A novel moderately halophilic bacterium for decolorizing azo dye under high salt condition

Abstract

Halomonas sp strain GTW was newly isolated from coastal sediments contaminated by chemical wastewater and was identified to be a member of the genus Halomonas by 16S rDNA sequence analysis and physical and biochemical tests. The optimal decolorization conditions were as follows: temperature 30 degrees C, pH 6.5.0-8.5, NaCl 10-20% (w/v) and the optimal carbon source was yeast exact. The results of experiments demonstrated that the bacteria could decolorize different azo dyes under high salt concentration conditions, and the decolorization rate of five tested azo dyes could be above 90% in 24 h. The exploitation of the salt-tolerant bacteria in the bio-treatment system would be a great improvement of conventional biological treatment systems and the bio-treatment concept.

Catalyzing denitrification of Paracoccus versutus by immobilized 1,5-dichloroanthraquinone

“…When the 1,5-dichloroanthraquinone concentration was over 25 mmol l -1 , the accelerating effect of 1,5-dichloroanthraquinone on the denitrification process was similar that of 25 mmol l -1 1,5-dichloroanthraquinone in this experiment, which might be related to the amount of nitrate reductase present. The accelerating effect by redox mediator on the denitrification was similar to the results during the decolorization of azo dye (Guo et al 2008). Different initial nitrate concentration (100-600 mg l -1 ) was conducted to study the effect of nitrate concentration on the denitrification rate with 25 mmol l -1 1,5-dichloroanthraquinone.…”

“…The morphologically distinct colonies were selected and transferred to new plates to check for purity. Then the isolated bacterium was identified by the 16 S ribosomal genomic DNA according to previous paper (Guo et al 2008). The optimum denitrification condition of the isolated bacterium was also conducted.…”

Optimization of Environmental Parameters on Microbial Degradation of Reactive Black Dye

“…It is also very likely that addition of mannitol, maltose and glucose might have switched away inoculum from the target substrate (Reactive Black). Guo et al [38] reported that bacterial strains grew well and completely decolorized K-2BP when yeast extract or peptone was present in the medium; however, glucose, glycerol, sucrose, lactose and starch resulted in lower rates of growth and decolorization of these dyes. Other researchers also have reported the maximum decolorization of azo dyes in presence of yeast extract by the bacteria they used [39].…”

“…It is very likely that all selected isolates were mesophilic bacteria because they all showed better decolorization in the temperature range of 25 to 35°C. Previously, Guo et al [38] reported optimum range of temperature of 28 to 35°C for the decolorization of dye contaminated by the inocula. The percentage of decolorization reached the highest value of 98% at 32°C.…”

Progress in decontamination by halophilic microorganisms in saline wastewater and soil

“…It has been shown that halophilic bacteria could decolorize different azo dyes under highsalt concentration conditions (Asad et al, 2007). Guo et al (2008) isolated Halomonas sp. strain GTW from the coastal sediments contaminated, and the strain GTW could grow well and completely decolorize K-2BP, with the decolorization percentage reaching the highest value (98%) at 30 C.…”