Optimization of culture media for bacterial cellulose production by fermentation of corn starch wastewater

Corn starch wastewater is a kind of high concentration organic wastewater discharged from starch processing.The study focused on producing bacterial cellulose utilized those wastewater,and optimizing medium component via adopting the Plackett- Burman design method and the Box- Behnken response surface analysis.Further,the structure of bacterial cellulose( BC) obtained from fermentation of corn starch wastewater was described by Fourier transform infrared spectrometer( FTIR) and scanning electron microscopy( SEM). Cellulose dry weight was defined as response value,three significant factors,which were sucrose,monopotassium phosphate and ethanol,were selected through the Plackett- Burman experiment,then the respective optimum concentration of those factors was determined by response surface method( RSM). The improved medium composition was as follows: dilution ratio of corn starch wastewater was 1 ∶ 4,extra sucrose,CaCl_2,KH_2PO_4,MgSO_4,citric acid and ethanol were 3.32 g /100 m L,0.3 g /100 m L,0.12 g /100 m L,0.05 g /100 m L,0.2 g /100 m L,1.50 m L / L,respectively. Eventually,the yield of BC was 1.63 times than that before optimization,and reached1.11 g /100 m L. The results suggested that the postoptimality medium of wastewater could meet the growth and metabolism of Acetobacter xylinum DS398,hence the bacterial cellulose production were improved significantly.The micrographs of FTIR and SEM further illustrated that BC produced in medium of corn starch wastewater possesses high purity,and the product's microstructure may be similar to coconut.