Influence of the culture medium on the production of siderophores by Rahnella aquatilis

GUIÑEZ, M.; SANSONE, G.; CALVENTE, V.; BENUZZI, D.; SANZ, M.I.

San Luis

Congreso; XXVII Reunión Científica Anual de la Sociedad de Biología de Cuyo; 2009

Influence of the culture medium on the production of siderophores by Rahnella aquatilis BNM 0523. Guiñez ME, Sansone MG, Calvente V, Benuzzi D, Sanz MI. Area Tecnol. Qca. y Biotecnología. UNSL. E-mail: vcalv@unsl.edu.ar.The aim of this work was study of production of siderophores by Rahnella aquatilis BNM 0523, which was isolated from apple skin and was proved as an efficient Control Agent (BCA) on apple postharvest decay. From preliminary assays it was possible to establish that this strain produces a siderophore type catecholate, probably Enterocheline. Siderophore synthesis is regulated by iron and influenced by other environmental factors. Taking into account this fact, the effect of culture medium composition on the production of siderophore was studied. The microorganismwas grown in 500 ml flask with 125 ml of Vitamin Free Medium (200 rpm at 28ºC by 48 h). Cells were removed by centrifugation; pH of the medium was controlled. Biomass was dried at 50ºC and weighed. Siderophore was detected in supernatant with the Arnow assay. It was observed that the production of the siderophore reached the highest concentration at the stationary phase of growth. The production was influenced largely for the presence of Fe into the culture medium. Fe concentrations of 2,5 uM reduced until 7 times the production. The use of different carbon sources such as succinate or lactate increased the production of siderophore, perhaps due to the stimulation of the aerobic metabolism increasing the need of Fe. In consequence, the microorganism would produce more siderophore for to improve its uptake of the metal.