Mutation and Selection of Hyaluronic Acid-Producing Strains

Abstract:

In this study, a mutant designated NC1150 which dose not produce streptolysin was selected from wild-type Streptococcus equisimilis by ultraviolet ray combined with 60Co-γ ray mutation. Through further 60Co-γ ray mutation a high-producing hyaluronic acid mutant designated NC168 was obtained. This selected mutant NC168 could produce hyluronic acid 1.01 times as much as the original strain NC1150 and relative molecular weight of hyaluronic acid touched 0.55×106 D. Furthermore, its hyaluronic acid output and relative molecular weight of hyaluronic acid maintained genetic stability after 10 generations and there was no reverse mutation on hemolysis.

Key words:Streptococcus equisimilis, Hyaluronic acid, Ultraviolet ray mutation, 60Co-γ ray mutation