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Biosynthesis of ursolic acid derivatives by microbial metabolism of ursolic acid with Nocardia sp. strains—Proposal of new biosynthetic pathways

Paper ID Volume ID Publish Year Pages File Format Full-Text
35176 45080 2010 9 PDF Available
Title
Biosynthesis of ursolic acid derivatives by microbial metabolism of ursolic acid with Nocardia sp. strains—Proposal of new biosynthetic pathways
Abstract

Our studies of the microbial-metabolism of triterpenoid ursolic acid by various Nocardia sp. strains, have led to the proposal of two novel pathways to produce triterpenoid derivatives. Nocardia sp. NRRL 5646, Nocardia sp. 44822 and Nocardia sp. 44000 generated the following ursolic acid derivatives: ursolic acid methyl ester, ursonic acid, ursonic acid methyl ester, 3-oxoursa-1,12-dien-28-oic acid and 3-oxoursa-1,12-dien-28-oic acid methyl ester. Nocardia sp. 45077 synthesized ursonic acid and 3-oxoursa-1,12-dien-28-oic acid while Nocardia sp. 46002 produced only ursonic acid and Nocardia sp. 43069 showed no metabolism at all. The conversion of ursolic acid by Nocardia sp. NRRL 5646 was independent of the medium used for the fermentation. An increase in temperature from 28 °C to 36 °C doubled the reaction rate of the biotransformation. The analysis of ursane metabolites was done by HPLC, while their structures were established using HPLC–APCIpos-MS/MS and HPLC–NMR spectroscopy. The pseudo molecular ion peaks were determined by HPLC–APCIpos-MS and used to measure their molecular weight. The product ion spectra of the metabolites showed the characteristic fragments of Δ12-oleanes and Δ12-ursanes indicating that a substitution in ring A or B was responsible for the decrease in molecular weight.Based on these results, two new biosynthetic pathways are proposed. These new pathways can presumably be used as strategic routes for the biotechnological production of triterpenoid derivatives. It is assumed that a 3β-hydroxysteroid dehydrogenase and a 3-ketosteroid-Δ1-dehydrogenase are involved in the transformation of the steroid.

Keywords
Nocardia sp.; Ursolic acid; Biotransformation; Ursane derivatives; Biosynthetic pathway
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Biosynthesis of ursolic acid derivatives by microbial metabolism of ursolic acid with Nocardia sp. strains—Proposal of new biosynthetic pathways
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Publisher
Database: Elsevier - ScienceDirect
Journal: Process Biochemistry - Volume 45, Issue 7, July 2010, Pages 1043–1051
Authors
, , , , , , , , , ,
Subjects
Physical Sciences and Engineering Chemical Engineering Bioengineering
Get Full-Text Now
Don't Miss Today's Special Offer
Price was $35.95
You save - $31
Price after discount Only $4.95
100% Money Back Guarantee
Full-text PDF Download
Online Support
Any Questions? feel free to contact us