Akhil N. Kabra

Development of a bioreactor for remediation of textile effluent and dye mixture: a plant-bacterial synergistic strategy.

The objective of the present work was to develop a plant-bacterial synergistic system for efficient treatment of the textile effluents. Decolorization of the dye Scarlet RR and a dye mixture was studied under in vitro conditions using Glandularia pulchella (Sweet) Tronc., Pseudomonas monteilii ANK and their consortium. Four reactors viz. soil, bacteria, plant and consortium were developed that were subjected for treatment of textile effluents and dye mixture. Under in vitro conditions G. pulchella and P. monteilii showed decolorization of the dye Scarlet RR (SRR) by 97 and 84%, within 72 and 96 h respectively, while their consortium showed 100% decolorization of the dye within 48 h. In case of dye mixture G. pulchella, P. monteilii and consortium-PG showed an ADMI removal of 78, 67 and 92% respectively within 96 h. During decolorization of SRR G. pulchella showed induction in the activities of enzymes lignin peroxidase and DCIP reductase while P. monteilii showed induction of laccase, DCIP reductase and tyrosinase, indicating their involvement in the dye metabolism. High Performance Liquid Chromatography (HPLC), Fourier Transform Infra Red Spectroscopy (FTIR) and High Performance Thin Layer Chromatography (HPTLC) confirmed the biotransformation of SRR and dye mixture into different metabolites. Soil, bacteria, plant and consortium reactors performed an ADMI removal of 42, 46, 62 and 93% in the first decolorization cycle while it showed an average ADMI removal of 21, 27, 59 and 93% in the next three (second, third and fourth) decolorization cycles respectively for the dye mixture within 24 h. Consortium reactor showed an average ADMI removal of 95% within 48 and 60 h for textile effluents A and B respectively for three decolorization cycles, while it showed an average TOC, COD and BOD removal of 74, 70 and 70%, 66, 72 and 67%, and 70, 70 and 66% for three decolorization cycles of the dye mixture (second, third and fourth decolorization cycles), effluent A and effluent B respectively. Degradation of the textile effluents and dye mixture into different metabolites by the consortium reactor was confirmed using HPLC and FTIR. Phytotoxicity studies revealed the non-toxic nature of the metabolites of degradation of dye mixture, effluents A and B by consortium reactor. The developed consortial reactor system performed efficient treatment of the dye mixture and textile effluents, and can be used for treating large amounts of textile effluents when implemented as a constructed wetland by proper engineering approach.

The role of Aster amellus Linn. in the degradation of a sulfonated azo dye Remazol Red: A phytoremediation strategy

Phytoremediation is a novel and promising approach for the treatment of pollutants. This study did explore the potential of Aster amellus Linn. to decolorize a sulfonated azo dye Remazol Red (RR), a mixture of dyes and a textile effluent. Induction in the activities of lignin peroxidase, tyrosinase, veratryl alcohol oxidase and riboflavin reductase was observed during RR decolorization, suggesting their involvement in the metabolism of RR. UV-Visible absorption spectrum, HPLC and FTIR analysis confirmed the degradation of RR. Four metabolites after the degradation of the dye were identified as 2-[(3-diazenylphenyl) sulfonyl] ethanesulfonate, 4-amino-5-hydroxynaphthalene-2,7-disulfonate, naphthalene-2-sulfonate and 3-(1,3,5-triazin-2-ylamino)benzenesulfonate by using GC/MS. Textile effluent and mixture of dyes showed 47% and 62% decrease respectively in American Dye Manufacturers Institute value. BOD of textile effluent and mixture of dyes were reduced by 75% and 48% respectively, COD of industrial effluent and mixture of dyes was reduced by 60% and 75% and TOC was reduced by 54% and 69% respectively after the treatment by A. amellus for 60 h; this indicated that the plant can be used for cleaning textile effluents. Toxicity study revealed the phytotransformation of RR into non-toxic products.

Differential fate of metabolism of a sulfonated azo dye Remazol Orange 3R by plants Aster amellus Linn., Glandularia pulchella (Sweet) Tronc. and their consortium

Plant consortium-AG of Aster amellus Linn. and Glandularia pulchella (Sweet) Tronc. showed complete decolorization of a dye Remazol Orange 3R in 36 h, while individually A. amellus and G. pulchella took 72 and 96 h respectively. Individually A. amellus showed induction in the activities of enzymes veratryl alcohol oxidase and DCIP reductase after degradation of the dye while G. pulchella showed induction of laccase and tyrosinase, indicating their involvement in the dye metabolism. Consortium-AG showed induction in the activities of lignin peroxidase, veratryl alcohol oxidase, laccase, tyrosinase and DCIP reductase. Two different sets of induced enzymes from A. amellus and G. pulchella work together in consortium-AG resulting in faster degradation of the dye. The degradation of the dye into different metabolites was confirmed using High Performance Liquid Chromatography and Fourier Transform Infra Red Spectroscopy. Gas Chromatography Mass Spectroscopy analysis identified four metabolites of dye degradation by A. amellus as acetamide, benzene, naphthalene and 3-diazenylnaphthalene-2-sulfonic acid, four metabolites by G. pulchella as acetamide, 3-diazenyl-4-hydroxynaphthalene-2-sulfonic acid, naphthalen-1-ol and (ethylsulfonyl)benzene, while two metabolites by consortium-AG as 2-(phenylsulfonyl)ethanol and N-(naphthalen-2-yl)acetamide. The non-toxic nature of the metabolites of Remazol Orange 3R degradation was revealed by phytotoxicity studies.

Phytoremediation potential of Portulaca grandiflora Hook. (Moss-Rose) in degrading a sulfonated diazo reactive dye Navy Blue HE2R (Reactive Blue 172).

Wild and tissue cultured plants of Portulaca grandiflora Hook. have shown to be able to decolorize a sulfonated diazo dye Navy Blue HE2R (NBHE2R) up to 98% in 40 h. A significant induction in the activities of lignin peroxidase, tyrosinase and DCIP reductase was observed in the roots during dye decolorization. The wild plants and tissue cultures could independently decolorize and degrade NBHE2R into metabolites viz. N-benzylacetamide and 6-diazenyl-4-hydroxynaphthalene-2-sulfonic acid. A dye mixture and a textile effluent were also decolorized efficiently by P. grandiflora. The phytotoxicity study revealed reduction in the toxicity due to metabolites formed after dye degradation.

Phytoremediation of textile effluent and mixture of structurally different dyes by Glandularia pulchella (Sweet) Tronc.

Plants of Glandularia pulchella (Sweet) Tronc. performed decolorization of structurally different dyes to varying extent because of induction of different set of enzymes in response to specific dyes. Differential pattern of enzyme induction with respect to time was obtained for lignin peroxidase, veratryl alcohol oxidase, tyrosinase and dichlorophenolindophenol reductase during the decolorization of dye mixture, whose combined action resulted in greater and faster decolorization of dyes. HPLC, FTIR and High Performance Thin Layer Chromatography (HPTLC) analysis confirmed degradation of dyes from textile effluent and mixture. HPTLC demonstrated progressive decolorization of dye mixture along with preferential degradation of the dyes. G. pulchella showed reduction in American Dye Manufacturers Institute from 405 to 21 and 418 to 22, in case of textile effluent and mixture of dyes respectively. The non-toxic nature of the metabolites of degraded textile dye effluent and mixture of dyes was revealed by phytotoxicity studies.

Phytoremediation of a sulphonated azo dye Green HE4B by Glandularia pulchella (Sweet) Tronc. (Moss Verbena)

PurposeThe dyes and dye stuffs present in effluents released from textile dyeing industries are potentially mutagenic and carcinogenic. Phytoremediation technology can be used for remediating sites contaminated with such textile dyeing effluents. The purpose of the work was to explore the potential of Glandularia pulchella (Sweet) Tronc. to decolorize different textile dyes, textile dyeing effluent, and synthetic mixture of dyes.MethodsEnzymatic analysis of the plant roots was performed before and after decolorization of dye Green HE4B. Analysis of the metabolites of Green HE4B degradation was done using UV–Vis spectroscopy, high-performance liquid chromatography (HPLC), Fourier transform infrared spectroscopy (FTIR), and gas chromatography–mass spectroscopy (GC-MS). The ability of the plant to decolorize and detoxify a textile dyeing effluent and a synthetic mixture of dyes was studied by a determination of the American Dye Manufacturer’s Institute (ADMI), biological oxygen demand (BOD), and chemical oxygen demand (COD). Phytotoxicity studies were performed.ResultInduction of the activities of lignin peroxidase, laccase, tyrosinase, and 2,6-dichlorophenol indophenol reductase was obtained, suggesting their involvement in the dye degradation. UV–Vis spectroscopy, HPLC, and FTIR analysis confirmed the degradation of the dye. Three metabolites of the dye degradation were identified, namely, 1-(4-methylphenyl)-2-{7-[(Z)-phenyldiazenyl] naphthalen-2-yl} diazene; 7,8-diamino-2-(phenyldiazenyl) naphthalen-1-ol; and (Z)-1,1′-naphthalene-2,7-diylbis (phenyldiazene) using GC-MS. ADMI, BOD, and COD values were reduced. The non-toxic nature of the metabolites of Green HE4B degradation was revealed by phytotoxicity studies.ConclusionThis study explored the phytoremediation ability of G. pulchella (Sweet) Tronc. in degrading Green HE4B into non-toxic metabolites.

Degradation of Remazol Red Dye by Galactomyces geotrichum MTCC 1360 Leading to Increased Iron Uptake in Sorghum vulgare and Phaseolus mungo from Soil

Removal of azo dyes from the effluent generated by textile industries is rather difficult. Azo dyes represent a major class of synthetic colorants that are both mutagenic and carcinogenic. Galactomyces geotrichum MTCC 1360, a yeast species, showed more than 96% decolorization of the azo dye Remazol Red (50 mg/L) within 36 h at 30°C and pH 11.0 under static condition with a significant reduction in the chemical oxygen demand (62%) and total organic carbon (41%). Peptone (5.0 g/L), rice husk (10 g/L extract), and ammonium chloride (5.0 g/L) were found to be more significant among the carbon and nitrogen sources used. The presence of tyrosinase, NADH-DCIP reductase, riboflavin reductase and induction in azo reductase and laccase activity during decolorization indicated their role in degradation. High performance thin layer chromatography analysis revealed the degradation of Remazol Red into different metabolites. Fourier transform infrared spectroscopy and high performance liquid chromatography analysis of samples before and after decolorization confirmed the biotransformation of dye. Atomic absorption spectroscopy analysis revealed a less toxic effect of the metabolites on iron uptake by Sorghum vulgare and Phaseolus mungo than Remazol Red dye. Remazol Red showed an inhibitory effect on iron uptake by chelation and an immobilization of iron, whereas its metabolites showed no chelation as well as immobilization of iron. Phytotoxicity study indicated the conversion of complex dye molecules into simpler oxidizable products which had a less toxic nature.

Biodegradation of Rubine GFL by Galactomyces geotrichum MTCC 1360 and subsequent toxicological analysis by using cytotoxicity, genotoxicity and oxidative stress studies

Galactomyces geotrichum MTCC 1360 showed 87 % decolorization of the azo dye Rubine GFL (50 mg l(-1)) within 96 h at 30 °C and pH 7.0 under static conditions, with significant reduction of chemical oxygen demand (67 %) and total organic carbon (59 %). Examination of oxidoreductive enzymes, namely laccase, tyrosinase and azo reductase, confirmed their role in decolorization and degradation of Rubine GFL. Biodegradation of Rubine GFL into different metabolites was confirmed using high-performance TLC, HPLC, Fourier transform IR spectroscopy and GC-MS analysis. During toxicological studies, cell death was observed in Rubine GFL-treated Allium cepa root cells. Toxicological studies before and after microbial treatment were done with respect to cytotoxicity, genotoxicity, oxidative stress, antioxidant enzyme status, protein oxidation and lipid peroxidation using root cells of A. cepa. The analysis with A. cepa showed that the dye exerts oxidative stress and subsequently has a toxic effect on the root cells, whereas its metabolites are less toxic. Phytotoxicity studies revealed the less toxic nature of the metabolites as compared with Rubine GFL.