Munir A. Anwar

National Institute for Biotechnology and Genetic Engineering, Shah Faisalabad, Punjab, Pakistan

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Publications (10)12.67 Total impact

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    ABSTRACT: Rhodococcus spp. (Eu-32) has the unique ability to metabolize organic sulphur containing compounds like dibenzothiophene through an extended sulphur specific pathway (Akhtar et al., in FEMS Microbiol Lett 301:95-102, 2009). Efforts were made to isolate and characterize the presumed desulphurizing genes (dszABC) involved in the sulphur specific pathway of isolate Eu-32 by employing standard and degenerate polymerase chain reaction primers. The partial dszA gene sequence of isolate Eu-32 showed 92 % sequence identity with a putative FMNH-2 dependent monooxygenase of Rhodococcus erythropolis PR4. The dszC gene sequence showed 99 % homology with the dibenzothiophene monooxygenase desulphurizing enzyme of another Rhodococcus species. The dszB gene was not unambiguously identified. A phylogenetic analysis by maximum likelihood method of the 16S rRNA gene and deduced DszA and C amino acid sequences suggest that horizontal gene transfer events might have taken place during the evolution of desulphurizing genes of Rhodococcus spp. (Eu-32).
    Full-text · Article · Dec 2014 · Biotechnology Letters
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    ABSTRACT: Out of 17 samples collected from diverse environments, 110 bacterial isolates of varied characteristics were screened for their dibenzothiophene-desulphurizing activity. A single isolate, Eu-32, originating from a soil sample taken from the roots of a eucalyptus tree, displayed dibenzothiophene-desulphurizing activity. This isolate metabolized dibenzothiophene to 2-hydroxybiphenyl (2-HBP), as detected by HPLC, and was also able to use other organic sulphur compounds as a sole sulphur source. Based on morphological, biochemical and molecular studies, it was found that the organism belongs to the genus Rhodococcus, with a maximum of 95% identity to species in this genus for the partial sequence of the 16S rRNA gene. Isolate Eu-32 could desulphurize 0.2 mM dibenzothiophene to 2-HBP in 72 h at a temperature of 30 degrees C and pH 7.0. The structure and molecular mass of metabolites produced from dibenzothiophene desulphurization were identified by GC-MS, and two sulphur-free products, 2-HBP and biphenyl, were detected in ethyl acetate extract. It was concluded that isolate Eu-32 is a unique desulphurizing biocatalyst that desulphurizes dibenzothiophene through an extended, sulphur-specific degradation pathway with the selective cleavage of C-S bonds.
    Full-text · Article · Sep 2009 · FEMS Microbiology Letters
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    ABSTRACT: The purpose of this study was to test the feasibility of using iron and sulphur oxidizing bacteria for the acid leaching of a high grade Pb–Zn ore material. Three strains (ATCC 13661, NCIMB 13537 and C2-TF) of Acidithiobacillus ferrooxidans and two strains (MT-TH1 and MT-13) of Sulfobacillus thermosulfidooxidans were tested in this study. The bioleaching was monitored by measuring the dissolved metals and by X-ray diffraction analysis of leach residues. The bioleaching efficiency varied between 0.014 and 0.35. The maximum dissolution of lead was achieved with the mesophilic At. ferrooxidans (NCIMB 13537) at 30 °C. The maximum recovery of zinc was achieved with moderately thermopilic S. thermosulfidooxidans (MT-TH1) at 45 °C.
    Full-text · Article · Jun 2009 · Hydrometallurgy
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    ABSTRACT: Culturable bacterial biodiversity and industrial importance of the isolates indigenous to Khewra salt mine, Pakistan was assessed. PCR Amplification of 16S rDNA of isolates was carried out by using universal primers FD1 and rP1and products were sequenced commercially. These gene sequences were compared with other gene sequences in the GenBank databases to find the closely related sequences. The alignment of these sequences with sequences available from GenBank database was carried out to construct a phylogenetic tree for these bacteria. These genes were deposited to GenBank and accession numbers were obtained. Most of the isolates belonged to different species of genus Bacillus, sharing 92-99% 16S rDNA identity with the respective type strain. Other isolates had close similarities with Escherichia coli, Staphylococcus arlettae and Staphylococcus gallinarum with 97%, 98% and 99% 16S rDNA similarity respectively. The abilities of isolates to produce industrial enzymes (amylase, carboxymethylcellulase, xylanase, cellulase and protease) were checked. All isolates were tested against starch, carboxymethylcellulose (CMC), xylane, cellulose, and casein degradation in plate assays. BPT-5, 11,18,19 and 25 indicated the production of copious amounts of carbohydrates and protein degrading enzymes. Based on this study it can be concluded that Khewra salt mine is populated with diverse bacterial groups, which are potential source of industrial enzymes for commercial applications.
    Full-text · Article · Mar 2008 · Brazilian Journal of Microbiology
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    ABSTRACT: Culturable bacterial biodiversity and industrial importance of the isolates indigenous to Khewra salt mine, Pakistan was assessed. PCR Amplification of 16S rDNA of isolates was carried out by using universal primers FD1 and rP1and products were sequenced commercially. These gene sequences were compared with other gene sequences in the GenBank databases to find the closely related sequences. The alignment of these sequences with sequences available from GenBank database was carried out to construct a phylogenetic tree for these bacteria. These genes were deposited to GenBank and accession numbers were obtained. Most of the isolates belonged to different species of genus Bacillus, sharing 92-99% 16S rDNA identity with the respective type strain. Other isolates had close similarities with Escherichia coli, Staphylococcus arlettae and Staphylococcus gallinarum with 97%, 98% and 99% 16S rDNA similarity respectively. The abilities of isolates to produce industrial enzymes (amylase, carboxymethylcellulase, xylanase, cellulase and protease) were checked. All isolates were tested against starch, carboxymethylcellulose (CMC), xylane, cellulose, and casein degradation in plate assays. BPT-5, 11,18,19 and 25 indicated the production of copious amounts of carbohydrates and protein degrading enzymes. Based on this study it can be concluded that Khewra salt mine is populated with diverse bacterial groups, which are potential source of industrial enzymes for commercial applications.
    Full-text · Article · Mar 2008 · Brazilian Journal of Microbiology
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    ABSTRACT: Pb-Zn ore bioleaching performances of pure un-adapted and metal ion-adapted cultures of Sulfobacillus thermosulfidooxidans as well as its consortium with acidophilic hetertrotroph (6A1TSB) were analyzed. Nearly 58% of Zn was solubilized form the ore with mixed consortium at the rate of 3.0 mg dm -3 h -1, whereas with pure adapted and un-adapted it was 55% and 40% respectively, in 360 h with bioleaching rates of 2.5 mg dm -3h -1 and 1.8 mg dm -3h -1. Similarly maximum lead dissolution (57%) was obtained with mixed consortium, while pure adapted and un-adapted cultures leached out 52% and 26% Pb, respectively. The leaching rates of lead with mixed consortium, pure adapted and un-adapted cultures were 1.25 mg dm -3 h -1, 1.0 mg dm -3h -1 and 0.439 mg dm -3h -1 respectively. Cell dry biomass production rates during bioleaching also followed the same pattern; with the mixed consortium having the highest biomass production rate i.e. 0.0030 g dm -3h -1 and same pattern was observed in case of rate of iron solublization.
    Full-text · Article · Feb 2008 · Journal- Chemical Society of Pakistan
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    Sadia Ilyas · Munir A. Anwar · Shahida B. Niazi · M. Afzal Ghauri
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    ABSTRACT: The present work was aimed at studying the bioleachability of metals from electronic scrap by the selected moderately thermophilic strains of acidophilic chemolithotrophic and acidophilic heterotrophic bacteria. These included Sulfobacillus thermosulfidooxidans and an unidentified acidophilic heterotroph (code A1TSB) isolated from local environments. Among the strategies adapted to obtain enhanced metal leaching rates from electronic scrap, a mixed consortium of the metal adapted cultures of the above-mentioned bacteria was found to exhibit the maximum metal leaching efficiency. In all the flasks where high metal leaching rates were observed, concomitantly biomass production rates were also high indicating high growth rates. It showed that the metal bioleaching capability of the bacteria was associated with their growth. At scrap concentration of 10 g/L, a mixed consortium of the metal adapted cultures was able to leach more than 81% of Ni, 89% of Cu, 79% of Al and 83% of Zn. Although Pb and Sn were also leached out, they were detected in the precipitates formed during bioleaching.
    Full-text · Article · Aug 2007 · Hydrometallurgy
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    Full-text · Conference Paper · Apr 2006
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    ABSTRACT: Random amplification of polymorphic DNA (RAPD), a PCR-based technique was applied to evaluate genomic diversity among three strains of Acidithiobacillus thiooxidans, five strains of Acidithiobacillus ferrooxidans and one acidophilic moderate thermophile strain, using 45 random primers of five different series. More than 2200 bands were observed, with an average of 45 bands per primer. Primer OPC-3 produced the maximum number of fragments whereas minimum numbers of fragments were produced with primer OPA-5. A dendrogram was generated using cluster analysis by the unweighted pair group method of arithmetic means (UPGMA). The dendrogram showed three groups with similarity ranging from 29 to 85%. The maximum similarity (85%) was observed between the strains T.t1 and T.t2 of Acidithiobacillus thiooxidans.
    Full-text · Article · Jan 2005 · World Journal of Microbiology and Biotechnology
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    ABSTRACT: A sensitive and precise spectrophotometric method has been developed for the determination of copper(I) in bacterial leach liquors produced by the action of Thiobacillus ferrooxidans and T. thiooxidans on copper ores. In this method bicinchoninic acid (BCA) has been used as the chromogenic reagent which produces a stable purple complex with Cu(I) which was found to obey Beer's Law and with ?max at 560 nm. The coloured complex has a molar extinction coefficient (e) value of 6.6 × 103 l mol-1 cm-1; specific absorptivity (a) value of 0.104 ml-1 g cm-1 and the Sandell sensitivity (S) value was 0.0096 µg cm2. Optimal conditions for development of coloration/sensitivity were determined. Interferences due to cations and anions were investigated and various masking agents for alleviating their inhibition were studied. The method has been found very useful in determining ratios of Cu(I) to Cu(II) in bacterial leach liquors and should play a significant role in determining the reaction mechanisms of biological leaching and for environmental monitoring.
    Full-text · Article · Mar 2000 · World Journal of Microbiology and Biotechnology