Biodetoxification of high amounts of malachite green by a multifunctional strain of Pseudomonas mendocina and its ability to metabolize dye adsorbed chicken feathers Venkatesh Chaturvedi a , Khushboo Bhange b , Renu Bhatt b , Pradeep Verma b,c, * a School of Biotechnology, Banaras Hindu University, Varanasi 221005, UP, India b Department of Biotechnology, Guru Ghasidas Vishwavidyalaya, Bilaspur, Chattisgarh, India c Department of Microbiology, Central University of Rajasthan, N.H. 8 Bandarsindri, Kishangarh, Ajmer 305801, Rajasthan, India Introduction Malachite green (4-[(4-dimethylaminophenyl)-phenyl- methyl]-N,N-dimethylaniline) is a triphenyl methane dye, which is widely used to color fabrics such as silk, nylon, wool, cotton, etc. [1]. It is employed as a potent antifungal/antibacterial agent in fish farming industry [2] and thus enormous amounts of MG is manufactured for its use in different applications [3]. Malachite green (MG) is shown to be toxic to animals including humans [4]. Ingestion of MG leads to respiratory ailments, infertility, muta- genic, carcinogenic effects on humans and other animals [2,5,6]. The intense color of dye interferes with sunlight entering the water bodies and drastically reduces photosynthesis [7]. Thus, remedia- tion of MG from environment by employing various physical methods such as adsorption [8,9], chemical methods using chemicals/strong oxidizing [10–12] and biological methods using various bacterial/fungal strains [1,13,14] has been suggested. Most simple, economical and widely employed method being adsorp- tion using low cost adsorbents such as poultry/chicken feathers [7], activated carbon [9], ginger waste [5], lotus seed char [15], Zea maize shell leaf [16]. A major disadvantage of such process is that the dye is not degraded or detoxified, it is rather trapped by the adsorbent and thus leaching of dye from adsorbent can have drastic consequences on environment [14]. Among the adsorbents employed, the use of chicken feathers as an adsorbent is particularly important [7]. Since, chicken feathers are considered as a waste material and are usually disposed in the environment by various poultry processing industries and also by local butchers without any treatment [17] and hence they can interact with other pollutants such as dyes like MG. This interaction can lead to Journal of Environmental Chemical Engineering 1 (2013) 1205–1213 ARTICLE INFO Article history: Received 24 May 2013 Accepted 13 September 2013 Keywords: Malachite green (MG) Detoxification Chicken feathers Adsorption Toxicity ABSTRACT Malachite green (MG) is a highly toxic, and recalcitrant tri-phenyl methane dye, which can be adsorbed on surface of chicken feathers, a non toxic poultry waste. This interaction can affect metabolism of chicken feathers by microbes in the environment. In this study, decolorization/degradation of MG and metabolism of MG adsorbed chicken feathers by Pseudomonas mendocina strain PM2 has been evaluated. Decolorization of different concentrations of MG by strain PM2 was studied. Degradation of MG was studied by UV–vis/FTIR analysis. Enzyme activities of selected enzymes were evaluated in order to ascertain their role in MG degradation. Microbial/phytotoxocity studies on MG and its degraded metabolites were carried out to confirm detoxification of MG after degradation. MG was adsorbed on surface of chicken feathers and its toxicity on strain PM2 and MG sensitive strain of Bacillus subtilis MTCC 441 was evaluated. Metabolism of native and MG adsorbed chicken feathers by strain PM2 and MTCC 441 was studied. Results showed that strain PM2 could decolorize up to 1800 mg/L MG. UV–vis/FTIR studies indicated degradation of MG by strain PM2. Assay of enzyme activity indicated involvement of MG reductase, lignin peroxidase and manganese peroxidase during degradation. Microbial/phytotoxici- ty study confirmed biodetoxification of MG after degradation. MG adsorbed chicken feathers were toxic to MTCC 441 and non toxic to strain PM2. Further, strain PM2 was able to metabolize MG adsorbed chicken feathers whereas MTCC 441 could not metabolize MG adsorbed chicken feathers. This study clearly indicates that MG adsorbed chicken feathers are difficult to be metabolized by MG sensitive strains. ß 2013 Elsevier Ltd. All rights reserved. * Corresponding author at: Department of Microbiology, Central University of Rajasthan, N.H. 8 Bandarsindri, Kishangarh, Ajmer 305801, Rajasthan, India. E-mail addresses: venkatesh_chaturvedi@rediffmail.com (V. Chaturvedi), vermaprad@yahoo.com (P. Verma). Contents lists available at ScienceDirect Journal of Environmental Chemical Engineering journal homepage: www.elsevier.com/locate/jece 2213-3437/$ – see front matter ß 2013 Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.jece.2013.09.009