scholarly journals Reduction of Hexavalent Chromium by Viable Cells of Chromium Resistant Bacteria Isolated from Chromite Mining Environment

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Satarupa Dey ◽  
Baishali Pandit ◽  
A. K. Paul
Keyword(s):  
Hexavalent Chromium ◽  
Divalent Cations ◽  
Reduction Process ◽  
Cost Effective ◽  
Batch Cultivation ◽  
Resistant Bacteria ◽  
Chromate Reduction ◽  
Viable Cells ◽  
Mining Environment ◽  
Chromite Mining

Environmental contamination of hexavalent chromium [Cr(VI)] is of serious concern for its toxicity as well as mutagenic and carcinogenic effects. Bacterial chromate reduction is a cost-effective technology for detoxification as well as removal of Cr(VI) from polluted environment. Chromium resistant and reducing bacteria, belonging to Arthrobacter, Pseudomonas, and Corynebacterium isolated from chromite mine overburden and seepage samples of Orissa, India, were found to tolerate 12–18 mM Cr(VI) during growth. Viable cells of these isolates were also capable of growing and reducing 100 μM Cr(VI) quite efficiently in Vogel Bonner (V.B.) broth under batch cultivation. Freshly grown cells of the most potent isolate, Arthrobacter SUK 1201, reduced 100 μM Cr(VI) in 48 h. Reduction potential of SUK 1201 cells decreased with increase in Cr(VI) concentration but increased with increase in cell density and attained its maximum at 1010 cells/mL. Chromate reducing efficiency of SUK 1201 was promoted in the presence of glucose and glycerol while the highest reduction was at pH 7.0 and 25°C. The reduction process was inhibited by divalent cations Ni, Co, and Cd, but not by Cu. Similarly, carbonyl cyanide m-chlorophenylhydrazone, N,N,-Di cyclohexyl carbodiimide, sodium azide, and sodium fluoride were inhibitory to chromate reduction, while 2,4 dinitrophenol promoted the process. Cells permeabilized by toluene increased the efficiency of Cr(VI) reduction and, thereby, indicate that Arthrobacter sp. SUK 1201, indigenous to chromite mining environment, could be used as an ideal tool for chromium bioremediation.

122 Bioactive Peptides for Enhancing Intestine Health

2021 ◽  
Vol 99 (Supplement_3) ◽  
pp. 65-65
Author(s):  
Julang Li ◽  
Nadeem Akhtar ◽  
Celina Osakowicz ◽  
Lauren Fletcher ◽  
Karmin O ◽  
...  
Keyword(s):  
Animal Health ◽  
Clinical Signs ◽  
Body Weight Loss ◽  
Cost Effective ◽  
Significant Rise ◽  
Feed Ratio ◽  
Resistant Bacteria ◽  
Intestinal Development ◽  
Antibiotic Resistant ◽  
Animal Trials

Abstract Intestinal disorders and colitis affect both animals and humans. The pathogenesis behind the inflammation is complex and not entirely understood. Furthermore, the significant rise in antibiotic-resistant bacteria has emphasized an urgent need for alternative anti-infective therapies. Antimicrobial peptides (AMPs) is one of the appealing alternative to antibiotics due to their antimicrobial activity, mode of actions, and potential role in tissue repair. Epidermal growth factor (EGF) plays an important role in intestinal proliferation and differentiation and thus promotes intestinal development. Using food grade microorganisms such as Lactococcus lactis and yeast as hosts, our laboratory has produced recombinant porcine protegrin-1 (PG-1), a pig originated antimicrobial peptide and EGF via fermentation. Oral administration of PG-1 reduced Citrobacter rodentium induced intestinal infection in mice. This was evidenced by reduced histopathological changes in the colon, prevention of body weight loss, milder clinical signs of disease, and ultimately more effective clearance of bacterial infection. On the other hand, animal trials using the recombinant EGF demonstrated that it enhances intestinal development and growth of early weaned pig fed with antibiotic-free diet. Moreover, piglets challenged with enterotoxigenic Escherchia coli (E. coli) K88 showed similar beneficial responses to EGF as those fed diets with antibiotic in terms of improving gain to feed ratio and lowering oxidative stress. Taken together, our findings suggest the potential for cost-effective production and application of recombinant bioactive proteins as alternatives to antibiotics in animal health and production.

DISPERSION OF COBALT FERRITE FUNCTIONALIZED GRAPHENE NANOPLATELETS IN PLA FOR EMI SHIELDING APPLICATIONS

2021 ◽  
Author(s):  
KANAT ANURAKPARADORN ◽  
ALAN TAUB ◽  
ERIC MICHIELSSEN
Keyword(s):  
Functional Groups ◽  
Electromagnetic Interference ◽  
High Speed ◽  
Magnetic Particles ◽  
Cobalt Ferrite ◽  
Reduction Process ◽  
Cost Effective ◽  
Graphene Nanoplatelets ◽  
Angle Of Incidence ◽  
Emi Shielding

The proliferation of wireless technology calls for the development of cost-effective Electromagnetic Interference (EMI) shielding materials that reduce the susceptibility of high-speed electronic circuits to undesired incoming radiation. Ideally, such materials offer protection over wide frequency ranges and are insensitive to the polarization or angle of incidence of the impinging fields. Here, next-generation EMI shielding materials composed of polymer composites with conductive and magnetic fillers are introduced. It is shown that careful control of the concentration and dispersion of the polymers’ conductive and magnetic constituents permits tuning of the composites’ intrinsic electrical and magnetic properties. The resulting EMI shields are lightweight, cheap and offer greater protection than traditional metal gaskets and foams. In this work, cobalt ferrite magnetic nanoparticles (CoFe2O4) decorated on graphene-based material were dispersed in polylactic acid (PLA) matrix for high EM absorption level in X-band (8-12 GHz). The decoration of the magnetic particles was performed on the as-prepared conductive graphene nanoplatelets (GNP) and reduced graphene oxide (rGO). GNP composites exhibited higher DC conductivity, and permittivity than rGO composites. This is attributed to issues associated with the reduction process, including a lack of conductivity due to the insulated oxygen functional groups and the reduction in the lateral size. Compared with rGOs, the lack of out-plane functional groups causes the cobalt ferrite nanoparticles to agglomerate and not cover the entire surface of the GNPs. These morphological differences improve the magnetization and EM absorption of the composite system. The compatibilizer (pyrene-PLA-OH) was added to the composites to enhance dispersion of the GNPs in the polymer matrix which benefits in higher absorption of the shield. The influence of the compatibilizer on parameter, the reflection loss (RL) of the composite were determined from the characterized intrinsic properties

Chromate Reduction by Chromium-Resistant Bacteria Isolated from Soils Contaminated with Dichromate

2003 ◽  
Vol 32 (4) ◽  
pp. 1228 ◽  
Author(s):  
F. A. O. Camargo ◽  
F. M. Bento ◽  
B. C. Okeke ◽  
W. T. Frankenberger
Keyword(s):  
Resistant Bacteria ◽  
Chromate Reduction

scholarly journals Bioreduction of Cr(VI) by Viable Cells and Cell-Free Extract of a Moderate Halophile, Halomonas Smyrnensis KS802 and Evaluation of Their in Vitro Efficacy in Tannery Effluent

2020 ◽  
Author(s):  
Jhuma Biswas ◽  
AK Paul
Keyword(s):  
Reductase Activity ◽  
Basal Medium ◽  
Tannery Effluent ◽  
Chromate Reduction ◽  
Cell Free Extract ◽  
Tannery Effluents ◽  
Moderate Halophile ◽  
Viable Cells ◽  
Reducing Ability ◽  
Halomonas Smyrnensis

Abstract The present study was aimed to characterize the chromate reducing ability of cells and cell-free extract (CFE) of Halomonas smyrnensis KS802 (GenBank Accession No. KU982965) and evaluate their effectiveness in tannery effluents. Viable cells of the strain reduced 200 µM Cr(VI) in basal medium for halophiles (MH) in 10 h and was inversely proportional to Cr(VI) concentrations. The rapid reduction by cells (10⁹ cells/mL) was achieved with 7.5% NaCl, at pH 7 and 37°C which increased with increasing cell density (10¹° cells/mL). While acetate, Cu³⁺, Fe³⁺, SO₄²⁻, and CO₃²⁻ were stimulating the reduction, the inhibitors retarded the process significantly. The NADH-dependent chromate reduction of the CFE was found to be constitutive with Km and Vmax values of 56.58 µM and 3.37 µM/min/mg protein respectively. The optimal reductase activity of the CFE was evident at 200 µM Cr(VI), 10% NaCl, pH 8.0 and at 45°C. A higher concentration of CFE and electron donors increased the enzyme activity but was impacted negatively by toxic metals and anions. Both the cells and CFE were capable of reducing Cr(VI) remarkably from tannery effluent. FTIR and XRD spectra of chromate reducing cells confirmed possible complexation of reduced Cr-species with functional groups on cell surface.

scholarly journals Reversion of antibiotic resistance in drug-resistant bacteria using non-steroidal anti-inflammatory drug benzydamine

2021 ◽  
Author(s):  
Yuan Liu ◽  
Ziwen Tong ◽  
Jingru Shi ◽  
Tian Deng ◽  
Ruichao Li ◽  
...  
Keyword(s):  
Cost Effective ◽  
Multidrug Resistant ◽  
Resistant Bacteria ◽  
Inflammatory Drug ◽  
Development Of Resistance ◽  
Drug Resistant Bacteria ◽  
Metabolic States ◽  
Anti Inflammatory ◽  
Approved Drugs

Antimicrobial resistance has been a growing concern that gradually undermines our tradition treatment regimen. The fact that few antibacterial drugs with new scaffolds or targets have been approved in the past two decades aggravates this crisis. Repurposing previously approved drugs as potent antibiotic adjuvants offers a cost effective strategy to mitigate the development of resistance and tackle the increasing infections by multidrug resistant (MDR) bacteria. Herein, we found that benzydamine, a widely used non-steroidal anti-inflammatory drug in clinic, remarkably potentiated broad spectrum antibiotic tetracyclines activity against a panel of clinical important resistant pathogens, including MRSA, VRE, MCRPEC and tet (X)-positive Gram negative bacteria. Further mechanistically experiments showed that benzydamine dissipated membrane potential (ΔΨ) in both Gram positive and negative bacteria, which in turn upregulated the transmembrane proton gradient (ΔpH) and promoted the uptake of tetracyclines. Additionally, benzydamine exacerbated the oxidative stress by triggering the production of ROS and suppressing GAD system mediated oxidative defensive. This mode of action explains the great bactericidal activity of the doxycycline benzydamine combination against different metabolic states of bacteria including persister cells. As a proof of concept, the in vivo efficacy of this combination therapy was evidenced in multiple animal infection models. These findings revealed that benzydamine is a promising tetracycline antibiotics adjuvant and has the potential to address life threatening infections by MDR bacteria.

Robust on-line control of hexavalent chromium reduction process using a Kalman filter

2002 ◽  
Vol 12 (3) ◽  
pp. 405-412 ◽  
Author(s):  
M.Marzuki Mustafa ◽  
S. Rozaimah ◽  
S. Abdullah ◽  
Rakmi A. Rahman
Keyword(s):  
Kalman Filter ◽  
Hexavalent Chromium ◽  
Reduction Process ◽  
Chromium Reduction ◽  
On Line

The effect of different divalent cations on the reduction of hexavalent chromium by zerovalent iron

2008 ◽  
Vol 84 (1-2) ◽  
pp. 170-175 ◽  
Author(s):  
Meifang Hou ◽  
Hongfu Wan ◽  
Tinglin Liu ◽  
Yanning Fan ◽  
Xinming Liu ◽  
...  
Keyword(s):  
Hexavalent Chromium ◽  
Divalent Cations ◽  
Zerovalent Iron

Metal–organic framework@silica as a stationary phase sorbent for rapid and cost-effective removal of hexavalent chromium

2018 ◽  
Vol 6 (6) ◽  
pp. 2742-2751 ◽  
Author(s):  
Worood A. El-Mehalmey ◽  
Ahmed H. Ibrahim ◽  
Arwa A. Abugable ◽  
Mohamed H. Hassan ◽  
Rana R. Haikal ◽  
...  
Keyword(s):  
Stationary Phase ◽  
Hexavalent Chromium ◽  
Metal Organic Framework ◽  
Cost Effective ◽  
Amino Derivative ◽  
Solid Sorbent ◽  
One Pot ◽  
Effective Removal ◽  
Metal Organic ◽  
Organic Framework

A one-pot synthesis is described to construct a composite of the amino-derivative Zr carboxylate metal–organic framework and silica gel (UiO-66-NH2@silica) as an efficient solid sorbent for hexavalent chromium.

scholarly journals Hexavalent chromium reduction from real electroplating wastewater by chemical precipitation

2020 ◽  
Vol 34 (1) ◽  
pp. 67-74
Author(s):  
Bharti Verma ◽  
Chandrajit Balomajumder
Keyword(s):  
Chemical Analysis ◽  
Hexavalent Chromium ◽  
Ferrous Sulfate ◽  
Reduction Process ◽  
Chemical Precipitation ◽  
Sodium Metabisulfite ◽  
Chromium Reduction ◽  
Naturally Occurring ◽  
Electroplating Process ◽  
Maximum Removal

The immense use of chromium in the electroplating process leads to the discharge of hexavalent chromium in its effluent. Since Cr(VI) is highly toxic, its exposure poses an acute risk of health. On the contrary, Cr(III) which is naturally occurring, is much less toxic than Cr(VI). Therefore the easiest way to deal with Cr(VI) is to reduce it into its trivalent form. Exhaustive chemical analysis was done to reduce Cr(VI) to Cr(III) by using sodium metabisulfite (Na2S2O5) and ferrous sulfate (FeSO4). And after the reduction process, precipitating agents such as (Ca(OH)2), (NaOH) and a combination of the two were used to precipitate Cr(III) as hydroxides. Various parameters were varied and optimized. It was observed that the % Cr(VI) reduction increased from 88% to 99.97% when the dosage of sodium metabisulfite increased from 40 mg/L to 100 mg/L at a pH of 2. The maximum removal of 98.2% was achieved by using the combination of Ca(OH)2 + NaOH at a pH of 9.   Bull. Chem. Soc. Ethiop. 2020, 34(1), 67-74. DOI: https://dx.doi.org/10.4314/bcse.v34i1.6

scholarly journals Natural outer membrane permeabilizers boost antibiotic action against irradiated resistant bacteria

2019 ◽  
Vol 26 (1) ◽  
Author(s):  
Hala A. Farrag ◽  
Nagwa Abdallah ◽  
Mona M. K. Shehata ◽  
Ebthag M. Awad
Keyword(s):  
Outer Membrane ◽  
Synergistic Effects ◽  
Epigallocatechin Gallate ◽  
Cost Effective ◽  
Resistant Bacteria ◽  
Permeability Barrier ◽  
Beta Lactamase ◽  
Conventional Antibiotics ◽  
Triton X

Abstract Background This study sought to develop new strategies for reverting the resistance of pathogenic Gram-negative bacilli by a combination of conventional antibiotics, potent permeabilizers and natural beta lactamase inhibitors enhancing the activity of various antibiotics. Methods The antibiotic susceptibility in the presence of natural non-antibacterial tested concentrations of phytochemicals (permeabilizers and natural beta lactamase inhibitors) was performed by disk diffusion and susceptibility assays. Thymol and gallic acid were the most potent permeabilizers and facilitated the passage of the antibiotics through the outer membrane, as evidenced by their ability to cause LPS release, sensitize bacteria to SDS and Triton X-100. Results The combination of permeabilizers and natural beta lactamase inhibitors (quercetin and epigallocatechin gallate) with antibiotics induced greater susceptibility of resistant isolates compared to antibiotic treatment with beta lactamase inhibitors alone. Pronounced effects were detected with 24.4 Gy in vitro gamma irradiation on permeability barrier, beta lactamase activity, and outer membrane protein profiles of the tested isolates. Conclusions The synergistic effects of the studied natural phytochemicals and antibiotics leads to new clinical choices via outer membrane destabilization (permeabilizers) and/or inactivation of the beta lactamase enzyme, which enables the use of older, more cost-effective antibiotics against resistant strains.

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