A biohybrid photobioanode mimicking the Z-scheme has been developed by functional integration of photosystem II (PSII) and PbS quantum dots (QDs) within an inverse opal TiO
architecture giving rise ...to a rather negative water oxidation potential of about -0.55 V vs. Ag/AgCl, 1 m KCl at neutral pH. The electrical linkage between both light-sensitive entities has been established through an Os-complex-modified redox polymer (P
), which allows the formation of a multi-step electron-transfer chain under illumination starting with the photo-activated water oxidation at PSII followed by an electron transfer from PSII through P
to the photo-excited QDs and finally to the TiO
electrode. The photobioanode was coupled to a novel, transparent, inverse-opal ATO cathode modified with an O
-reducing bilirubin oxidase for the construction of a H
O/O
photobioelectrochemical cell reaching a high open-circuit voltage of about 1 V under illumination.
Enzymatic microarchitectures with spatially controlled reactivity, engineered molecular sieving ability, favorable interior environment, and industrial productivity show great potential in synthetic ...protocellular systems and practical biotechnology, but their construction remains a significant challenge. Here, we proposed a Pickering emulsion interface-directed synthesis method to fabricate such a microreactor, in which a robust and defect-free MOF layer was grown around silica emulsifier stabilized droplet surfaces. The compartmentalized interior droplets can provide a biomimetic microenvironment to host free enzymes, while the outer MOF layer secludes active species from the surroundings and endows the microreactor with size-selective permeability. Impressively, the thus-designed enzymatic microreactor exhibited excellent size selectivity and long-term stability, as demonstrated by a 1000 h continuous-flow reaction, while affording completely equal enantioselectivities to the free enzyme counterpart. Moreover, the catalytic efficiency of such enzymatic microreactors was conveniently regulated through engineering of the type or thickness of the outer MOF layer or interior environments for the enzymes, highlighting their superior customized specialties. This study provides new opportunities in designing MOF-based artificial cellular microreactors for practical applications.
F420-dependent enzymes are found in many microorganisms and can catalyze a wide range of redox reactions, including those with some substrates that are otherwise recalcitrant to enzyme-mediated ...reductions. Unfortunately, the scarceness of the cofactor prevents application of these enzymes in biocatalysis. The best F420-producing organism, Mycobacterium smegmatis, only produces 1.4 μmol per liter of culture. Therefore, we synthesized the unnatural cofactor FO-5′-phosphate, coined FOP. The FO core-structure was chemically synthesized, and an engineered riboflavin kinase from Corynebacterium ammoniagenes (CaRFK) was then used to phosphorylate the 5′-hydroxyl group. The triple F21H/F85H/A66I CaRFK mutant reached 80% of FO conversion in 12 h. The same enzyme could produce 1 mg (2.5 μmol) of FOP in 50 mL of reaction volume, which translates to a production of 50 μmol/L. The activity toward FOP was tested for an enzyme of each of the three main structural classes of F420-dependent oxidoreductases. The sugar-6-phosphate dehydrogenase from Cryptosporangium arvum (FSD-Cryar), the F420:NADPH oxidoreductase from Thermobifida fusca (TfuFNO), and the F420-dependent reductases from Mycobacterium hassiacum (FDR-Mha) all showed activity for FOP. Although the activity for FOP was lower than that for F420, with slightly lower k cat and higher K m values, the catalytic efficiencies were only 2.0, 12.6, and 22.4 times lower for TfuFNO, FSD-Cryar, and FDR-Mha, respectively. Thus, FOP could be a serious alternative for replacing F420 and might boost the application of F420-dependent enzymes in biocatalysis.
Biocatalysis has emerged as a strong tool for the synthesis of active pharmaceutical ingredients (APIs). In the early twentieth century, whole cell biocatalysis was used to develop the first ...industrial biocatalytic processes, and the precise work of enzymes was unknown. Biocatalysis has evolved over the years into an essential tool for modern, cost-effective, and sustainable pharmaceutical manufacturing. Meanwhile, advances in directed evolution enable the rapid production of process-stable enzymes with broad substrate scope and high selectivity. Large-scale synthetic pathways incorporating biocatalytic critical steps towards >130 APIs of authorized pharmaceuticals and drug prospects are compared in terms of steps, reaction conditions, and scale with the corresponding chemical procedures. This review is designed on the functional group developed during the reaction forming alcohol functional groups. Some important biocatalyst sources, techniques, and challenges are described. A few APIs and their utilization in pharmaceutical drugs are explained here in this review. Biocatalysis has provided shorter, more efficient, and more sustainable alternative pathways toward existing small molecule APIs. Furthermore, non-pharmaceutical applications of biocatalysts are also mentioned and discussed. Finally, this review includes the future outlook and challenges of biocatalysis. In conclusion, Further research and development of promising enzymes are required before they can be used in industry.
•Synthesis of chiral alcohols for applications in active pharmaceutical industries through biocatalysis also has vast applications in the production of fine chemicals from chiral molecules.•Cost-effectiveness and reducing environmental hazards using green chemistry and mild reaction conditions.•Biocatalysis allows a high degree of selectivity in chiral alcohol synthesis, permitting the creation of enantiomerically pure molecules.•Bioprocess engineering, reactor design, and enzyme immobilisation techniques will continue to progress, allowing the scale-up of biocatalytic processes for chiral alcohol production.
The EU low-carbon economy aims to reduce the level of CO
emission in the EU to 80% by 2050. High efforts are required to achieve this goal, where successful CCU (Carbon Capture and Utilization) ...technologies will have a high impact. Biocatalysts offer a greener alternative to chemical catalysts for the development of CCU strategies since biocatalysis conforms 10 of the 12 principles of green chemistry. In this study, a multienzymatic system, based on alcohol dehydrogenase (ADH), pyruvate decarboxylase (PDC), and lactate dehydrogenase (LDH), that converts CO
and ethanol into lactic acid leading to a 100% atom economy was studied. The system allows cofactor regeneration, thus reducing the process cost. Through reaction media engineering and enzyme ratio study, the performance of the system was able to produce up to 250 μM of lactic acid under the best conditions using 100% CO
, corresponding to the highest concentration of lactic acid obtained up to date using this multienzymatic approach. For the first time, the feasibility of the system to be applied under a real industrial environment has been tested using synthetic gas mimicking real blast furnace off-gases composition from the iron and steel industry. Under these conditions, the system was also capable of producing lactic acid, reaching 62 μM.
The Cover Feature shows that a variety of powerful enzymes are capable of oxyfunctionalizing and valorizing small alkanes. More information can be found in the Minireview by D. Mahor et al.
The implementation of ortho-quinone methide (o-QM) intermediates in complex molecule assembly represents a remarkably efficient strategy designed by Nature and utilized by synthetic chemists. o-QMs ...have been taken advantage of in biomimetic syntheses for decades, yet relatively few examples of o-QM-generating enzymes in natural product biosynthetic pathways have been reported. The biosynthetic enzymes that have been discovered thus far exhibit tremendous potential for biocatalytic applications, enabling the selective production of desirable compounds that are otherwise intractable or inherently difficult to achieve by traditional synthetic methods. Characterization of this biosynthetic machinery has the potential to shine a light on new enzymes capable of similar chemistry on diverse substrates, thus expanding our knowledge of Nature’s catalytic repertoire. The presently known o-QM-generating enzymes include flavin-dependent oxidases, hetero-Diels–Alderases, S-adenosyl-l-methionine-dependent pericyclases, and α-ketoglutarate-dependent nonheme iron enzymes. In this review, we discuss their diverse enzymatic mechanisms and potential as biocatalysts in constructing natural product molecules such as cannabinoids.
The natural aroma compound (+)-nootkatone was obtained in selective conversions of up to 74mol % from inexpensive (+)-valencene substrate by using a comparatively greener biocatalytic process ...developed based on modifications of the previously published Firmenich method. Buffer identity and concentration, pH, temperature and downstream work-up procedures were optimized to produce a crude product in which >90% of (+)-valencene had been converted, with high chemoselectivity observed for (+)-nootkatone production. Interestingly, the biotransformation was carried out efficiently at temperatures as low as 21 ºC. Surprisingly, the best results were obtained when an acidic pH in the range of 3-6 was applied, as compared to the previously published procedure in which it appeared to be necessary to buffer the pH optimally and fixed throughout at 8.5. Furthermore, there was no need to maintain a pure oxygen atmosphere to achieve good (+)-nootkatone yields. Instead, air bubbled continuously at a low rate through the reaction mixture via a submerged glass capillary was sufficient to enable the desired lipoxygenase-catalyzed oxidation reactions to occur efficiently. No valencene epoxide side-products were detected in the organic product extract by a standard GCMS protocol. Only traces of the anticipated corresponding α- and β-nootkatol intermediates were routinely observed.
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•A greener method was developed to produce (+)-nootkatone biocatalytically.
Abstract
Synthetic nano/micromotors are a burgeoning class of materials with vast promise for applications ranging from environmental remediation to nanomedicine. The motility of these motors is ...generally controlled by the concentration of accessible fuel, and therefore, engineering speed‐regulation mechanisms, particularly using biological triggers, remains a continuing challenge. Here, control over the movement of superassembled porous framework micromotors via a reversible, biological‐relevant pH‐responsive regulatory mechanism is demonstrated. Succinylated β‐lactoglobulin and catalase are superassembled in porous framework particles, where the β‐lactoglobulin is permeable at neutral pH. This permeability allows the fuel (H
2
O
2
) to access catalase, leading to autonomous movement of the micromotors. However, at mild acidic pH, succinylated β‐lactoglobulin undergoes a reversible gelation process, preventing the access of fuel into the micromotors where the catalase resides. To one's knowledge, this study represents the first example of chemically driven motors with rapid, reversible pH‐responsive motility. Furthermore, the porous framework significantly enhances the biocatalytic activity of catalase, allowing ultralow H
2
O
2
concentrations to be exploited at physiological conditions. It is envisioned that the simultaneous exploitation of pH and chemical potential of such nanosystems could have potential applications as stimulus‐responsive drug delivery vehicles that benefit from the complex biological environment.
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