Optimization of Fermentation Conditions for Bacillus megaterium ZS-3
In order to increase the number of effective bacteria of Bacillus megaterium ZS-3 and reduce the fermenta-tion cost of ZS-3,combination of single factor,orthogonal,and response surface method were used to investigate the fermentation conditions to produce the highest number of viable ZS-3,including carbon source,nitrogen source,inor-ganic salt,rotation speed,liquid filling volume,pH,temperature,inoculation volume,and other culture conditions.The results showed that strain ZS-3 optimal carbon,nitrogen source and inorganic salt were soluble starch 1.0%(mass fraction),corn milk dry powder 0.5%,diammonium hydrogen phosphate 0.5%,aluminum potassium sulfate dodecahydrate 0.5%;optimal cultivation conditions were rotation speed of 200 r/min,liquid filling volume 40%,pH of 6.67,30.37 ℃,and inoculation volume 1.31% (v/v),the biomass reached the highest.After optimization,the number of cultured cells reached 1.21 × 109 cfu/mL,the number of viable cells in ZS-3 is 3.9 times those of the vi-able cells produced under the original cultivation conditions.The fermentation cost reduced and provided theoretical basis and data support for the possible industrial expansion of fermentation production in the future.