Breeding of Bacterial Cellulose Strain Induced by Ultra-High Pressure and Optimization of Fermentation Medium

In order to obtain high-yield strains of bacterial cellulose (BC), the primary bacterial cellulose strain was induced by ultra-high pressure. Plackett-Burman design was employed to evaluate variables which were relevant to yield of BC which was produced by strain induced by ultra-high pressure. Fermentation medium composition was optimized through Box-Behnken experiment. The results show that mutagenic pressure and time on the strain of bacterial cellulose have significant or extremely significant influence. The mutagenic conditions of BC strain are pressure of 250 MPa, time of 15 min, and temperature of 25 ℃. The mutagenic strain M438 with high cellulose production capacity and genetic stability is obtained through the ultra-high pressure treatment. The key factors affected bacterial cellulose production of mutation strain M438 are yeast juice, MgSO4, and anhydrous ethanol. The optimistic fermentation medium is as follows, carbon source 5% (glucose∶sucrose=4∶1), yeast juice 1.25%, CaCl2 0.15%, ZnSO4 0.2%, K2HPO4 0.2%, MgSO4 0.93%, fumaric acid 0.3%, and ethanol 0.5%. BC yield of M438 cultured with optimized fermentation medium is as 1.84 times as that cultured with the initial fermentation medium, and is as 2.69 times as that of the unmutant strain. Ultra-high pressure technology for mutation breeding of bacterial cellulose strain is feasible. BC producing capacity of M438 can be significantly improved through fermentation medium optimization.