full issue - Association of Biotechnology and Pharmacy

More documents

Recommendations

Info

Current Trends in Biotechnology and Pharmacy Vol. 5 (3) 1273 -1281 July 2011, ISSN 0973-8916 (Print), 2230-7303 (Online) 1273 Simple Approach to Reactive Dye Decolorization Using Trichosanthes dioica Proteins at Low Concentration of 1-hydroxybenzotriazole Farrukh Jamal Department of Biochemistry, Dr. Ram Manohar Lohia Avadh University, Faizabad-224001, U.P., India For Correspondence - journal.farrukh@gmail.com Abstract Enzymatic catalysis in the presence of redox mediators has emerged as an effective and feasible technique for degradation of complex structural compounds. We investigated peroxidase from Trichosanthes dioica to study decolorization of reactive dyes namely Reactive Blue15 (RB15) and Reactive Red4 (RR4) under different experimental conditions like pH, temperature, time interval, enzyme concentration and in the presence of redox mediators. Six different redox mediators; syringaldehyde, guaiacol, 1-hydroxy-benzotriazole (HOBT), vanillin, bromophenol and quinol were simultaneously evaluated. T. dioica peroxidase showed remarkable decolorization of reactive dye in the presence of 1-hydroxybenzotriazole. At an enzyme concentration of 0.45 EUmL -1 the peroxidase decolorized Reactive Red15 almost completely up to a maximum of 98.6% whereas Reactive Red4 decolorized upto 68.2% with 1.0 mM 1-hydroxybenzotriazole. Maximum decolorization was recorded at a temperature range of 40°C to 50°C at pH 5.0. Time activity plot exhibited maximum decolorization at 90 min and 180min for RB15 and RR4 respectively. It can be concluded that T. dioica peroxidase could be a potential source for developing an inexpensive and efficient method for the treatment of recalcitrant reactive dyes that are potentially toxic or even carcinogenic. Key words: Reactive Dyes; 1-hydroxybenzotriazole; Decolorization; Trichosanthes dioica Peroxidase Introduction Commercially available synthetic dyes are not only growing in number but their application spectrum is also widening. Dyes released from textile industries pose a serious threat to all forms of life. Thus, there is a great environmental concern about the fate of these unbound compounds (1). These discharged dyes form toxic products, while their strong color causes turbidity which even at very low concentrations alters the aquatic environment. Effluents from the textile industries containing dye are highly coloured and are therefore visually identifiable (2). These synthetic reactive dyes bond covalently with fabric and contain chromophoric groups like anthraquinone, azo, triarylmethane etc. along with reactive group’s viz., vinyl sulphone, chlorotriazine, trichloropyrimidine etc.(3,4). The complex aromatic structure of the dyes is resistant to light, biological activity, ozone and other degradative environmental conditions. This renders conventional waste water treatment ineffective. Anionic and non-ionic azo dyes release toxic amines due to the reactive cleavage of azo groups (5). Till date scientists have been trying to develop a single and economical method Simple approach to reactive dye decolorization
Current Trends in Biotechnology and Pharmacy Vol. 5 (3) 1273 -1281 July 2011, ISSN 0973-8916 (Print), 2230-7303 (Online) 1274 for the treatment of dyes in the textile waste water but it still remains a big challenge (6).Various physico-chemical methods pertaining to treatment of textile wastewater for removal of dye has been studied (7,8,9). The major disadvantage associated are their high cost, low efficiency, limited versatility, interference by other wastewater constituents and handling of the waste generated. Decolorization of dye wastewater is an area where innovative treatment technologies should be investigated. The focus in recent times has shifted towards enzyme based treatment of colored wastewater/industrial effluents. Bioremediation is a viable tool for restoration of contaminated subsurface environments. It is gaining importance due to its cost effectiveness, environmental friendliness and production of less sludge as compared to chemical and physical decomposition processes. The redox mediated enzyme catalysis has wide application in degradation of polycyclic aromatic hydrocarbons which includes phenols, biphenyls, pesticides, insecticides etc. (10, 11). The plant of our interest Trichosanthes dioica commonly known as pointed gourd is widely planted and abundantly available in tropical areas. The aim of the present study was to evaluate the effectiveness of peroxidase from Trichosanthes dioica in decolorizing industrially important reactive dyes under varying experimental conditions of pH, temperature, time interval and enzyme concentration. Materials and methods Dyes and Chemicals : The reactive dyes namely Reactive Blue 15 (RB15) Reactive Red 4 (RR 4), ammonium sulphate, and Tween -20 were procured from Sigma Chemical Co. (St. Louis, MO, USA) and all other chemicals were of analytical grade. Redox mediator’s viz., syringaldehyde, guaiacol, 1- hydroxybenzotriazole (HOBT), vanillin, bromophenol, and quinol were obtained from SRL Chemicals (Mumbai, India). The pointed gourds were purchased from the local market. Partial purification of T. dioica by ammonium sulphate precipitation : A 100 g of T. dioica fruit pulp was homogenized in 200 mL of 100mM sodium acetate buffer, pH 5.6. The homogenate was filtered through four layers of cheesecloth and then centrifuged at the speed of 10,000 × g on a Remi C-24 Cooling Centrifuge for 25 min at 4°C. By adding 20-80% (w/v) of ammonium sulphate, salt fractionation was carried out with the clear supernatant. The content was stirred overnight to get maximum precipitate at 4 o C. The precipitate was collected by centrifugation at 10,000 × g on a Remi C-24 Cooling Centrifuge, dissolved in 100mM sodium acetate buffer, pH 5.6 and dialyzed against the assay buffer (12). T. dioica peroxidase activity assay : Protein concentration was estimated by taking BSA as a standard protein and following the procedure of Lowry et al (1951) (13). Peroxidase activity was determined by a change in the optical density (A 460 nm) at 37°C by measuring the initial rate of oxidation of 6.0 mM o-dianisidine HCl in the presence of 18.0 mM H 2 O 2 in 0.1 M glycine- HCl buffer, pH 4.0, for 20 min at 37°C. One unit of peroxidase activity was defined as the amount of enzyme protein that catalyzes the oxidation of o-dianisidine-HCl in the presence of H 2 O 2 into 1.0 µmol of chromophoric complex (ε m = 30,000 M -1 cm -1 ) per min at 37 °C (12). Preparation and treatment of reactive dye solution : The reactive dyes were prepared in 0.1 M glycine HCl buffer, pH 4.0. RB15 and RR4 were independently incubated with pointed gourd peroxidase (PGP) (0.45 EUmL -1 ) in 0.1M glycine HCl buffer, pH 4.0 in the presence of 0.8 mM Farrukh Jamal
Page 3 and 4:
ISSN 0973-8916 Current Trends in Bi
Page 5 and 6:
Current Trends in Biotechnology and
Page 7 and 8:
Page 9 and 10:
Page 11 and 12:
Page 13 and 14:
Page 15 and 16:
Page 17 and 18:
Page 19 and 20:
Page 21 and 22:
Page 23 and 24: Current Trends in Biotechnology and
Page 61 and 62: β Current Trends in Biotechnology
Page 73: Current Trends in Biotechnology and
Page 125 and 126:
Page 127 and 128:
Page 129 and 130:
Page 131 and 132:
Page 133 and 134:
Page 135 and 136:
Page 137 and 138:
Page 139 and 140:
Page 141 and 142:
Page 143 and 144:
Page 145 and 146:
Page 147 and 148:
Page 149 and 150:
Page 151 and 152:
Page 153 and 154:
Page 155 and 156:
Page 157 and 158:
Page 159 and 160:
Page 161 and 162:
Page 163 and 164:
Page 165 and 166:
Page 167 and 168:
Page 169 and 170:
Page 171 and 172:
Page 173 and 174:
Page 175:
(December 7-9, 2011) Venue: Karunya
show all

full issue - Association of Biotechnology and Pharmacy

You also want an ePaper? Increase the reach of your titles

Delete template?

Save as template?