RESUMEN
As in many other microorganisms, the growth rate of C. tropicalis is affected by phenol. Besides, when the yeast is aerobically cultivated in a medium containing phenol, using a bubble column, the yeast cell flotation phenomenon occurs, which makes the continuous operation of this type of reactor difficult. Therefore, a system of phenol degradation, which recycles the biomass separated by flotation, was devised in this work. In order to reduce the substrate toxicity observed at high phenol concentrations, the bubble column used in the biodegradation studies was fed in a semibatch mode. So, a semicontinuous system was implemented to treat effluents with relatively high concentrations (> 9,000 ppm) of phenol, by replacing periodically about 22% of the bioreactor operational volume. The phenol removal efficiencies obtained with this system were higher than 98.7%.
Asunto(s)
Biodegradación Ambiental , Candida tropicalis/fisiología , Micología/instrumentación , Fenol/metabolismo , Biomasa , Reactores Biológicos , Diseño de Equipo , Micología/métodos , Contaminantes Químicos del Agua/metabolismoRESUMEN
The object of this work was to carry out a kinetic study on the Candida tropicalis cell lysis and to obtain a kinetic model that would describe the inhibitory and lytic effects of phenol on the yeast growth. From the experiments, a model for the growth kinetic behavior of the yeast was evolved. The proposed model describes satisfactorily the inhibitory and lytic effects of phenol on yeast cultures. From the kinetic model constants, it was found that C. tropicalis showed high affinity and tolerance toward phenol. The overall growth yields decreased when the initial phenol concentration increased, and it may be due to an increased maintenance coefficient and to cell lysis.