Biodegradação de azocorantes por bacterias isoladas de efluentes industrais / Biodegradação of azocorantes for isolated bacteria of effluent industrials

AUTOR(ES)
DATA DE PUBLICAÇÃO

2005

RESUMO

The expansion of the industrial textile park in Brazil has increased the consumption of azo-reactive dyes, used in the dying of cotton. This increase is due to the greater production of cotton, owing to climatic conditions, which favour its growth. Studies, which elucidate the biodegradation of reactive azo dyes, are necessary to perfect effluent treatment processes, which have not been effective for the removal of these dyes. The objective of this work was to isolate microorganisms from textile effluents able to decolourise or degrade reactive azo dyes RB 220 or RR 198 or both, and to obtain more information to improve existing treatment processes. In addition, the reduction in the Chemical Oxygen Demand (COD), of the culture media containing dye was also investigated. The microorganisms were isolated from the effluent using the surface-seeding technique. A pre-selection, with 62 bacterial strains, was undertaken, through visual growth, in liquid and solid media, with dyes as the only carbon source (0.03%). Seventeen strains were pre-selected and a study carried out, in which it was found that the presence of an extra carbon source was needed to aid discoloration. Three strains were selected and tested for their ability to discolour and reduce the COD, when grown in a liquid medium with agitation, glucose and folic acid. Five strains were selected for their discoloration capacity, reduction in COD in microaerobic conditions, varying the concentration of glucose, yeast extract and folic acid vitamin. Either the discoloration or degradation analyses or both were realised via absorbance and scanning spectrophotometry. The degradation was confirmed by high-performance liquid chromatography. Some discoloration occurred for all the strains. A greater reduction in the COD by the bacteria was observed under aerobic conditions. The strains were identified as Bacillus sp, Trichococcus sp and Enterobacter sp.

ASSUNTO(S)

corantes coloring bacterias bacterium biodegradação

ACESSO AO ARTIGO

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