• KSBB Journal
• /
• v.27 no.2
• /
• pp.75-85
• /
• 2012

Although, microbial arsenic mobilization by dissimilatory arsenate-reducing bacteria (DARB) and the practical use to the removal technology of arsenic from contaminated soil are expected, most previous research mainly has been focused on the geochemical circulation of arsenic. Therefore, in this review we summarized the previously reported DARB to grasp the characteristic for bioremediation of arsenic. Evidence of microbial growth on arsenate is presented based on isolate analyses, after which a summary of the physiology of the following arsenate-respiring bacteria is provided: Chrysiogenes arsenatis strain BAL-$1^T$, Sulfurospirillum barnesii, Desulfotomaculum strain Ben-RB, Desulfotomaculum auripigmentum strains OREX-4, GFAJ-1, Bacillus sp., Desulfitobacterium hafniense DCB-$2^T$, strain SES-3, Citrobacter sp. (TSA-1 and NC-1), Sulfurospirillum arsenophilum sp. nov., Shewanella sp., Chrysiogenes arsenatis BAL-$1^T$, Deferribacter desulfuricans. Among the DARB, Citrobacter sp. NC-1 is superior to other dissimilatory arsenate-reducing bacteria with respect to arsenate reduction, particularly at high concentrations as high as 60 mM. A gram-negative anaerobic bacterium, Citrobacter sp. NC-1, which was isolated from arsenic contaminated soil, can grow on glucose as an electron donor and arsenate as an electron acceptor. Strain NC-1 rapidly reduced arsenate at 5 mM to arsenite with concomitant cell growth, indicating that arsenate can act as the terminal electron acceptor for anaerobic respiration (dissimilatory arsenate reduction). To characterize the reductase systems in strain NC-1, arsenate and nitrate reduction activities were investigated with washed-cell suspensions and crude cell extracts from cells grown on arsenate or nitrate. These reductase activities were induced individually by the two electron acceptors. Tungstate, which is a typical inhibitory antagonist of molybdenum containing dissimilatory reductases, strongly inhibited the reduction of arsenate and nitrate in anaerobic growth cultures. These results suggest that strain NC-1 catalyzes the reduction of arsenate and nitrate by distinct terminal reductases containing a molybdenum cofactor. This may be advantageous during bioremediation processes where both contaminants are present. Moreover, a brief explanation of arsenic extraction from a model soil artificially contaminated with As (V) using a novel DARB (Citrobacter sp. NC-1) is given in this article. We conclude with a discussion of the importance of microbial arsenate reduction in the environment. The successful application and use of DARB should facilitate the effective bioremediation of arsenic contaminated sites.

• Economic and Environmental Geology
• /
• v.34 no.4
• /
• pp.345-354
• /
• 2001

The effects on arsenic geochemistry of indigenous microorganisms isolated from an area contaminated with high concentration of arsenic were investigated. Arsenite exerted higher inhibitory effects on the microbes' growth than arsenate. During incubation of the microbes in an arsenate-spiked medium over 24 hours, decrease in microbial growth was observed as arsenate content increased. Arsenate of 150 mM or over apparently inhibited cell growth. However, further incubation for up to 4 days in the high arsenate concentration medium resulted in cell growth, implying that the microorganisms adjusted their biochemical functions to detoxify arsenic and maintain growth. Two types of microbes were observed during 20 hours to reduce arsenate to arsenite in solution through a detoxification mechanism. As well, decrease in the total arsenic content occurred over a 4-day incubation with the same microbes in an arsenate-spiked medium. Therefore it is suggested that microorganisms can influence arsenic speciation in natural settings and this may be applied to efficient bioremediation of arsenic-contaminated sites.

• Korean Journal of Soil Science and Fertilizer
• /
• v.41 no.6
• /
• pp.369-373
• /
• 2008

Special concern has been given to the elevated arsenic content in soils because of its high mobility and toxicity. Layered double hydroxide (LDH) which has a high anionic exchange capacity is another potential anion adsorbent for toxic anions such as arsenic, chromate and selenium etc. The uptake of arsenate from aqueous solutions by the calcined Mg-Al LDH has been investigated. The sorption capacity was about 530 mmol/kg. Sorption isotherm was defined as L-type in which arsenate was removed by LDH through anion uptake reaction. Arsenate sorption by the calcined Mg-Al LDH was occurred by reconstruction of LDH's framework. Competitive adsorption revealed that Mg-Al LDH had higher selectivity for arsenate than for sulfate. These results strongly suggest that calcined Mg-Al LDH has a promising potential for efficient removal of toxic metal oxides like arsenates from aqueous environments.

• Economic and Environmental Geology
• /
• v.38 no.5 s.174
• /
• pp.579-585
• /
• 2005

Cheap and environmental sound biosorbent was made for the adsorption of arsenate using an waste activated sludge. The biosorbents were methylated in 9hours and 24 hours respectively for the better adsorption of arsenate. The amount adsorbed of arsenate(V) increased with increasing methylation time. The specific arsenate adsorption was 0.06mmol As(V)/g biomass when the biosorbent was methylated in 24 hours. The methylated biosorbents were also studied with pH 5, 7 and 9. The pH of the solution affect the amount of adsorption of arsenate of the biosorbent even though it was methylated. The specific arsenate adsorption of the biosorbent at pH 5 was best and it was three times greater than the amount of arsenate adsorbed at pH 9.

• Korean Journal of Plant Resources
• /
• v.27 no.4
• /
• pp.344-353
• /
• 2014

This study was carried out to analyze the effect of arsenic types on growth and arsenic accumulation ability of Pteris multifida. Among arsenic pollution sources, Sodium arsenate, Calcium arsenate, Sodium arsenite and Potassium arsenite were treated in horticultural compost contaminated with $500mg{\cdot}kg^{-1}$. P. multifida was cultivated for 12 weeks. The results of study, Calcium arsenate treatment showed slightly decreased growth of P. multifida. But, growth of P. multifida cultivated in the remaining arsenic treatment was similar to untreated control plot. With only short-term cultivation of 4 weeks, aerial part of P. multifida in Sodium arsenate treatment showed high arsenic accumulation of $2,289.5mg{\cdot}kg^{-1}DW$. The arsenic accumulation ($2,956.0mg{\cdot}kg^{-1}DW$) was the highest at 12 week. On the other hand, underground part showed the highest arsenic accumulation in Potassium arsenite treatment ($2,470.2mg{\cdot}kg^{-1}DW$) and Calcium arsenate treatment accumulated $1,060.7mg{\cdot}kg^{-1}DW$ of arsenic. Regardless of arsenic types, aerial part of P. multifida was absorbed more than $1000mg{\cdot}kg^{-1}DW$ of arsenic. And removal of arsenic in soil was also higher. Therefore, Pteris multida is considered to be suitable phytoremediation meterial of various arsenic contaminated areas.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
• /
• 2005.04a
• /
• pp.175-177
• /
• 2005

Effect of arsenite, arsenate and dimethylarsinic acid (DMA) on the growth of seedling plants were investigated in order to compare the toxicity of arsenic species in soil environments. Test plants were mung bean (Phaseolus radiatus), wheat (Triticum aestivum), barely (Hordeum vulgare), cucumber (Cucumis sativus L.). Seedling growth in As-contaminated soil were significantly reduced in all test species. Arsenite was more toxic than arsenate and DMA. Among the test plants, mung bean was most sensitive to arsenic, followed by cucumber, wheat, and barely.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.34 no.1
• /
• pp.55-59
• /
• 1989

Sodium methyl arsenate has been evaluated as a male sterilizing agent for the system of producing hybrid rice seeds. The compound was the most effective at the concentration of 0.02％. When applied as a foliar spray to four rice varieties at 15 days before heading, sodium methyl arsenate has produced 99％ male sterility. But the most effective time for application of the compound was 5 days before heading because of its phytotoxic effects. Effective application volume of the compound solution has depended on the growth of the plants treated. Varietal difference on the activity of the compound has been detected.

• Journal of Microbiology and Biotechnology
• /
• v.12 no.1
• /
• pp.31-38
• /
• 2002

Bacteria have evolved various types of resistance mechanism to toxic heavy metals, such as arsenic and antimony. An arsenical and antimonial resistant bacterium was isolated from a shallow creek draining a coal-mining area near Taebaek City, in Kangwon-Do, Korea. The isolated bacterium was identified and named as Pseudomonas sp. KM20 after biochemical and physiological studies were conducted. A plasmid was identified and its function was studied. Original cells harboring the plasmid were able to grow in the presence of 15 mM sodium arsenite, while the plasmid-cured (plasmidless) strain was sensitive to as little as 0.5 mM sodium arsenate. These results indicated that the plasmid of Pseudomonas sp. KM20 does indeed encode the arsenic resistance determinant. In growth experiments, prior exposure to 0.1 mM arsenate allowed immediate growth when they were challenged with 5 mM arsenate, 5 mM arsenite, or 0.1 mM antimonite. These results suggested that the arsenate, arsenite, and antimonite resistance determinants of Pseudomonas sp. KM20 plasmid were indeed inducible. When induced, plasmid-bearing resistance cells showed a decreased accumulation $of\;73^As$ and showed an enhanced efflux $of\;^73As$. These results suggested that plasmid encoded a transport system that extruded the toxic metalloids, resulting in the lowering of the intracellular concentration of toxic oxyanion. In a Southern blot study, hybridization with an E. coli R773 arsA-specific probe strongly suggested the absence of an arsA cistron in the plasmid-associated arsenical and antimonial resistance determinant of Pseudomonas sp. KM20.

• Analytical Science and Technology
• /
• v.32 no.1
• /
• pp.1-6
• /
• 2019

Chinese brake fern (Pteris vittata) has potential for application in the phytoremediation of arsenic introduced by lead arsenate-based pesticides. In this study, Chinese brake ferns were used to extract arsenic, mainly in field and greenhouse experiments, and to assess the performance of simultaneous phytoaccumulation of arsenic and lead from homogenized soil in the greenhouse, with the application of EDTA and electric potential. The ferns have been shown to be effective in accumulating high concentrations of arsenic, and extracting both arsenic and lead from the contaminated soil, with the addition of a chelating agent, EDTA. The maximum increase in lead accumulation in the ferns was 9.2 fold, with a 10 mmol/kg addition of EDTA. In addition, the application of EDTA in combination with electric potential increased the lead accumulation in ferns by 10.6 fold at 5 mmol/kg of EDTA and 40 V (dc), compared to controls. Therefore, under application of EDTA and electric potential, Chinese brake fern is able to extract arsenic and lead simultaneously from soil contaminated by lead arsenate.

• Proceedings of the Korean Society of Crop Science Conference
• /
• 1989.02a
• /
• pp.24-25
• /
• 1989