Abstract

ROMERO-PERDOMO, F; CAMELO-RUSINQUE, M; CRIOLLO-CAMPOS, Paola  and  BONILLA-BUITRAGO, Ruth. Effect of temperature and pH on the biomass production of Azospirillum brasilense C16 isolated from Guinea grass. Pastos y Forrajes [online]. 2015, vol.38, n.3, pp.171-175. ISSN 0864-0394.

The objective of the study was to evaluate the effect of temperature and pH on the cell viability of the strain Azospirillum brasilense C16. Five temperatures (between 28 and 36 ºC) and five pH values (from 4,5 to 8,5) were studied. The effect of temperature was evaluated by measuring the radial growth (mm) of the strain, on a filter paper in sweet potato agar. In the case of pH to quantify the growth rate, biomass production and time of duplication of the strain a Rushton-type turbine-agitated fermenter was used; the fermentation conditions were: 400 rpm, 1 Lpm and 30 ºC, during 24 hours. The pH and temperature significantly influenced (p< 0,05) the production of A. brasilense C16. The temperature of 30 ºC was the most favorable for the strain to be multiplied, with 23,21 mm of radial growth; while the temperature higher than or equal to 34 ºC inhibited its growth. The best results were obtained with a pH value of 6,8, with significant differences (p< 0,05) compared with the others. Under this condition the highest growth rate values (1,79 h^-1) and biomass production (8,65 log10 CFU mL^-1), and the lowest value of the duplication time (1,09 h^-1), were obtained. These results have biotechnological applicability, and are very important at the moment of defining and controlling the conditions of massive biomass production of A. brasilense C16 for future formulations in diverse crops of interest in Colombia.

Keywords : Bacterium; grass; inoculation.

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