Volume 6 Special Issue 1 2012
Microbiology

ISBN 978-4-903313-90-0

Guest Editor

Chandicharan Rath

North Orissa University, India

CONTENTS AND ABSTRACTS

Shewli Bhattacharya, Jnanendra Rath, Samit Ray (India) Composition, Basic Features and Distribution of`Cyanobacteria in Soil Crusts – A Review (pp 1-12)

Full Text [PDF]

ABSTRACT

Invited Review: Many of the cyanobacterial species are capable of growing on the soil and other terrestrial habitats. Soil particles form an intimate association with cyanobacteria and this results in the formation of cyanobacterial crusts that covers the surface of the soil as a coherent layer. The crusts cover the open spaces between the plantations and the soil surface remain covered by these highly specialized organisms. Crusts are found in an astonishing variety of habitats throughout the world – in desert and semi-desert plant communities ranging from shrubs and succulent desert to open woodlands, in steppe formation in both northern and southern hemisphere, in the gaps between evergreen shrubs and in the forests, on open ground or between alpine or tundra vegetation. Cyanobacteria were the major component of the blackish-brown crusts on the upper surface of the soil. Major works on cyanobacterial crusts have been reported from Africa, North and South America, Europe, Mediterranean region and Asia. Reports from India are meager. Cyanobacterial soil crusts are an important source of fixed carbon and nitrogen, which enrich the soil. They act as ecological indicator, polysaccharides produced by them prevent desiccation, presence of cyanobacteria in the soil augments mineral upake by vascular plants and seed germination is enhanced. Considering the significance of cyanobacterial soil crusts in improving the soil condition and fertility attempts are being made to develop soil crusts artificially. In this review, crust formation, types of cyanobacterial crusts, physiological and biochemical characters of crust cyanobacteria, importance of cyanobacterial crusts in ecology and their distribution in various parts of the world have been discussed in detail.

Ashok Kumar, Shamsher Singh Kanwar (India) Lipase Production in Solid-State Fermentation (SSF): Recent Developments and Biotechnological Applications (pp 13-27)

Full Text [PDF]

ABSTRACT

Invited Review: Lipases are the most widely used biocatalysts, because they can catalyze several unnatural and remarkable reactions in non-aqueous media, such as bio-fuel production, production of value-added products such as esters, organic acids, food, beverage, cosmetics and pharmaceutical materials. Solid-state fermentation (SSF) represents an interesting alternative to produce industrial enzymes at lower costs due to the possibility of using inexpensive agro-industrial residues as culture media. This review aims to explore various agriculture by-products like husk, straw, agricultural raw materials, waste of the oil industry, among others that are locally available and are also cost-effective requiring low nutrient supplementation to produce microbial lipase(s) in SSF. Enzyme production is associated with the growth of the bacterial culture. The physico-chemical fermentation parameters such as pH of the medium, moisture content, particle-size, nature of particles and microbial inoculum level play crucial role(s) in lipase production. SSF has gained renewed interest and fresh attention of researchers to develop processes to achieve large-scale enzyme production by solid waste treatment and in its application in the industry to synthesize the products of commercial value.

Madan Lal Verma (India/Australia), Shamsher Singh Kanwar (India) Harnessing the Potential of Thermophiles: The Variants of Extremophiles (pp 28-39)

Full Text [PDF]

ABSTRACT

Invited Review: Extremophiles are life-forms that thrive under some of the harshest conditions found on earth. In recent years, extremophiles have been discovered in such inhospitable places as active volcanoes, deep sea vents, and the ultra-saline remnants of extinct inland seas. Extensive studies of extremophiles ecology, physiology, and molecular biology have yielded valuable information about life processes at every level, with a number of important industrial applications. This review articles summarize the most outstanding features of thermophilic microorganisms that can survive under extreme conditions. The latest findings on the thermophiles, the protein structure of these exotic organisms, potential applications of extremophiles in biotechnology industries including the production of enzymes, are discussed in the present research study.

Lata Kumari, Shamsher Singh Kanwar (India) Cholesterol Oxidase: Role in Pathogenesis (pp 40-47)

Full Text [PDF]

ABSTRACT

Invited Review: Cholesterol oxidase (COx) catalyzes the oxidation of cholesterol into 4-cholesten-3-one. COx has various clinical and industrial applications. Cholesterol oxidase a bifunctional FAD-containing microbial enzyme belongs to the family oxidoreductases. In recent time, cholesterol oxidase has received great attention due to its wide use in clinical (determination of serum cholesterol) and laboratory practices. The COx has also been implicated in the manifestation of some of the diseases of bacterial (tuberculosis), viral (HIV) and non-viral prion origin (Alzheimer’s). This review summarize the important pathogenic features of COx enzyme, its protein structure, pathogenic bacteria requiring COx for their virulence in host, and some of its clinical applications.

Sanjay Kumar Ojha, Snehasish Mishra, Sarat Kumar Nayak, Mrutyunjay Suar (India) Molecular Biology and Biochemistry for Enhanced Biomethanation (pp 48-56)

Full Text [PDF]

ABSTRACT

Invited Review: Methanogenic bacteria are one amongst the three classes of Archaebacteria representing the most primitive dwellers of the Earth, reportedly since some 3.5 billion years ago. While their activity is inhibited by oxygen, these bacteria are robust enough to appear in a wide variety of ecological niches, such as, the intestinal tracts of ruminants, sewage digesters, groundwater and deep soil/water. Biomethanation by these is an interesting biotechnology that converts almost all types of organic polymers including the recalcitrant lignocelluloses, to methane and carbon dioxide. This process can be enhanced by manipulating various physical, chemical and molecular factors, though molecular level manipulation needs deeper understandings. Research in genetics, gene regulation and expression of methanogens is rapidly progressing. Relatively proficient genetic manipulation system, including cloning, expression and identification of new species in the last few years is definitely going to provide direction and leads to future investigations. Methyl CoM reductase (MCR), the enzyme responsible for biomethanation, constitutes approximately 10% of the total protein in methanogenic cultures. The significance and abundance of MCR inevitably focused initial attention on elucidating its structure and the mechanisms directing its synthesis and regulation. MCR-coding genes have been cloned and sequenced from various methanogens, though biomethanation process as a whole needs to be further understood and standardised. A plausible solution to biomethanation enhancement at the molecular level seems to lie in metagenomics. The biochemistry and microbiology of anaerobiosis of organic polymers to methane and the roles of the participating microbes are discussed here, along with their molecular biology, application and suggestions for enhanced biogas production.

Smita Lata, Smriti Shrivastava, Pratyoosh Shukla (India) An Insight on Recent Advances on Immobilization Methods for Industrial Enzymes and its Relevance to Xylanases (pp 57-61)

Full Text [PDF]

ABSTRACT

Invited Mini-Review: Immobilization is the key for optimizing the operational performance of an enzyme in industry. Immobilization of an enzyme provides greater resistance to changes in physiological conditions such as pH or temperature and leads to the reuse of catalysts, easier reactor operation and separation of products with a wider choice of bioreactors. By virtue of this it provides a cost-effective industrial process. It allows enzymes to be held in place throughout the reaction, following which they are easily separated from the products and can be used again in a far more efficient process and so can be widely used in industries for enzyme-catalyzed reactions. Glycoside hydrolases are enzymes hydrolyzing glycosidic linkages in complex plant polysaccharides and are thus utilized in a number of industries using plant polysaccharides as the raw material. Xylanases are glycoside hydrolases diversely used in various industries including the paper and pulp industry, brewing, animal feed, starch, textiles, etc. The present review describes the state of the art of basic immobilization strategies of enzyme immobilization. We further focus on immobilization of xylanases for commercial applications in various industries.

Sarabjeet Singh Ahluwalia (India) Waste Biomaterials for Removal of Heavy Metals – An Overview (pp 62-67)

Full Text [PDF]

ABSTRACT

Invited Mini-Review: Environment fortification must require the use of natural products instead of chemicals to minimize pollution. The detoxification of metal pollutants from wastewater by the development of biomaterials having higher affinity, capacity and selectivity had been found to be as an alternative over conventional technologies that were often inadequate to reduce concentrations in wastewater to acceptable regulatory standards. Plant-derived biomaterials and biomaterials of agricultural by-products for biosorption of heavy metals are an innovative and alternative low cost technology for treatment and/or reuse of waste products. Biotechnological exploitation of biosorption technology to remove heavy metals depends upon the efficiency of the regeneration of the biosorbent after metal desorption. The purpose of this paper is to approach one of the most relevant parts of biotechnology, namely bioremediation with its particular branch – biosorption – applied for heavy metal removal. In addition to that available information on the various cheaper biomaterials occurring as natural biosorbent, for clean up operation applications along with metal binding mechanism have been highlighted.

Santosh Kumar Sethi, Siba Prasad Adhikary (India) Azotobacter: A Plant Growth-Promoting Rhizobacteria Used as Biofertilizer in Organic Farming (pp 68-74)

Full Text [PDF]

ABSTRACT

Invited Mini-Review: Nitrogen fixation is mainly responsible for improvement of crop yield. In this regard, diazotrophs like Rhizobium, Azotobacter and Azospirillum are important as they enrich nitrogen nutrition in N-deficient soils. Of these, Azotobacter promotes plant growth as well as nitrogen fixation. Thus technology has been developed for making use of Azotobacter biofertilizer for nitrogen and non-nitrogen fixing plants and popularized by educating about their benefits in agriculture to users for practicing integrated nitrogen management.

Elsa Marric, Jyotirmayee Mohanta, Bharati Behera, Abhaya Kumar Dalai (India) Effect of Metal Ions on Biphasic Production of Thermostable Amylase by Bacillus sp. Isolated from a Local Hot Spring from Odisha, India (pp 75-78)

Full Text [PDF]

ABSTRACT

Original Research Paper: The effect of various metal ions on colony growth of five amylase-positive thermo-tolerant Bacillus strains was studied. The metal ions used could be grouped into two categories. One group comprised metal ions that have less than 30% inhibition (Ca²⁺ and Mg²⁺) and the second group consisted of metal ions that impart more than 30% inhibition (Pb²⁺, Ag²⁺, Cr²⁺, Zn²⁺, Hg²⁺ and Cu²⁺). However, Mn²⁺ had an intermediate effect relative to the different strengths of ions used. All strains showed a biphasic pattern of amylase activity with two peaks at 48 and 96 h of culture. To observe the effect of ions on amylase activity at crucial points in the biphasic amylase production curve, i.e. at 48, 72 and 96 h of incubation, two strains, ARBE LlCrg and ARBE UuSs, were selected on the basis of maximum and minimum amylase activity, respectively. Ca²⁺ and Cu²⁺ were selected from the two groups of metal ions with respect to their effect on colony growth. The general biphasic trend was marked with Ca²⁺ and Cu²⁺ supplementation for both strains, although amylase activity increased with Ca²⁺ supplementation and decreased in the presence of Cu²⁺. When starch was added the biphasic trend was more pronounced. However, Ca²⁺ supplementation blurred the biphasic trend.

Sridevi Jagavati, Vimala Rodhe Adivikatla, Nirupama Paritala, Venkateswar Rao Linga (India) Cellulase Production by Co-Culture of Trichoderma sp. and Aspergillus sp. under Submerged Fermentation (pp 79-83)

Full Text [PDF]

ABSTRACT

Original Research Paper: The demand for cellulases is increasing globally because of its potential in the production of cellulosic bioethanol. The major applications of cellulases are in the textile and detergent industries. Cellulases have most promising application in the bioconversion of renewable lignocellulosic biomass into fermentable sugars which can be fermented to ethanol by yeasts. Species of fungi like Trichoderma and Aspergillus are known to be cellulase producers. Fungi of the genus Trichoderma produce relatively large quantities of endo-β-glucanase (E.C.3.2.1.4) and exo-β-glucanase (EC.3.2.1.91), but only low levels of β-glucosidase (EC.3.2.1.21), while those of the genus Aspergillus produce relatively large quantities of endo-β-glucanase and β-glucosidase with low levels of exo-β-glucanase production. Furthermore, the β-glucosidases of T. reesei are subject to product (glucose) inhibition, whereas, those of Aspergillus species are more glucose-tolerant. Most often, T. reesei cellulase preparations are supplemented with Aspergillus, for cellulose saccharification on an industrial scale. The present investigation aims to demonstrate cellulase production by co-culture of Trichoderma sp. and Aspergillus sp. isolated from a degrading wood source. The results showed an increased filter paper activity of 0.46 U/ml for co-culture of Trichoderma sp. and Aspergillus sp. in the ratio of 1:1, when compared to individual filter paper activities of 0.24 and 0.20 U/ml for Trichoderma sp. and Aspergillus sp., respectively. There was also an increase in CMCase and β-glucosidase activities of co-culture, when compared to their monoculture counterparts. The maximum CMCase activity was 13.46 U/ml for co-culture (1:1), when compared to CMCase activities of monocultures, i.e., 8.01 U/ml for Trichoderma sp. and 6.87 U/ml for Aspergillus Maximum β-glucosidase activity of 2.02 U/ml was shown by co-culture (1:1). The monocultures of Trichoderma sp. and Aspergillus sp. showed much lower levels of β-glucosidase i.e., 0.43 U/ml and 0.98 U/ml, respectively.

Vimala Rodhe Adivikatla, Sateesh Lanka, Sridevi Jagavati, Venkateswarlu Bandi, Venkateswar Rao Linga (India) A Co-culture Process with Pichia stipitis NCIM 3498 and Thermotolerant Saccharomyces cerevisiae VS3 for Ethanol Production using Acid Hydrolysate of Delignified Sorghum Straw (pp 84-90)

Full Text [PDF]

ABSTRACT

Original Research Paper: Rising oil prices has attracted the research on bioconversion of lignocellulosic biomass to ethanol as an alternative fuel. Pretreatment of lignocellulosic biomass causes release of fermentable sugars both hexoses and pentoses. An efficient conversion of these two sugars is a prerequisite for a profitable process of bioethanol production from lignocellulose. Considering the approaches available for this conversion, co-culture is a simple process, employing two different organisms for the fermentation of the two sugars. The NaOH delignified sorghum straw released maximum amount of reducing sugars (30.0 g/l) in biphasic dilute acid hydrolysis. The microbial co-cultures of Pichia stipitis NCIM 3498 and thermotolerant Saccharomyces cerevisiae VS3 were employed for efficient bioconversion of mixed sugars present in the hydrolysate into ethanol. The fermentation of detoxified acid hydrolysate with monocultures of P. stipitis, S. cerevisiae VS3 and co-culture produced 10.25 ± 0, 7.40 ± 0.07, and 12.0 ± 0.55 g/L ethanol, respectively.

Sravanthi Koti, Sai Prashanti, Jahnavi Gentela, Srilekha Kothagauni, Sridevi Jagavati, Venkateswar Rao Linga (India) Optimization of Pretreatment of Wheat Straw using Alkali and Biphasic Acid Hydrolysis (pp 91-94)

Full Text [PDF]

ABSTRACT

Original Research Paper: Pretreatment is an important step in the conversion of biomass to biofuels. Alkali pretreatment increases cellulose digestibility and it is the most effective method for lignin solubilization, exhibiting minor cellulose and hemicellulose solubilization compared to acid or hydrothermal processes. The present study describes the potential of pretreatment of wheat straw to degrade lignin and facilitate conversion of polymers to single monomers using alkali treatment followed by biphasic acid hydrolysis. Two alkalis (NaOH and KOH) at various concentrations (0.25, 0.5, 0.75 and 1 M) and at two incubation periods (6 and 12 h at room temperature) were used to delignify wheat straw. 1 M NaOH incubated for 6 h significantly degraded lignin (77%) with minimum sugar loss (1.6%). Further, delignified wheat straw was subjected to two different biphasic acid hydrolyses; firstly, biphasic acid hydrolysis was performed with 2% sulphuric acid at 121°C for 1 h followed by 4% sulphuric acid at 121°C for 1 h. Secondly, biphasic acid hydrolysis was performed with 3% sulphuric acid followed by 4% sulphuric acid under the same conditions. The conversion of holocellulose (cellulose + hemicellulose) during the above two different biphasic acid hydrolyses was 52 ± 2 and 41 ± 2%, respectively.

C. U. Agbo, E. C. Okechukwu (Nigeria), Jaime A. Teixeira da Silva (Japan), E. I. Eze (Nigeria) Gongronema latifolia Clones: Genetic Effects on some Phytochemical Composition and Anti-microbial Activity against Salmonella typhi (pp 95-101)

Full Text [PDF]

ABSTRACT

Original Research Paper: The levels of some phytochemicals (alkaloids, phenols and tannins) and in vitro anti-microbial activity of different genetic resources and plant parts of Gongronema latifolia on Salmonella typhi were determined. There were significant (P = 0.05) differences in genetic effects and plant parts in phytochemical composition and anti-microbial activity against S. typhi. The leaves showed significantly higher phenolic contents (3.81 mg/100 g) than the stems (0.42 mg/100 g). Conversely, the stems contained higher alkaloid and tannin levels (12.50 and 4.67%, respectively) than the leaves (7.80 and 2.99%, respectively). Clone ABS-42-ABA had the highest phenol (4.02 mg/100 g) and alkaloid (13.75%) levels while clone ANS-38-AWKA had the lowest level of phenol (0.24 mg/100 g). The tannin level was significantly higher in clone IMS-20-NJIABA (6.03%) and lower in clone AKS-33-EKPENE EDIENE (2.11%). The leaves expressed significantly higher anti-microbial activity (2.4 mg/ml) against S. typhi than the other plant parts. The antimicrobial activity of the clones on S. typhi was significantly higher in ABS-42-ABA (2.15 mg/ml), and lowest in AKS-33-EKPENE EDIENE (6.43 mg/ml). The phenol concentration had a significantly higher negative correlation with minimum inhibitory concentration (MIC) than other phytochemicals. Similarly, path coefficient analysis indicated that phenol had a higher negative direct effect on MIC. Antibacterial properties shown by the clones and their parts provide a scientific basis and thus validate the use of the plant in treatment of typhoid fever and other bacterial diseases. Also, the varying efficacy by the different genetic resources and the plant parts with respect to phytochemical contents and anti-microbial activity against S. typhi could be the basis for further selection and improvement of the species for pharmacological purposes against typhoid fever.

Pushpita Mishra, Sriprakash Mohanty, Mrinal Samanta, Chandi Charan Rath (India) Reestablishment of Cellulase-Producing Bacteria in the Intestine of Grass Carp (Ctenopharyngodon idella) (pp 102-108)

Full Text [PDF]

ABSTRACT

Original Research Paper: Cellulase-producing aeorobic bacterial flora in the intestine of phytophagous Chinese grass carp (Ctenopharyngodon idella) were isolated and characterized using selective carboxymethylcellulose agar (CMC-agar) medium. Bacteria were identified and characterized by conventional, biochemical and API kits. Out of 48 bacteria isolated, 26 were cellulase-positive. b-glucosidase activity was measured to discover potential cellulase-producing strains. Bacillus, Erwinia and Actinobacillus species were good b-glucosidase producers (0.186, 0.181 and 0.180 U/ml/h, respectively). Antibiotic sensitivity tests were conducted for all the isolates against 22 antibiotics based on their spectrum in order to find the most sensitive antibiotic and hence making the intestine devoid of cellulase-producing bacteria and again establishing the potent cellulolytic bacteria by a dip treatment. Antibiogram results revealed that almost all isolates were resistant to clindamycin, erythromycin and metronidazole but sensitive to ciprofloxacin and trimethoprim. This information might contribute to the utilization of these extracellular enzyme-producing bacteria in commercial aquaculture.

Subhadip Mahapatra, Debdulal Banerjee (India) Production and Characterization of Thermal Acid Amylase from Aspergillus aculeatus DBF9 (pp 109-112)

Full Text [PDF]

ABSTRACT

Original Research Paper: Amylase was produced through submerged fermentation of Aspergillus aculeatus DBF9. Initial media pH of 6.0, incubation time of 48 h and an incubation temperature of 30°C were found optimum for amylase production. The enzyme was partially purified through acetone precipitation. Amylase activity was found highest at 50°C and at pH 5.5. The enzyme was stable within a temperature range of 30-40°C and pH 5.0-7.0. Among different metal ions studied, Cu⁺² showed maximum induction (46%) of enzyme activity. Significant inhibitory effect of EDTA (80%) on amylase activity was noticed. From SDS-PAGE and native protein gel electrophoresis only one type of amylase was found from Aspergillus aculeatus DBF9.

Sama Jagadish Kumar, Goli Jyosthna Khanna, Koppaka Nithya, Linga Venkateswar Rao (India) Production of Xylitol from Alkali Pre-Treated Corn Cobs Hydrolysate (pp 113-117)

Full Text [PDF]

ABSTRACT

Original Research Paper: Corn cobs consist of cellulose, hemicellulose, lignin and pectin, with about 80% of fermentable sugars of which approximately 48% of sugars are derived from cellulose and 32% sugars derived from hemi cellulose. Both the compounds cellulose and hemicellulose are very important as they have wide range of applications in production of various value added products like ethanol and xylitol. When corn cobs (100 g dry weight) were treated with sodium hydroxide in alkali pretreatment method, 43.83 ± 0.13 g (95%) of hemicellulose (contains 70-90% of xylose) and 0.022 ± 0.011 mg/ml of lignin was obtained. During this process, inhibitor compounds like phenolics and furfurals were found to be 0.27 ± 0.01 mg/ml and 0.0031 ± 0.00040 mg/ml, respectively. Hydrolysate obtained by this alkali pretreatment method gave high yield of hemicellulose and less quantity of inhibitors when compared with normal acid pretreatment method. Hemicellulose pellet obtained by alkali pretreatment method yielded 32.83 ± 0.10 g of xylose (90%), which when further, subjected to fermentation with wild and adapted (20 cycles) Candida tropicalis WP, produced 0.63 and 0.69 g xylitol/g xylose, respectively.

Ashima Kapoor, Shraddha Sharma, Shveta Prakash (India) Optimization of Culture Conditions for the Production of Lipase from Gliomastix indicus and its Enzymatic Properties (pp 118-122)

Full Text [PDF]

ABSTRACT

Research Note: Gliomastix indicus is a novel filamentous fungus which was isolated from a wasteland soil sample collected from Tamil Nadu, India. The strain was tested for the production of extracellular lipase by a submerged fermentation technique and was found to produce 10.6 U/ml lipase activity. The culture conditions were optimized for maximum enzyme production. Parameters such as temperature, incubation period, pH, carbon and nitrogen source were studied. Maximum growth and lipase production were observed after 72 h of incubation at 30°C in culture medium with an initial pH of 7.5. Among the number of oils tested as a carbon source as well as inducer for lipase production, linseed oil at 1% (v/v) resulted in a marked increase in lipase production. Malt extract at 1% was the best nitrogen source. The optimization of various growth parameters resulted in a 2.62-fold increase in lipase activity (27.8 U/ml). Some properties of lipase which are desirable for its industrial applications were characterized. Crude lipase had broad substrate specificity, exhibiting maximal activity with linseed oil as substrate. The enzyme had an optimum temperature of 45°C, with 80% of the maximum activity retained at 45°C. Lipase from G. indicus also exhibited appreciable stability in different organic solvents except n-butanol, suggesting that it has potential to be used in the oil and detergent industries. Among the additives, Ca²⁺ stimulated lipase activity whereas Mn²⁺ and Hg²⁺ had an inhibitory effect.

Chiliveri Swarupa Rani, Panda Smita Hasini, Linga Venkateswar Rao (India) Isolation and Screening of Polygalacturonase-Producing Bacillus sp. (pp 123-126)

Full Text [PDF]

ABSTRACT

Research Note: Polygalacturonases (PGases) are the depolymerizing enzymes which cleave the α (1,4) glycosidic bonds between two galacturonic acid residues and are being used for the pretreatment of waste water from vegetable food processing industries containing pectinaceous material, processing and degumming of plant fibers such as ramie, sunn hemp, buel, etc. In the present study, 20 bacterial strains were isolated from different samples: soil, spoiled vegetables and fruits, and Godavari River water. All the strains were screened for their ability to utilize pectin as the sole carbon source. Out of the 20 bacterial strains studied, 12 possessed pectinolytic activity as evident from zones of hydrolysis on pectin plates. Selected strains were used for pectinase production by submerged fermentation using 0.25% citrus pectin and the enzyme filtrates were assayed for PGase activity by the DNS method. The effect of temperature, pH on enzyme activity and different media on enzyme production was studied. Maximum enzyme production was shown by strain 11 with medium 1 and optimum PGase activity was found to be at pH 9 at 60°C. Based on cultural and morphological studies the strains were preliminarily identified and assigned to the genus Bacillus.

Aparajita Majumder, Supradip Sarkar, Subhash Chandra Kole (India) Characterization of Efficient Arsenic-Removing Bacteria from In-vitro Conditions (pp 127-130)

Full Text [PDF]

ABSTRACT

Research Note: A total of 20 arsenic-tolerant bacterial strains were isolated from arsenic-contaminated soil of eastern India by using basal salt minimal medium (BSMYI) medium supplemented with 150-500 mg l^-1 of arsenate (As^V). Among them, 10 isolates exhibited higher arsenic resistance and could grow in up to 12,000 mg l^-1 of arsenate (As^V) and 200 mg l^-1 of arsenite (As^III). Those 10 isolates were incubated for 3 days in BSMYI medium containing 25 mg l^-1 of both As^V and As^III separately to assess their ability to remove arsenic. The isolates could remove 1.0-6.4 mg l^-1 of As^V and 2.0-7.6 mg l^-1 of As^III from the arsenic-amended media. The bacterial isolate AGH-21 showed the highest arsenic-removing capacity, both for As^V (25.6%) and As^III (30.4%). The isolated pure culture showed white irregular undulating colonies on a BSMYI agar slant and was an encapsulated endospore-forming Gram-positive bacterium. Molecular characterization of the strain based on sequencing of 16SrDNA and subsequent comparison with existing databases identified the organism as Bacillus flexus.