehydrogenase (ADH) showed activities up to 8.9 mU/cm2, retained up to 86 % of initial activity in three conversion cycles without any reduction in flux, and allowed to increase non-optimal pH activity (pH 10) by up to 81 % and improve storage stability by up to 53 % compared to the free enzyme. We discovered statistically significant (p < 0.01) relationships between: (1) polyamine backbone type (linear vs branched) and membrane permeability; (2) membrane isoelectric point and immobilization yield; and (3) membrane WCA and immobilization efficiency. To our knowledge, this is the first systematic study of the effect of polyelectrolyte chemistry on performance of immobilized enzyme − which showed the method’s strong potential for customizing properties and maximizing the productivity of EMRs.

Enhancement of biocatalytic activity in enzymatic membrane reactors: Controlled modification with novel PAH/PDA composites as a tool to optimize reactor performance

Enzymatic membrane (EM) is a tool allowing to simultaneously upgrade enzymatic catalysis and membrane separation processes. However, their commercial use is often restricted by a trade-off between catalytic and mass transfer properties of the system. Herein, we report a new approach to the design of enzymatic membrane reactors (EMRs) - aimed to find the optimal balance between biocatalytic activity, water permeability, and enzyme loading; where we used co-deposited polyallylamine hydrochloride/polydopamine (PAH/PDA) membrane coatings as a tool to control the overall reactor performance. First, we demonstrate that tailoring the PAH/PDA coating chemistry can be more effective for promotion of total biocatalytic activity of EM with immobilized alcohol dehydrogenase (ADH) than increasing the amount of immobilized enzyme on a membrane support. Then, we show how the PAH/PDA ratio (0, 1:10, 1:2, 5:2), modification time (0.25, 1, 4, 16 h) and ionic strength (0.1–1.0 M NaCl) affect morphology of the membrane coating and alter the mechanisms of ADH-support interactions. Lastly, we illustrate the versatility of the PAH/PDA-coated membranes for application in other enzymatic systems on the example of glycerol dehydrogenase (GDH) and evaluate the performance of two EMRs as a function of applied pressure (1–3 bar). The final values of biocatalytic activities 25.4 ± 4.0 and 3.5 ± 0.3 mU/cm2 (which correspond to 140 ± 22 and 67 ± 5% immobilization efficiencies) for immobilized ADH and GDH, respectively, demonstrate that PAH/PDA-coated membranes not only can be used for simultaneous reaction and recovery of the biocatalyst, but also for enhancement of enzymatic activity - due to opportunity of reaction rate control in the membrane reactor.

Preparation of Alcohol Dehydrogenase-Zinc Phosphate Hybrid Nanoflowers through Biomimetic Mineralization and Its Application in the Inhibitor Screening.

A biomimetic mineralization method was used in the facile and rapid preparation of nanoflowers for immobilizing alcohol dehydrogenase (ADH). The method mainly uses ADH as an organic component and zinc phosphate as an inorganic component to prepare flower-like ADH/Zn3(PO4)2 organic-inorganic hybrid nanoflowers (HNFs) with the high specific surface area through a self-assembly process. The synthesis conditions of the ADH HNFs were optimized and its morphology was characterized. Under the optimum enzymatic reaction conditions, the Michaelis-Menten constant (Km) of ADH HNFs (β-NAD+ as substrate) was measured to be 3.54 mM, and the half-maximal inhibitory concentration (IC50) of the positive control ranitidine (0.2-0.8 mM) was determined to be 0.49 mM. Subsequently, the inhibitory activity of natural medicine Penthorum chinense Pursh and nine small-molecule compounds on ADH was evaluated using ADH HNFs. The inhibition percentage of the aqueous extract of P. chinense is 57.9%. The vanillic acid, protocatechuic acid, gallic acid, and naringenin have obvious inhibitory effects on ADH, and their percentages of inhibition are 55.1%, 68.3%, 61.9%, and 75.5%, respectively. Moreover, molecular docking analysis was applied to explore the binding modes and sites of the four most active small-molecule compounds to ADH. The results of this study can broaden the application of immobilized enzymes through biomimetic mineralization, and provide a reference for the discovery of ADH inhibitors from natural products.

Immobilization of Alcohol Dehydrogenase on Organofunctionalized Glass Beads and Comparative Studies: It’s Beneficial Uses

In this Research Study immobilization of Alcohol Dehydrogenase enzyme on glass beads was done. k-carrageenan is a natural polysaccharide like cellulose obtained from seaweeds. ADH was immobilized by Covalent coupling. Then for further study, various parameters like Thermostability , pH study, storage stability and Reusability were optimized and carried out the comparison studies. Furthermore, FTIR analysis was done to prove that the enzyme was immobilized on the support bead. And the application was done with 3 different fruit juices. i.e. sugarcane juice, pineapple juice, and watermelon juice. In addition, this study introduces a new achievement of the eco-friendly effect of immobilized enzyme.

Electrospun aluminum silicate nanofibers as novel support material for immobilization of alcohol dehydrogenase

Ceramic materials with high surface area, large and open porosity are considered excellent supports for enzyme immobilization owing to their stability and reusability. The present study reports the electrospinning of aluminum silicate nanofiber supports from sol-gel precursors, the impact of different fabrication parameters on the microstructure of the nanofibers and their performance in enzyme immobilization. A change in nanofiber diameter and pore size of the aluminum silicate nanofibers was observed upon varying specific processing parameters, such as the sol-composition (precursor and polymer concentration), the electrospinning parameters and the subsequent heat treatment (calcination temperature). The enzyme, alcohol dehydrogenase (ADH), was immobilized on the aluminum silicate nanofibers by physical adsorption and covalent bonding. Activity retention of 17% and 42% was obtained after 12 d of storage and repeated reaction cycles for physically adsorbed and covalently bonded ADH, respectively. Overall, the immobilization of ADH on aluminum silicate nanofibers resulted in high enzyme loading and activity retention. However, as compared to covalent immobilization, a marked decrease in the enzyme activity during storage for physically adsorbed enzymes was observed, which was ascribed to leakage of the enzymes from the nanofibers. Such fibers can improve enzyme stability and promote a higher residual activity of the immobilized enzyme as compared to the free enzyme. The results shown in this study thus suggest that aluminum silicate nanofibers, with their high surface area, are promising support materials for the immobilization of enzymes.

Metal-Phenolic Network-Functionalized Magnetic Nanoparticles for Enzyme Immobilization.

Metal-phenolic network (MPN) coating is an emerging class of surface functionalization method and has attracted ever-growing interest in areas of bioengineering and biotechnology. Although various applications for MPN coatings, including drug delivery, cytoprotection, and antimicrobial surfaces, have been studied in the form of films and capsules, their interaction with enzyme molecules and the subsequent influence of biocatalytic properties are poorly understood. Herein, MPN coatings composed of different types of metal ions (CuII, FeIII, ZnII, MnII, AuIV) coordinated with tannic acid (TA) were fabricated on Fe3O4 nanoparticles as a facile nanoplatform for immobilizing alcohol dehydrogenase (ADH). The results show that the different polarization capacities of metal ions (i.e., Lewis acids) could affect the hydrophilicity and hydrophobicity of the coordinated MPN coatings, while the enzyme immobilization rate, biocatalytic activity, and stability are in turn influenced by the surface properties of the MPN coatings. Among the different metal ions, the Fe3O4-TA-ZnII showed the highest enzyme immobilizing efficiency (91.53%) and catalytic activity (60.45 U/mg ADH). Besides, the enzyme re-usability and tolerance to extreme conditions were both enhanced after immobilization. These results highlight an advanced strategy for the interfacial construction of hybrid heterogeneous biocatalytic systems with potential use in biomedical applications.

Carbon-black combined with TiO2 and KuQ as sustainable photosystem for a reliable self-powered photoelectrochemical biosensor

Since our first work published in Electrochemistry Communication in 2010 (12, 346–350), many carbon black-(CB) based electrochemical printed (bio)sensors have been reported in the literature, addressing voltammetric and potentiometric measurements. Herein, we report the first photoelectrochemical biosensor based on a printed electrode modified with CB. In detail, the photoelectrochemical sensor has been designed by using, in addition to CB, and TiO2, KuQ dye because the use of only TiO2 and CB still requires UV irradiation, while KuQ is characterized by a broad and intense absorption spectrum in the visible region allowing for an easy set-up with a cost-effective portable laser. Once optimized the fabrication and working conditions, namely the solvent for the TiO2 dispersion (i.e. water/dimethylformamide (1:1 v/v)), the amount of TiO2/KuQ to cast onto the working electrode surface (i.e. 4 μg), the applied potential (i.e. +0.4 V), and the working solution (i.e. Tris buffer at pH 8.8), the sensor was challenged for NADH measurement obtaining a linear range up to 8 mM and a detection limit, calculated as 3 σb/slope, equal to 20 µM. The subsequent immobilization of Alcohol Dehydrogenase demonstrated the capability of this biosensor to detect ethanol up to 1 M, with the detection limit equal to 0.062 mM, indicating that the CB-TiO2/KuQ modification can regenerate the coenzyme even in the immobilized form, with improved analytical performances in terms of enhancement of the linearity. Finally, ethanol was detected in a real sample, i.e. white wine, with a good recovery value of 91.60 ± 0.01%, demonstrating the applicability of the developed miniaturized biosensor in white wine samples.

Immobilization of Alcohol Dehydrogenase, Acetaldehyde Lyase, and NADH Oxidase for Cascade Enzymatic Conversion of Ethanol to Acetoin

Acetoin, a four-carbon hydroxyl-keto compound, is used in the food, pharmaceutical, and chemical industries. The cascade enzymatic production is considered a promising and efficient method to produce acetoin. However, the stability and compatibility of the enzymes under the same catalytic conditions are challenges that need to be resolved. In this work, alcohol dehydrogenase, acetaldehyde lyase, and NADH oxidase were selected to work at the same conditions to efficiently convert ethanol into acetoin. These three enzymes were immobilized on epoxy-modified magnetic nanomaterials to obtain highly stable biocatalysts. The stability and the immobilization conditions, including temperature, pH, enzyme–carrier ratio, and immobilization time, were optimized to obtain the immobilized enzymes with a high catalytic activity. The cascade reactions catalyzed by the immobilized enzymes yielded a high conversion of 90%, suggesting that the use of immobilized enzymes is a promising way to produce acetoin.

Screen‐printing of nanocube‐based flexible microchips for the precise biosensing of ethanol during fermentation

AbstractThe real‐time and full concentration analysis of ethanol during the fermentation reaction allows the precise control of the microbial metabolism to promote the conversion rate; however, only few techniques can directly detect the fermentation broth without pretreatment. To address this issue, a screen‐printed biosensing microchip (SPBM) was proposed to analyze the ethanol concentration in fermentation, relying on designing a well‐defined nanocubic structure of an Au nanoparticles/nickel hexacyanoferrate nanocomposite. This nanocomposite was then made into a printing ink for the direct fabrication of a SPBM. The as‐prepared microchip exhibits an ultrahigh electrocatalysis on nicotinamide adenine dinucleotide with a high sensitivity of 96.2 ± 2.9 μA·mM−1·cm−2. Moreover, after the immobilization of alcohol dehydrogenase, the accurate and rapid monitoring of the ethanol concentration during the real fermentation reaction can be realized within an ultrawide linear range of 0.1–10 M in the broth without any pretreatment.

Effect of pH on membrane fouling during alcohol dehydrogenase immobilization in PES membrane

Fouling-induced enzyme immobilization is a technique to immobilize enzyme by positively manipulating the knowledge of membrane fouling. In this study, Alcohol dehydrogenase (ADH) (EC 1.1.1.1) was immobilized in the support layer of ultrafiltration PES membrane at different solution pH (acid, neutral and alkaline). ADH catalyses formaldehyde (CHOH) to methanol (CH3OH) and simultaneously oxidised nicotinamide adenine dinucleotide (NADH) to NAD+. The initial feed amount of enzyme is 3.0 mg. The objective of the study aims at the effect of different pH of feed solution during enzyme immobilization, in terms of permeate flux, observed rejection, enzyme loading and fouling mechanism. The results showed that, pH 5 holds the highest enzyme loading which is 65% while pH 7 holds the lowest at 52% out of 3.0 mg as the initial enzyme feed. The permeate flux for each pH decreased with increasing cumulative permeate volume. The observed rejection is inversely correlated with the pH where increase in pH will cause a lower observed rejection. The fouling model predicted that irreversible fouling occurs during enzyme immobilization at pH 7 with standard blocking mechanism while reversible fouling occurs at pH 5 and 9 with intermediate and complete blocking, respectively.

Epoxy Functionalized Carboxymethyl Dextran Magnetic Nanoparticles for Immobilization of Alcohol Dehydrogenase

Microbial inhibition of carboxymethyl dextran (CMD) magnetic nanoparticles (MNPs) was investigated on two different bacterial cultures, Escherichia coli and Staphylococcus aureus, where inhibition properties of CMD-MNPs were confirmed, while uncoated MNPs exhibited no inhibition properties. To such CMD-MNPs, enzyme alcohol dehydrogenase (ADH) from Saccharomyces cerevisiae was immobilized. Later on, CMD-MNPs were functionalized, using an epoxide cross-linker epichlorohydrin (EClH) for another option of ADH immobilization. Residual activities of immobilized ADH onto epoxy functionalized and non-functionalized CMD-MNPs were determined. Effect of cross-linker concentration, temperature of immobilization and enzyme concentration on residual activities of immobilized ADH were determined, as well. With optimal process conditions (4% (v/v) EClH, 4 °C and 0.02 mg/mL of ADH), residual activity of immobilized ADH was 90%. Such immobilized ADH was characterized using FT-IR, SEM and DLS analysis.

Immobilization of alcohol dehydrogenase from Saccharomyces cerevisiae onto carboxymethyl dextran-coated magnetic nanoparticles: a novel route for biocatalyst improvement via epoxy activation

A novel method is described for the immobilization of alcohol dehydrogenase (ADH) from Saccharomyces cerevisiae onto carboxymethyl dextran (CMD) coated magnetic nanoparticles (CMD-MNPs) activated with epoxy groups, using epichlorohydrin (EClH). EClH was used as an activating agent to bind ADH molecules on the surface of CMD-MNPs. Optimal immobilization conditions (activating agent concentration, temperature, rotation speed, medium pH, immobilization time and enzyme concentration) were set to obtain the highest expressed activity of the immobilized enzyme. ADH that was immobilized onto epoxy-activated CMD-MNPs (ADH-CMD-MNPs) maintained 90% of the expressed activity. Thermal stability of ADH-CMD-MNPS after 24 h at 20 °C and 40 °C yielded 79% and 80% of initial activity, respectively, while soluble enzyme activity was only 19% at 20 °C and the enzyme was non-active at 40 °C. Expressed activity of ADH-CMD-MNPs after 21 days of storage at 4 °C was 75%. Kinetic parameters (KM, vmax) of soluble and immobilized ADH were determined, resulting in 125 mM and 1.2 µmol/min for soluble ADH, and in 73 mM and 4.7 µmol/min for immobilized ADH.

Efficient Nicotinamide Adenine Dinucleotide Phosphate [NADP(H)] Recycling in Closed‐Loop Continuous Flow Biocatalysis

AbstractBiocatalytic redox reactions regularly depend on expensive cofactors that require recycling. For continuous conversions in flow chemistry, this is often an obstacle since the cofactor is washed away. Here, we present a quasi‐stationary recycling system for nicotinamide adenine dinucleotide phosphate utilizing an immobilized alcohol dehydrogenase. Four model substrates were reduced with high enantioselectivity as a proof of concept. The two‐phase system enables continuous production as well as quick substrate changes. This setup may serve as a general cofactor regeneration module for continuous biocatalytic devices employing (co‐)substrates being miscible in organic solvent. The system resulted in space‐time yields up to 117 g L−1 h−1 and total turnover numbers for nicotinamide adenine dinucleotide phosphate higher than 12,000 mol/mol are possible.magnified image

Immobilization of Alcohol Dehydrogenase in membrane: Fouling mechanism at different enzyme concentration

Fouling induced enzyme immobilization on polymer membrane with controlled variables can retain enzyme stability and performance. In this study, the effect of enzyme concentration towards the fouling-induced enzyme immobilization was investigated. Alcohol dehydrogenase (ADH) was used as model enzyme to be immobilized on poly(ether) sulfone (PES) membrane at different concentration (0.05, 0.10 and 0.20 g/L). The transmembrane pressure and pH were fixed at 2 bar and pH 7 respectively during the process takes place. The result shows that higher enzyme concentration gives higher loading efficiency with 83.95%. Hermia’s model predicted that standard and intermediate blocking dominating the fouling mechanism at all enzyme concentration tested.

Simultaneous separation and biocatalytic conversion of formaldehyde to methanol in enzymatic membrane reactor

Combination of the reaction simultaneously with separation inside a single process unit or commonly known as reactive separation technology is widely studied nowadays as it would give mutual benefits for both enzymatic catalysis and membrane separation process. Alcohol dehydrogenase (ADH) at 0.10 g/L (dissolved in 0.10 M Tris-HCl buffer) was immobilized on commercially available PES and PVDF membrane at pH 7 and TMP 2 bar by reverse filtration method. Then the immobilized enzyme was subjected to the biocatalytic conversion of formaldehyde to methanol. The immobilization process successfully immobilized 87.67% and 70.94% of ADH enzyme in/on the PVDF and PES membrane, respectively. The subsequent reaction was able to convert formaldehyde to methanol as high as 90% conversion and a high biocatalytic productivity of 460 µmol CH3OH/mgenzyme·h for PVDF membranes. Enzyme relative activity could be retained for at least seven consecutive cycles. This study suggested that immobilization of ADH on the polymer membrane can increase enzyme loading and also retain its activity for a simultaneous conversion and separation of formaldehyde to methanol.

Ketoisophorone Synthesis with an Immobilized Alcohol Dehydrogenase

AbstractThe monoterpenoid α‐isophorone is sourced from the available and renewable plant dry matter, as well as a waste recovery operation from acetone. This compound, can be hydroxylated to 4‐hydroxy‐isophorone which is the main precursor for the synthesis of ketoisophorone. On its turn, ketoisophorone is a key intermediate for the production of carotenoids and Vitamin E. Here, the enzymatic oxidation of 4‐hydroxy‐isophorone to ketoisophorone is demonstrated employing an alcohol dehydrogenase (ADHaa) from Artemisia annua and a NADPH oxidase (NOX), as a cofactor regeneration enzyme. After 24 h of reaction and an initial substrate concentration of 50 mM, 95.7 % yield and a space time yield of 6.52 g L−1 day−1 could be obtained. Furthermore, the immobilization of the alcohol dehydrogenase was studied on 17 different supports. An epoxy‐functionalized agarose resulted in the highest metrics, 100±0% immobilization yield and 58.2±3.5 % retained activity. Finally, the immobilized ADHaa was successfully implemented in 4 reaction cycles (96 h operation) presenting a biocatalyst yield of 23.4 g product g−1 of enzyme. It represents a 2.5‐fold increase compared with the reaction with soluble enzymes.

Immobilization of Alcohol Dehydrogenase on Titania Nanoparticles To Enhance Enzyme Stability and Remove Substrate Inhibition in the Reaction of Formaldehyde to Methanol

Both physical and chemical procedures were applied to immobilize yeast alcohol dehydrogenase (yADH) on titania nanoparticles. It was found that chemical immobilization is an authentic method due to providing a strong bond between the enzyme and the support. The immobilization was confirmed by Fourier transform infrared spectroscopy and transmission electron microscopy. The immobilization parameters such as enzyme concentration, time of immobilization, and glutaraldehyde concentration were optimized based on the maximum immobilization yield and the best enzyme catalytic performance. Activity and kinetics of yADH before and after immobilization were studied, and the stability of enzyme at different pHs and temperatures was investigated. The optimum pH for the incubation and activity of yADH was obtained at 7.0, and the activity of immobilized yADH reached more than 80% of its initial activity after 30 days of storage at 4 °C. The reusability of yADH was improved by immobilization as revealed by retaining 84...

Multi‐walled Carbon Nanotubes Non‐covalently Functionalized with Polyarginine: A New Alternative for the Construction of Reagentless NAD+/Dehydrogenase‐based Ethanol Biosensor

AbstractThis work reports for the first time the development of a reagentless enzymatic amperometric biosensor for ethanol based on the use of a glassy carbon electrode (GCE) modified with multi‐walled carbon nanotubes (MWCNTs) non‐covalently functionalized with polyarginine (Polyarg) as platform for the robust immobilization of alcohol dehydrogenase (ADH) and NAD+. The new strategy allows to obtain an integrated GCE/MWCNTs‐Polyarg/NAD+‐ADH ethanol biosensor with important advantages compared to the existing ethanol biosensors: avoids the external addition of the cofactor for each measurement, ensures a fast and sensitive quantification of ethanol due to the intimate interaction of the components, and allows the detection at considerably lower potentials due to the catalytic activity of the carbon nanostructures. These unique properties have made possible a very efficient ethanol quantification with a sensitivity of (1487±6) μA M−1, detection limit of 0.65 μM, response time of 8 s, and reproducibility of 5.5 % with a very successful application for the quantification of ethanol in different commercial beverages.

Immobilization and stabilization of alcohol dehydrogenase on polyvinyl alcohol fibre

A polyvinyl alcohol (PVA) fibrous carrier has been chemically modified for the immobilization of yeast alcohol dehydrogenase (ADH) with an aim to increase its stability over a wide pH range, prolong its activity upon storage, and enhance its reusability. The strategy for immobilization involved functionalization of the fibrous carrier with chloropropinoyl chloride followed by amination with ethylenediamine. Tethering of the ADH enzyme to the PVA scaffold was achieved with glutaraldehyde. The activity profile of the immobilized enzyme was compared to soluble enzyme as a function of pH, temperature and reusability. The immobilization of ADH on PVA fibrous carrier shifted the optimal reaction pH from 7 to 9, and improved the thermostability at 60 °C. Furthermore, the immobilized enzyme retained 60% of its original activity after eight cycles of reuse. These results demonstrate that PVA based textiles can serve as a flexible, reusable carrier for enzyme immobilization.

Immobilization of alcohol dehydrogenase on ceramic silicon carbide membranes for enzymatic CH3OH production

AbstractBACKGROUNDAlcohol dehydrogenase (ADH; EC 1.1.1.1) catalyzes oxidation of CH3OH to CHOH during NAD+ reduction to NADH. ADH can also accelerate the reverse reaction, which is studied as part of cascadic enzymatic conversion of CO2 to CH3OH. In the present study, immobilization of ADH onto macroporous membranes of silicon carbide (SiC) was investigated for CHOH to CH3OH conversion.RESULTSImmobilization techniques included physical adsorption directly to the membrane and functionalization of the membrane with polyethylenimine (PEI) or (3‐aminopropyl)triethoxysilane (APTES) followed by glutaraldehyde (GA) cross‐linking. Enzyme loadings, flux, NADH conversion, and overall ADH reusability were assessed. Enzyme loadings were similar, but substrate conversion was approximately 2 and 2.5 times higher for APTES‐GA and PEI‐GA, respectively, and the relative activity retention was better than for physical adsorption. Membrane surface treatment with NaOH prior to APTES‐GA immobilization resulted in significant improvement in enzyme loading and a doubling of ADH activity as well as higher activity during recycling as the ADH destabilization rate was unaffected.CONCLUSIONSThe results provided proof‐of‐concept for the use of NaOH‐treated SiC membranes for covalent enzyme immobilization and biocatalytic efficiency improvement of ADH during multiple reaction cycles. These data have implications for the development of robust extended enzymatic reactions. © 2018 Society of Chemical Industry