Impact of environmental stress on biochemical parameters of bacteria reducing chromium

Batool, Rida; Yrjälä, Kim; Hasnain, Shahida

doi:10.1590/s1517-83822014000200028

Cited by 18 publications

(8 citation statements)

References 30 publications

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“…The results obtained from TEM analysis of B. subtilis MNU16 demonstrated the allocation of FDP inside and outside cells which might be due to the exposure of hexavalent chromium treatments. Similarly, study conducted by Batool et al (2014) reported similar pattern of FDP and cell disruption in cells of P. aeruginosa and Ochrobactrum intermedium treated with different concentrations of Cr(VI). Further, in the present study, the deposition of EDP inside the B. subtilis MNU16 might be due to the accumulation and intracellular reduction of Cr(VI) as shown in Figures 2C,D .…”

Section: Discussionsupporting

confidence: 60%

Tolerance and Reduction of Chromium(VI) by Bacillus sp. MNU16 Isolated from Contaminated Coal Mining Soil

et al. 2017

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The bacterium MNU16 was isolated from contaminated soils of coal mine and subsequently screened for different plant growth promoting (PGP) activities. The isolate was further identified by 16S rRNA sequencing as Bacillus subtilis MNU16 with IAA concentration (56.95 ± 0.43 6μg/ml), siderophore unit (9.73 ± 2.05%), phosphate solubilization (285.13 ± 1.05 μg/ml) and ACC deaminase activity (116.79 ± 0.019 μmoles α-ketobutyrate/mg/24 h). Further, to evaluate the metal resistance profile of bacterium, the isolate was screened for multi-metal resistance (viz. 900 mg/L for Cr, 600 mg/L for As, 700 mg/L for Ni and 300 mg/L for Hg). Additionally, the resistance pattern of B. subtilis MNU16 against Cr(VI) (from 50 to 300 mg/L) treatments were evaluated. An enriched population was observed at 0–200 mg/L Cr(VI) concentration while slight reductions were observed at 250 and 300 mg/L Cr(VI). Further, the chromium reduction ability at 50 mg/L of Cr(VI) highlighted that the bacterium B. subtilis MNU16 reduced 75% of Cr(VI) to 13.23 mg/L within 72 h. The localization of electron dense precipitates was observed in the TEM images of B. subtilis MNU16 which is might be due to the reduction of Cr(VI) to Cr(III). The data of fluorescence microscopy and flow cytometry with respect to Cr(VI) treatments (50–300 mg/L) showed a similar pattern and clearly revealed the less toxic effect of hexavalent chromium upto 200 mg/L Cr(VI) concentration. However, toxicity effects were more pronounced at 300 mg/L Cr(VI). Therefore, the present study suggests that the plant growth promoting potential and resistance efficacy of B. subtilis MNU16 will go a long way in developing an effective bioremediation approach for Cr(VI) contaminated soils.

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Section: Discussionsupporting

confidence: 60%

Tolerance and Reduction of Chromium(VI) by Bacillus sp. MNU16 Isolated from Contaminated Coal Mining Soil

et al. 2017

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“…As both bacterial strains were normally maintained on chromate supplemented media so chromate was accumulated intra‐cellularly. In routine, these strains were maintained on chromate supplemented medium so when the cells were grown in the chromate free medium, the intra‐cellularly accumulated Cr(VI) was reduced to Cr(III) and deposited on the periphery of bacterial cell walls . 13 C NMR spectrum of EPS produced by P. aeruginosa Rb‐1 and O. intermedium Rb‐2 under stress and stress free conditions showed that EPS may be a glucan.…”

Section: Discussionmentioning

confidence: 99%

“…For FTIR analysis, all EPS fractions were centrifuged and lyophilized, followed by weighing. Then 20 mg of finely ground EPS fraction was used to get the information specific to the functional groups by KBr disc method .…”

Section: Methodsmentioning

confidence: 99%

Production of EPS under Cr(VI) challenge in two indigenous bacteria isolated from a tannery effluent

Batool

Yrjälä

Shaukat

et al. 2015

J. Basic Microbiol.

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Indigenous Cr(VI) reducing bacterial strains Pseudomonas aeruginosa Rb-1 and Ochrobactrum intermedium Rb-2 were evaluated for EPS production under Cr(VI) challenged and free conditions. Strain Rb-2 was more efficient in total EPS production (13.63 mg g(-1)) than Rb-1 (4.15 mg g(-1)) under Cr(VI) stress. Thick covering of capsular material around the cells of both bacterial strains was detected by electron microscopy. Transmission electron micrographs showed the appearance of pilli like structures under chromium stress by two bacteria suggested the possible involvement of this in exchange of hereditary material to increase their chances of survival under stress conditions. FTIR study showed involvement of sulphonate and hydroxyl groups in the binding with Cr(VI) ions. Solid-state (13) C NMR spectra revealed that EPS produced by both strains exhibited structural similarity with the glucan. The partial psl gene sequences of Rb-1 and Rb-2 showed homology with psl gene of Pseudomonas aeruginosa PAO1 and capsular polysaccharide biosynthesis protein of various strains of Pseudomonas. This is the first report on the identification of psl gene from Ochrobacterum in NCBI GenBank database up to our knowledge.

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“…Similar observations were made during transitional elemental supplementation reducing the viability of B. subtilis , C. rubrum and Pseudomonas sp. (Vijayalakshmi et al 2011 ; Batool et al 2014 ).…”

Section: Resultsmentioning

confidence: 99%

Elucidation of impact of heavy metal pollution on soil bacterial growth and extracellular polymeric substances flexibility

2016

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Metal bioaccessibility is an alarming issue in croplands of mining sites due to overloading of toxic metals. Hence, the present study is aimed to determine the overloading of toxic metal in croplands across the Tawag village, Hutti, Raichur, India. Correspondingly, to identify the soil bacterial growth, physiological oxidative stress enzyme activity and surface macromolecular functional group evolution were analysed in and around the toxic metal contaminated sites through FT-IR and FT-Raman spectrometry. The evaluated results attribute that the study area is heavily polluted with the toxic metals such as arsenic, cadmium, chromium, lead and zinc. However, biochemical and 16S rRNA gene sequence homology tree confirmed that the arsenic and cadmium-resistant isolate belongs to Bacillus sp. MDPMK-02 and retrieved unique Gene Bank ID KT596811 (accession number) at National Centre for Biotechnology information (NCBI), India. Additionally, sodium arsenite-amended culture media possessing reduced biomass and enhanced the activity of oxidative stress defence enzymes such as superoxide dismutase (SOD) and catalase (CAT) than cadmium chloride-amended medium and control. Subsequently, the infrared (IR) and Raman spectral analytical assessment distinguish that arsenic-treated Gram-positive isolate membrane fetched high percentage of hydration, elevation of surface polysaccharides, proteins and polyhydroxybutyric acid (PHBA) molecular specific stretch intensity compared to cadmium exposures. From these results, the study concluded that the mining wastes significantly pollute the surrounding croplands, and also Bacillus sp. MDPMK-02 possesses good chemosensing for cross-protection and bio-adaptation of toxic metal ions. Hence, these isolates can be compiled and implemented in environmental hazardous management techniques such as bioremediation, bioleaching and biodegradation.

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Impact of environmental stress on biochemical parameters of bacteria reducing chromium

Cited by 18 publications

References 30 publications

Tolerance and Reduction of Chromium(VI) by Bacillus sp. MNU16 Isolated from Contaminated Coal Mining Soil

Tolerance and Reduction of Chromium(VI) by Bacillus sp. MNU16 Isolated from Contaminated Coal Mining Soil

Production of EPS under Cr(VI) challenge in two indigenous bacteria isolated from a tannery effluent

Elucidation of impact of heavy metal pollution on soil bacterial growth and extracellular polymeric substances flexibility

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