Characterization of a salt resistant bacterial strain Proteus sp. NA6 capable of decolorizing reactive dyes in presence of multi-metal stress

Abstract

Microbial biotechnologies for the decolorization of textile wastewaters have attracted worldwide attention because of their economic suitability and easiness in handling. However, the presence of high amounts of salts and metal ions in textile wastewaters adversely affects the decolorization efficiency of the microbial bioresources. In this regard, the present study was conducted to isolate salt tolerant bacterial strains which might have the potential to decolorize azo dyes even in the presence of multi-metal ion mixtures. Out of the tested 48 bacteria that were isolated from an effluent drain, the strain NA6 was found relatively more efficient in decolorizing the reactive yellow-2 (RY2) dye in the presence of 50 g L(-1) NaCl. Based on the similarity of its 16S rRNA gene sequence and its position in a phylogenetic tree, this strain was designated as Proteus sp. NA6. The strain NA6 showed efficient decolorization (>90 %) of RY2 at pH 7.5 in the presence of 50 g L(-1) NaCl under static incubation at 30 °C. This strain also had the potential to efficiently decolorize other structurally related azo dyes in the presence of 50 g L(-1) NaCl. Moreover, Proteus sp. NA6 was found to resist the presence of different metal ions (Co(+2), Cr(+6), Zn(+2), Pb(+2), Cu(+2), Cd(+2)) and was capable of decolorizing reactive dyes in the presence of different levels of the mixtures of these metal ions along with 50 g L(-1) NaCl. Based on the findings of this study, it can be suggested that Proteus sp. NA6 might serve as a potential bioresource for the biotechnologies involving bioremediation of textile wastewaters containing the metal ions and salts.

Enzymatic detoxification of azo dyes by a multifarious Bacillus sp. strain MR-1/2-bearing plant growth-promoting characteristics

“…A promising feature of this strain to perform its activity in the wastewaters is the onset of metabolic activity under abiotic stress conditions. Such metal tolerance in dye decolorizing bacterial strains was also reported in several previous studies (Hussain et al 2013;Najme et al 2015;Abbas et al 2016). Recently, it was found that thermophilic microflora were able to decolorize direct black G dye up to 97% in 8 h by simultaneously employing laccase, manganese peroxidase, lignin peroxidase, and azoreductase enzymes (Chen et al 2018).…”

“…The isolate MR-1/2 showed the maximum decolorization at a pH range of 6-8. It is common that the azo dye decolorization activity of bacterial strains is maximum near neutral to alkaline pH (Hussain et al 2013;Najme et al 2015;Abbas et al 2016). The percent deviation Table 5 Phytotoxicity evaluation of decolorized reactive red-120 with mungbean seeds NRR0 non-inoculated with no reactive red-120, NRR100 non-inoculated with 100 mg L −1 reactive red-120, NRR500 non-inoculated with 500 mg L −1 reactive red-120, WRR0 inoculated with MR-1/2 and no reactive red-120, WRR100 inoculated with MR-1/2 and 100 mg L −1 reactive red-120, WRR500 inoculated with MR-1/2 and 500 mg L −1 reactive red-120 **Different lower case letters represent significance between the treatments means (Fisher's LSD; P ≤ 0.05).…”

“…During the last decade, use of biological approaches for removal of dyes has attracted global attention because of their cost competitiveness and environmentally friendly nature. Microorganisms have been reported for their potential of degradation and removal of various textile dyes (Abbas et al 2016;Maqbool et al 2016;Hussain et al 2017). The use of microbes is preferred because of the several advantages, e.g., their low cost, effectiveness against recalcitrant compounds, reduced sludge production under given ecological conditions and easy handling.…”

Characterization of Rhizospheric Bacillus Strains SG36 and SG42 for Decolorization of Reactive Yellow 2 Dye and Vigna radiata Growth Promotion in Dye Contaminated Soil

“…Contamination of the agricultural soils with synthetic dyes due to the use of different wastewaters for irrigation purpose under water scarce conditions is an emerging challenge because the dyes affect the biological properties of the soils as well as the growth of the crops (Imran et al 2015). One of the ways to overcome this situation is the isolation, characterization and application of the bacterial strain which have the potential not only to cope with the dyes in soils but Despite that various bacterial strains harbor different PGP characteristics including P solubilization and IAA production (Shahid et al 2012;Baig et al 2014;Shahid et al 2015;Akram et al 2016;Maqsood et al 2021) as well as for decolorization of different dyes (Hussain et al 2013;Abbas et al 2016;Baig et al 2019;Imran et al 2019). However, the present study is unique in that it reports two rhizospheric bacterial strains SG36 and SG42 which possess PGP characteristics together with capability to decolorize dyes.…”

Kinetics of Halophilic Enzymes

“…Stems of Tamarix chinensis [113] Labrenzia suaedae YC6927 T Root of Sauceda maritime [114] Kocuria arsenatis CM1E1 T Prosopis laevigata [115] Proteus sp. NA6 Textile effluent drain [116] Candidatus Desulfonatronobulbus propionicus Hypersaline soda lakes [117] Novosphingobium pokkalii L3E4 T Rhizosphere of salinetolerant pokkali rice [118] Marinobacter aquaticus M6-53 T Marine saltern located in Huelva, Spain [119] Agrobacterium salinitolerans YIC 5082 T…”