Conversion of G-hansenii PJK into non-cellulose-producing mutants according to the culture condition

The conversion of a cellulose-producing cell (Cel(+)) from Gluconacetobacter hansenii PJK (KCTC 10505 BP) to a non-cellulose-producing cell (Cel(-)) was investigated by measuring the colony forming unit (CFU). This was achieved in a shaking flask with three slanted baffles, which exerted a strong shear stress. The addition of organic acid, such as glutamic acid and acetic acid, induced the conversion of microbial cells from a wild type to Cel(-) mutants in a flask culture. The supplementation of 1% ethanol to the medium containing an organic acid depressed the conversion of the microbial cells to Cel(-) mutants in a conventional flask without slanted baffles, The addition of ethanol to the medium containing an organic acid; however, accelerated the conversion of microbial cells in the flask with slanted baffles. The Cel(+) cells from the agitated culture were not easily converted into Cel(-) mutants on the additions of organic acid and ethanol to a flask without slanted baffles, but some portion of the Cel(+) cells were converted to Cel(-) mutants in a flask with slanted baffles. The conversion ratio of Cel(+) cells to Cel(-) mutants was strongly related to the production of bacterial cellulose independently from the cell growth.