n-Butyl levulinate synthesis using lipase catalysis: comparison of batch reactor versus continuous flow packed bed tubular microreactor

Kinetic Aspects of Esterification and Transesterification in Microstructured Reactors

Microstructured reactors offer fast chemical engineering transfer and precise microfluidic control, enabling the determination of reactions' kinetic parameters. This review examines recent advancements in measuring microreaction kinetics. It explores kinetic modeling, reaction mechanisms, and intrinsic kinetic equations pertaining to two types of microreaction: esterification and transesterification reactions involving acids, bases, or biocatalysts. The utilization of a micro packed-bed reactor successfully achieves a harmonious combination of the micro-dispersion state and the reaction kinetic characteristics. Additionally, this review presents micro-process simulation software and explores the advanced integration of microreactors with spectroscopic analyses for reaction monitoring and data acquisition. Furthermore, it elaborates on the control principles of the micro platform. The superiority of online measurement, automation, and the digitalization of the microreaction process for kinetic measurements is highlighted, showcasing the vast prospects of artificial intelligence applications.

Biocatalytic Performance of β-Glucosidase Immobilized on 3D-Printed Single- and Multi-Channel Polylactic Acid Microreactors

Microfluidic devices have attracted much attention in the current day owing to the unique advantages they provide. However, their application for industrial use is limited due to manufacturing limitations and high cost. Moreover, the scaling-up process of the microreactor has proven to be difficult. Three-dimensional (3D) printing technology is a promising solution for the above obstacles due to its ability to fabricate complex structures quickly and at a relatively low cost. Hence, combining the advantages of the microscale with 3D printing technology could enhance the applicability of microfluidic devices in the industrial sector. In the present work, a 3D-printed single-channel immobilized enzyme microreactor with a volume capacity of 30 μL was designed and created in one step via the fused deposition modeling (FDM) printing technique, using polylactic acid (PLA) as the printing material. The microreactor underwent surface modification with chitosan, and β-glucosidase from Thermotoga maritima was covalently immobilized. The immobilized biocatalyst retained almost 100% of its initial activity after incubation at different temperatures, while it could be effectively reused for up to 10 successful reaction cycles. Moreover, a multi-channel parallel microreactor incorporating 36 channels was developed, resulting in a significant increase in enzymatic productivity.

Esters in the Food and Cosmetic Industries: An Overview of the Reactors Used in Their Biocatalytic Synthesis

Esters are versatile compounds with a wide range of applications in various industries due to their unique properties and pleasant aromas. Conventionally, the manufacture of these compounds has relied on the chemical route. Nevertheless, this technique employs high temperatures and inorganic catalysts, resulting in undesired additional steps to purify the final product by removing solvent residues, which decreases environmental sustainability and energy efficiency. In accordance with the principles of "Green Chemistry" and the search for more environmentally friendly methods, a new alternative, the enzymatic route, has been introduced. This technique uses low temperatures and does not require the use of solvents, resulting in more environmentally friendly final products. Despite the large number of studies published on the biocatalytic synthesis of esters, little attention has been paid to the reactors used for it. Therefore, it is convenient to gather the scattered information regarding the type of reactor employed in these synthesis reactions, considering the industrial field in which the process is carried out. A comparison between the performance of the different reactor configurations will allow us to draw the appropriate conclusions regarding their suitability for each specific industrial application. This review addresses, for the first time, the above aspects, which will undoubtedly help with the correct industrial implementation of these processes.

Process optimization for enzymatic production of a valuable biomass-based ester from levulinic acid

The enzymatic production of isoamyl levulinate via esterification of isoamyl alcohol (IA) and levulinic acid (LA), a biomass-based platform chemical with attractive properties, in a solvent system has been performed in this study. For such a purpose, a low-cost liquid lipase (Eversa^® Transform 2.0) immobilized by physical adsorption via hydrophobic interactions (mechanism of interfacial activation) on mesoporous poly(styrenene-divinylbenzene) (PSty-DVB) beads was used as heterogeneous biocatalyst. It was prepared at low ionic strength (5 mmol.L^-1 buffer sodium acetate pH 5.0) and 25 ℃ using an initial protein loading of 40 mg.g^-1 of support. Maximum protein loading of 31.2 ± 2.8 mg.g^-1 of support and an immobilization yield of 83% was achieved. The influence of relevant factors (biocatalyst concentration and reaction temperature) on ester production was investigated using a central composite rotatable design (CCRD). Maximum acid conversion percentage of 65% was achieved after 12 h of reaction at 40 °C, 20% of mass of heterogeneous biocatalyst per mass of reaction mixture (20% m.m^-1), and LA:IA molar ratio of 1:1.5 in a methyl isobutyl ketone (MIBK) medium. The biocatalyst retained around of 30% of its initial activity after five consecutive esterification batches under optimal experimental conditions. The proposed experimental procedure can be considered as an acceptable green process (EcoScale score of 66.5), in addition to the fact that a new strategy is proposed to sustainably produce a valuable industrial ester (isoamyl levulinate) from biomass-based materials using an immobilized and low-cost commercial lipase as catalyst.

Process intensification using immobilized enzymes for the development of white biotechnology

Process intensification of biocatalysed reactions using different techniques such as microwaves, ultrasound, hydrodynamic cavitation, ionic liquids, microreactors and flow chemistry in various industries is critically analysed and future directions provided.

Recent developments in microreactor technology for biocatalysis applications

Through the use of microfluidics technology, one can severely accelerate the development and optimization of biocatalytic processes. In this work, the authors present a comprehensive review of the recent advances in the field.

Continuous Flow Upgrading of Selected C2-C6 Platform Chemicals Derived from Biomass

The ever increasing industrial production of commodity and specialty chemicals inexorably depletes the finite primary fossil resources available on Earth. The forecast of population growth over the next 3 decades is a very strong incentive for the identification of alternative primary resources other than petro-based ones. In contrast with fossil resources, renewable biomass is a virtually inexhaustible reservoir of chemical building blocks. Shifting the current industrial paradigm from almost exclusively petro-based resources to alternative bio-based raw materials requires more than vibrant political messages; it requires a profound revision of the concepts and technologies on which industrial chemical processes rely. Only a small fraction of molecules extracted from biomass bears significant chemical and commercial potentials to be considered as ubiquitous chemical platforms upon which a new, bio-based industry can thrive. Owing to its inherent assets in terms of unique process experience, scalability, and reduced environmental footprint, flow chemistry arguably has a major role to play in this context. This review covers a selection of C₂ to C₆ bio-based chemical platforms with existing commercial markets including polyols (ethylene glycol, 1,2-propanediol, 1,3-propanediol, glycerol, 1,4-butanediol, xylitol, and sorbitol), furanoids (furfural and 5-hydroxymethylfurfural) and carboxylic acids (lactic acid, succinic acid, fumaric acid, malic acid, itaconic acid, and levulinic acid). The aim of this review is to illustrate the various aspects of upgrading bio-based platform molecules toward commodity or specialty chemicals using new process concepts that fall under the umbrella of continuous flow technology and that could change the future perspectives of biorefineries.

Microfluidic tools for lipid production and modification: a review

Microfluidics has great potential as an efficient tool for a large range of applications in industry. The ability of such devices to deal with an extremely small amount of fluid has additional benefits, including superlatively fast and efficient mass and heat transfer. These characteristics of microfluidics have attracted an enormous amount of interest in their use as a novel tool for lipid production and modification. In addition, lipid resources have a close relationship with energy resources, and lipids are an alternative renewable energy source. Here, recent advances in the application of microfluidics for lipid production and modification, especially in the discovery, culturing, harvesting, separating, and monitoring of lipid-producing microorganisms, will be reviewed. Other applications of microfluidics, such as the modification of lipids from microorganisms, will also be discussed. The novel microfluidic tools in this review will be useful in applications to improve lipid production and modification in the future.

Novozym 435: the “perfect” lipase immobilized biocatalyst?

Novozym 435 (N435) is a commercially available immobilized lipase produced by Novozymes with its advantages and drawbacks.