Harnessing the potential of deep eutectic solvents in biocatalysis: design strategies using CO to formate reduction as a case study.

Introduction: Deep eutectic solvents (DESs) have emerged as green solvents with versatile applications, demonstrating significant potential in biocatalysis. They often increase the solubility of poorly water-soluble substrates, serve as smart co-substrates, modulate enzyme stereoselectivity, and potentially improve enzyme activity and stability. Despite these advantages, screening for an optimal DES and determining the appropriate water content for a given biocatalytic reaction remains a complex and time-consuming process, posing a significant challenge.

Development of a Microbioreactor for Biofilm Cultivation.

To improve our understanding of growth and biofilm formation under different environmental conditions, two versions of a microfluidic reactor with two channels separated by a polydimethylsiloxane (PDMS) membrane were developed. The gas phase was introduced into the channel above the membrane, and oxygen transfer from the gas phase through the membrane was assessed by measuring the dissolved oxygen concentration in the liquid phase using a miniaturized optical sensor and oxygen-sensitive nanoparticles. biofilm formation was monitored in the growth channels of the microbioreactors, which were designed in two shapes: one with circular extensions and one without.

Immobilization of His-tagged amine transaminases in microreactors using functionalized nonwoven nanofiber membranes.

Process intensification is crucial for industrial implementation of biocatalysis and can be achieved by continuous process operation in miniaturized reactors with efficiently immobilized biocatalysts, enabling their long-term use. Due to their extremely large surface-to-volume ratio, nanomaterials are promising supports for enzyme immobilization. In this work, different functionalized nanofibrous nonwoven membranes were embedded in a two-plate microreactor to enable immobilization of hexahistidine (His)-tagged amine transaminases (ATAs) in flow.

Tuning Mechanical Characteristics and Permeability of Alginate Hydrogel by Polyvinyl Alcohol and Deep Eutectic Solvent Addition.

Alginate-based hydrogels are widely utilized for various applications, including enzyme immobilization and the development of drug delivery systems, owing to their advantageous characteristics, such as low toxicity, high availability and cost-effectiveness. However, the broad applicability of alginate hydrogels is hindered by their limited mechanical and chemical stability, as well as their poor permeability to hydrophobic molecules. In this study, we addressed the mechanical properties and chemical resistance of alginate hydrogels in a high-pKa environment by the copolymerization of alginate with polyvinyl alcohol (PVA).

Novel Approach for the Isolation and Immobilization of a Recombinant Transaminase: Applying an Advanced Nanocomposite System.

The increasing application of recombinant enzymes demands not only effective and sustainable fermentation, but also highly efficient downstream processing and further stabilization of the enzymes by immobilization. In this study, a novel approach for the isolation and immobilization of His-tagged transaminase from Chromobacterium violaceum (CvTA) has been developed. A recombinant of CvTA was simultaneously isolated and immobilized by binding on silica nanoparticles (SNPs) with metal affinity linkers and additionally within poly(lactic acid) (PLA) nanofibers.

The Potential of Brewer's Spent Grain in the Circular Bioeconomy: State of the Art and Future Perspectives.

Brewer's spent grain (BSG) accounts for approximately 85% of the total mass of solid by-products in the brewing industry and represents an important secondary raw material of future biorefineries. Currently, the main application of BSG is limited to the feed and food industry. There is a strong need to develop sustainable pretreatment and fractionation processes to obtain BSG hydrolysates that enable efficient biotransformation into biofuels, biomaterials, or biochemicals.

Hydrogel-Based Enzyme and Cofactor Co-Immobilization for Efficient Continuous Transamination in a Microbioreactor.

A microbioreactor was developed in which selected amine transaminase was immobilized together with the cofactor pyridoxal phosphate (PLP) to allow efficient continuous transamination. The enzyme and cofactor were retained in a porous copolymeric hydrogel matrix formed in a two-plate microreactor with an immobilization efficiency of over 97%. After 10 days of continuous operation, 92% of the initial productivity was retained and no leaching of PLP or enzyme from the hydrogel was observed.

Let the Biocatalyst Flow.

Industrial biocatalysis has been identified as one of the key enabling technologies that, together with the transition to continuous processing, offers prospects for the development of cost-efficient manufacturing with high-quality products and low waste generation. This feature article highlights the role of miniaturized flow reactors with free enzymes and cells in the success of this endeavor with recent examples of their use in single or multiphase reactions. Microfluidics-based droplets enable ultrahigh-throughput screening and rapid biocatalytic process development.

Trametes versicolor in lignocellulose-based bioeconomy: State of the art, challenges and opportunities.

Although Trametes versicolor is one of the most investigated white-rot fungi, the industrial application of this fungus and its metabolites is still far from reaching its full potential. This review aims to highlight the opportunities and challenges for the industrial use of T. versicolor according to the principles of circular bioeconomy.

Development of a Microfluidic Platform for R-Phycoerythrin Purification Using an Aqueous Micellar Two-Phase System.

Temperature-dependent aqueous micellar two-phase systems (AMTPSs) have recently been gaining attention in the isolation of high-added-value biomolecules from their natural sources. Despite their sustainability, aqueous two-phase systems, and particularly AMTPSs, have not been extensively applied in the industry, which might be changed by applying process integration and continuous manufacturing. Here, we report for the first time on an integrated microfluidic platform for fast and low-material-consuming development of continuous protein purification using an AMTPS.

Covalent Immobilization of Microbial Cells on Microchannel Surfaces.

Microfluidic devices with integrated biological material have found many applications in analytics (e.g., protein and DNA analysis), biochemistry (e.

Copolymeric Hydrogel-Based Immobilization of Yeast Cells for Continuous Biotransformation of Fumaric Acid in a Microreactor.

Although enzymatic microbioreactors have recently gained lots of attention, reports on the use of whole cells as biocatalysts in microreactors have been rather modest. In this work, an efficient microreactor with permeabilized cells was developed and used for continuous biotransformation of fumaric into industrially relevant L-malic acid. The immobilization of yeast cells was achieved by entrapment in a porous structure of various hydrogels.

The Promises and the Challenges of Biotransformations in Microflow.

The challenges of transition toward the postpetroleum world shed light on the biocatalysis as the most sustainable way for the valorization of biobased raw materials. However, its industrial exploitation strongly relies on integration with innovative technologies such as microscale processing. Microflow devices remarkably accelerate biocatalyst screening and engineering, as well as evaluation of process parameters, and intensify biocatalytic processes in multiphase systems.

Development of microreactors with surface-immobilized biocatalysts for continuous transamination.

The industrial importance of optically pure compounds has thrown a spotlight on ω-transaminases that have shown a high potential for the synthesis of bioactive compounds with a chiral amine moiety. The implementation of biocatalysts in industrial processes relies strongly on fast and cost effective process development, including selection of a biocatalyst form and the strategy for its immobilization. Here, microscale reactors with selected surface-immobilized amine-transaminase (ATA) in various forms are described as platforms for high-throughput process development.

Microscale technology and biocatalytic processes: opportunities and challenges for synthesis.

Despite the expanding presence of microscale technology in chemical synthesis and energy production as well as in biomedical devices and analytical and diagnostic tools, its potential in biocatalytic processes for pharmaceutical and fine chemicals, as well as related industries, has not yet been fully exploited. The aim of this review is to shed light on the strategic advantages of this promising technology for the development and realization of biocatalytic processes and subsequent product recovery steps, demonstrated with examples from the literature. Constraints, opportunities, and the future outlook for the implementation of these key green engineering methods and the role of supporting tools such as mathematical models to establish sustainable production processes are discussed.

Evaluation of biotreatability of ionic liquids in aerobic and anaerobic conditions.

The aim of our study was to set up an approach for reliable biotreatability assessment of ionic liquids (ILs). As a case study, two different ILs were selected: pyridinium-based 1-butyl-3-methylpyridinium dicyanamide ([bmpyr][dca]) and imidazolium-based 1-butyl-3-methylimidazole tetrafluoroborate ([bmim][BF4]). Toxicity in aerobic conditions was determined by measurement of inhibition of oxygen consumption by activated sludge, while their biodegradability was calculated from measurements of oxygen consumption and dissolved organic carbon elimination.

Continuous steroid biotransformations in microchannel reactors.

The use of microchannel reactor based technologies within the scope of bioprocesses as process intensification and production platforms is gaining momentum. Such trend can be ascribed a particular set of characteristics of microchannel reactors, namely the enhanced mass and heat transfer, combined with easier handling and smaller volumes required, as compared to traditional reactors. In the present work, a continuous production process of 4-cholesten-3-one by the enzymatic oxidation of cholesterol without the formation of any by-product was assessed.

Optimization of laccase production by Trametes versicolor cultivated on industrial waste.

Laccases are very interesting biocatalysts for several industrial applications. Its production by different white-rot fungi can be stimulated by a variety of inducing substrates, and the use of lignocellulosic wastes or industrial by-products is one of the possible approaches to reduce production costs. In this work, various industrial wastes were tested for laccase production by Trametes versicolor MZKI G-99.

Immobilization of yeast cells within microchannels of different materials.

Saccharomyces cerevisiae was successfully immobilized on the inner wall surface of channels of submillimeter diameter, which can be further used for the development of a highly productive continuous biotransformation process within a microfluidic device. Covalent bonding by means of 3-aminopropyltriethoxysilane (APTES) and glutaraldehyde was used for immobilization of cells to microchannels made of glass, polystyrene (PS), polytetrafluoroethylene (PTFE), perfluoroalkoxy (PFA) and fluorinated ethylene propylene (FEP). All tested materials were successfully functionalized with H2SO4 to promote silanization.

Oxidation of Coniferyl Alcohol Catalyzed by Laccases from Trametes versicolor.

Oxidation of coniferyl alcohol catalyzed by commercial laccase and crude laccase produced during the submerged cultivation of Trametes versicolor MZKI G-99 in a medium containing the waste from paper industry was investigated. pH of 6.6 and temperature of 35 °C was found to be optimal for coniferyl alcohol oxidation catalyzed by commercial laccase.

Lipase-catalyzed synthesis of isoamyl acetate in an ionic liquid/n-heptane two-phase system at the microreactor scale.

A continuously operated psi-shaped microreactor was used for lipase-catalyzed synthesis of isoamyl acetate in the 1-butyl-3-methylpyridinium dicyanamide/n-heptane two-phase system. The chosen solvent system with dissolved Candida antarctica lipase B, which was attached to the ionic liquid/n-heptane interfacial area due to its amphiphilic properties, was shown to be highly efficient and enabled simultaneous esterification and product removal. At preliminarily selected conditions regarding the type of acyl donor, its molar ratio to alcohol and enzyme concentration, 48.

Steroid extraction in a microchannel system--mathematical modelling and experiments.

The continuous ethyl acetate extraction of progesterone and 11alpha-hydroxyprogesterone, a reactant and the product of the biotransformation step involved in corticosteroid production, was studied in a microchannel at different flow velocities. In addition, non-steady state batch extraction without mixing was performed and modelled in order to verify the theoretically predicted parameters. In order to analyze experimental data and to forecast microreactor performance, a three-dimensional mathematical model with convection and diffusion terms was developed considering the velocity profile for laminar flow of two parallel phases in a microchannel at steady-state conditions.