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Characterization of a novel arabinose‐tolerant α ‐ l‐ arabinofuranosidase with high ginsenoside Rc to ginsenoside Rd bioconversion productivity
Author(s) -
Xie J.,
Zhao D.,
Zhao L.,
Pei J.,
Xiao W.,
Ding G.,
Wang Z.,
Xu J.
Publication year - 2016
Publication title -
journal of applied microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.889
H-Index - 156
eISSN - 1365-2672
pISSN - 1364-5072
DOI - 10.1111/jam.13040
Subject(s) - bioconversion , ginsenoside , chemistry , recombinant dna , biochemistry , enzyme , fermentation , beta glucosidase , stereochemistry , enzyme assay , gene , ginseng , medicine , alternative medicine , pathology
Aims (i) To investigate the enzymatic characterization of α ‐ l‐ arabinofuranosidase from Thermotoga thermarum DSM 5069. (ii) To evaluate the performance of its excellent properties on converting ginsenoside Rc to ginsenoside Rd. Methods and Results The thermostable α ‐ l‐ arabinofuranosidase (Tt‐Afs) gene from T. thermarum DSM 5069 was cloned and overexpressed. Recombinant Tt‐Afs was purified, and its molecular weight was approx. 55 kD a. Its optimal activity was at pH 5·0 and 95°C. It has high selectivity for cleaving the outer arabinofuranosyl moieties at the C‐20 carbon of ginsenoside Rc and its sugar‐tolerance makes Tt‐Afs a promising candidate for the production of ginsenoside Rd. In a reaction at 85°C and pH 5·0, 25 g l −1 of ginsenoside Rc was transformed into 21·8 g l −1 of Rd within 60 min, with a corresponding molar conversion of 99·4% and a high ginsenoside Rd productivity of 21800 mg l −1 h −1 . Conclusions We have successfully cloned and overexpressed the novel α ‐ l‐ arabinofuranosidase from T. thermarum DSM 5069. The high ginsenoside Rd productivity and detailed characterization of recombinant Tt‐Afs was provided. Significance and Impact of the Study The result shows a high productivity on the bioconversion from high concentration ginsenoside Rc to ginsenoside Rd, which also give rise to a potential commercial enzyme application.