The DNA contents

the internal grain densities

the surface roughness and the cell sizes of Serratia marcescens ZSG cells were detected to have different changes by the flow cytometry when ZSG cells were cultivated in the medium with the different carbon sources.Through mutagenizing compoundly ZSG cells

a stable mutant strain ZSG7 was gained

of which the prodigiosin(PG) production in the 250 ml conical flask and in 5 L fermentor were increased by 62.5% and 269% compared with the the original strain yields

respectively.PG production of fermentation with the optimal culture medium in the 250 ml conical flask was increased by 100% compared with the unoptimized.After dissolved oxygen(DO) was optimized by step controlling

the PG production was increased by 30.9% compared with the DO-unoptimized.After constant pH was optimized

the PG production was increased by 35.9% compared with the pH-unoptimized.After the fed-batch components were optimized

the PG production was increased by 47.6% compared with the batch fermentation with constant pH7.The kinetic models about bacteria growth and PG formation of the batch fermentation with constant pH7 and the fed-batch fermentation were built based on the Logistic equation and Luedeking-Piret equation.With the fitting model parameters

the models could provide reasonable description for the processes of the batch fermentation with constant pH7 and the fed-batch fermentation.