Optimization of cultivation medium for the production of antibacterial agents

Abstract

Optimization of the cultivation medium for production of antibiotic effective against pathogenic bacteria Staphylococcus aureus using strain of Streptomyces spp. isolated from the environment represents the aim of this study. After the biosynthesis, the medium was analyzed by determining residual sugar and nitrogen, and the antibiotic activity was determined using diffusion-disc method. Experiments were carried out in accordance with the Box-Behnken design, with three factors varied on three levels (glucose: 10.0, 30.0 and 50.0 g/L; soybean meal: 5.0, 15.0 and 25.0 g/L; phosphates: 0.5, 1.0 and 1.5 g/L) and for the optimization of selected parameters Response Surface Methodology was used. The obtained model with the desirability function of 0.985 estimates that the lowest amounts of residual sugar (0.89 g/L) and nitrogen (0.24 g/L) and the largest possible inhibition zone diameter (21.88 mm) that with its antibiotic activity against S. aureus creates the medium containing 10.0 g/L glucose, 5.0 g/L soybean meal and 1.04 g/L phosphates.

Optimization of media for antimicrobial compounds production by Bacillus subtilis

“…This method is more satisfactory and effective than others, because it can study many variables simultaneously with a low number of observations, saving time and costs (DEEPAK et al, 2008). In statistics-based approaches, response surface methodology (RSM) is a well-known method applied in the optimization of cultivation media for the production of antimicrobial agents effective against Staphylococcus aureus (EL-SERSY et al, 2009;GRAHOVAC et al, 2013). RSM is a group of statistical techniques for designing experiments, building models, evaluating the effects of factors, and searching for the optimum conditions (POPOV et al, 2010).…”

Formulation of medium for bactericides biosynthesis using wild type Streptomyces sp.

“…The observed antimicrobial activity of the medium with fructose was significantly higher than the value of the same parameter for the medium with glucose obtained under the same experimental conditions [20]. Hence, when the cultivation medium contained 10 g/L monosaccharide, 5 g/L soybean meal and 1.5 g/L phosphates, the measured inhibition zone diameter for fructose-and glucose-containing media were 31 and 22 mm [20], respectively. Other authors also investigated the effects of these sugars on antibiotics production by wild type Streptomyces strains.…”

“…In order to investigate the influence of various carbon, nitrogen, and phosphorus sources on the bactericide biosynthesis using wild strain Streptomyces sp., the cultivations were carried out under identical conditions on media that were formulated in accordance with the Box-Behnken experimental design (varied factors, Table 1). The results presented in this study represent the continuation of research conducted with glucose-containing media [20]. Based on data collected from the available literature [28][29][30], easily adopted monosaccharide (fructose), fermentable disaccharides (lactose and sucrose), difficult to adopt polysaccharide (starch) and hydrocarbon (glycerol) were selected as carbon sources for further investigation.…”

“…Hence, the optimization of carbon source, soybean meal and phosphates content in media for the biosynthesis of bactericide effective against Staphylococcus aureus ATCC 11632 was carried out using response surface methodology and method of desirability function. To optimize the composition of the glucose-containing medium, a previously published mathematical model was used [20].…”

“…Since the microbiological production of antibacterial components is affected by many factors, it is usually very difficult to determine which of them has the greatest impact. Therefore, RSM is increasingly used for mathematical modeling and optimization of the biotechnological production of these compounds [14,[19][20][21][22][23]. This research represents a major challenge for scientists because the biotechnological processes are difficult to describe by mathematical equations due to the complex metabolism of producing a microorganism, the usage of raw materials of undefined composition, and the changes that occur during the bioprocess being performed at selected technical and technological parameters.…”