Environmental pollution has been recognized as one of the major problems of the modern world. The increasing demand for water and the dwindling supply has made the treatment and reuse of industrialeffluents an attractive option. Textile effluents are of concern because they colour the drains and ultimately the water bodies. They also diminish the water quality. The ability of microorganisms todegrade and metabolize a wide variety of compounds has been recognized and exploited in various biotreatment processes. This study investigated the potential of bacteria isolated from textile industrieswastewater and drains (textile effluent adapted bacteria) and isolates from a municipal landfill (effluent non-adapted bacteria). We discovered effluent adapted strains of Acinetobacter, Bacillus and Legionellawith potentials for colour removal and strains of Acinetobacter, Bacillus and Pseudomonas with chemical oxygen demand (COD) removal activities. Only strains of Bacillus with potentials for use incolour and COD removal were isolated from the landfill. Plasmid screening did not reveal the presence of plasmids in the isolates. Thus the involvement of extra-chromosomal genes is not suggested. Inconclusion, as a preliminary step in the development of textile effluent biotreatment using indigenous microbes, we have discovered some strains with potency to decolourize and/or remove COD

Gbenle, GO

Olukanni, OD

Osuntoki, AA

English

AJOL - African Journals Online

  African Journal of Biotechnology Vol. 5 (20), pp. 1980-1984, 16 October 2006 Available online at http://www.academicjournals.org/AJB ISSN 1684–5315 © 2006 Academic Journals      Full Length Research Paper  Textile effluent biodegradation potentials of textile effluent-adapted and non-adapted bacteria  Olukanni O. D.*, Osuntoki, A. A. and Gbenle, G. O.  Department of Biochemistry, College of Medicine, University of Lagos. PMB 12003, Lagos Nigeria  Accepted 29 June, 2006  Environmental pollution has been recognized as one of the major problems of the modern world. The increasing demand for water and the dwindling supply has made the treatment and reuse of industrial effluents an attractive option. Textile effluents are of concern because they colour the drains and ultimately the water bodies. They also diminish the water quality. The ability of microorganisms to degrade and metabolize a wide variety of compounds has been recognized and exploited in various biotreatment processes. This study investigated the potential of bacteria isolated from textile industries wastewater and drains (textile effluent adapted bacteria) and isolates from a municipal landfill (effluent non-adapted bacteria). We discovered effluent adapted strains of Acinetobacter, Bacillus and Legionella with potentials for colour removal and strains of Acinetobacter, Bacillus and Pseudomonas with chemical oxygen demand (COD) removal activities. Only strains of Bacillus with potentials for use in colour and COD removal were isolated from the landfill. Plasmid screening did not reveal the presence of plasmids in the isolates. Thus the involvement of extra-chromosomal genes is not suggested. In conclusion, as a preliminary step in the development of textile effluent biotreatment using indigenous microbes, we have discovered some strains with potency to decolourize and/or remove COD.  Key words: Textile effluent, dyes, biodegradation, decolourization, COD removal.   INTRODUCTION  Industrialization is vital to a nation’s economy because it serves as a vehicle for development. However, there are associated problems resulting from the introduction of industrial waste products into the environment. Many of these products are problematic because of persistence (low biodegradability) and/or toxicity. The textile industries produce effluents that contain several types of chemicals such as dispersants, leveling agents, acids, alkalis, carriers and various dyes (Cooper, 1995.). In many Nigerian cities, the textile factories daily discharge millions of litres of untreated effluents in the forms of wastewater into public drains that eventually empty into rivers (Olayinka and Alo, 2004). This alters the pH, increases the biochemical oxygen demand (BOD) and  chemical  oxygen  demand  (COD),  and  gives   the    *Corresponding authors E-mail: olukannio@run.edu.ng, Tel: 2348059360929. rivers intense colourations (Ajayi and Osibanjo, 1980). The use of these water resources is limited and the eco-system is affected.  Several methods are used in the treatment of textile effluents to achieve decolourization. These include phy-siochemical methods such as filtration, specific coagula-tion, use of activated carbon and chemical flocculation. Some of these methods are effective but quite expensive (Do et al., 2002; Maier et al., 2004). Biotreatment offers a cheaper and environmentally friendlier alternative for colour removal in textile effluents. The ubiquitous nature of bacteria makes them invaluable tools in effluent biotreatment. The chemical nature of dyes varies, but azo dyes are the most widely used.  The oxidative decolourizations of dyes of several classes have been reported and azo dyes were found to be the most recalcitrant compounds. (Maeir et al., 2004). The decolourization of azo dyes has been found to be effective under anaerobic conditions.        However, the anaerobic degradation yields aromatic amines which are mutagenic and toxic to humans and cannot be metabolized further under the conditions which generated them (Chung and Stevens, 1993; Do et al., 2002). In activated sludge treatments of dye effluents, reactive azo dyes and aromatic amino derivatives are a non-biodegradable class of compounds which can even inhibit activated sludge organism (Maeir et al., 2004).  It is thus important to explore the possibilities of isolating efficient aerobic degraders for use in decolourization and biotreatment of textile effluents. In a bid to exploit the biodegradation abilities of our indigenous microbial flora for remediative purposes, we isolated and screened organisms for the ability to decolourize and/or reduce the COD of textile effluents. The isolates were also screened for plasmids in order to determine the contribution of extra-chromosomal genetic factors to the degradative ability. The study is aimed at discovering isolates with the potential for use in biological treatment of textile effluents.   MATERIALS AND METHODS  Materials  All chemicals used are of analytical grade.  The reactive dyes used: Orange P3R, Yellow P3R, Blue H5R, Violet P3R, Brown P5R, Black V3R, Orange P2R were kindly donated by one of the textile companies whose effluent was used as a source of effluent adapted bacteria.   Sterilization techniques  All glasswares were washed with detergent, rinsed thoroughly with distilled water and oven sterilized at 80oC for 2.5 h.  All polypropylene tubes and tips used as well as media and solutions prepared were sterilized by autoclaving at 121oC for 15 - 25 min.  Inoculations were done with flame sterilized loops and all experiments were performed wearing sterile disposable hand gloves.   Sources of organisms  Textile effluent-adapted bacteria were isolated from effluent samples collected from the discharge and drainage pipes of three textile industries in the Oshodi/Isolo Local Government area of Lagos, Nigeria. The textile effluent non-adapted bacteria were isolated from soil samples taken from a municipal landfill.  All isolations were done on nutrient agar using enrichment culture techniques and the organisms identified to the generic level using the Cowan and Steel Scheme (1993).   Preparation of simulated effluent  A stock dye solution was prepared with 80 mg of each of the seven dyes used per L; giving a concentration of 5.6 g dyes mix/L. To prepare the simulated effluent the stock solution was supplemented with modified minimal medium (Mills et al., 1978) to get a final conc- Olukanni et al.      1981    entration of 56 mg/L.   Determination of biodegradation activity  Potential decolourization and COD removal of the simulated effluent by each isolate were investigated.  Into 20 ml simulated effluent 2 x 105 cfu of the isolate was added in transparent bottles (200 mg/L starch and 250 mg/L yeast extract were added as co-substrates) and cocked with sterile cotton wool.  After 14 days decolourization and COD removal were measured. Decolourization was determined by measuring the absorbance of the simulated effluent at the effluent pre-determined λ max (485 nm) and the absorbance of the treated simulated effluent.  The % decolourization was calculated as [(Ao – At)/Ao]   x 100%, Where Ao is absorbance of the simulated effluent and At the absorbance of the treated simulated effluent 14 days post microbial innoculation. The COD of the simulated and treated effluents were determined by a standard spectroscopic method (APHA, 1980).   Plasmid screening  The isolates were screened for plasmids using the plasmid isolation technique described by Kado and Liu (1981) followed by electrophoresis on 0.8% agarose gels. The gels were stained with ethidium bromide and viewed on a UV transilluminator.   RESULTS  Source and identity of isolates  A total of 24 isolates were obtained; eighteen organisms belonging to the genera, Bacillus, Acinetobacter, Legionella, Staphylococcus and Pseudomonas were isolated from the textile effluents (effluent-adapted bacteria) while six isolates belonging to the genus Bacillus were isolated from the landfill site (effluent non-adapted isolates). The sources and identity of the isolates are shown on Table 1.   Biodegradation  The majority of the effluent adapted isolated showed colour-removing activities between 40.74 and 47.73% while the others had activities of between 17.91 and 36.69%. For the effluent adapted bacteria, isolates of Acinetobacter, Legionella and Bacillus may be potentially useful in decolourization processes, whereas the six non-adapted Bacillus isolates seem to be potentially useful (Table 2). The non-adapted isolates had decolourization activities of between 40.25 and 46.63% (Table 2). This was similar to that of the majority of the effluent adapted organisms.  The non-adapted Bacillus isolates had a relatively higher mean % COD removal when compared to the adapted microbes of the same species (Table 3) or to the mean % COD removal for all the adapted isolates (Table 4). Only effluent-adapted isolates of Acinetobacter, Pseu-domonas  and  Bacillus species have relatively high COD   1982           Afr. J. Biotechnol.    Table 1: Source and identity of bacteria isolates.  LAB. # Grams reaction Shape Aerobic growth MacConkey growth Lactose fermentation Endospore Motility Catalase Oxidase Identity (Genus) T1 - S + + + - - + - Acinetobacter T2 - S + + + - - + - Acinetobacter T3 - R + + - - + - + Legionella T4 + R + + + + + + - Bacillus T5 - R + + - - + + + Pseudomonas T6 + S + + + - - + - Staphylococcus T7 + R + + + + + + - Bacillus T8 + R + + - + - + - Bacillus T9 + S + + + - - + - Staphylococcus T10 - R + + + + - + w Bacillus T11 + R + + + - + + - Bacillus T12 - S + + + - - + - Acinetobacter T13 - R + + + + - + - Bacillus T14 + R + + - + - + - Bacillus T15 + R + + + - - + - Bacillus T16 - R + + - + - + - Bacillus T17 + R + - ND + + + - Bacillus T18 + R + - ND - + + - Bacillus N1 + R + + + ND + + - Bacillus N2 + R + + + ND + + - Bacillus N3 + R + + + ND + + + Bacillus N4 + R + + + ND + + - Bacillus N5 + R + - ND ND + ND - Bacillus N6 + R + - ND ND + ND - Bacillus  +  Positive -           Negative w    weak reaction ND  Not determined R     Rod shape S     Spherical T     Textile adapted strains N  Non – adapted strains     removal activities while all the non-adapted isolates have high COD removal capabilities (Table 3).   Plasmid screening  Plasmids were not detected in any of the isolates from the effluent adapted or non-adapted sources.   DISCUSSION  The textile industries are multi-chemical utilizing concerns of which dyes of various types are of importance.  During the dyeing process a substantial amount of dyes and other chemicals are lost in the waste water.  Estimates put the dye losses at between 10–15% (Vaidya and Datye, 1982). Though not generally toxic to the environ-ment, dyes colour water bodies and may hinder light penetration thereby affecting aquatic life and limiting the utilization (Ajayi and Osibanjo, 1980; Goncalves et al., 2000). It has been reported that a typical textile effluent contains a dye mass concentration of 10–50 mg/L (Clarke and Anliker, 1980). However, the human eye can detect levels as low as 0.005 mg/L of reactive dyes in a clear river (Pierce, 1994). In our study a simulated efflu-ent with a dye mass of 56 mg/L was used. The simulated effluent was supplemented with starch and yeast extract to provide nutrients for biomass maintenance and to enhance biodegration (Do et al., 2002, Padmavathy et al., 2003).   Olukanni et al.      1983    Table 2. Biodegradation of simulated textile effluent under aerobic condition.                                  Table 3. Mean biodegradative activities of the isolated genera.  Genus N % COD removal # % Decolourization# Acinetobacter 3 46.60 ± 4.03 47.36 ± 0.31 Bacillus      T - Strains 11 42.40 ± 4.92 41.13 ± 1.69      N - Strains 6 55.89 ± 1.70 43.95 ± 0.91 *Pseudomonas 1 42.00 36.69 *Legionella 1 28.23 46.50 Staphylococcus 2 30.35 ± 8.79 26.75 ±  8.86  T Textile effluent adapted N Non – adapted # values in Mean ± SEM *1 strain each    This study discovered effluent adapted strains of Acinetobacter, Bacillus and Legionella with potentials for colour removal and strains of Acinetobacter, Bacillus and Pseudomonas with potential use for COD removal (Table 2). The municipal landfill site soils yielded strains of bacillus with potentials for use in colour and COD remov-al (Table 2). This may be due to the significant exposure of these organisms to a myriad of chemicals and mate-rials some of which contain dyes which are deposited in the landfill which may cause a release of dyes to the soil. The results suggest that the non-adapted bacillus species have a relatively higher potential use than the textile effluent adapted isolates (Table 4). Reports how-ever indicate that though several microorganisms may  COD mgl-1 Lab. # Identity (Genus) Initial Final % Removal % Decolourization T1 Acinetobacter 1038 474 54.35 47.61 T2 Acinetobacter 1038 575 44.61 46.75 T3 Legionella 1038 745 28.23 46.50 T4 Bacillus 1038 788 24.08 47.24 T5 Pseudomonas 1038 602 42.00 36.69 T6 Staphylococcus 1038 632 39.11 35.58 T7 Bacillus 1038 618 40.46 34.72 T8 Bacillus 1038 800 22.93 31.29 T9 Staphylococcus 1038 814 21.58 17.91 T10 Bacillus 1038 832 19.85 35.83 T11 Bacillus 1038 511 50.77 36.69 T12 Acinetobacter 1038 614 40.85 47.73 T13 Bacillus 1038 726 30.06 44.79 T14 Bacillus 1038 625 39.79 43.07 T15 Bacillus 1038 415 60.02 46.99 T16 Bacillus 1038 378 63.58 44.54 T17 Bacillus 1038 452 56.45 40.74 T18 Bacillus 1038 432 58.38 46.50 N1 Bacillus 1038 420 59.54 44.05 N2 Bacillus 1038 414 60.12 44.29 N3 Bacillus 1038 520 49.90 42.82 N4 Bacillus 1038 495 52.31 40.25 N5 Bacillus 1038 432 58.38 45.64 N6 Bacillus 1038 466 55.11 46.63   1984           Afr. J. Biotechnol.    Table 4. Mean biodegradative activities of textile effluent adapted and non-adapted bacteria.   Strain N % COD removal % Decolourization T - Strains 18 40.95 ± 3.35 40.62 ± 1.85 N – Strains 6 55.89 ± 1.70 43.95 ±  0.91   seem to have a potential for dye degradation, very few strains can withstand the conditions of dyeing effluents (Maeir et al., 2004); thus the effluent-adapted strains may be better candidates for potential bioremediative uses. However, our result does not indicate the involvement of extra-chromosomal genes in the degradative activity of the isolates. In conclusion, as a preliminary step in the development of textile effluent biotreatment processes involving indige-nous microbes, we have discovered textile effluent adapted strains of Acinetobacter and Bacillus, and efflu-ent non-adapted Bacillus species with potential use in effluent treatment.   ACKNOWLEDGEMENTS  The authors are grateful to Mr. Simeon of Atlantic Textile Mills (ATM), Oshodi and Staff of the Biotechnology Laboratory of Nigerian Institute of Medical Research (NIMR), Yaba, Lagos.   REFERENCES  Ajayi SO, Osibanjo O (1980). The state of environment in Nig. Pollution studies of textile industries in Nig. Monogra. 1:76–86.  APHA (1980). American Public Health Association standard methods for the examination of water and wastewater. R.R Donnelley and sons. 15th ed. Chung KT, Stevens SEJ (1993). Degradation of azo dyes by environmental microorganisms and helminthes. Environ. Toxico. Chem. 12:2121–2132. Clarke EA,  Anliker R (1980). Organic dyes and pigments. Handbook of Environmental Chemistry. Springer Verlag. Cooper P (1995). Colour in dyehouse effluent. Society of dyers and colourists, Bradford Cowan, Steel’s (1993). manual for the identification of Medical Bacteria, 3rd Edition. Cambridge University Press. Do T, Shen J, Cawood G, Jeckins R (2002). Biotreatment of textile effluent using Pseudomonas spp. Immobilized on polymer supports. In: Advances in biotreatment for textile processing. Hardin, I.R; Akin D.E & Wilson J.S (Eds). University of Georgia Press.     Goncalves IMC, Gomes A, Bras R, Ferra MIA, Amorin MTP, Porter RS (2000). Biological treatment of effluent containing textile dyes. JSDC. 116:393–397. Kado CI, Liu ST (1981). Rapid procedure for detection and isolation of large and small plasmids. J. bacterial 145, pp.1365 – 1373. Maier J, Kandelbauer A, Erlacher A, Cavaco – Paulo A, Gubits GM (2004). A new alkali – thermostable azoreductase from bacillus sp. Strain SF. Appl. Environ. Microbial 70: 837 – 844.  Mills AL, Breuil C, Colwell RR (1978). Enumeration of petroleum-degrading marine and estuarine microorganisms by the most probable number method. Can. J. Microbial. 24: 552-557. Olayinka KO, Alo BI (2004). Studies on industrial pollution in Nig. The effect of Textile effluent on the quality of ground waters in some parts Lagos. Nig. J. Health. Biomed. Sci. Padmavanthy S, Sandhyan S, Swaminathan K, Subrahmanyarn YV, Chakrabarti T, Kaul SN (2003). Aerobic decolourisation of reactive azo dyes in presence of cosubstrates. Chem. Biochem. Eng. Q. 17 (2) pp. 147-151. Pierce J (1994). Colour in textile effluents – the origins of the problem. JSDC 110. 131-133. Vaidya AA, Datye KV (1982). Environmental pollution during chemical processing of synthetic fibers. Colourage 14: 3-10.                                 

Textile effluent biodegradation potentials of textile effluent-adapted and non-adapted bacteria

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Textile effluent biodegradation potentials of textile effluent-adapted and non-adapted bacteria

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