Coordinate action of exiguobacterial oxidoreductive enzymes in biodegradation of reactive yellow 84A dye

Abstract

A novel bacterial species identified as Exiguobacterium sp. RD3 degraded the diazo dye reactive yellow 84A (50 mg l(-1)) within 48 h at static condition, at 30 degrees C and pH 7. Lower salinity conditions were found to be favorable for growth and decolorization. Enzymatic activities of an H(2)O(2) independent oxidase along with laccase and an azoreductase suggest their prominent role during the decolorization of reactive yellow 84A. Presence of an H(2)O(2) independent oxidase in Exiguobacterium sp. RD3 was confirmed and hydrogen peroxide produced was detected by a coupled iodometric assay. Azoreductase activity was prominent in presence of cofactors NADH and NADP in mineral salt medium. Considerable depletion of COD of the dye solution during degradation of dye was indicative of conversion of complex dye into simple oxidizable products. Products of degradation were analyzed by HPLC, FTIR and GCMS. A possible product of the degradation was identified by GCMS. Degradation of dye resulted with significant reduction of phytotoxicity, confirming the environmentally safe nature of the degradation metabolites.

Degradation analysis of Reactive Red 198 by hairy roots of Tagetes patula L. (Marigold)

“…Significantly, high amount of the NADH-DCIP reductase and laccase was observed in B. juncea roots and shoots during the degradation of the textile effluent (Ghodake et al 2009). The azoreductase is a key enzyme expressed in azo dye degrading bacteria that cleaves azo bonds reductively (Dhanve et al 2008). After decolorization, induced azoreductase activity in Tagetes hairy roots indicated and confirmed its role for the reduction of azo bonds in the dye degradation.…”

“…Azoreductase assay was performed in a reaction mixture (2 mL) containing 4.45 lM methyl red, 100 lM NADH in 50 mM potassium phosphate buffer at pH 7.4. The initial rate was determined by measuring the decrease in absorbance at 430 nm (Dhanve et al 2008). Mn peroxidase was determined by the modified method of Hatvani and Mecs (2001).…”

Performance of Isolated Kocuria sp. SAR1 in Light Crude Oil Biodegradation

“…The 16S rDNA sequences (Query sequence) were initially analyzed at NCBI server (http://www.ncbi.nlm.nih.org) using BLAST tool (http:// blast.ncbi.nlm.nih.gov/Blast.cgi) and corresponding sequences from database were downloaded. Evolutionary history was inferred using the Neighbor-joining method [29]. The tree was drawn to the scale, with branch lengths in the same units as those of the evolutionary distance used to infer the phylogenetic tree.…”

Potencial biossotivo e biodegradativo da Saccharomyces cerevisiae imobilizada em alginato de cálcio e em células livres na remoção de corantes têxteis de efluente

“…: grupo sulfônico (DHANVE et al, 2009;SILVERSTEIN;BASSLER;MORRILL, 1979;JUÁREZ-HERNÁNDEZ et al, 2008). : anel aromático (POLUNIN et al, 2008).…”

“…, indicando a presença de grupos fenólicos provenientes da transformação das carbonilas do grupo das quinonas (ABBAS et al, 2008;DHANVE et al, 2009;POLJANŠEK;KRAJNC, 2005;SILVERSTEIN;BASSLER;MORRILL, 1979) : estiramento das ligações azóicas (-N=N-) (DYER, 1969;GUP;GIZIROGLU;KIRKAN, 2007;. É importante observar que com 48 horas de tratamento com apenas 10 gotas da suspensão 2% de células livres, a banda na região de 1400 cm -1 já ficou mais evidente, mostrando a possível quebra do grupo quinona com a formação do grupo fenólico, que é caracterizada nesta região do espectro (ABBAS et al, 2008;DHANVE et al, 2009;POLJANŠEK;KRAJNC, 2005 -anel aromático (POLUNIN et al, 2008). Todas as bandas ficaram mais evidentes com 72 horas de tratamento.…”