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Induction of xylanase in thermophilic fungi Scytalidium thermophilum and Sporotrichum thermophile
Joshi, Chetna;Khare, Sunil Kumar;
Brazilian Archives of Biology and Technology , 2012, DOI: 10.1590/S1516-89132012000100003
Abstract: regulation of xylanase production in two thermophilic fungi scytalidium thermophilum and sporotrichum thermophile was investigated. the expression of xylanase was found to be inducible in both the cases. various carbon sources were tested so as to identify the inducers. soy flour and oat spelt xylan induced maximum level of xylanase in scytalidium thermophilum and sporotrichum thermophile respectively. induction of xylanase in scytalidium thermophilum led to simultaneous induction of cellulase. the zymography of enzyme preparations revealed that different carbon sources caused differential expression of multiple isoforms of xylanase in scytalidium thermophilum, but same isoforms were expressed by sporotrichum thermophile irrespective of the carbon source used.
Purification and characterization of ?-glucosidase from Melanocarpus sp. MTCC 3922
Kaur,Jatinder; Chadha,Bhupinder S; Kumar,Badhan A; Kaur,Ghatora, S; Saini,Harvinder S;
Electronic Journal of Biotechnology , 2007,
Abstract: this study reports the purification and characterization of ?-glucosidase from a newly isolated thermophilic fungus, melanocarpus sp. microbial type culture collection (mtcc) 3922. the molecular weight of ?-glucosidase was determined to be ~ 92 and 102 kda with sds page and gel filtration, respectively, and pi of ~ 4.1. it was optimally active at 60oc and ph 6.0, though was stable at 50oc and ph 5.0 - 6.0. the presence of dtt, mercaptoethanol and metal ions such as na+, k+, ca2+, mg2+and zn2+ positively influenced the activity of ?-glucosidase but the activity was inhibited in the presence of cuso4. ?-glucosidase recognized pnp- ?-glucopyranoside (pnpg) as the preferred substrate, and showed very low affinity for pnp- ?-d-cellobioside. km and vmax for the hydrolysis of pnpg by ?-glucosidase was calculated as 3.3 mm and 43.68 μmolmin-1mg protein-1, respectively and kcat was quantified as 4 x 103 min-1. ?-glucosidase activity was enhanced appreciably in the presence of alcohols (methanol and ethanol) moreover, purified ?-glucosidase showed putative transglycosylation activity that was positively catalyzed in presence of methanol as an acceptor molecule
Complete Genome Sequence of the Aerobic CO-Oxidizing Thermophile Thermomicrobium roseum  [PDF]
Dongying Wu, Jason Raymond, Martin Wu, Sourav Chatterji, Qinghu Ren, Joel E. Graham, Donald A. Bryant, Frank Robb, Albert Colman, Luke J. Tallon, Jonathan H. Badger, Ramana Madupu, Naomi L. Ward, Jonathan A. Eisen
PLOS ONE , 2009, DOI: 10.1371/journal.pone.0004207
Abstract: In order to enrich the phylogenetic diversity represented in the available sequenced bacterial genomes and as part of an “Assembling the Tree of Life” project, we determined the genome sequence of Thermomicrobium roseum DSM 5159. T. roseum DSM 5159 is a red-pigmented, rod-shaped, Gram-negative extreme thermophile isolated from a hot spring that possesses both an atypical cell wall composition and an unusual cell membrane that is composed entirely of long-chain 1,2-diols. Its genome is composed of two circular DNA elements, one of 2,006,217 bp (referred to as the chromosome) and one of 919,596 bp (referred to as the megaplasmid). Strikingly, though few standard housekeeping genes are found on the megaplasmid, it does encode a complete system for chemotaxis including both chemosensory components and an entire flagellar apparatus. This is the first known example of a complete flagellar system being encoded on a plasmid and suggests a straightforward means for lateral transfer of flagellum-based motility. Phylogenomic analyses support the recent rRNA-based analyses that led to T. roseum being removed from the phylum Thermomicrobia and assigned to the phylum Chloroflexi. Because T. roseum is a deep-branching member of this phylum, analysis of its genome provides insights into the evolution of the Chloroflexi. In addition, even though this species is not photosynthetic, analysis of the genome provides some insight into the origins of photosynthesis in the Chloroflexi. Metabolic pathway reconstructions and experimental studies revealed new aspects of the biology of this species. For example, we present evidence that T. roseum oxidizes CO aerobically, making it the first thermophile known to do so. In addition, we propose that glycosylation of its carotenoids plays a crucial role in the adaptation of the cell membrane to this bacterium's thermophilic lifestyle. Analyses of published metagenomic sequences from two hot springs similar to the one from which this strain was isolated, show that close relatives of T. roseum DSM 5159 are present but have some key differences from the strain sequenced.
Tryptophan Oxidative Metabolism Catalyzed by Geobacillus Stearothermophilus: A Thermophile Isolated from Kuwait Soil Contaminated with Petroleum Hydrocarbons
Jassim M. Al-Hassan, Samira Al-Awadi, Sosamma Oommen, Abdulaziz Alkhamis and Mohammad Afzal
International Journal of Tryptophan Research , 2012, DOI: 10.4137/IJTR.S6457
Abstract: Tryptophan metabolism has been extensively studied in humans as well as in soil. Its metabolism takes place mainly through kynurenine pathway yielding hydroxylated, deaminated and many other products of physiological significance. However, tryptophan metabolism has not been studied in an isolated thermophilic bacterium. Geobacillus stearothermophilus is a local thermophile isolated from Kuwait desert soil contaminated with petroleum hydrocarbons. The bacterium grows well at 65 °C in 0.05 M phosphate buffer (pH 7), when supplied with organic compounds as a carbon source and has a good potential for transformation of steroids and related molecules. In the present study, we used tryptophan ethyl ester as a carbon source for the bacterium to study the catabolism of the amino acid at pH 5 and pH 7. In this endeavor, we have resolved twenty one transformation products of tryptophan by GC/LC and have identified them through their mass spectral fragmentation.
Thermophile-specific proteins: the gene product of aq_1292 from Aquifex aeolicus is an NTPase  [cached]
Klinger Claudia,Ro?bach Michael,Howe Rebecca,Kaufmann Michael
BMC Biochemistry , 2003,
Abstract: Background To identify thermophile-specific proteins, we performed phylogenetic patterns searches of 66 completely sequenced microbial genomes. This analysis revealed a cluster of orthologous groups (COG1618) which contains a protein from every thermophile and no sequence from 52 out of 53 mesophilic genomes. Thus, COG1618 proteins belong to the group of thermophile-specific proteins (THEPs) and therefore we here designate COG1618 proteins as THEP1s. Since no THEP1 had been analyzed biochemically thus far, we characterized the gene product of aq_1292 which is THEP1 from the hyperthermophilic bacterium Aquifex aeolicus (aaTHEP1). Results aaTHEP1 was cloned in E. coli, expressed and purified to homogeneity. At a temperature optimum between 70 and 80°C, aaTHEP1 shows enzymatic activity in hydrolyzing ATP to ADP + Pi with kcat = 5 × 10-3 s-1 and Km = 5.5 × 10-6 M. In addition, the enzyme exhibits GTPase activity (kcat = 9 × 10-3 s-1 and Km= 45 × 10-6 M). aaTHEP1 is inhibited competitively by CTP, UTP, dATP, dGTP, dCTP, and dTTP. As shown by gel filtration, aaTHEP1 in its purified state appears as a monomer. The enzyme is resistant to limited proteolysis suggesting that it consists of a single domain. Although THEP1s are annotated as "predicted nucleotide kinases" we could not confirm such an activity experimentally. Conclusion Since aaTHEP1 is the first member of COG1618 that is characterized biochemically and functional information about one member of a COG may be transferred to the entire COG, we conclude that COG1618 proteins are a family of thermophilic NTPases.
Production of ?-Glucosidase by Penicillium purpurogenum
Dhake, A.B.;Patil, M.B.;
Brazilian Journal of Microbiology , 2005, DOI: 10.1590/S1517-83822005000200013
Abstract: the fungus penicillium purpurogenum was found to produce intracellular ?-glucosidase. maximum activity of ?-glucosidase was observed on sucrose. various cultural parameters of cultivation of p. purpurogenum for production of ?-glucosidase were optimized. maximum enzyme content was observed after 96 hours of cultivation at 30o;c. addition of amino acids histidine and cysteine induced ?-glucosidase synthesis to certain extent. the optimum temperature and ph for ?-glucosidase activity was 50o;c and 5.5 respectively. ?-glucosidase of p.purpurogenum shows stability at ph 2 thus it could be an ideal enzyme for debittering in fruit juice and wine industries.
Kinetics of Cellulase and Xylanase of Chaetomium thermophile with Respect to Aeration  [PDF]
Kishwar Hayat,Haq Nawaz,Farooq Latif,M. Asghar
Pakistan Journal of Biological Sciences , 2001,
Abstract: The purpose of present study was to determine the effect of dissolved O2 on cellulase and xylanase production by Chetomium thermophile in growth medium of wheat straw. The concentration of dissolved oxygen was optimized through stirring. Kinetic parameters including substrate utilization (g substrate L/h) and enzyme production (IU) was studied from the maximum slope in plots of substrate utilized (g/L) and enzyme produced (IU/L) vs time of fermentation. Specific rate of product formation (QP) and substrate utilization (Qs) was also determined.
欧 亚 种 葡 萄 简 约 栽 培 技 术  [PDF]
杨巧云1,王新香2
北方园艺 , 2010, DOI: 10.11937/bfyy.201017027
Abstract:
Thermophile-specific proteins: the gene product of aq_1292 from Aquifex aeolicus is an NTPase
Claudia Klinger, Michael Ro?bach, Rebecca Howe, Michael Kaufmann
BMC Biochemistry , 2003, DOI: 10.1186/1471-2091-4-12
Abstract: aaTHEP1 was cloned in E. coli, expressed and purified to homogeneity. At a temperature optimum between 70 and 80°C, aaTHEP1 shows enzymatic activity in hydrolyzing ATP to ADP + Pi with kcat = 5 × 10-3 s-1 and Km = 5.5 × 10-6 M. In addition, the enzyme exhibits GTPase activity (kcat = 9 × 10-3 s-1 and Km= 45 × 10-6 M). aaTHEP1 is inhibited competitively by CTP, UTP, dATP, dGTP, dCTP, and dTTP. As shown by gel filtration, aaTHEP1 in its purified state appears as a monomer. The enzyme is resistant to limited proteolysis suggesting that it consists of a single domain. Although THEP1s are annotated as "predicted nucleotide kinases" we could not confirm such an activity experimentally.Since aaTHEP1 is the first member of COG1618 that is characterized biochemically and functional information about one member of a COG may be transferred to the entire COG, we conclude that COG1618 proteins are a family of thermophilic NTPases.The comparison of protein coding sequences from complete genomes led to a classification, based on sequence similarities, that assigns proteins to clusters of orthologous groups (COGs) [1,2]. Phylogenetic patterns search [3] is a tool to retrieve COGs that contain protein sequences that match a certain predefined pattern of organisms. Recently, Forterre [4] used this tool to identify reverse gyrase as the only hyperthermophile-specific protein. Another survey identified 30 COGs enriched in hyperthermophilic procaryotes [5]. In contrast, we here extended a similar search with respect to a group consisting of both thermophiles and hyperthermophiles i. e. the currently 3 organisms with optimal growth temperatures between 55 and 80°C were included. This search retrieved COG1618 as one of the high ranking clusters containing a protein from every of the 13 thermophilic and, by including only one representative, the fewest sequences from mesophilic genomes of the current COG database. Thus, amongst others, the COG1618 proteins belong to a group of thermophile-
Screening of Supports for the Immobilization of -Glucosidase  [PDF]
Joelise de Alencar Figueira,Fernanda Furlan Gon?alves Dias,Hélia Harumi Sato,Pedro Fernandes
Enzyme Research , 2011, DOI: 10.4061/2011/642460
Abstract: A set of supports were screened for the immobilization of a partially purified extract of β-glucosidase from Aspergillus sp. These supports, namely, Eupergit, Amberlite, alginate, gelatin, polyvinyl alcohol- (PVA-) based matrices (Lentikats), and sol-gel, have proved effective for the implementation of some other enzyme-based processes. The initial criterion for selection of promising supports prior to further characterization relied on the retention of the catalytic activity following immobilization. Based on such criterion, where immobilization in sol-gel and in Lentikats outmatched the remaining approaches, those two systems were further characterized. Immobilization did not alter the pH/activity profile, whereas the temperature/activity profile was improved when sol-gel support was assayed. Both thermal and pH stability were improved as a result of immobilization. An increase in the apparent (Michaelis constant) was observed following immobilization, suggesting diffusion limitations. 1. Introduction β-Glucosidases (β-D-glucoside glucohydrolases, EC 3.2.1.21) are enzymes that transfer a glycosyl group between oxygen nucleophiles. They are, therefore, accountable for the hydrolysis of β-glycosidic linkages in amino-, alkyl-, or aryl-β-D-glucosides, cyanogenic glycosides, and di- and short chain oligo-saccharides [1, 2]. β-glucosidases can be used in the production of aromatic compounds, in the stabilization of juices and beverages, and in the improvement of the organoleptic properties of food and feed products; they are also used in biomass degradation, in the production of fuel ethanol from cellulosic agricultural residues, and in the synthesis of alkyl- and arylglycosides from natural polysaccharides or their derivatives and alcohols, by reversed hydrolysis or trans-glycosylation, leading to products with applications in pharmaceutical, cosmetic, and detergent industries [1, 3–5]. The immobilization of β-glucosidase in a solid carrier offers the prospect of cost savings and widens the flexibility of process design, by enabling continuous operation (or multiple cycles of batch operation on a drain-and-fill basis) and simplifying downstream processing. Enzyme immobilization also allows for a high-biocatalyst load within the bioreactor, thus leading to high-volumetric productivities [6, 7]. Guidelines for cost analysis of bioconversion processes have been recently suggested [8]. In the present work, several immobilization methods were screened as suitable approaches for the immobilization of a β-glucosidase from an Aspergillus sp. Specifically,
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