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Title of Thesis

Naeem Ali
Institute/University/Department Details
Department of Microbiology/ Quaid-i-Azam University of Islamabad
Number of Pages
Keywords (Extracted from title, table of contents and abstract of thesis)
textile dyes, indigenous microorganisms, xenobiotics compounds, fungi, bacteria, microbially rich sludge, textile effluents

Textile dyes have always been considered in the context of recalcitrant xenobiotics compounds in water and soil ecology. Present research work is focused on the bioremediation abilities of different indigenous biological resources like fungi, bacteria and microbially rich sludge for the treatment of Textile dyes.

Physiochemical characterization of effluent of a local textile industry at three different sites showed a considerably high values of temperature (40°C), pH (9.50), EC (3.57µs/m), BOD (548 mg-l), COD (1632 mg-l), TSS (5496 mg-l), TDS (2512 mg-l), heavy metal ions (0.28-6 mg-l) and color compared to the desired values of National Environmental Quality Standards. However, a gradual decline in almost all pollution indicators down the stream (sink) suggested that natural remediation was at work.

Fungal (9 No) and bacterial strains (10 No) were isolated from the textile wastewater pond. Based upon initial screening on the basis of their growth on dye containing media, five fungal isolates were selected and further adapted to higher concentration (10-1000 mg-l) of four structurally different dyes [Acid red (AR) 151 (Diazo), Orange (Or) II (Monoazo), Drimarene blue (Db) K2RL (Reactive anthraquinone based) and Sulfur black (Sb) (Anthraquinone based)] on solid culture medium. Different levels of resistance (550-850 mg-l) for growth on dye containing media were observed by fungal isolates on the four dyes. However, maximum resistance level was shown by Aspergillus niger SAl against AR 151.

When dye decolorization in liquid media was tested for all the four dyes under static condition, maximum result was observed in case of AR 151 (68 %) and Or 11 (44 %) by A. niger SAL While, Penicillium spp. SA5 for Sb , Alternaria spp. SA4 and A. tereus SA3 for Db K2RL showed maximum decolorization of 59, 43 and 42 % respectively. Decolorization efficiency of the fungal isolates was significantly improved (45-100 %) under shaking condition (100 rpm). Further, the residual amount of the products (sulfanilic acid, a. naphthol and aniline) in the treatment of AR 151 and Or II by selected fungal isolates kept quite low suggested their further mineralization.

Physicochemical conditions also showed their effects on the dye decolorization abilities of the fungal strains. Maximum decolorization of dyes was noted in a pH range of 5-7, in mesophilic temperature (25-35oC) conditions. It kept ‰50-‰ 100 % at 100-400 mg-1 of dyes, 6-10 mg-1 of glucose and 0.1-0.5 mg-1 of urea concentration in the mineral salt medium (STE). Enhanced decolorization/degradation of dyes (70-100 %) with significant removal of CODs was observed by applying pregrown fungal biomass (dry/live wet) in repeated batch and continuous mode.

Out of ten bacterial isolates, Lactobacillus spp. N3A, Bacillus subtilis N4A, Micrococcus spp. N5A, Bacillus spp. N6A and Bacillus megaterium N7 A showed comparatively higher resistance levels against four dyes (337-537 mg-1). Highest growth resistance against AR 151 (750 mg-1), Db K2RL (600 mg-1) and Sb (450 mg-1) was observed by Bacillus subtilis N4A and against Or II (650 mg-1) by Bacillus megaterium N7A. The average decolorization abilities of the bacterial isolates for four dyes was 25-46 % under static condition (anoxic) in 8 days and it considerably improved in most of the bacterial isolates after addition of yeast extract(1 %) in STE. Based upon initial screening, selected bacterial isolates Bacillus subtilis N4A, E. coli NIOA and consortium (of ten bacterial isolates) were further trailed in decolorization of AR 151 and Or II under aerobic condition. A comprehensive mineralization of AR 151 and Or II was observed by bacterial consortium.

Actual and Simulated textile effluents were treated aerobically with sludge in a rotatory bioreactor (30°C) for 10 days. COD, BOD and color removal were 52, 84, 83 % and 74, 48,43 % in actual effluent and simulated effluent respectively. However, the results were further improved to permissible limits of National Environmental Quality Standards with sludge inocula enriched and pretreated with glucose for 24 hrs before use.

Results of present study have significantly proved the role of indigenous microbial strains (bacteria/fungi) in the bioremediation of Textile dyes. Decolorization of dyes by the fungal isolates showed a three stage phenomenon. Initial biosorption/bioadsorption of dyes (1st step) into/onto the fungal mycelia, followed with reduction (2nd step) and then mineralization of reduction products of dyes (3rd step). Further studies on metabolic understanding and application of these microbial isolates as bioremediation agents could be of much interest in future.

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6752.84 KB
S. No. Chapter Title of the Chapters Page Size (KB)
1 0 Contents
616.72 KB
2 1 General Introduction 1
707.15 KB
  1.1 Water Pollution And Its Effects 1
  1.2 Environmental Challenges In Pakistan 1
  1.3 Textile Industry And Pakistan 3
  1.4 Textile Effluents 4
  1.5 Dyes 4
  1.6 Techniques Used For The Removal Of Dyes 16
  1.7 Research Objectives & Thesis Outline 25
3 2 Review Of Literature 25
1118.09 KB
  2.1 Textile Industry And Its Affects 25
  2.2 Biotechnological Approaches For The Treatment Of Textile Dyes 25
  2.3 Microbes From Different Source Used In Decolorization / Degradation Of Dyes 29
4 3 Experimental 58
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  3.1 Characterization Of Kohinoor Textile Mill Effluent 58
  3.2 Isolation And Characterization Of Fungal Strains For The Decolorization Of Textile Dyes 63
  3.3 Effect Of Different Physicochemical Factors On The Decolorization / Degradation Of Dyes By Different Fungal Isolates 92
  3.4 Screening Of Different Bacterial Isolates For The Aerobic Decolorization Of Textile Dyes Under Different Operational Conditions 127
  3.5 Application Of Different Biological Techniques For The Treatment Of Textile Dyes And Effluents 145
5 4 Discussion 181
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  4.1 Characterization Of The Kohinoor Textile Mill (KTM) Effluents 181
  4.2 Application Of Different Fungal Isolates For The Decolorization / Degradation Of Dyes 183
  4.3 Effects Of Physicochemical Factors On Decolorization / Degradation Of Dyes By Different Fungal Isolates 186
  4.4 Application Of Pregrown Biomass Of Different Fungi On The Decolorization / Degradation Of Dyes Under Different Conditions 190
  4.5 Decolorization Of Colored Simulated Textile Effluent By Different Inoculum Preparation (Slurry) Of Penicillium Spp . Sa5 And Sawdust 193
  4.6 Treatment Of Textile Effluent By Sludge Under Aerobic Conditions 194
  4.7 Aerobic Decolorization / Degradation Of Dyes Bacteria Under Different Operational Conditions 196
6 5 Conclusion 201
81.93 KB
7 6 Future Prospects And Suggestions 204
45.51 KB
8 7 References 205
794.24 KB
9 8 Appendix 229
180.96 KB