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International audience; Levoglucosan (LGA) is an anhydrous pyrolytic sugar that has gained increasing attention in recent years. The highest focus on the conversion of LGA and other anhydro carbohydrates obtained from cellulose aims at the valorization of these molecules and their application in multiple fields such as chemical and pharmaceutical industries. LGA presents a rigid structure with three hydroxyl groups on a pyranose ring, making it a promising building block for the synthesis of bio-based thermoplastic polymers with pending OH groups as soon as a regioselective polymerization is reached. In this work, a lipase-catalyzed series of LGA-containing terpolymers were synthesized for the first time via regioselective transesterification in two-stage polymerization. LGA was reacted with diethyl adipate/sebacate and α,ω-diols to give terpolymers with up to 35% of LGA content (related to the α,ω-diol content), number-average molecular weights (Mn) of up to 7900 g·mol–1, and up to 94% yield. It was observed that the amount of LGA in the polymer structure affects the crystallinity, hydrophilicity, and melting point of the polymers. We also evaluated the effect of LGA loading and the comonomer’s size on yields, molecular weight, and the incorporation of LGA in the polymer structure. High loads of LGA lead to a decrease in the yield, but a higher molecular weight and higher extent of LGA incorporation in the polymer can be obtained.

International audience; Studies involving the transformation of lignocellulosic biomass into high value-added chemical products have been intensively conducted in recent years. Its matrix is mainly composed of cellulose, hemicellulose and lignin, being, therefore, an abundant and renewable source for obtaining several platform molecules, with levoglucosan (LG) standing out. This anhydrous carbohydrate can be acylated to obtain carbohydrate fatty acid esters (CFAEs). Here, these compounds were obtained via enzymatic acylation of LG, commercially obtained (Start BioScience®), with different acyl donors in continuous flow. Through the experimental design using a model reaction, it was possible to optimize the reaction conditions, temperature and residence time, obtaining a maximum conversion at 61 C and 77 min. In addition, there was a productivity gain of up to 100 times in all comparisons made with the batch system. Finally, CFAEs were applied in tests of interfacial tension and biological activity. For a mixture of 4-and 2-O-lauryl-1,6-anhydroglucopyranose (MONLAU), the minimum interfacial tension (IFT min) obtained was 96 mN m À1 and the critical micelle concentration (CMC) was 50 mM. Similar values were obtained for a mixture of 4-and 2-O-palmitoyl-1,6-anhydroglucopyranose (MONPAL), not yet reported in the literature, of 88 mN m À1 in 50 mM. For a mixture of 4-and 2-O-estearyl-1,6anhydroglucopyranose (MONEST) and 4-and 2-O-oleoyl-1,6-anhydroglucopyranose (MONOLE), CMC was higher than 60 mM and IFT min of 141 mN m À1 and 102 mN m À1 , respectively. Promising data were obtained for minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) of MONLAU against Staphylococcus aureus strains at 0.25 mM.

Sustainability in chemistry heavily relies on heterogeneous catalysis. Enzymes, the main catalyst for biochemical reactions in nature, are an elegant choice to catalyze reactions due to their high activity and selectivity, although they usually suffer from lack of robustness. To overcome this drawback, enzyme-decorated nanoporous heterogeneous catalysts were developed. Three different approaches for Candida antarctica lipase B (CAL-B) immobilization on a covalent organic framework (PPF-2) were employed: physical adsorption on the surface, covalent attachment of the enzyme in functional groups on the surface and covalent attachment into a linker added post-synthesis. The influence of the immobilization strategy on the enzyme uptake, specific activity, thermal stability, and the possibility of its use through multiple cycles was explored. High specific activities were observed for PPF-2-supported CAL-B in the esterification of oleic acid with ethanol, ranging from 58 to 283 U mg-1 , which was 2.6 to 12.7 times greater than the observed for the commercial Novozyme 435.

Enantiomerically pure alcohols and amines are important building blocks for the pharmaceutical and agrochemical industries. Among the different approaches to reach these compounds, enzyme-catalyzed kinetic resolution (EKR) of racemates is one of the most widely studied and employed methodologies. In this kind of reaction, the acyl donor plays an important role, making the search for new acylating agents an attractive field. Herein, we report our results over the use of PEG600 carboxylates as acylating agent for separation of amines and alcohols enantiomers in continuous flow. For the EKR of 1-phenylethylamine, PEG600-diester show the best results, and (S)-1-phenylethylamine was obtained with high yield and enantiomeric purity (49% yield and >99% (S)) with a productivity of 211 mg h−1 genzyme−1. (R)-1-phenylethylamine was recovered after chemical hydrolysis of the amide formed with high yield and ee (35% yield and 95% ee). In addition, the immobilized enzyme remains active for at least 20 h operation. On the other hand, (R)- and (S)-1-phenylethanol was obtained after continuous lipase-catalyzed hydrolysis of the ester (formed after reaction with PEG) in good conversions to both enantiomers, with a productivity of 68 mg h−1 g enzyme−1 for the (S)- enantiomer and 64 mg h−1 genzyme−1 for the (R) enantiomer.

In this work lipase CaLB was immobilized on functionalized Pd-SiO 2 nanoparticles in order to simplify the DKR of α-methylbenzylamine. Hybrid biocatalysts showed immobilization efficiencies of 82%, 80% and 76% when containing 1, 5 and 10% of Pd respectively. On DKR reaction values of ee > 99% and conversion of 82% were found with only 1% of Pd, generating a productivity of 2.21 mg of product h −1 mg of support −1 against 0.76 found by N435®. Compared to commercial N435®, the novel biocatalysts showed protein loads about 15-fold lower and higher activity, demonstrating competitive performances and high industrial applications.

BACKGROUND In this work, lipase B from Candida antarctica (CaLB) was immobilized on Purolite® ECR8205F, Purolite® ECR8214F and Immobead® IB150 P epoxy resins with no modification to their surfaces. Biocatalysts were evaluated for thermal stability and applied in reactions of hydrolysis, esterification and the synthesis of glyceryl carbonate by transesterification with dimethyl-carbonate both with glycerol and Macauba oil as well as dynamic kinetic resolution of α-methylbenzylamine, all of them compared with commercial Novozyme 435®. RESULTS Protein desorption of the biocatalysts with Triton X-100 showed that lipase was immobilized by covalent single-bond type binding. The immobilization efficiencies were 55.1% for the biocatalyst 8205, 57.1% for 8214, and 14.9 for the 150P, demonstrating the intense effect of surface and material composition on lipase immobilization. The biocatalysts also showed higher initial velocities of esterification and hydrolysis reactions as well as higher thermal stability than Novozyme 435®. On glycerol carbonate synthesis, conversion of 97% and selectivity higher than 99% was demonstrated by enzyme 8214, similar to Novozyme 435®. On kinetic dynamic resolution, conversions higher than 94% and and enantiomeric excesses greater than 90% were also depicted. CONCLUSION Compared with commercial preparation Novozyme 435®, the novel biocatalysts obtained by immobilization on new epoxy resins demonstrated protein loads about 10-fold lower and higher specific activity. In all reactions performed, competitive performances were found, demonstrating high potential for industrial applications. © 2017 Society of Chemical Industry

The combination of enzymatic and chemical reaction steps is one important area of research in organic synthesis, preferentially as cascade reactions in one-pot to improve total conversion and achieve high operational stability. Here, the combination of the Suzuki-Miyaura reaction is described to synthesize biaryl compounds followed by a transamination reaction. Careful optimization of the reaction conditions required for the chemo- and biocatalysis reaction enabled an efficient two-step-one-pot reaction yielding the final chiral amines with excellent optical purity (>99 % ee) in up to 84 % total conversion. Key to the success was the protein engineering of the amine transaminases from Asperguillus fumigatus (4CHI-TA) where single alanine mutations increased the conversion up to 2.3-fold. Finally, the transfer to a continuous flow system after immobilization of the best 4CHI-TA variant is demonstrated.

Development of asymmetric transformations for the synthesis of chiral molecules has achieved great results in the last decade. Besides the great evolution achieved during recent years in the biotechnology and biocatalysis fields, industrial processes using enzymatic approaches are few and a more broad application of such technology towards the synthesis of chiral molecules is still under development. Herein we report our results on the immobilization of lipase B from Candida antarctica on five different commercial supports for the development of a continuous-flow kinetic resolution of alcohol. Immobilization on Accurel MP1000 gave the best results arriving at productivities of around 140 g per h per g of protein and the immobilized biocatalyst could be recycled 5 times without significant loss of activity.

Sporopollenin exine capsules (SECs), derived from the spores of Lycopodium clavatum, have been functionalised with 1,n-diamines and the resulting aminoalkyl microcapsules used to immobilize Candida antarctica lipase B (Cal B) via a glutaradehyde-based diimine covalent linker. The supported enzyme efficiently catalyzes the esterification of oleic acid with ethanol. Initial rates using the SEC-CalBs were comparable to the commercial enzyme Novozym 435, but displayed up to 20-fold higher specific activity. The supported enzymes could also be recycled and after four cycles displayed only a modest decrease in conversions. In a kinetic resolution the SEC-CalBs efficiently acetylated rac-1-phenylethanol, with conversions up to 37% after 5 hours and product enantiomeric excesses of >99%. Related to this, the dynamic resolution of rac-1-phenylethylamine, in the presence of Pd–BaSO4 and ammonium formate, led to the acetylated amine with a 94% conversion and >99% ee.