However, it is difficult to obtain GA in a good yield
by this method, because many by-products are also
produced. On the other hand, it has been disclosed that
an enzyme named glycyrrhizinic acid hydrolase from
Aspergillus niger selectively hydrolyzed 3-O-β-Dglucuronide
linkage of GL without cleavage of the terminal
glucuronobiose bond to give GA and glucuronobiose (β-Dglucuronyl-(
1-2)-D-glucuronic acid) in a high yield without
formation of glucuronic acid (Muro et al. 1986).