Asymmetric synthesis of tert-butyl (3R,5S)-6-chloro-3,5-dihydroxyhexanoate using a self-sufficient biocatalyst based on carbonyl reductase and cofactor co-immobilization

From discovery to application: Enabling technology-based optimizing carbonyl reductases biocatalysis for active pharmaceutical ingredient synthesis

The catalytic conversion of chiral alcohols and corresponding carbonyl compounds by carbonyl reductases (alcohol dehydrogenases), which are NAD(P) or NAD(P)H-dependent oxidoreductases, has attracted considerable attention. However, existing carbonyl reductases are insufficient to meet the demands of diverse industrial applications; hence, new enzymes with functions that can expand the toolbox of biocatalysts are urgently required. Developing precisely controlled chiral biocatalysts is of great significance for the efficient development of a broad spectrum of active pharmaceutical ingredients via biosynthesis. In this review, we summarized methods for discovering novel natural carbonyl reductases from various perspectives. Furthermore, advances in protein engineering, utilizing known sequence and structural information as well as catalytic dynamics mechanisms to improve potential functions, are also addressed. The exponential growth in data-driven tools over the past decade has made it possible to de novo design carbonyl reductases. Additionally, various applications of these high-performance carbonyl reductases and different strategies for coenzyme regeneration involving photocatalysis during the reaction process were reviewed. These advancements will bring new opportunities and challenges to the fields of green chemistry and biosynthesis in the future.

Unlocking Industrial Potential: Phase-Transition Coimmobilization of Multienzyme Systems for High-Efficiency Uridine Diphosphate Galactose Production

Transitioning from batch to continuous industrial production often improves the economic returns and production efficiency. Immobilization is a critical strategy that can facilitate this shift. This study refined the previously established method for synthesizing uridine diphosphate galactose (UDP-Gal) by employing thermophilic enzymes. Three thermophilic enzymes (galactokinase, uridine diphosphate glucose pyrophosphorylase, and inorganic pyrophosphatase) were coimmobilized on the pH-responsive carrier Eudragit S-100, promoting enzyme recovery and reuse while their industrial potential was assessed. The coimmobilization system efficiently catalyzed UDP-Gal production, yielding 13.69 mM in 1.5 h, attaining a UTP conversion rate of 91.2% and a space-time yield (STY) of 5.16 g/L/h. Moreover, the system exhibited exceptional reproducibility, retaining 58.9% of its initial activity after five cycles. This research highlighted promising prospects for coimmobilization in industrial synthesis and proposed a novel methodology for enhancing UDP-Gal production in the industry. In addition, the phase-transition property of Eudragit S-100 paves the way for further exploration with the one-pot synthesis of poorly soluble galactosides.

Efficient Synthesis of cis-4-Propylcyclohexanol Using a Mutant Alcohol Dehydrogenase Coupled with Glucose Dehydrogenase

cis-4-Propylcyclohexanol is an important intermediate for synthesizing trans-2-(4-propylcyclohexyl)-1,3-propanediol, which is widely used in the manufacture of liquid crystal displays. In this study, cis-4-propylcyclohexanol was prepared using a mutant alcohol dehydrogenase from Lactobacillus kefir (LK-TADH, A94T/F147L/L199H/A202L) coupled with glucose dehydrogenase. Using the optimal catalytic conditions, 125 g/L (250 g) of 4-propylcyclohexanone was completely transformed after 5 h, and 225.8 g of cis-4-propylcyclohexanol (cis/trans ratio of 99.5:0.5) was obtained through extraction and rotary evaporation at a yield of 90.32%. This study reports a potential method for the green production of cis-4-propylcyclohexanol as the key intermediate of trans-2-(4-propylcyclohexyl)-1,3-propanediol at an industrial level.

Application of Ketoreductase in Asymmetric Synthesis of Pharmaceuticals and Bioactive Molecules: An Update (2018-2020)

With the rapid development of genomic DNA sequencing, recombinant DNA expression, and protein engineering, biocatalysis has been increasingly and widely adopted in the synthesis of pharmaceuticals, bioactive molecules, fine chemicals, and agrochemicals. In this review, we have summarized the most recent advances achieved (2018-2020) in the research area of ketoreductase (KRED)-catalyzed asymmetric synthesis of chiral secondary alcohol intermediates to pharmaceuticals and bioactive molecules. In the first part, synthesis of chiral alcohols with one stereocenter through the bioreduction of four different ketone classes, namely acyclic aliphatic ketones, benzyl or phenylethyl ketones, cyclic aliphatic ketones, and aryl ketones, is discussed. In the second part, KRED-catalyzed dynamic reductive kinetic resolution and reductive desymmetrization are presented for the synthesis of chiral alcohols with two contiguous stereocenters.