Effects of ascorbic acid on α-l-arabinofuranosidase and α-l-arabinopyranosidase activities from Bifidobacterium longum RD47 and its application to whole cell bioconversion of ginsenoside

Abstract

Bifidobacterium longum RD47 was cultured in 24 kinds of modified MRS broths containing various ingredients to select the most promising source that induces microbial enzymes. Among the various ingredients, ascorbic acid significantly enhanced α-l-arabinofuranosidase and α-l-arabinopyranosidase activities in Bifidobacterium longum RD47. Addition of 2 % ascorbic acid (w/v) to MRS showed the maximum enzyme activities. Both whole cell and disrupted cell homogenates showed efficient ρ-nitrophenyl-β-d-glucopyranoside and ρ-nitrophenyl-β-d-glucofuranoside hydrolysis activities. The initially enhanced α-l-arabinopyranosidase and α-l-arabinofuranosidase activities by ascorbic acid were maintained over the cell disruption process. The optimal pH of α-l-arabinofuranosidase and α-l-arabinopyranosidase was 5.0 and 7.0, respectively. Both enzymes showed the maximum activities at 40.0 °C. Under the controlled condition using Bifidobacterium longum RD47, ginsenoside Rb2, and Rc were converted to ginsenoside Rd.

Keywords: Ascorbic acid; Bifidobacterium; Bioconversion; Ginsenosides; α-l-Arabinofuranosidase; α-l-Arabinopyranosidase.

Fig. 1

Relative enzyme activities of Bifidobacterium longum Rd47 cultured in the various broths (n = 3). Cell lysis solution was treated to samples. Error bars standard deviation. White bars α-arabinofuranosidase, black bars α-arabinopyranosidase

Fig. 2

The effect of ascorbic acid on the production of α-L-arabinofuranosidase and α-L-arabinopyranosidase from Bifidobacterium longum Rd47 (n = 3). Cell lysis solution was treated to samples. Error bars represent standard deviation. White bars α-arabinofuranosidase, black bars α-arabinopyranosidase, black circles population growth

Fig. 3

The effect of cell disruption (Sonication) on α-l-arabinofuranosidase and α-l-arabinopyranosidase activities from Bifidobacterium longum Rd47 (n = 3). Error bars represent standard deviation. White bars α-arabinofuranosidase, black bars α-arabinopyranosidase, black circles degree of cell disruption

Fig. 4

The effect of ginseng extracts on the production of α-l-arabinofuranosidase and α-l-arabinopyranosidase from Bifidobacterium longum Rd47 (n = 3). Enzyme activities were evaluated without disruption step. Error bars standard deviation. White bars α-arabinofuranosidase, black bars α-arabinopyranosidase, black circles population growth

Fig. 5

TLC profile of ginsenosides conversion using disrupted cell

Fig. 6

TLC profile of ginsenosides conversion using whole cell