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

Abstract

The aim of this study was formulation of medium for the production of bactericide effective against Staphylococcus aureus and Escherichia coli using Streptomyces sp. isolated from the soil. Biosynthesis of antibacterial compounds was performed on media prepared in accordance with Box-Behnken design with three factors on three levels and three repetitions in the central point where the contents of the carbon source (10.0-50.0 g/L), soybean meal (5.0-25.0 g/L) and phosphates (0.5-2.5 g/L) were varied. Fructose, lactose, sucrose, starch and glycerol were used as carbon sources. Since the cultivation broths showed activity only against Staphylococcus aureus, the values of inhibition zone diameters for this microorganism were statistically processed using response surface methodology and desirability function approach in order to optimize relations of varied nutrients. Media with glucose were not used in these experiments, but the mathematical model defined in previous research was applied for optimization. The developed models predict that optimal concentrations of carbon source, soybean meal and phosphates are about 10.0, 5.0 and 0.5 g/L, respectively, except in the lactose-containing medium, where the optimal phosphate content is 0.9 g/L. Performing the bioprocess in optimal media, the maximum inhibition zone diameter against Staphylococcus aureus was formed by the medium with fructose (34.5 mm). [Project of the Serbian Ministry of Education, Science and Technological Development, Grant no. TR-31002]

Optimization of glycerol-based medium composition for antifungal metabolites production by Bacillus subtilis

“…This situation can be explained by the facts from previously published literature. Decrease in the values of observed response with increasing substrate concentration indicates that higher concentration of carbon source in cultivation medium can negatively affect the biosynthesis of secondary metabolites, such as desired antimicrobial compounds (Veličković et al, 2018). On the other hand, literature data indicate that metabolic activity of microorganisms is inhibited at high substrate concentration (Liu, 2013).…”

Xanthomonas campestris biocontrol agent: Selection, medium formulation and bioprocess kinetic analysis

“…Different lactic acid bacteria are examined for biological control of Xcc [19]. Streptomycetes are also considered as potential candidates for biological control of black rot [20], due to their beneficial trait of producing large number of different metabolites, enzymes and antibiotics with antagonistic activities against microbial pathogens [21]. Different yeasts are also investigated as biological control agents for black rot [22].…”