Biotransformation of ginsenoside Rf to Rh1 by recombinant beta-glucosidase.

An Aspergillus niger strain was isolated from the soil around ginseng fruit. In vitro enzyme assays showed that this strain had the ability to transform total ginsenosides (TGS) into several new products. In a further biochemical study, a beta-glucosidase gene isolated from this strain, bgl1, was expressed in Saccharomyces cerevisiae. His-tagged BGL1 protein (approximately 170 kD) showed the ability to transform ginsenoside Rf into Rh(1).