OPTIMIZATION OF FERMENTATION MEDIUM FOR ACETOIN PRODUCTION BYBacillus subtilisSF4-3 USING STATISTICAL METHODS

Abstract

To improve the acetoin-producing ability of Bacillus subtilis SF4-3, isolated from "natto," a Japanese traditional food, the fermentation medium was optimized in shake-flask fermentation by statistically designed methods. Based on results of the single-factor experiment, orthogonal experiment, and Plackett-Burman design, yeast extract, corn steep liquor, and urea were identified as showing significant influence on the acetoin production. Subsequently, the optimum combination of the three factors was investigated by the Box-Behnken design (BBD) of response surface methodology (RSM) in order to further enhance the acetoin production. The maximum acetoin yield of 45.4 g/L was predicted when the concentrations of yeast extract, corn steep liquor, and urea were 8.5 g/L, 14.6 g/L, and 3.8 g/L, respectively. The results were further confirmed in triplicate experiments using the optimized medium (glucose 160 g/L, yeast extract 8.5 g/L, corn steep liquor 14.6 g/L, urea 3.8 g/L, manganese sulfate 0.05 g/L, ferrous sulfate 0.05 g/L), and an acetoin yield of 46.2 g/L was obtained in the validation experiment, which was in agreement with the prediction. After the optimization of medium components, an increase of 36.28% in acetoin production was achieved in comparison to that at the initial medium levels.

Response surface optimization of conditions for culturing <i>Azotobacter chroococcum</i> in <i>Agaricus bisporus</i> industrial wastewater

“…First, the Plackett-Burman experimental design is a two-level design method based on the principle of incompletely balanced blocks. It can filter out factors that significantly influence experimental results with the fewest experiments and facilitate making experimental results more scientific (Tian et al, 2014). Second, the Box-Behnken experimental design is an effective method to study interactions between several factors, which can be used to reduce development costs, optimize processing conditions, improve product quality, and solve practical production problems Khoshayand et al, 2011).…”

Optimization of the culture condition of Bacillus mucilaginous using Agaricus bisporus industrial wastewater by Plackett–Burman combined with Box–Behnken response surface method

“…It can filter out factors that significantly influence experimental results with the fewest experiments and facilitate making experimental results more scientifically. Therefore, it is generally used in media or conditions of fermentation (Atli et al 2013; Tian et al 2014; Mohan et al 2016), methods or technology of extraction (Chen et al 2015b, 2017b), and so on. In this study, three significant factors including shaking speed, culturing temperature, and initial pH were filtered out with Plackett–Burman.…”

Statistical Optimization of Acetoin Production Using Corn Steep Liquor as a Low-Cost Nitrogen Source by Bacillus Subtilis CICC 10025

“…A three-level factor was employed to generate 17 experimental runs by considering the effect of glucose concentration (g/L), inoculum size (% v/v), and corn steep liquor (% w/v). The range and the levels of the independent variables investigated using the Box-Behnken experimental design ( Table 1) were chosen based on variables previously reported to influence acetoin [11,26]. The minimum, center point, and maximum levels of each variable were coded as −1, 0, and +1, respectively.…”

“…The production of acetoin by microbial fermentation has been reported to gain increasing interest due to its safety and environmental friendliness [3,4]. Intensive efforts have been taken to enhance microbial production of acetoin, including screening of high-yield acetoin-producing strains [5,6], metabolic engineering breeding [7][8][9], and fermentation optimization [9][10][11]. The price of chemically generated acetoin (racemic) is over $ 16.2/kg, and biologically generated dietary acetoin can be two times more expensive [12].…”