SHORT COMMUNICATION Degradation of 4-nitrophenol in presence of heavy metals by a halotolerant Bacillus sp. strain BUPNP2, having plant growth promoting traits Kriti Sengupta 1 & Tushar Kanti Maiti 2 & Pradipta Saha 1 Received: 21 January 2015 /Accepted: 20 May 2015 # Springer Science+Business Media Dordrecht 2015 Abstract A halotolerant 4-nitrophenol (4-NP) degrading bac- terial strain designated as BUPNP2 was isolated by enrich- ment culture technique from the rhizospheric soil of rice plants (Oryzae sativa) of an agricultural field located in Memari within Burdwan district of West Bengal, India. It was identi- fied as a member of genus Bacillus by 16S rRNA gene based molecular phylogenetic approach. The strain was capable of degrading 4-NP (0.3 mM) as sole source of carbon through 4- nitrocatechol (4-NC) as intermediate. The strain also tolerated up to 12 % NaCl (w/v). The degradation capacity of 4-NP was enhanced by this strain up to 0.6 mM in presence of cellulose, starch and glucose. The strain could tolerate several heavy metals such as cadmium, chromium, iron, lead, nickel and zinc and it was degrading 4-NP in presence of each of these heavy metals. Glucose, starch and cellulose also enhanced 4- NP degradation capacity of the strain even in presence of each of these heavy metals. The strain BUPNP2 also possessed important plant growth promoting (PGP) traits such as pro- duction of siderophore, indole acetic acid (IAA), ammonia; phosphate solubilization along with protease, lipase, amylase and cellulase activities. Thus, the halotolerant strain BUPNP2 has biotechnological potential and can be utilized for biore- mediation of heavy metal infested 4-NP contaminated agricultural soil (common in industrial belt) where it might also help in plant growth promotion. Keywords Decolorization . 4-Nitrophenol . Degradation . Halotolerant . Heavy metal tolerance . Plant growth promoting (PGP) bacteria 1 Introduction Agricultural soil is often contaminated with 4-NP due to ex- tensive use of pesticides. Dye and leather industries are also major source of releasing 4-NP into water bodies which ulti- mately reaches to soil by irrigation process (Kou-San and Parales 2010). United States environmental protection act has enlisted 4-NP as a prior pollutant which is toxic to plants, animals, including human and microbes (Keith and Telliard 1979). Microorganisms are known to neutralize the action of toxic compounds by biotransformation or mineralization. Some members of the genera Arthrobacter, Rhodococcus, Ba- cillus, Pseudomonas, Bhurkholderia and Serratia are reported for 4-NP degradation (Prakash et al. 1996; Kadiyala and Spain 1998 ; Pandey et al. 2003; Chauhan et al. 2010; Sengupta and Saha 2014). Some of them utilize 4-NP as sole carbon source and some degrade it co-metabolically in presence of carbohy- drate source (Jamshidian et al. 2013). Soil is usually rich in complex substrates mostly derived from plant and animal de- bris which might be used by microbes for co-metabolism of toxic compounds (Nannipieri et al. 2003). In addition to 4-NP contamination, soil also gets polluted by heavy metals due to effluents of above mentioned industries, excessive use of pes- ticides and chemical fertilizers. The latter also increases the soil salinity and leads to salt stressed condition for microor- ganisms inhabiting those niches (Adesemoye et al. 2009). Thus, the microbial decomposers, plant growth promoters Electronic supplementary material The online version of this article (doi:10.1007/s13199-015-0327-1) contains supplementary material, which is available to authorized users. * Pradipta Saha psaha@microbio.buruniv.ac.in 1 Department of Microbiology, Burdwan University, Golapbag, Burdwan 713104, WB, India 2 Microbiology Laboratory, Department of Botany, Burdwan University, Golapbag, Burdwan 713104, WB, India Symbiosis DOI 10.1007/s13199-015-0327-1