MEDIUM OPTIMIZATION OF Burkholderia gladioli pv. agaricicola ENHANCED THE PRODUCTION OF ANTIMICROBIAL SUBSTANCES

Numerous species in the genus Burkholderia have interesting properties for potential industrial applications including production of antibiotics, biosurfactants, bioplastics and degradation of environmental contaminants. The aim of this research was study the effect of differ-ent carbon and nitrogen sources on Burkholderia gladioli pv. agaricicola strain ICMP11096 growth and bioactivity of produced secondary me-tabolites against gram-positive bacterium Bacillus megaterium and plant pathogenic fungi Rhizoctonia solani. The additional carbon sources were sucrose, fructose and lactose whereas, the additional nitrogen sources were, urea, potassium nitrate and ammonium nitrate. The results demonstrated that the addition of new carbon and nitrogen sources to the minimal mineral nutrient media lead to decreasing the growth rate of studied bacterial strain and increasing the production of bioactive substances. The maximum production of bioactive substances of studied bacterial strain was obtained using ammonium nitrate and lactose. The purified filtrate of the studied bacterial strain was fractionated by High Performance Liquid Chromatography (HPLC) and the antimicrobial activity of five isolated single peaks was evaluated against gram positive bacteria B. megaterium ITM100 and gram negative bacteria Escherichia coli ITM103. The most bioactive peak was number two with 12800 and 6400 Ua.ml-1 against B. megaterium and E. coli, respectively. The obtained results suggested that the nutrient amendments can increase the production of antimicrobial substances and this may be a useful strategy for improving the biocontrol efficiency

INFLUENCE OF NUTRIENT MEDIA ON THE PRODUCTION OF METABOLITES PRODUCED BY BURKHOLDERIA GLADIOLI PV. AGARICICOLA

Bacterial species in the genus of Burkholderia have numerous interesting properties of potential industrial applications, including production of antibiotics, biosurfactant, bioplastics, and degradation of environmental contaminants. Bacterial biosynthesis of antibiotics is highly dependent on environmental factors, including types of nutrient, pH, and temperature. Burkholderia gladioli pv. agaricicola (Bga) , plant, fungi and bacteria pathogens, have the ability to produce in vitro secondary metabolites with relevant biological activities. As the nutrient media play un important role on the bacterial growth and on the production of metabolites, in this work the effects of addition of different carbon and nitrogen sources to liquid minimal mineral media (MMA), were investigated in relation to the production of bioactive metabolites. Results showed that the transition into stationary phase and the growth rate of bacteria increased, due to less competition for nutrient components, resulting in high antifungal activity vs. Rhizoctonia solani (Rs) and Bacillus megaterium (Bm). The maximum growth and antimicrobial activity of Bga were obtained after incubation for 13 days at 25 C° by using ammonium nitrate and lactose while the production of metabolites increased of 400%