title: Bioconversion of glycyrrhizinic acid in liquorice into 18-beta-glycyrrhetinic acid by Aspergillus parasiticus speare BGB.
abstract: A filamentous fungi strain, Aspergillus parasiticus Speare BGB, producing beta-glucuronidase was screened to transform glycyrrhizinic acid (GL) in liquorice into 18-beta-glycyrrhetinic acid (GA). Under the following cultivate conditions in shake flask, 1% GL (purity 30%), medium capacity 40% of flask, the initial pH value at 4.5, cultivate temperature of 32 degrees C, inoculum size of 5% and culturing time for 96 h the bioconversion ratio of GL into GA could reach 95%. A variety of parameters of submerged state fermentation, including the growth characteristics of A. parasiticus Speare BGB, the change amount of GL and GA, and the activity of beta-glucuronidase, were monitored simultaneously. GA was separated and purified by macroporous resin, silica gel column chromatography followed by recrystalization with the final purity over 98%. Purified product was identified as GA by the infrared absorption spectrum, molecular weight, and nuclear magnetic resonance. This study provided a new and efficient approach of obtaining GA by microbial transformation.
authors.affiliation: College of Life Sciences, Key Laboratory of Bio-resources and Eco-environment of Ministry of Education, Sichuan University Chengdu 610064, PR China.
authors.forename: J
authors.initials: J
authors.lastname: Wang
authors.forename: Q
authors.initials: Q
authors.lastname: Sun
authors.forename: P
authors.initials: P
authors.lastname: Gao
authors.forename: J F
authors.initials: JF
authors.lastname: Wang
authors.forename: C
authors.initials: C
authors.lastname: Xu
authors.forename: Q L
authors.initials: QL
authors.lastname: Sun
mesh_terms: D001230:Aspergillus / Q000201:enzymology* / Q000302:isolation & purification*; D005285:Fermentation; D006034:Glycyrrhetinic Acid / Q000378:metabolism*; D029882:Glycyrrhiza uralensis / Q000382:microbiology*; D019695:Glycyrrhizic Acid / Q000378:metabolism*
chemical_list: D019695:Glycyrrhizic Acid; D006034:Glycyrrhetinic Acid