In-Vitro and In-Silico Characterization of Xylose Reductase from Emericella nidulans

Abstract

Background: Lignocellulosic residues generated by various anthropogenic activities can be a potential raw material for many commercial products such as biofuels, organic acids and nutraceuticals including xylitol. Xylitol is a low-calorie nutritive sweetener for diabetic patients. Microbial production of xylitol can be helpful in overcoming the drawbacks of traditional chemical production process and lowring cost of production. Objective: Designing efficient production process needs the characterization of required enzyme/s. Hence current work was focused on in-vitro and in-silico characterization of xylose reductase from Emericella nidulans. Methods: Xylose reductase from one of the hyper-producer isolates, Emericella nidulans Xlt-11 was used for in-vitro characterization. For in-silico characterization, XR sequence (Accession No: Q5BGA7) was used. Results: Xylose reductase from various microorganisms has been studied but the quest for better enzymes, their stability at higher temperature and pH still continues. Xylose reductase from Emericella nidulans Xlt-11 was found NADH dependent and utilizes xylose as its sole substrate for xylitol production. In comparison to whole cells, enzyme exhibited higher enzyme activity at lower cofactor concentration and could tolerate higher substrate concentration. Thermal deactivation profile showed that whole cell catalysts were more stable than enzyme at higher temperature. In-silico analysis of XR sequence from Emericella nidulans (Accession No: Q5BGA7) suggested that the structure was dominated by random coiling. Enzyme sequences have conserved active site with net negative charge and PI value in acidic pH range. Conclusion: Current investigation supported the enzyme’s specific application i.e. bioconversion of xylose to xylitol due to its higher selectivity. In-silico analysis may provide significant structural and physiological information for modifications and improved stability.

Biological and Pharmacological Potential of Xylitol: A Molecular Insight of Unique Metabolism

“…The application of xylitol varied widely from food, nutraceuticals, beverage to pharma industries, making it one of the top 12 global bio-products [1,2] with a rapidly growing market share, which is expected to cross USD 1.14 billion by 2023. Xylitol is considered as a "Generally Recognized as Safe" (GRAS) additive by the Food and Drug Administration (FDA) and as a low-calorie sweetener by more than 35 countries [1,3]. The chemically less reactive nature of xylitol offers unique pharmacological properties for the treatment of various ailments.…”

Preparation and Immobilization Mechanism on a Novel Composite Carrier PDA-CF/PUF to Improve Cells Immobilization and Xylitol Production

“…D-Xylitol (2R,3R,4S)-pentane-1,2,3,4,5-pentol, a natural five-carbon sugar alcohol, is among the most valuable microbial products commonly used as a sweetening agent. The application of xylitol varies widely from food, nutraceuticals, and beverage to pharma industries, making it one of the top 12 global bio-products [ 1 , 2 ] with a rapidly growing market share. Xylitol is considered a “Generally Recognized as Safe” (GRAS) additive by the Food and Drug Administration (FDA) and as a low-calorie sweetener by more than 35 countries [ 1 , 3 ].…”