Screening and Evaluation of Multi-metal Tolerance of Chromate Resistant Marine Bacteria Isolated from Water and Sediment Samples of Paradip Port, Odisha Coast (original) (raw)
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British microbiology research journal, 2016
Pollution of water is one of the major concerns for whole world. Heavy metals, toxic waste and various effluents from industrialization and anthropogenic sources causes pollution of river water. These pollutants have adverse effects on health of human and other living beings in terrestrial and aquatic environment and also affect the food chain. The present study was an attempt to evaluate the water quality of river Hasdeo at Sarvamangla Nagar, Korba (Chhattisgarh). Pollution level was measured by estimating the water quality parameters [physicochemical i.e. temperature, pH, DO, BOD, COD and Level of heavy metal pollutants]. Pollution of heavy metals were observed in following order [Fe>Pb>Cd>Zn]. In addition, the bacteriological analyses involved most abundant bacterial species tolerant to heavy metal pollution and isolation identification of these heavy metal resistant bacteria from the river water of Hasdeo. The bacteriological analyses showed the population density [in %] of most abundant metal resistant bacterial species were Pseudomonas sp. [38%], Bacillus sp. [27%], E. Coli [20%] and Enterobacter sp. [15%]., The results of the present investigation revealed that, the river Hasdeo water at Sarvamangla Nagar was highly contaminated with heavy metals and require suitable action for the removal of pollutant by using the these metal tolerant bacteria as bio-remediating heavy metal pollutant which are very harmful to human health and environment.
Isolation and Characterization of Chromium-Tolerant Bacteria from Chromium-Containing Waste Water
Serious chromium (Cr 6+) contamination of both surface water and ground water has been reported in the Palar River Basin of Vellore District (Tamil Nadu), India due to the discharge of improperly treated effluents from tanneries and other industries in and around Ranipet. The primary objective of this study was to isolate and identify a potent chromate-reducing bacterial strain. Treated and untreated tannery effluent samples were collected from Ranipet at three different locations for Cr 6+ analysis and the bacterial population was enumerated. The effluents characteristically contained high levels of Cr. Hence in the present study attempts were made to isolate and characterize chromate-resistant and-reducing bacterial strains. The majority of the chromate-resistant bacterial isolates from the tannery effluents showed a minimum inhibitory concentration (MIC) of Cr 6+ ranging from 100 to 1500 mg/l. About 32.14% of the total 56 isolates of bacterial strains were able to grow at 200 mg/l Cr 6+. The potent Cr 6+-resistant strains of Proteus sp. V16 and Pseudomonas mendocina V42 showed a very high tolerance level to 1500 mg/l and were able to show 100% Cr 6+ reduction up to 400 mg/l within 80 and 75 h, respectively. The present study conclusively demonstrates the ability of native microbial population present in tannery effluent to reduce Cr 6+ compounds and is the first report on chromate-reducing bacterial strains from Ranipet tannery effluents showing tolerance up to 1500 mg/l. Proteus sp. V16 and Pseudomonas mendocina V42 have great potential for bioremediation of Cr 6+-containing wastes. This approach permits the selection of bacterial strains which could be used for specific environmental clean up operations.
Diversity of chromium-resistant and -reducing bacteria in a chromium-contaminated activated sludge
Journal of Applied Microbiology, 2002
This study attempts to establish a relationship between the Cr(VI) resistance of the culturable microbial community and the Cr(VI) resistance and Cr(VI)-reducing ability of representative strains of each population, in order to assess whether these are exclusive characteristics of one microbial group or abilities shared among many groups. Methods and Results: A group of 48 Cr(VI)-resistant isolates, with different colony types, was isolated from chromium-contaminated activated sludge. Sodium dodecyl sulphatepolyacrylamide gel electrophoresis protein patterns and fatty acid methyl ester analysis identified six populations, representing 54% of the isolated bacteria, as belonging to the genera Acinetobacter and Ochrobactrum. The remaining populations included strains identified as species of the b-Proteobacteria and high G + C Gram-positive bacteria. The Cr(VI) resistance and reduction ability of the strains were tested. All but two isolates grew in the presence of 1 mmol l)1 Cr(VI). During enrichment, all isolates were able to survive to 2 mmol l)1 Cr(VI) and complete Cr(VI) reduction was achieved. Representative strains of each population were able to partially reduce (5AE4-39AE1%) the Cr(VI) present in the growth medium. Conclusions: Most of the identified isolates have never been reported to be Cr(VI)-resistant and/or Cr(VI)-reducing strains. The mechanisms of Cr(VI) resistance and reduction may differ from group to group; therefore, it is evident that both Cr(VI) resistance and reduction are shared abilities and not an exclusive characteristic of a single group, possibly reflecting horizontal genetic transfer resulting from selective pressure in this contaminated environment. Significance and Impact of the Study: To our knowledge, this is the first study of a microbial community under chronic chromate stress and, as the success of microbial-based metal remediation technologies requires a better understanding of the microbial community and the population response to metal stress, it may contribute to the implementation of a strategy of bioremediation of chromate-contaminated environments.
Bulletin of Environmental Contamination and Toxicology, 2008
This study was aimed at assessing the ability of Bacillus sp.ev3 to reduce hexavalent chromium into its trivalent form. Bacillus sp.ev3 could tolerate Cr 6+ (4800 lg/mL), Pb 2+ (800 lg/mL), Cu 2+ (200 lg/mL), Cd 2+ (50 lg/mL), Zn 2+ (400 lg/mL), Ni 2+ (4000 lg/mL) and Hg 2+ (50 lg/mL). Bacillus sp.ev3 showed optimum growth at 37°C and pH at 7. Bacillus sp.ev3 could reduce 91% of chromium from the medium after 96 h and was also capable to reduce 84% chromium from the industrial effluents after 144 h. Cell free extracts of Bacillus sp.ev3 grown in the presence of Cr showed reduction of 70%, 45.6% and 27.4% at concentrations of 10 lg Cr 6+ /mL, 50 lg Cr 6+ /mL and 100 lg Cr 6+ /mL, respectively.
Role of Heavy Metal Resistant Bacteria for Bioremediation of Polluted Environment
THE JOURNAL OF MICROBIOLOGY AND MOLECULAR GENETICS
Bioremediation refers to the use of microorganisms to reduce or eliminate contaminants from water and soil. In the current research, different bacterial strains were screened for their chromate and arsenate reduction potential. For the removal of arsenic, eight arsenic resistant bacterial strains AsK03, AsK04, AsK06, AsK07, AsK08, AsK09, AsK15 and AsK18 and for chromium removal, eight chromium resistant bacterial strains CrK02, CrK08, CrK12, CrK14, CrK16, CrK19, CrK20 and CrK21 were isolated and selected, respectively, from several contaminated soil and water samples taken from tanneries located in Kasur. Resistance to chromium and arsenic was shown by all the strains on nutrient agar at preliminary concentration of 500 µg ml-1 . The maximum tolerable concentration (MTC) of these isolates was also studied. It was found that for arsenic resistance, two strains AsK04 and AsK09 had highest MTC of 100 mg ml-1 , AsK18 had 75 mg ml-1 , AsK03, AsK06 and AsK15 had 50 mg ml-1 and AsK07 and A...
World Journal of Microbiology and Biotechnology, 2019
Investigation of bacterial chromate tolerance has mostly focused on strains originating from polluted sites. In the present study, we isolated 33 chromate tolerant strains from diverse environments harbouring varying concentrations of chromium (Cr). All of these strains were able to grow on minimal media with at least 2 mM hexavalent chromium (Cr(VI)) and their classification revealed that they belonged to 12 different species and 8 genera, with a majority (n = 20) being affiliated to the Bacillus cereus group. Selected B. cereus group strains were further characterised for their chromate tolerance level and the ability to remove toxic Cr(VI) from solution. A similar level of chromate tolerance was observed in isolates originating from environments harbouring high or low Cr. Reference B. cereus strains exhibited the same Cr(VI) tolerance which indicates that a high chromate tolerance could be an intrinsic group characteristic. Cr(VI) removal varied from 22.9% (strain PCr2a) to 98.5% (strain NCr4). Strains NCr1a and PCr12 exhibited the ability to grow to the greatest extent in Cr(VI) containing media (maximum growth of 65.3% and 64.9% relative to that in the absence of Cr(VI), respectively) accompanied with high chromate removal activity (73.7% and 74.4%, respectively), making them prime candidates for the investigation of chromate tolerance mechanisms in Gram-positive bacteria and Cr(VI) bioremediation applications.
Environmental technology, 2017
Pollution of the aquatic environment by heavy metals leads to the selection of resistant bacterial communities. These resistant microorganisms have detoxification mechanisms to survive in the polluted environment, such as biosorption and biotransformation. Optimization of these mechanisms constitutes an innovative biotechnological tool for the treatment of liquid effluents. The aims of this investigation were to evaluate the bacterial resistance to zinc, copper, chromium (VI) and lead in surface water streams from Buenos Aires, Argentina; to select a chromium-resistant strain able to remove the metal in batch process, and to evaluate the potential of this strain to remove chromium (VI) in liquid effluents. Bacterial resistance to the metals was evaluated by determining the Minimal Inhibitory Concentration (MIC). The kinetic of chromium (VI) removal by one of the resistant strains was studied in nutrient broth with 50 and 100 mg L(-1) of the metal, as well as an effluent from an elec...
Journal of Applied Microbiology, 2009
Aims: To investigate the genetic basis of Cr(VI) resistance and its reduction to Cr(III) in indigenous bacteria isolated from tannery effluent.Methods and Results: Four bacteria resistant to high Cr(VI) levels were isolated and identified as Bacillus spp. Their Cr(VI) reduction ability was tested. To assess the genetic basis of Cr(VI) resistance and reduction, plasmid transfer and curing studies were performed. Among all, B. brevis was resistant to 180 μg Cr(VI) ml−1 and showed the greatest degree of Cr(VI) reduction (75·8%) within 28 h and its transformant was resistant to 160 μg Cr(VI) ml−1 and reduced 69·9% chromate. It harboured a stable 18 kb plasmid DNA. Transfer and curing studies revealed that both the chromate resistance and reduction were plasmid mediated. The presence of other metal cations did not have any significant effect on Cr(VI) bioreduction.Conclusions: Bacillus brevis was resistant to elevated Cr(VI) levels and may potentially reduce it in short time from an environment where other metal ions are also present in addition to chromium ions. The strain tested shows a positive correlation between genetic basis of Cr(VI) resistance and reduction.Significance and Impact of the Study: To our knowledge, this is the first study on the genetic correlation between chromium resistance and reduction in bacteria. Such strains may potentially be useful in biotechnological applications and in situ Cr(VI) bioremediation.
African Journal of Biotechnology, 2010
The Cr (VI) reducing capacity of bacteria has been investigated in many different soils and waters but little or no information is available from soils originating from bauxite mine areas. From soil, mud and rhizospheres of the floating aquatic plant Potamogeton natans L. and the terrestrial plant Carduus acanthoides L., the Cr content was determined and the microbial populations were sampled. The highest total chromium concentration (204.6 mgkg -1 ) was found in the rhizosphere of C. acanthoides. To determine the numbers and percentages of chromate-resistant bacteria, the autochthonous microbial populations were subjected to different Cr (VI) concentrations (40, 100, 300 and 1000 mM as K 2 Cr 2 O 7 ). At 1000 mM Cr (VI) in the medium, about 25% of bacteria from soil and 45% of bacteria from the rhizospheres were resistant. Of 34 bacterial isolates, within 24 h, only Bacillus stearothermophilus 12 ms, Pseudomonas sp. 12 bk3 and Serratia fonticola 7 be were able to reduce 50 µM Cr (VI). Using prolonged 72 h incubation, they were able to reduce 500 M Cr (VI) concentrations added to the medium. These chromate-resistant bacteria isolated from rhizosphere of plants growing in bauxite mine soil have great potential for bioremediation of Cr (VI)-polluted wastes.
In the biosphere, chromium is widespread heavy metal occurring in trivalent chromium (Cr 3+) and hexavalent chromium (Cr 6+) forms. Trivalent chromium has been extensively used in different industries. Hexavalent chromium is an environmental pollutant, toxic, carcinogenic and mutagenic metal whereas trivalent form is less soluble in water and even an essential nutrient. The distinctive capability of different isolated bacterial species, to reduce hexavalent chromium into trivalent form is going to be used in bioremediation. The present study was aimed to isolate and identify chromium resistant bacteria species from chromium mines. Random samples (n= 3) were taken and biochemical test were applied to identify chromium resistant bacterial species. Four bacterial species, belonged to genus Bacillus (iso-four, seven, eight, nine) were identified as B.pumilus, B.circulans, B.subtilis and B.sphaericus respectively. Isolates belonged to genus enterobacter (iso-one and iso-five) were identified as salmonella enteric and E.arogenes respectively. Isolate belonged to genus arthrobacter (Iso-three) was identified as A. creatinolyticus. Isolate belonged to genus pseudomonas (iso-two) was identified as p.fluorescene. Isolate belonged to genus staphylococcus; (iso-six) was identified as S.aureus, while iso-ten belonged to micrococcusluteus. All the isolates showed ability to tolerate chromium but iso-eight B.subtilis showed highest resistance against chromium. Furthermore, these bacterial species alter hexavalent Cr into trivalent Cr. This ability is being used on commercial scale to remove or minimize chromium pollutants.