Decolorization of Azo Dyes with Enterobacter agglomerans Immobilized in Different Supports by Using Fluidized Bed Bioreactor

Abstract

Immobilized cells of Enterobacter agglomerans, able to reduce azo dyes enzymatically, were used as a biocatalyst for the decolorization of synthetic medium containing the toxic azo dye methyl red (MR). This bacterial strain exhibits high ability to completely decolorize 100 mg/L of MR after only 6 h of incubation under aerobic conditions. Cells of E. agglomerans were immobilized in calcium alginate, polyacylamide, cooper beech, and vermiculite, and were used for the decolorization of MR from synthetic water by using a fluidized bed bioreactor. The highest specific decolorization rate was obtained when E. agglomerans was entrapped in calcium alginate beads and was of about 3.04 mg MR/g cell/h with a 50% conversion time ( t(1/2)) of about 1.6 h. Moreover, immobilized cells in calcium alginate continuously decolorized MR even after seven repeated experiments without significant loss of activity, while polyacrylamide-, cooper beech-, and vermiculite-immobilized cells retained only 62, 15, and 13% of their original activity, respectively.

Degradation of immobilized azo dyes by Klebsiella sp. UAP-b5 isolated from maize bioadsorbent

“…UAP-b5 was initially supported on SOMAP2, the decolorization rate of RB5 and BB41 solutions was lower than for bacteria growing in liquid medium. In contrast, 95% of a methyl red solution [23] was decolorized by supported P. agglomerans in 6 h.…”

“…Similarly, Nigam et al [24] previously reported fungi-mediated decolorization of RB5 after 48 h and Mohanty [1] reported a reduction of 46% in the amine metabolite concentration after 48 h following a two-stage anaerobic-aerobic treatment using sludge. Following the results of Moutaouakkil et al [23], we assume that the anaerobic decolorization of the immobilized dye coincided with the growth of Klebsiella sp. UAP-b5.…”

“…Additional research on degradation of dyes has focused on joint adsorption and degradation using several different methodologies: (i) biosorption of dye from solution onto biomass [20,21]; (ii) degradation of dye by "immobilized microorganisms" that are supported on solid matter in contact with a dye that is in solution [22,23]; and (iii) dye adsorption by a moist solid substrate that is in contact with inoculated microorganisms in the absence of free water [24]. In the first two methods, efficacy is evaluated by a technique that analyzes dye concentration in solution (typically spectrophotometry).…”

Analysis of electrode microbial communities in an up-flow bioelectrochemical system treating azo dye wastewater

“…18 genera with relative abundance > 1% in the four microbial communities were shown in Table 2. Enterobacter obviously dominated in all samples (relative abundance varied from 30.61 to 40.06%) which was capable of azo dye reduction [31] as well as electricity generation [32]. Desulfovibrio presented > 5% of relative abundance in all samples and was reported to be involved in electricity generation [33] and azo dye reduction [34].…”

Les colorants textiles sources de contamination de l’eau : CRIBLAGE de la toxicité et des méthodes de traitement

“…Certaines de ces bactéries, telles que Enterobacter agglomerans (MoUTAoUAkkIL et al, 2003;MoUTAoUAkkIL et al, 2004) D'autres sont capables d'utiliser les amines aromatiques formées comme sources uniques de carbone, aboutissant ainsi à une dégradation complète ou « minéralisation » des colorants azoïques. Ces bactéries dégradent les molécules colorantes par la succession de deux étapes enzymatiques : une azoréduction, non sensible à l'oxygène, suivie d'une métabolisation à oxygène dépendant (BLüMEL et al, 1998;WoNG et yUEN, 1998).…”