scholarly journals Novel hybrid biofilm system using synthetically engineered curli fibres

Author(s):  
Harshini Ramesh ◽  
Keerthana Pasumarthi ◽  
Maggie Hou ◽  
Jennifer Lee

Hydraulic fracturing, a popular mining technique, generates heavy metal contamination in nearby freshwater aquifers. This poses a threat to both the surrounding ecosystems an  human health if exposed. Existing methods of heavy metal removal can produce additional hazardous byproducts. This proposal presents the use of a hybrid biofilm filter containing graphene and curli fibres with metal binding sites. Curli fibres are amyloid fibrils found on the extracellular biofilm of Escherichia coli (E coli.). Through the use of plasmid vectors, E. coliwill be engineered to produce secreted curli fibres with metal-binding residues. The stability and cohesive properties of the curli fibres augments the adherence to the graphene scaffolding, thus allowing for generation of a hybrid biofilm. With the filtration design and various experimental controls proposed, this model is ready for empirical proof of concept and subsequent quantitative optimization.

2020 ◽  
Vol 58 (5A) ◽  
pp. 22
Author(s):  
Dao Thanh Son ◽  
Van Tai Nguyen ◽  
Thuy Nhu Quynh Vo ◽  
Vinh Quang Tran ◽  
Thi My Chi Vo ◽  
...  

Heavy metal contamination is among the globally environmental and ecological concerns. In this study we assessed the development of the two green algae Schroederia setigera and Selenastrum bibraianum under exposures to 5 – 200 µg/L of Ni, Zn, and Cd in the laboratory conditions. Heavy metal removal efficiency of S. setigera was also tested in 537 µg Ni/L, 734 µg Zn/L, and 858 µg Cd/L. We found that the exposures with these heavy metals caused inhibitory on the growth of S. bibraianum. The S. bibraianum cell size in the 200 µg Zn/L treatment was around two times smaller than the control. However, Zn and Cd at the concentration of 200 µg/L did not inhibit the growth of S. setigera over 18 days of exposure. The S. setigera also grew well during 8 days exposed to Ni at the same concentration. Besides, the alga S. setigera could remove 66% of Zn, 18% of Cd and 12% of Ni out of the test medium after 16 days of incubation. The Vietnam Technical Regulation related to metals should be considered for ecological protection. We recommend to test the metal removal by the alga S. setigera at pilot scale prior to apply it in situ


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.


2006 ◽  
Vol 53 (6) ◽  
pp. 221-226 ◽  
Author(s):  
D. Sano ◽  
K. Myojo ◽  
T. Omura

Water pollution with toxic heavy metals is of growing concern because heavy metals could bring about serious problems for not only ecosystems in the water environment but also human health. Some metal removal technologies have been in practical use, but much energy and troublesome treatments for chemical wastes are required to operate these conventional technologies. In this study, heavy metal-binding proteins (HMBPs) were obtained from metal-stimulated activated sludge culture with affinity chromatography using copper ion as a ligand. Two-dimensional electrophoresis revealed that a number of proteins in activated sludge culture were recovered as HMBPs for copper ion. N-termini of five HMBPs were determined, and two of them were found to be newly discovered proteins for which no amino acid sequences in protein databases were retrieved at more than 80% identities. Metal-coordinating amino acids occupied 38% of residues in one of the N-terminal sequences of the newly discovered HMBPs. Since these HMBPs were expected to be stable under conditions of water and wastewater treatments, it would be possible to utilize HMBPs as novel adsorbents for heavy metal removal if mass volume of HMBPs can be obtained with protein cloning techniques.


Author(s):  
Harendra Kumar Sharma ◽  
Irfan Rashid Sofi ◽  
Khursheed Ahmad Wani

Heavy metal contamination in water is a serious concern to the environment and human health. High concentrations of heavy metals in the environment can be toxic to a variety of living species. Natural bio-absorbents are abundant and inexpensive and considered a waste if not managed properly. The role of bio-absorbents has been widely studied and has been utilized for the removal of heavy metals. The objective of the chapter is to search the database for different absorbents and their efficiency for the removal of heavy metals. Key words related to the study have been used to select different papers published by the researchers all over the world. A rigorous three-tier process has been utilized by the authors to select the papers from the database for the current study. This chapter has identified a few research gaps in the field of heavy metal removal by using different low cast absorbents that need to be taken into account in future research.


Author(s):  
Gor Gevorgyan ◽  
Armine Mamyan ◽  
Tatevik Boshyan ◽  
Tigran Vardanyan ◽  
Ashok Vaseashta

The concentrations of some heavy metals (Fe, Zn, Mn, Cu, Mo, Pb, Cd) were measured in river waters, macrozoobenthos, and fish (Kura scrapers) from one of the most developed mining areas in Armenia, the Debed River catchment basin. In order to assess heavy metal contamination and its hydro-ecological and health effects, the macrozoobenthos quantitative and qualitative parameters, geo-accumulation index, and hazard index were determined. Microalgal extraction experiments were conducted to assess the microalgal remediation efficiency for heavy metal removal from mining wastewaters. The results showed that the rivers in many sites were polluted with different heavy metals induced by mining activities, which adversely affected macrozoobenthos growth and caused human health risks in the case of waters used for drinking purposes. However, the river fish, particularly Kura scrapers, were determined to be safe for consumption by the local people, as per the conditions of the evaluated fish ingestion rate. The results have shown that microalgal remediation, particularly with Desmodesmus abundans M3456, can be used for the efficient removal ~(62–100%) of certain emerging contaminants (Mn, Pb, Cu, Zn, Cd) from mining wastewater discharged in the Debed catchment basin.


2019 ◽  
Vol 18 (1) ◽  
pp. 66-71 ◽  
Author(s):  
Stefan Demcak ◽  
Magdalena Balintova ◽  
Maria Demcakova ◽  
Inga Zinicovscaia ◽  
Nikita Yushin ◽  
...  

Abstract The heavy metal removal from wastewater is very important due to their persistent character in aquatic environment. The use of wooden sawdust is emerging as a potential alternative to the existing conventional technologies for the removal of metal ions from aqueous solutions. The aim of this work is to study the Cu(II) removal of from water by unconventional waste products including the wooden sawdust of poplar, cherry, spruce and hornbeam. The FT-IR spectra of the studied wooden sawdust confirmed the presence of functional groups that have potential for heavy metal binding. The highest efficiency of Cu(II) removal was observed for poplar wooden sawdust at static (86 %) and dynamic (88 %) adsorption experiments. Data obtained by neutron activation analysis revealed that ion exchange is also a mechanism of metal removal by the selected wooden sawdust.


Author(s):  
Yuhuan Fei ◽  
Yun Hang Hu

Heavy metal contamination has caused serious impacts on the environments and risks towards human health, promoting intensive R&D efforts for removal of heavy metals from their primary sources (industrial and...


Nanomaterials ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1792
Author(s):  
Zhaoyuan Gong ◽  
Hiu Ting Chan ◽  
Qilei Chen ◽  
Hubiao Chen

Toxic heavy metal contamination in food and water from environmental pollution is a significant public health issue. Heavy metals do not biodegrade easily yet can be enriched hundreds of times by biological magnification, where toxic substances move up the food chain and eventually enter the human body. Nanotechnology as an emerging field has provided significant improvement in heavy metal analysis and removal from complex matrices. Various techniques have been adapted based on nanomaterials for heavy metal analysis, such as electrochemical, colorimetric, fluorescent, and biosensing technology. Multiple categories of nanomaterials have been utilized for heavy metal removal, such as metal oxide nanoparticles, magnetic nanoparticles, graphene and derivatives, and carbon nanotubes. Nanotechnology-based heavy metal analysis and removal from food and water resources has the advantages of wide linear range, low detection and quantification limits, high sensitivity, and good selectivity. There is a need for easy and safe field application of nanomaterial-based approaches.


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