The effect of exopolysaccharide biosynthesis and related enzyme activities of <i>Grifola frondosa</i> by the addition of ethanol extracts from traditional Chinese medicine, <i>Gastrodia tuber</i>

Abstract

Grifola frondosa is an edible medicinal polypore mushroom and its exopolysaccharide (EPS) has demonstrated immunomodulatory effects in many previous studies. After adding the Gastrodia tuber components in culture medium of G. frondosa, both EPS and biomass production were significantly increased. As a result, we detected two enzymes which are related to EPS synthesis. Our results suggested that the activity of α-phosphoglucomutase (α-PGM) increased, while the activity of phosphoglucose isomerase decreased. Mixture components of ethanol extract of Gastrodia tuber was more effective than pure gastrodine. A maximum dry cell weight of 138.5 mg l⁻¹ and the EPS at 0.606 g l^-1 were obtained when the unprocessed Gastrodia tuber culture was added.

Key words: Exopolysaccharide, phosphoglucomutase (PGM), phosphoglucose isomerase (PGI), Grifola frondosa, Gastrodia tuber.