scholarly journals Unraveling the Underlying Heavy Metal Detoxification Mechanisms of Bacillus Species

2021 ◽  
Vol 9 (8) ◽  
pp. 1628
Author(s):  
Badriyah Shadid Alotaibi ◽  
Maryam Khan ◽  
Saba Shamim

The rise of anthropogenic activities has resulted in the increasing release of various contaminants into the environment, jeopardizing fragile ecosystems in the process. Heavy metals are one of the major pollutants that contribute to the escalating problem of environmental pollution, being primarily introduced in sensitive ecological habitats through industrial effluents, wastewater, as well as sewage of various industries. Where heavy metals like zinc, copper, manganese, and nickel serve key roles in regulating different biological processes in living systems, many heavy metals can be toxic even at low concentrations, such as mercury, arsenic, cadmium, chromium, and lead, and can accumulate in intricate food chains resulting in health concerns. Over the years, many physical and chemical methods of heavy metal removal have essentially been investigated, but their disadvantages like the generation of chemical waste, complex downstream processing, and the uneconomical cost of both methods, have rendered them inefficient,. Since then, microbial bioremediation, particularly the use of bacteria, has gained attention due to the feasibility and efficiency of using them in removing heavy metals from contaminated environments. Bacteria have several methods of processing heavy metals through general resistance mechanisms, biosorption, adsorption, and efflux mechanisms. Bacillus spp. are model Gram-positive bacteria that have been studied extensively for their biosorption abilities and molecular mechanisms that enable their survival as well as their ability to remove and detoxify heavy metals. This review aims to highlight the molecular methods of Bacillus spp. in removing various heavy metals ions from contaminated environments.

2021 ◽  
Vol 897 ◽  
pp. 109-115
Author(s):  
Sri Martini ◽  
Kiagus Ahmad Roni ◽  
Dian Kharismadewi ◽  
Erna Yuliwaty

This review article presents the usage of various animal bones such as chicken bone, fish bone, pig bone, camel bone, and cow bone as reliable biosorbent materials to remove heavy metals contained in contaminated water and wastewater. The sources and toxicity effects of heavy metal ions are also discussed properly. Then specific insights related to adsorption process and its influential factors along with the proven potentiality of selected biosorbents especially derived from animal bone are also explained. As the biosorbents are rich in particular organic and inorganic compounds and functional groups in nature, they play an important role in heavy metal removal from contaminated solutions. Overall, after conducting study reports on the literature, a brief conclusion can be drawn that animal bone waste has satisfactory efficacy as effective, efficient, and environmentally friendly sorbent material.


Author(s):  
Muibat Fashola

Introduction: Indiscriminate dumping of spent oils enriched with heavy metals has led to increase in heavy metals load in the soil. Heavy metals exert toxic effects on biodegradation of organic pollutant in cocontaminated soil and there is need to find suitable strategies for their removal. Aim: The aim of this study was to assess the heavy metals resistance capability of indigenous Bacillus species in hydrocarbon polluted soil to nickel (Ni), Cadmium (Cd), Lead (Pb) and Chromium (Cr). Materials and Methods: Heavy metal tolerant bacteria were isolated from hydrocarbon polluted soil using Luria-Berthani agar supplemented with the respective metals and spread plate techniques. The isolates were putatively identified on the basis of their colonial morphology and biochemical characteristics and their antibiotics susceptibility pattern were evaluated using disc diffusion method. Results: The maximum tolerable concentration (MTC) of the four heavy metals to the selected isolates was 2 mM. Four bacteria isolates able to withstand the MTC were putatively identified as Bacillus subtilis, Bacillus megaterium, Bacillus laterosporus and Bacillus polymyxa. Out of the four Bacillus species, only B. laterosporus did not show multiple tolerance to the tested antibiotics which show that there is correlation between heavy metal tolerance and antibiotics resistance by the isolates. Conclusion: Multiple heavy metal tolerance Bacillus spp. were isolated from crude oil polluted soil. These bacteria could be suitable agents for bioaugmentation of hydrocarbon polluted soil co-contaminated with heavy metals.


2001 ◽  
Vol 44 (10) ◽  
pp. 53-58 ◽  
Author(s):  
L. C. Aralp ◽  
A. Erdincler ◽  
T. T. Onay

Heavy metal concentration in sludge is one of the major obstacles for the application of sludge on land. There are various methods for the removal of heavy metals in sludge. Using sulfur oxidizing bacteria for microbiological removal of heavy metals from sludges is an outstanding option because of high metal solubilization rates and the low cost. In this study, bioleaching by indigenous sulfur oxidizing bacteria was applied to sludges generated from the co-treatment of municipal wastewater and leachate for the removal of selected heavy metals. Sulfur oxidizing bacteria were acclimated to activated sludge. The effect of the high organic content of leachate on the bioleaching process was investigated in four sets of sludges having different concentrations of leachate. Sludges in Sets A, B, C and D were obtained from co-treatment of wastewater and 3%, 5%, 7% and 10% (v/v) leachate respectively. The highest Cr, Ni and Fe solubilization was obtained from Set A. Sulfur oxidizing bacteria were totally inhibited in Set D that received the highest volume of leachate.


2018 ◽  
Vol 6 (28) ◽  
pp. 13624-13632 ◽  
Author(s):  
He Ding ◽  
Yang Chen ◽  
Tianyi Fu ◽  
Peng Bai ◽  
Xianghai Guo

Nanosheet-based magadiites are promising adsorbents with controlled interlayer space and a well-defined 2D structure, which make them new candidates for heavy metal removal.


2020 ◽  
Vol 8 (4) ◽  
pp. 505 ◽  
Author(s):  
Muhammad Faheem ◽  
Sadaf Shabbir ◽  
Jun Zhao ◽  
Philip G Kerr ◽  
Nasrin Sultana ◽  
...  

Cadmium (Cd), chromium (Cr) and lead (Pb) are heavy metals that have been classified as priority pollutants in aqueous environment while methane-oxidizing bacteria as a biofilter arguably consume up to 90% of the produced methane in the same aqueous environment before it escapes into the atmosphere. However, the underlying kinetics and active methane oxidizers are poorly understood for the hotspot of epipelon that provides a unique micro-ecosystem containing diversified guild of microorganisms including methane oxidizers for potential bioremediation of heavy metals. In the present study, the Pb2+, Cd2+and Cr6+ bioremediation potential of epipelon biofilm was assessed under both high (120,000 ppm) and near-atmospheric (6 ppm) methane concentrations. Epipelon biofilm demonstrated a high methane oxidation activity following microcosm incubation amended with a high concentration of methane, accompanied by the complete removal of 50 mg L−1 Pb2+ and 50 mg L−1 Cd2+ (14 days) and partial (20%) removal of 50 mg L−1 Cr6+ after 20 days. High methane dose stimulated a faster (144 h earlier) heavy metal removal rate compared to near-atmospheric methane concentrations. DNA-based stable isotope probing (DNA-SIP) following 13CH4 microcosm incubation revealed the growth and activity of different phylotypes of methanotrophs during the methane oxidation and heavy metal removal process. High throughput sequencing of 13C-labelled particulate methane monooxygenase gene pmoA and 16S rRNA genes revealed that the prevalent active methane oxidizers were type I affiliated methanotrophs, i.e., Methylobacter. Type II methanotrophs including Methylosinus and Methylocystis were also labeled only under high methane concentrations. These results suggest that epipelon biofilm can serve as an important micro-environment to alleviate both methane emission and the heavy metal contamination in aqueous ecosystems with constant high methane fluxes.


2020 ◽  
Vol 81 (9) ◽  
pp. 1797-1827 ◽  
Author(s):  
Ya-Nan Xu ◽  
Yinguang Chen

Abstract Industrial development has led to generation of large volumes of wastewater containing heavy metals, which need to be removed before the wastewater is released into the environment. Chemical and electrochemical methods are traditionally applied to treat this type of wastewater. These conventional methods have several shortcomings, such as secondary pollution and cost. Bioprocesses are gradually gaining popularity because of their high selectivities, low costs, and reduced environmental pollution. Removal of heavy metals by sulfate-reducing bacteria (SRB) is an economical and effective alternative to conventional methods. The limitations of and advances in SRB activity have not been comprehensively reviewed. In this paper, recent advances from laboratory studies in heavy metal removal by SRB were reported. Firstly, the mechanism of heavy metal removal by SRB is introduced. Then, the factors affecting microbial activity and metal removal efficiency are elucidated and discussed in detail. In addition, recent advances in selection of an electron donor, enhancement of SRB activity, and improvement of SRB tolerance to heavy metals are reviewed. Furthermore, key points for future studies of the SRB process are proposed.


2016 ◽  
Vol 7 (4) ◽  
pp. 387-419 ◽  
Author(s):  
Renu ◽  
Madhu Agarwal ◽  
K. Singh

Heavy metals are discharged into water from various industries. They can be toxic or carcinogenic in nature and can cause severe problems for humans and aquatic ecosystems. Thus, the removal of heavy metals from wastewater is a serious problem. The adsorption process is widely used for the removal of heavy metals from wastewater because of its low cost, availability and eco-friendly nature. Both commercial adsorbents and bioadsorbents are used for the removal of heavy metals from wastewater, with high removal capacity. This review article aims to compile scattered information on the different adsorbents that are used for heavy metal removal and to provide information on the commercially available and natural bioadsorbents used for removal of chromium, cadmium and copper, in particular.


2019 ◽  
Vol 7 (12) ◽  
pp. 697 ◽  
Author(s):  
Chaolin Fang ◽  
Varenyam Achal

The global energy crisis and heavy metal pollution are the common problems of the world. It is noted that the microbial fuel cell (MFC) has been developed as a promising technique for sustainable energy production and simultaneously coupled with the remediation of heavy metals from water and soil. This paper reviewed the performances of MFCs for heavy metal removal from soil and water. Electrochemical and microbial biocatalytic reactions synergistically resulted in power generation and the high removal efficiencies of several heavy metals in wastewater, such as copper, hexavalent chromium, mercury, silver, thallium. The coupling system of MFCs and microbial electrolysis cells (MECs) successfully reduced cadmium and lead without external energy input. Moreover, the effects of pH and electrode materials on the MFCs in water were discussed. In addition, the remediation of heavy metal-contaminated soil by MFCs were summarized, noting that plant-MFC performed very well in the heavy metal removal.


2020 ◽  
Vol 1010 ◽  
pp. 489-494
Author(s):  
Abdul Hafidz Yusoff ◽  
Rosmawani Mohammad ◽  
Mardawani Mohamad ◽  
Ahmad Ziad Sulaiman ◽  
Nurul Akmar Che Zaudin ◽  
...  

Conventional methods to remove heavy metals from polluted water are expensive and not environmentally friendly. Therefore, this study was carried out to investigate the potential of agricultural waste such as pineapple peel (Ananas Cosmos) as low-cost absorbent to remove heavy metals from synthetic polluted water. The results showed that Cd, Cr and Pb were effectively removed by the biosorbent at 12g of pineapple peels in 100 mL solution. The optimum contact time for maximum adsorption was found to be 90 minutes, while the optimum pH for the heavy metal’s adsorption was 9. It was demonstrated that with the increase of adsorbent dosage, the percent of heavy metals removal was also increased due to the increasing adsorption capacity of the adsorbent. In addition, Langmuir model show maximum adsorption capacity of Cd is 1.91 mg/g. As conclusions, our findings show that pineapple peel has potential to remove heavy metal from polluted water.


2009 ◽  
Vol 620-622 ◽  
pp. 125-128 ◽  
Author(s):  
Sung Won Kang ◽  
Seog Ku Kim ◽  
Sang Leen Yun ◽  
Hye Cheol Oh ◽  
Jae Hwan Ahn

This research was conducted to investigate the application of the novel upflow-type filtration device using hydrophobia media made of expanded polypropylene (EPP) from driveways site. The higher level of motorway-derived heavy metal contamination exists in stormwater runoff from a road section and the heavy metal levels were higher than the regulated Korean environmental guideline in lake and river. For Cd, Cr, Cu, Pb and Zn, the influent event mean concentrations (EMCs) during 8 storm periods were 2.75, 37.3, 90.5, 118.5 and 546.5 µg/L, respectively. The novel upflow-type filtration device with main mechanism of filtration and adsorption showed removal (>91%, >93%, >85%, >91% and >80%) of the studied heavy metals (Cd, Cr, Cu, Pb and Zn) and differences of medians of removal efficiencies among heavy metals were not statistically signficant by Kruskal-Wallis test (p>0.05) during 8 storm events. It is found that EPP media is very effective at the removal of the heavy metals, and the magnitude of heavy metal removal in a decreasing order is Cr, Cd, Pb, Cu and Zn.


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