UNIVERSITY OF DAR ES SALAAM
COLLEGE OF NATURAL AND APPLIED SCIENCE
Dept: Molecular biology and biotechnology Name: Ernest Medard Reg#:2010-04-00120 Degree program: Bsc. MBB BL 390: research project TITLE: production of Laccase and Pectinase enzymes by Schizophyllum spp and its application in dye decolorization Project supervisor: Dr. R. Masalu Lab scientist: Mr. Chuwa
Due to rapid industrialization and urbanization, a lot of chemicals including dyes are manufactured and used in day-to-day life. Dyes are synthetic and aromatic molecular structural compounds. According to their dissociation in an aqueous solution, dyes can be classified as acid, direct reactive dyes (anionic), basic dyes (cationic) and disperse dyes (nonionic). They are used on several substrates in food, cosmetics, paper, plastic and textile industries. Solutions retain them by physical adsorption by making compounds with metals and salts using covalent bonds. Many chemical dyes have been used increasingly in textile and dyeing industries because of their ease and cost effectiveness in synthesis, firmness and variety in color compared to that of natural dyes. About 100,000 commercial dyes are manufactured including several varieties of dyes such as acidic, basic, reactive, azo, diazo, anthraquinone based meta complex dyes. Over 10,000 dyes with an annual production of over 7 X 105 metric tons are commercially available (Campos et al., 2001). Approximately 50% of the dyes are released in the industrial effluents (Zollinger, 1991).
Dyes are poly-aromatic molecules that give a permanently color to materials like textile fabrics (Vandevivere et al., 1998). Dyes can create an environmental problem since they resist biodegradation, and several of them and/or their degradation products are toxic (Moawad et al., 2003).Environmental regulatory agencies in several countries are adopting stringent regulations for the discharge of colored effluents from textile and dyestuff manufacturers. These dyes pose a great concern to the community, a good example is one report explaining how the cities of Kingston and Toronto (Ontario, Canada) modified their municipal by-laws in 2000 to prohibit the discharge of colored effluents to the municipal sewage (City of Kingston, 2000; City of Toronto, 2000). Laccases belong to the group of phenoloxidases; they are very common, widely distributed oxidative enzymes detected in many plants and secreted by numerous fungi. On the other hand pectinase is a general term for enzymes, such as pectolyase, pectozyme and polygalacturonase,
commonly referred to in brewing as pectic enzymes. These break down pectin, a polysaccharide substrate that is found in the cell walls of plants. The ability of the white rot fungi, shizophyllum spp to produce these enzymes has received attention in the research field. It should be known that these enzymes are able to degrade different phenolic compounds which are harmful to the environment and the biological at large. This study is therefore aiming at screening for production of laccase and pectinase enzymes from schizophyllum spp, and investigate the applicability of the enzymes in dye decolorization.
Statement of the research problem: Dye decolorization is presently one of the major areas of scientific activity. While coloured organic" compounds generally impart only a minor fraction of the organic load to the environment, (10% to 50% of the initial dye load will be present in the dye bath effluent, Vandevivere etal 1998, Moilanen etal 2010) their colour renders the environment unsafe and even the water aesthetically unacceptable. Effluent discharge from textile and dyestuff industries (leather, cosmetics food and paper printing) to neighbouring water bodies, open lands space and wastewater treatment systems is currently causing significant health concerns to environmental regulatory agencies. Colour removal, in particular, has recently become of major scientific interest, as...
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