Biotransformation with a New Acinetobacter sp. Isolate for Highly Enantioselective Synthesis of a Chiral Intermediate of Miconazole

A sustainable approach of turning potato waste towards bioethanol production using indigenous microbes of Himachal Pradesh, India

Potato peel waste is one of the zero-value wastes with the potential of bioethanol production through the Waste to Energy (WtE) approach. The newly isolated, phenotypically characterized, and molecular identified high-altitude strain, B. amyloliquefaciens, shown promising starch hydrolysis (12.06 g/L reducing sugars) over acid hydrolysis and is capable of working at 30-50 °C and pH 6.0-8.0. The ethanol production by Acinetobacter sp. (a newly isolated, phenotypically characterized, molecular identified) has been modelled and optimized through the central composite design of response surface methodology by taking the fermentation variables as input variables and ethanol yield as the output variable. The ethanol production by Acinetobacter sp. showcased a non-linear relationship of fermentation variables with the ethanol yield (5.83 g/L) with a 99.11% desirability function (R²) and 97.50 adj. R² values. Optimal fermentation variables of 38.8% substrate concentration, 7% inoculum, pH 5.45 have been utilized for bioethanol production in 55.27 h at 27 °C. Overall, the present study evaluated the efficiency of newly isolated, indigenous extremophilic microbes of The Himalayan region in sustainable bioethanol production from zero-value waste "Potato peel waste" through the WtE approach. Moreover, the present study introduces the promising, unexplored extremophilic microbial strains with the starch-hydrolyzing and fermentation capabilities to bioethanol biorefinery.

Challenges and opportunities of using immobilized lipase as biosensor

Over the years, the science of biosensors has evolved significantly. The first or earliest generation of biosensors only detected either the decrease or increase of product or reactant-based natural mediators as the pathway for electron transfer. The subsequent second-generation biosensors were biomolecule based and used artificial redox mediators, such as organic dyes to detect and to increase the reproducibility and sensitivity of the result. However, the recent generation of biosensors work mostly on the principle of electron mobility, with different criteria, such as selectivity, precision, sensitivity, etc., can be used to quantify, efficiently. This review deals with exploring the scope and applications of Immobilized lipase biosensors. Generally, Triglycerides or TG molecules are either detected using Gas Chromatography or, using a chemical or an enzymatic assay. Immobilization of lipase on solid supports has led to increased stability and reusability of the enzyme in non-aqueous solvents. With better enzyme performance, efficient product recovery, and separation from the reaction, immobilized lipase biosensors are garnering increasing interest worldwide. Along with so many advantages including but not limiting to ones mentioned earlier, immobilized lipase-based biosensors come with their own set of challenges, such as the partitioning of the analyte with aqueous medium, slower reaction rate, etc., they have been discussed in the following review. Alongside, we also review the development of a new generation of biosensors and bioelectronic devices based on nanotechnology.

Biocatalytic approaches for the synthesis of optically pure vic-halohydrins

Enantiopure vicinal halohydrins (vic-halohydrins) are highly valuable building blocks for the synthesis of many different natural products and pharmaceuticals, and biocatalytic methods for their synthesis have received considerable interest. This review emphasizes the application of biocatalytic approaches as an efficient alternative or complement to conventional chemical reactions, with a special focus on the asymmetric reductions catalyzed by ketoreductases, kinetic resolution catalyzed using lipases or esterases, stereoselective biotransformation catalyzed by halohydrin dehalogenases, asymmetric hydroxylation catalyzed by cytochrome P450 monooxygenases, asymmetric dehalogenation catalyzed by haloalkane dehalogenases, and aldehyde condensation catalyzed by aldolases. Although many chiral vic-halohydrins have been successfully synthesized using wild-type biocatalysts, their enantioselectivity is often too low for enantiopure synthesis. To overcome these limitations, catalytic properties of wild-type enzymes have been improved by rational and semi-rational protein design or directed evolution. This review briefly introduces the research status in this field, highlighting aspects of basic academic research in the biocatalytic synthesis of optically active vic-halohydrins by employing such unconventional approaches. KEY POINTS: • Outlines the enzymatic strategies for the production of enantiopure vic-halohydrins • Highlights recent advances in biocatalytic production of enantiopure vic-halohydrins • Provide guidance for efficient preparation of enantiopure vic-halohydrins.