fulltext.study @t Gmail

Pathways and kinetics analysis of biotransformation of Dioscorea zingiberensis by Aspergillus oryzae

Paper ID Volume ID Publish Year Pages File Format Full-Text
3880 197 2010 8 PDF Available
Title
Pathways and kinetics analysis of biotransformation of Dioscorea zingiberensis by Aspergillus oryzae
Abstract

In this paper, the pathways and kinetics for the production of diosgenin via biotransformation of Dioscorea zingiberensis C.H. Wright by Aspergillus oryzae CICC 2436 were analyzed. After 120 h of biotransformation at 30 °C, the concentration of diosgenin in the culture reached 36.87 ± 1.27 μmol/g raw herb, which was 21.2 times its initial concentration. A number of steroidal compounds were also isolated as minor products from the biotransformation, and one of these was identified as a novel compound named 3-O-β-d-glucopyranosyl (1 → 3) – β-d-glucopyranosyl (1 → 4) – β-d-glucopyranosyl-diosgenin (diosgenin-triglucoside). The biotransformation consisted of two stages: the release of steroids from the herb (accompanied by fungal growth) and hydrolysis of the steroids by glycosidases. Kinetic analysis and mathematical modelling showed that the process of biotransformation could be described by first-order kinetics under the condition of high Km/[S] values. It consisted of a cascade of consecutive and parallel reactions involving three kinds of enzymes, five steroid saponins and their sapogenin. The main hydrolysis reactions that led to the production of diosgenin were also discussed.

Keywords
Dioscorea zingiberensis; Aspergillus oryzae; Diosgenin; Biotransformation; Pathways analysis; Kinetic modeling
First Page Preview
Pathways and kinetics analysis of biotransformation of Dioscorea zingiberensis by Aspergillus oryzae
Publisher
Database: Elsevier - ScienceDirect
Journal: Biochemical Engineering Journal - Volume 52, Issues 2–3, 15 November 2010, Pages 123–130
Authors
, , , , , , ,
Subjects
Physical Sciences and Engineering Chemical Engineering Bioengineering