M BASU

S BHATTACHARYA

A K PAUL

University of Calcutta (informally known as Calcutta University or CU) is a collegiate public state university located in Kolkata, West Bengal, India.&nbsp;Within India it is recognized as a &quot;Five-Star University&quot; and accredited &quot;A&quot; Grade by National Assessment and Accreditation Council.

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The University of Calcutta has secured the Fifth position among the Universities of India in the prestigious &quot;Indian University Ranking 2019&quot; list, released by the NIRF of the Ministry of Human Resource Development, Government of India.

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It was established on 24 January 1857, and was one of the first institutions in Asia to be established as a multidisciplinary and Western-style university. Its alumni and faculty include several heads of state, heads of government, social reformers, prominent artists, only academy award winner and Dirac medal winner in India, many Fellows of the Royal Society and five Nobel laureates as of 2019 which is highest in South Asia.

University Of Calcutta

Bulletin of Environmental Contamination and Toxicology

Hexavalent chromium or Cr(VI) enters the environment through several anthropogenic activities and it is highly toxic and carcinogenic. Hence it is required to be detected and remediated from the environment. In this study, low-cost and environment-friendly methods of biosensing and bioremediation of Cr(VI) have been proposed. Crude cell free extract (CFE) of previously isolated Enterobacter aerogenes T2 (GU265554; NII 1111) was prepared and exploited to develop a stable biosensor for direct estimation of Cr(VI) in waste water, by using three electrodes via cyclic voltammetry. For bioremediation studies, a homogeneous solution of commercially available sodium alginate and CFE was added dropwise in a continuously stirred calcium chloride solution. Biologically modified calcium alginate beads were produced and these were further utilized for bioremediation studies. The proposed sensor showed linear response in the range of 10-40 μg L-1 Cr(VI) and the limit of detection was found to be 6.6 μg L-1 Cr(VI). No interference was observed in presence of metal ions, e.g., lead, cadmium, arsenic, tin etc., except for insignificant interference with molybdenum and manganese. In bioremediation studies, modified calcium alginate beads showed encouraging removal rate 900 mg Cr(VI)/m 3 water per day with a removal efficiency of 90%, much above than reported in literature. The proposed sensing system could be a viable alternative to costly measurement procedures. Calcium alginate beads, modified with CFE of E. aerogenes, could be used in bioremediation of Cr(VI) since it could work in real conditions with extraordinarily high capacity. © 2014 Copyright Taylor and Francis Group, LLC.

Journal of Environmental Science and Health - Part A Toxic/Hazardous Substances and Environmental Engineering

Biosensing and bioremediation of Cr(VI) by cell free extract of Enterobacter aerogenes T2

Microbiological analysis of overburden samples collected from chromite mining areas of Orissa, India revealed that they are rich in microbial density as well as diversity and dominated by Gramnegative (58%) bacteria. The phenotypically distinguishable bacterial isolates (130) showed wide degree of tolerance to chromium (2-8 mM) when tested in peptone yeast extract glucose agar medium. Isolates (92) tolerating 2 mM chromium exhibited different degrees of Cr+6reducing activity in chemically defined Vogel Bonner (VB) broth and complex KSC medium. Three potent isolates, two belonging to Arthrobacter spp. and one to Pseudomonas sp. were able to reduce more than 50 and 80% of 2 mM chromium in defined and complex media respectively. Along with Cr+6(MIC 8.6-17.8 mM), the isolates showed tolerance to Ni+2, Fe+3, Cu+2and Co+2but were extremely sensitive to Hg+2followed by Cd+2, Mn+2and Zn+2. In addition, they were resistant to antibiotics like penicillin, methicillin, ampicillin, neomycin and polymyxin B. During growth under shake-flask conditions, Arthrobacter SUK 1201 and SUK 1205 showed 100% reduction of 2 mM Cr+6in KSC medium with simultaneous formation of insoluble precipitates of chromium salts. Both the isolates were also equally capable of completely reducing the Cr+6present in mine seepage when grown in mine seepage supplemented with VB concentrate. © 2013, Sociedade Brasileira de Microbiologia.

Fulltext

Brazilian Journal of Microbiology

Hexavalent chromium reduction by aerobic heterotrophic bacteria indigenous to chromite mine overburden

Arthrobacter sp. SUK 1201, a chromium resistant and reducing bacterium having 99% sequence homology of 16S rDNA with Arthrobacter sp. GZK-1 was isolated from chromite mine overburden dumps of Orissa, India. The objective of the present study was to optimize the cultural conditions for chromate reduction by Arthrobacter sp. SUK 1201. The strain showed 67% reduction of 2mM chromate in 7 days and was associated with the formation of green insoluble precipitate, which showed characteristic peak of chromium in to energy dispersive X-ray analysis. However, Fourier transform infrared spectra have failed to detect any complexation of end products of Cr(VI) reduction with the cell mass. Reduction of chromate increased with increased cell density and was maximum at 10 10cells/ml, but the reduction potential decreased with increase in Cr(VI) concentration. Chromate reducing efficiency was promoted when glycerol and glucose was used as electron donors. Optimum pH and temperature of Cr(VI) reduction was 7.0 and 35°C respectively. The reduction process was inhibited by several metal ions and metabolic inhibitors but not by Cu(II) and DNP. These findings suggest that Arthrobacter sp. SUK 1201 has great promise for use in Cr(VI) detoxification under a wide range of environmental conditions. © 2012 Elsevier B.V.

Journal of Hazardous Materials

Optimization of cultural conditions for growth associated chromate reduction by Arthrobacter sp. SUK 1201 isolated from chromite mine overburden

Serpentine soils collected from Saddle Hills, Chidyatapu and Rutland of Andaman Islands, India were analyzed for physico-chemical and microbiological characteristics and compared with those from adjacent non-serpentine localities. The serpentine soils contained high levels of nickel (1740.0-8033.4 mg/kg dry soil), cobalt (93.2-533.4 mg/kg dry soil) and chromium (302.9-4437.0 mg/kg dry soil), in addition to 62-152 g of iron and 37-60 g of magnesium per kg dry soil. Characteristically the serpentine soils showed low microbial density (6.2-11.3 × 106 colony forming unit/g soil) and activity (1.7-3.5 μg fluorescein/g dry soil/h) than non-serpentine outcrops. Serpentine microbial population was dominated by bacteria which represented 5.12 to 9.5 × 106 cfu/g of soil, while the fungal population ranged from 0.17 to 3.21 × 106 cfu/g of soil. A total of 342 (200 from serpentine and 142 from non-serpentine soils) isolates were compared for Ni, Co and Cr resistance. Serpentine microflora was in general, highly resistant than non-serpentine ones and showed a metal-resistance profile of Cr &gt; Ni &gt; Co. Amongst the serpentine isolates, 8 and 11 bacteria tolerated &gt;12.0 mM Ni and &gt;16.0 mM Cr respectively, while 6 fungal isolates showed a minimum inhibitory concentration (MIC) value &gt;8.0 mM Co. These 25 serpentine strains also showed co-resistance to Cu, Zn and Mn but were sensitive to Hg and Cd. The selected bacterial isolates were resistant to ampicillin, penicillin G and polymyxin B, whereas fungal strains showed resistance to amphotericin B, nystatin and fusidic acid. © 2005 Wiley-VCH Verlag GmbH &amp; Co. KGaA.

Journal of Basic Microbiology

Occurrence of heavy metal-resistance in microflora from serpentine soil of Andaman

Serpentine soils of Andaman Islands, India characteristically contain high levels of nickel, cobalt and chromium and are colonized by indigenous nickel-hyperaccumulating plants. Attempts have been made to isolate and characterize nickel-resistant microorganisms from these hitherto unexplored naturally nickel-percolated soils. The majority of the nickel-resistant organisms showed a minimum inhibitory concentration (MIC) of Ni2+ ranging from 300 to 400 mg/l and about 3.4% of the total 89 isolates representing bacterial strains were able to grow at 400 mg/l Ni2+. The potent Ni2+-resistant strains AND305 and AND603 were tentatively identified as Pseudomonas spp. and strain AND408 as Bacillus sp. following detailed analysis of morphological and physio-biochemical characteristics. Growth kinetics of these Ni2+-resistant bacteria showed a prolonged lag phase in Ni2+-containing media, which extended with increasing nickel concentration. In addition to Ni2+, these isolates were also resistant to Co2+, Cd2+, Cr6+, Fe3+, Cu2+, Mg2+, Mn2+ (50-200 mg/l) and Hg 2+ (0.5-2.0 mg/l) and the multiple metal-resistance of the isolates were also associated with the resistance to antibiotics ampicillin, cycloserine and penicillin G.

World Journal of Microbiology and Biotechnology

Isolation and characterization of nickel-resistant microflora from serpentine soils of Andaman

Water, Air, and Soil Pollution

Chromium-resistant microorganisms isolated from evaporation ponds of a metal processing plant

Applied and Environmental Microbiology

Reduction of Chromate by Desulfovibrio vulgaris and Its c3 Cytochrome

Sorption of Heavy Metals to the Filamentous Bacterium Thiothrix Strain A1

Atmospheric Environment. Part B. Urban Atmosphere

Call for papers

Applied Microbiology and Biotechnology

A method for removal of toxic chromium using dialysis-sac cultures of a chromate-reducing strain of Enterobacter cloacae

Isolation and characterization of chromium-resistant bacteria from tannery effluents

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ISSN	0007-4861