RESUMEN
Delftia tsuruhatensis BM90, previously isolated from Tyrrhenian Sea and selected for its ability to degrade a wide array of phenolic compounds, was immobilized in chemically modified macro porous cellulose. The development of bacterial adhesion on the selected carrier was monitored by scanning electron microscopy. Evident colonization started already after 8h of incubation. After 72h, almost all the carrier surface was covered by the bacterial cells. Extracellular bacterial structures, such as pili or fimbriae, contributed to carrier colonization and cell attachment. Immobilized cells of D. tsuruhatensis were tested for their ability to biodegrade a pool of 20 phenols in repeated batch process. During the first activation batch (72h), 90% of phenols degradation was obtained already in 48h. In the subsequent batches (up to 360h), same degradation was obtained after 24h only. By contrast, free cells were slower: to obtain almost same degradation, 48h were needed. Thus, process productivity, achieved by the immobilized cells, was double than that of free cells. Specific activity was also higher suggesting that the use of immobilized D. tsuruhatensis BM90 could be considered very promising in order to obtain an efficient reusable biocatalyst for long-term treatment of phenols containing effluents.
Asunto(s)
Reactores Biológicos/microbiología , Células Inmovilizadas/citología , Delftia/citología , Polifenoles/metabolismo , Análisis de Varianza , Biodegradación Ambiental , Células Inmovilizadas/química , Células Inmovilizadas/metabolismo , Celulosa/química , Delftia/química , Delftia/metabolismo , Equipo Reutilizado , PorosidadRESUMEN
The white-rot fungi Panus tigrinus, Funalia trogii and Trametes versicolor have been tested in shake flasks for the reduction of olive washing wastewater (OWW) pollutants and production of oxidases on OWW-based media. P. tigrinus was rejected for its scarce performance. F. trogii showed best production of laccase (27 000 Ug(-1)), while T. versicolor appeared a good pollutant degrader reducing colour, COD and phenols by 60, 72 and 87%, respectively. Only T. versicolor grew well in bubble-column bioreactor: its OWW depollution, in continuous process, led to colour, COD and phenols reduction by 65%, 73% and 89%, respectively. Optimal dilution rate was 0.225d(-1) (0.225 m(3) of effluent treated daily per m(3) of bioreactor). Thus, a small bioreactor (10 m(3)) could treat daily the amount of OWW produced by a standard olive washing machine (2m(3)d(-1)). For these reasons, this process could be proposed as a simple, efficient and low-cost OWW treatment.