Wang X, Chen R, Wu Y, Wang D, Wei D. Nitrate Metabolism Decreases the Steroidal Alcohol Byproduct Compared with Ammonium in Biotransformation of Phytosterol to Androstenedione by Mycobacterium neoaurum.
Appl Biochem Biotechnol 2019;
190:1553-1560. [PMID:
31792785 DOI:
10.1007/s12010-019-03175-y]
[Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2019] [Accepted: 11/11/2019] [Indexed: 11/24/2022]
Abstract
In biotransformation of phytosterol to 4-androstene-3,17-dione (AD) by Mycobacterium, the steroidal alcohol (such as 22-hydroxy-23,24-bisnorchol-4-ene-3-one, HBC) was a main byproduct. To weaken the accumulation of this byproduct in sterol biotransformation, ammonium was substituted by nitrate as nitrogen resource. The nitrate was utilized by Mycobacterium and led to metabolic flux shift towards AD production. The ratio of AD/HBC increased maximally from 2.1 to 5.5 and AD production increased correspondently. In the meanwhile, the nitrate metabolism resulted in the decreased intracellular redox level (NADH/NAD+) maximally by 59.5% and a slight descent tendency with the increase of the nitrate concentrations. It indicated that the nitrate utilization effectively decreased the steroidal alcohol production by regulating intracellular redox level in sterol biotransformation. These results gave an insight into the mechanism of the steroidal alcohol formation in sterol biodegradation and provided a simple strategy to regulate the metabolic distribution.
Collapse