Optimization of the medium for Lactobacillus acidophilus by Plackett-Burman and steepest ascent experiment

Abstract

Background. Lactobacillus acidophilus not only improves the intestinal fl ora balance but also inhabits the growth of undesirable microorganisms in intestine, which is benefi t to the health of humans and animals. Plackett-Burman and steepest ascent experiment are the rapid and concise ways of screening the main effective factors. This study is aimed to select the main infl uence factors and optimize the medium for Lactobacillus acidophilus by Plackett-Burman experiment and steepest ascent experiment. Material and methods. The ideal carbon source was screened among glucose, maltose, lactose and whey powder, and the ideal nitrogen source was screened among casein hydrolysate, peptone, yeast extract powder, fi sh meal, carbamide, ammonium sulfate and sodium nitrate by single factor experiment. Plackett-Burman and steepest ascent experiment were applied to screen the main effective factors of Lactobacillus acidophilus among peptone, beef extract, yeast extract powder, glucose, K 2 HPO 4 , C 6 H 14 O 7 N 2 , CH 3 COONa, MgSO 4 and Tween-80. Result. The results indicated that glucose (p = 0.01510) as negative factor and K 2 HPO 4 (p = 0.02017) as positive effect were the signifi cant growth factors of Lactobacillus acidophilus, CH 3 COONa (p = 0.09273) as positive effect was an important factor, and the optimized medium was as follows: glucose -21 g/L, K 2 HPO 4 -3.5 g/L, CH 3 COONa -6.5 g/L, peptone -10 g/L, beef extract -8 g/L, yeast extract powder -8 g/L, C 6 H 14 O 7 N 2 -2 g/L, MgSO 4 -0.2 g/L and Tween-80 -1 mL/L when the maximum viable count could achieve 2.72·10 9 cfu/mL. Discussion. The experimental model is reliable and the experimental results are of good stability. Variance analysis is performed to determine the adequacy and signifi cance of the linear model. Thus, Plackett-Burman and steepest ascent experiment improve the veracity of optimization the medium for Lactobacillus acidophilus compared with the previous research.

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

“…The experimental design included 6 factors and the experimental number selected was N = 12. A, B, C, D, E, and F represents precooked liquid solubility, initial pH, inoculum size, culture temperature, shaking speed, and liquid volume, respectively (Chen et al 2015a, 2017a; Gao et al 2016). Based on the results of the single-factor experiments, each factor was taken to two levels (Table 2).…”

“…The steepest ascent method changes the gradient direction of the experimental value into the direction of hill climbing. Based on the effect of each factor, the change step size can be determined, which can be used to quickly and economically approximate the optimal value area (Chen et al 2015a; Gao et al 2016). According to the size of the key factor effect value in the Plackett–Burman experiment, the change distance and direction of climbing can be determined.…”

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

“…C, F, and I were set as blank terms to estimate the experimental error. A, B, D, E, G, and H represented precooked liquid solubility, initial pH, inoculum size, liquid volume, temperature, and shaking speed, respectively (Chen et al, 2015Gao et al, 2016). Based on the results of the single-factor experiments, each factor was taken to one high level (+1) and one low level (-1).…”

“…The steepest ascent method changes the gradient direction of the experimental value into the direction of hill climbing. Based on the effect of each factor, the change step size can be determined, which can be used to quickly and economically approximate the optimal value area (Chen et al, 2015;Gao et al, 2016). According to the size of the key factor effect value in the Plackett-Burman experiment, the change distance and direction of climbing can be determined.…”

Plackett-Burman design and response surface optimization of conditions for culturing Saccharomyces cerevisiae in Agaricus bisporus industrial wastewater [pdf]

“…Based on the effect of each factor, the steepest ascent design is used to quickly and economically approximate the optimal value area. Therefore, according to the size of the key factor effect value in the Plackett-Burman experiment, the change distance and direction of climbing can be determined, which can be used to determine the best level range (Chen et al, 2015). And the design of the steepest ascent experiment is shown in Table 2.…”