scholarly journals Laccase Did It again: A Scalable and Clean Regeneration System for NAD+ and Its Application in the Synthesis of 12-oxo-Hydroxysteroids

Catalysts ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 677 ◽  
Author(s):  
Fabio Tonin ◽  
Elisabet Martì ◽  
Isabel W. C. E. Arends ◽  
Ulf Hanefeld

The specific oxidation of 12α-OH group of hydroxysteroids is required for the preparation of cheno- and ursodeoxycholic acid (CDCA and UDCA, respectively). The C12 oxidation of hydroxysteroids into their 12-oxo derivatives can selectively be performed by employing 12α-hydroxysteroid dehydrogenases. These enzymes use NAD(P)+ as an electron acceptor, which has to be re-oxidized in a so-called “regeneration system”. Recently, the enzyme NAD(P)H oxidase (NOX) was applied for the regeneration of NAD+ in the enzymatic preparation of 12-oxo-CDCA from cholic acid (CA), which allows air to be used as an oxidant. However, the NOX system suffers from low activity and low stability. Moreover, the substrate loading is limited to 10 mM. In this study, the laccase/mediator system was investigated as a possible alternative to NOX, employing air as an oxidant. The laccase/mediator system shows higher productivity and scalability than the NOX system. This was proven with a preparative biotransformation of 20 g of CA into 12-oxo-CDCA (92% isolated yield) by employing a substrate loading of 120 mM (corresponding to 50 g/L). Additionally, the performance of the laccase/mediator system was compared with a classical ADH/acetone regeneration system and with other regeneration systems reported in literature.

2004 ◽  
Vol 35 (2-3) ◽  
pp. 113-120 ◽  
Author(s):  
Susana Camarero ◽  
Olga Garcı́a ◽  
Teresa Vidal ◽  
José Colom ◽  
José C del Rı́o ◽  
...  

2009 ◽  
Vol 84 (3) ◽  
pp. 442-446 ◽  
Author(s):  
Ana P. M. Tavares ◽  
Raquel O. Cristóvão ◽  
José A. F. Gamelas ◽  
José M. Loureiro ◽  
Rui A. R. Boaventura ◽  
...  

2011 ◽  
Vol 102 (11) ◽  
pp. 6536-6540 ◽  
Author(s):  
Q.H. Xu ◽  
Y.P. Wang ◽  
M.H. Qin ◽  
Y.J. Fu ◽  
Z.Q. Li ◽  
...  

2013 ◽  
Vol 734-737 ◽  
pp. 2089-2093
Author(s):  
Fan Liu ◽  
Yu Liu ◽  
Jia Chuan Chen ◽  
Zhen Wang

In this Paper the Two-Stage Method of Enzyme-Mild Acidic Hydrolysis was Adopted to Separate Lignin from the APMP and the Modified Pulp Samples.And then Analyze the Lignin Structure Changes of the Modified APMP Lignin by Laccase and LMS(laccase/mediator System). it was Found that no Oxidation Took Place on Carbohydrates in the LMS, and Lignin Cα Hydroxyl Oxidization Produce α Carbonyl and H2O2 Bleaching can also Oxidation of Lignin, make the Conjugate C = α Increase;the Syringyl Structure Hydroxyl Content Increase, the Lignin Structure Macromolecular Side Chain Fracturing; Laccase and LMS Oxidative Degradation Chromophoric Group Unsaturated C = O, which can Improve the Brightness of Pulp and Create Better Conditions for Unbleached Pulp.


2018 ◽  
Vol 52 (18) ◽  
pp. 10617-10626 ◽  
Author(s):  
Qi Luo ◽  
Xiufen Yan ◽  
Junhe Lu ◽  
Qingguo Huang

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