Beneficial substrate partitioning boosts non-aqueous catalysis in de novo enzyme-alginate beads

Synthetic reactions often involve solvents incompatible with biocatalysts. Here, we encapsulate de novo heme-containing enzymes in calcium-alginate beads to facilitate heterogeneous biocatalysis in organic solvents. After encapsulation, enzymes remained structured and retained activity even when the beads are suspended in organic solvents. Carbene transferase activity, brought about by the heme cofactor, was enhanced when reactions were performed in organic solvent with alginate-encapsulated enzymes. Activity-solvent dependencies revealed that the activity boost is due to beneficial partitioning of the substrate between the beads and organic phase. Encapsulation furthermore facilitates enzyme recycling after the reaction. Alginate encapsulation opens up novel opportunities for biocatalysis in organic solvent systems, combining desired solvent properties of organic chemistry with enzymatic selectivity and proficiency.

Heterogeneous Biocatalysts for the Final Stages of Deep Processing of Renewable Resources into Valuable Products

Heterogeneous biocatalysis is a part of biotechnology and it has commercial potential for industrial implementation, in particular the final stages of deep processing of renewable raw materials. The commercially attractive heterogeneous biocatalysts are prepared by immobilizing practically valuable enzymatic active substances onto solid inorganic supports. Heterogeneous biocatalytic processes of the target conversion of substrate into valuable market product are carried out in periodic or continuous modes using traditional batch and packed-bed reactors, as well as novel types of vortex reactors in accordance with the principles of green chemistry. Heterogeneous biocatalysts for the final stages of deep processing of vegetable raw materials such as starch and oils are described here. One of the biocatalysts is glucoamylase immobilized by adsorption on mesoporous carbon support Sibunit™ type. This glucoamylase-active biocatalyst is used at the stage of starch saccharification, i.e., hydrolysis of dextrin to treacle and glucose syrups used in food and confectionary industries. The second of the biocatalysts is recombinant T. lanuginosus lipase immobilized on mesoporous silica KSK™ type and macroporous carbon aerogel. These lipase-active biocatalysts can effectively compete with traditional organic synthesis catalysts, and they are used in low-temperature processes carried out in unconventional anhydrous media such as interesterification of vegetable oils’ triglycerides with ethyl acetate for producing ethyl esters of fatty acids (biodiesel and vitamin F) and esterification of fatty acids with aliphatic alcohols for synthesis of various esters used as fragrances, flavorings, odors, emollients, and nonionic surfactants in perfume and cosmetics industries. The prepared heterogeneous biocatalysts due to their high enzymatic activity and operational stability are promising for practical implementation.