arsenic bioremediation using diffenet biological factors

7/28/2019 Arsenic bioremediation using diffenet biological factors

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Bioremediation of arsenic using algae,

bacteria and fungi

Mohamed Wahby Hussein

M.Sc. Candidate

Faculty of science - Alexandria University

16 May 2013


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Introduction

The global water budget contains about 97.2% saltywater, mainly in oceans, and only 2.8% is available as

fresh water at any time on the planet. Out of this

2.8% of fresh water, about 2.2% is available as

surface water and 0.61% as ground water. Water that

collects below the land surface in soil, sediment, and

permeable rock strata is called groundwater(Ehrlich,

H.L., Newman, D.K., 2009).

Mohamed Wahby - M.Sc. candidate -Faculty of science, Alexnadria University


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Introduction (contd.)

Out of those 0.61% of stored ground water, only

about 0.25% can be economically extracted with the

present drilling technology (the remaining being at

greater depths). Thus, it can be said that the groundwater is the most possible accessible water source

on earth (Raghunath, 2006)



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Arsenic definition

Arsenic is a toxic metalloid found in rocks, soil, water,

sediments, and air. Despite its low crustal abundance

(0.0001%), it is widely distributed in nature and is

commonly associated with the ores of metals likecopper, lead, and gold (Johri, 2012).



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Mobilization and accumulation

Mobilization of arsenic due to the oxidation of

arsenic bearing pyrite minerals. Insoluble arsenic

bearing minerals such as arsenopyrite (FeAsS) are

rapidly oxidized when exposed to atmosphere,releasing soluble arsenite As(III), sulphate (SO4-2),

and ferrous iron Fe(II).

FeAsS +13Fe+3 + 8H2O = 14 Fe+2 + SO4

-2 +13H+ +H3AsO4 (Aq.)



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Dissolution of arsenic rich iron oxyhydroxides

(FeOOH) due to onset of reducing conditions in the

subsurface.

Under oxidizing conditions, and in the presence ofFe, inorganic species of arsenic are predominantly

retained in the solid phase through interaction with

FeOOH coatings on soil particles.



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Release of arsenic sorbed to aquifer minerals by

competitive exchange with phosphate (H2PO-4) ions

that migrate into aquifers from the application of

fertilizers to surface soil. The second mechanism involving dissolution of

FeOOH under reducing conditions is considered to

be the most probable reason for excessive arsenic

accumulation in groundwater.



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Volcanoes are also considered as a geological source

of arsenic to the environment with the total

atmospheric annual emissions from volcanoes being

estimated at 31,000 mg/year.



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Sources of arsenic

From anthropogenic activities, arsenic discharged

onto land originate from commercial wastes (~40%),

coal ash (~22%), mining industry (~16%), and the

atmospheric fallout from the steel industry (~13%).



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Sources of arsenic

Biological sources

contribute only small

amounts of arsenic

into soil and waterecosystems. Arsenic

accumulates readily in

living tissues because

of its strong affinity forproteins, lipids, and

other cellular

components .Mohamed Wahby - M.Sc. candidate -

Faculty of science, Alexnadria University


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Accumulation and transportation in

food chain

Aquatic organisms canaccumulate arsenic easily,thus accumulatingconsiderably higher

concentrations than theirsurroundings (i.e.,biomagnification). Theseorganisms contribute to

environmentalcontamination uponconsumption ordisposal/degradation.



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Effect of arsenic on human health

Arsenic problem was first identified in West Bengal in

the 1990s when people started showing typical signs

of arsenicosis, beginning with skin rashes and leading

to cancers of major organs such as the lungs,kidneys, and bladder.



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Effect of arsenic on human health

(Contd)

There are millions of people are at risk of developing

health effects associated with the ingestion or

arsenic. A number of large aquifers in various parts

of the world have been identified with arsenic

occurring at concentrations above 10 g/L, the

maximum concentration limit (MCL) recommended

for drinking water by the World Health Organization.



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Algae in bioremediation



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Algae in bioremediation



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Bioremediation (Algae)

The alga releases metallothioneins which chemically

binds to the metal as a defense mechanism to

remove the metal from its regular cellular activity.



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Chlorella sp. and Scenedesmus sp. are the two most

common algae species used for metal uptake.



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Chlorella sp. was exposed to concentrations of arsenite

ranging from 0 to 100 g/mL. The cell growth ofChlorella sp.

was not affected by the arsenite until it was exposed to

concentrations higher than 50 g/mL.

At concentrations greater than 50 g As/mL, the cell growth

of the species was suppressed. It was concluded that

Chlorella sp. retained approximately 50% of arsenite from a

solution. Also, it was observed that most of the biosorption

was rapid and occurred in the first 15 min by the Chlorellasp.



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Scenedesmusabundans as a possible cost effective

method of bioremediation of arsenic from water



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Scenedesmusabundans biomass (40 mg/L) wasexposed to varying concentrations of As(III) i.e. 1, 5,10, 20, 50 and 100 mg/L and samples were obtainedat certain time intervals to analyze for residual

arsenic concentrations.

The removal of As(III) was found to be around 70%.Algal morphology changed in presence of arsenic.Sorption of arsenic with algae could be modelled by

the conventional Langmuir isotherm. The isothermconstants indicate a high adsorptive capacity of theselect alga for arsenic.



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It was studied that As (V) biosorption using dried

algae (Lessonia nigrescens) collected in Valparaiso

bay, Chile. The experiments were performedusing

laboratory solutions (200 mg/L, pH 2.5, 4.5 and 6.5). Lessonia nigrescens showed very good adsorption

capacities and its use may be interesting for small

scaledrinking water treatment, deserving further

investigation.



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Lessonia nigrescens



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It was investigated the effectiveness and suitability of

driedmacro-algae (Spyrogira spp.) in removing

arsenic from acid mine drainage(AMD) and other

waters from the Poopo lake basin (Bolivia, Andean

highlands)finding higher efficiency i.e. 8090% of As

removal was attained within 4 days.



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Bioremediation (Bacteria)

Corynebacterium glutamicum, which is used for the

industrial production of amino acids and nucleotides,

is one of the most arsenic-resistant microorganisms

described to date (up to 12 mM arsenite and >400mM arsenate).



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Analysis of the C. glutamicum genome revealed the

presence of two complete ars operons ( ars1 and

ars2 ) comprising the typical three-gene structure

arsRBC, with an extra arsC1located downstream

from arsC1 ( ars1 operon), and two orphan genes (

arsB3 and arsC4).



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It was confirmed that the involvement of both ars

operons in arsenic resistance in C. glutamicum by

disruption and amplification of those genes.

The strains obtained by them were resistant to up to60 mM arsenite, one of the highest levels of

bacterial resistance to arsenite so far described.

They are attempting to obtain C. glutamicum mutant

strains able to remove arsenic from contaminatedwater.



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Bioremediation (Bacteria)

Also, It was reported that arsenic removal by three

bacterial strains namely, Ralstonia eutropha MTCC

2487, Pseudomonas putida MTCC 1194 and Bacillus

indicus MTCC 4374, from wastewater (pH 7.1, 29o

C)containing 15 mg/L arsenic were 67%, 60% and 61%,

respectively. It was also observed that arsenic

concentration of 15 mg/L prolonged the stationary

phase of these strains.



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Genetically engineered organisms

Genetically engineering methods could be used to

enhance intracellular accumulation of both As(III)

and As(V).

It was found that Escherichia coliover expressing

ArsR accumulated 5- and 60-fold-higher levels of

As(III) and As(V) than cells withoutArsR over

expression. The level of arsenic accumulation was

1.5 2.2 nmol/mg dry weight (110173 m gAs/g dw).The engineered cells removed 98% of 0.05 mg/L

As(III) from contaminated water after 1 h.



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Bioremediation (fungi)

It was investigated the bioaccumulation of arsenic inthree filamentous fungi,Aspergillus niger, Serpulahimantioides and Trametes versicolorand theirpossible application in remediation of arsenic.

They were exposed to arsenopyrite (FeAsS) inconcentrations 0.2%, 0.4%, 0.6% and 0.8% (W/V).

T. versicolorwas the most efficient in accumulationwith all amounts, accumulating up to 15 times the

amounts accumulated byA . nigerwhich was the leasteffective in accumulation.



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It was reported that the maximum adsorption

capacities of As(III) onto Penicillium purpurogenum

fungal biomass reached 35.6 mg/g under non-

competitive conditions and 3.4 mg/g undercompetitive conditions by other ions [e.g., Cd(II),

Pb(II), Hg(II)] after 4 h (pH 5, 20C). The fungus could

be used for ten cycles for biosorption.



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Penicillium purpurogenum



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It was reported that Penicillium chrysogenum (a

waste byproduct from antibiotic production) pre-

treated with surfactants (hexadecyl-

trimethylammonium bromide and dodecylamine)and a cationic polyelectrolyte was able to remove

significant amounts of As(V) from waters. At pH 3,

the removal capacities of the modified biomass

ranged from 33.3 to 56.1 mg arsenic/g biomass.



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Methodology

1. Site description and sample collection

2. Chemical analysis for determination of arsenicconcentration

3. Enrichment and isolation of arsenic-resistantbacteria

4. Determination of isolates ability of arsenictransformation and bioaccumulation:

Screening of the arsenate reducing and oxidizingbacteria

Ability of bacteria on bioaccumulation arsenic



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Methodology

5. Identification of most promising organism

5.1. Phenotypic identification

5.1.1. Morphological characterization

5.1.2. Biochemical characterization

5.1.3. Physiological characterization



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Methodology

5.2. Genetic identification of isolated

microorganisms

5.2.1. Isolation of bacterial DNA

5.2.2. PCR amplification of 16S ribosomal

(r)RNA

5.2.3. Analysis of sequence data

6. Determination of maximum tolerance

concentration



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References

Ehrlich, H.L., Newman, D.K. (2009). Geomicrobiology(Fifth edition ed.). NewYork, USA: Taylor & Francis Group

Raghunath, H. (2006). Hydrology, Principles, analysis, design. New Delhi: NewAge International

Johri, B. P. (2012). Microorganisms in environmental management, microbesand environment. New York: Springer

Bolan, N. S. (2008). Manipulating bioavailability to manage remediation ofmetal-contaminated soils. Developments in Soil Science, 32 , 657-678.

Ferguson, J. F., & Gavis, J. (1972). A review of the arsenic cycle in naturalwaters. Water research, 6(11) , 1259-1274.

WHO. (2001).Arsenic in drinking-water, background document fordevelopment of WHO guidelines for drinking-water. Geneva: WHO.

WHO. (1996). Guidelines for drinking water; Health criteria and othersupporting information. Geneva, Switzerland: World Health Organization.

Wang, S., & Zhao, X. . (2009). On the potential of biological treatment forarsenic contaminated soils and groundwater.Journal of environmentalManagement, 2367-2376.

arsenic bioremediation using diffenet biological factors

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