Effect of Environmental Factors on Biodecolourization of Textile Effluents Using Mutagenised Strains of Pseudomonas and Bacillus Species

Abstract

Aim: To determine the effects of varying environmental factors on textile effluents biodecolourization ability of mutagenised strains of Bacillus and Pseudomonas species isolated from dye contaminated soil. Study Design: This research study was done using random sampling technique. Place and Duration of Study: Challawa industrial Estate Kano; Department of microbiology, Ahmadu Bello University, between November 2014 and September 2015. Materials and Methods: Samples were collected near a textile industry located at Challawa industrial Estate Kano. 20 liters of textile effluent were collected randomly at different points of stream where effluents are discharged and 20 g of dye contaminated soil was also collected at different location near the stream. Bacillus cereus, Bacillus firmus, Pseudomonas aeruginosa and Pseudomonas fluorescens were isolated using standard procedure and identified using Microgen biochemical test kit. The Bacillus and Pseudomonas species were modified using Ultra-violet rays at 254 nm and Nitrous acid at different time interval (5, 10, 15, 20, 25 and 30 min). Biodecolorization ability of parent strains and wild strains and effects of varying environmental factors (pH, temperature, agitation, incubation period and co-substrates) was examined. Results: The modified strains (B8UV30) had higher textile effluent decolourization potentials of 60.30±0.02% than the parent strain (B8WS) which showed 42.26±0.10% biodecolourization activities. The activities of the parent and modified strains were further compared based on effect of environmental factors (temperature, pH, incubation period, agitation and co-substrates). Examination of effects of varying environmental factor showed that the isolates exhibited different activities at different incubation conditions. At temperature of 35ºC, pH7, presence of co-substrate, incubation at 14 day and shaking, the isolates showed higher decolourization activities of 52.92±0.79, 58.82±1.02, 56.42±0.11, 66.16±1.16 and 58.38±0.01 respectively.  Conclusion: This study showed that mutation and environmental parameters used in this study has an effect on biodecolorization potentials of the strains and this could be employed in the biodecolourization of textile effluents to meet acceptable levels prior to discharge of textile effluents into the receiving environment.