Optimization of culture media for Bacillus species by statistical experimental design methods

Abstract

The medium compositions of Bacillus species (three strains) were optimized sequentially through two statistical experimental designs, Plackett-Burman and the Box-Behnken, which were determined by representative threefactor response-surface methodology. pH and DO control was found to enhance the viable cell number of Bacilli. Most strains grew well in the optimum condition and reached nearly up to of 5×10 9 CFU/mL. Additionally, when three of the Bacilli were cultivated in the optimized medium with pH and DO control, the viable cell number increased 3.6 times in B. subtilis, 64.1 times in B. licheniformis and 8.3 times in B. coagulans, respectively, in comparison with the original industrial medium.

Effect of medium components and culture conditions in Bacillus subtilis EA-CB0575 spore production

“…Different authors have selected factors that have a significant effect by means of factorial designs or fractional factorials [10,29] but go directly to an optimization design or to a response surface method (RSM). However, in this study, a full factorial design was used to define the optimization zone and, once in this zone, a CC design was used to find the optimum point for each variable.…”

“…Furthermore, during the stationary growth phase in a fermentation process, when nutrients are exhausted, the culture initiates sporulation at a cell density of about 10 8 cells/mL [8]. Under ideal conditions, typical cell densities and sporulation efficiencies for B. subtilis will be in the range of 1.00 9 10 8 -1.52 9 10 10 CFU/mL [9][10][11][12] and Electronic supplementary material The online version of this article (doi:10.1007/s00449-015-1428-1) contains supplementary material, which is available to authorized users. 30-80 %, respectively using serial dilution and plate count methods [11][12][13][14].…”

“…Different optimum culture media and culture conditions for AEFB sporulation have been reported, where each particular strain has its own requirements and optimum conditions [10,12,17,18]. For example, the presence of glutamate in the medium benefits the growth of B. cereus while for other species of Bacillus this compound inhibits growth [19].…”

“…For example, the presence of glutamate in the medium benefits the growth of B. cereus while for other species of Bacillus this compound inhibits growth [19]. It has also been reported that adding salts to the media improves sporulation, but high concentrations of heavy metals contained in these salts could affect growth [10]. Elements such as Ca, Mn, Mg, Fe and Zn in appropriate concentrations are essential in sporulation since they are present in the spore layers and enable it to resist high temperatures [11] and the last two elements accelerate the sporulation process [3,20].…”

Screening of Effective Markers for Mesophilic Bacterium Growth Using Factorial Experimental Design

“…Where β i are the values of the regression coefficients, β 0 being the constant term, β 1 , β 2 and β 3 the linear effects, β 12 , β 13 and β 23 the interaction effects while the A(x 1 ), B(x 2 ), C(x 3 ) are the independently coded variables (nutrient concentration, temperature difference, acclimation time and agitation respectively). Stepwise deletion of terms was applied to eliminate the statistically non-significant terms.…”