CATALYTIC SPECTROPHOTOMETRIC DETERMINATION OF Mn(II ...

African Journals Online (AJOL)

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method is based on the catalytic effect of Mn(II) with the oxidation of Celestine blue .... water samples were filtered through a 0.45 μm pore size membrane filter to remove suspended .... slope of the calibration graph as the optimization criterion. ..... In presence of Phen as stability enhancement agent in indicator system. ( ) +.

Ship-borne measurements of microbial enzymatic activity: A rapid biochemical indicator for microbial water quality monitoring

Science.gov (United States)

Stadler, Philipp; Loken, Luke; Crawford, John; Schramm, Paul; Sorsa, Kirsti; Kuhn, Catherine; Savio, Domenico; Striegl, Rob; Butman, David; Stanley, Emily; Farnleitner, Andreas H.; Zessner, Matthias

2017-04-01

Contamination of aquatic ecosystems by human and animal wastes is a global concern for water quality. Disclosing fate and transport processes of fecal indicator organism (FIO) in large water bodies is a big challenge due to material intensive and time consuming methods used in microbiological water quality monitoring. In respect of utilization of large surface water resources there is a dearth of rapid microbiological methods that allow a near-real time health related water quality monitoring to be implemented into early warning systems. The detection of enzymatic activities has been proposed as a rapid surrogate for microbiological pollution monitoring of water and water resources (Cabral, 2010; Farnleitner et al., 2001, 2002). Methods such as the beta-D-Glucuronidase assay (GLUC), targeting FIO such as E. coli, were established. New automated enzymatic assays have been implemented during the last years into on-site monitoring stations, ranging from ground- to surface waters (Ryzinska-Paier et al., 2014; Stadler et al., 2017, 2016). While these automated enzymatic methods cannot completely replace assays for culture-based FIO enumeration, they yielded significant information on pollution events and temporal dynamics on a catchment specific basis, but were restricted to stationary measurements. For the first time we conducted ship-borne and automated measurements of enzymatic GLUC activity on large fresh water bodies, including the Columbia River, the Mississippi River and Lake Mendota. Not only are automated enzymatic assays technically feasible from a mobile vessel, but also can be used to localize point sources of potential microbial fecal contamination, such as tributaries or storm drainages. Spatial and temporal patterns of enzymatic activity were disclosed and the habitat specific correlation with microbiological standard assays for FIO determined due to reference samples. The integration of rapid and automated enzymatic assays into well-established systems

Multireversible redox processes in pentanuclear bis(triple-helical) manganese complexes featuring an oxo-centered triangular {Mn(II)2Mn(III)(μ3-O)}5+ or {Mn(II)Mn(III)2(μ3-O)}6+ core wrapped by two {Mn(II)2(bpp)3}-.

Science.gov (United States)

Romain, Sophie; Rich, Jordi; Sens, Cristina; Stoll, Thibaut; Benet-Buchholz, Jordi; Llobet, Antoni; Rodriguez, Montserrat; Romero, Isabel; Clérac, Rodolphe; Mathonière, Corine; Duboc, Carole; Deronzier, Alain; Collomb, Marie-Noëlle

2011-09-05

A new pentanuclear bis(triple-helical) manganese complex has been isolated and characterized by X-ray diffraction in two oxidation states: [{Mn(II)(μ-bpp)(3)}(2)Mn(II)(2)Mn(III)(μ-O)](3+) (1(3+)) and [{Mn(II)(μ-bpp)(3)}(2)Mn(II)Mn(III)(2)(μ-O)](4+) (1(4+)). The structure consists of a central {Mn(3)(μ(3)-O)} core of Mn(II)(2)Mn(III) (1(3+)) or Mn(II)Mn(III)(2) ions (1(4+)) which is connected to two apical Mn(II) ions through six bpp(-) ligands. Both cations have a triple-stranded helicate configuration, and a pair of enantiomers is present in each crystal. The redox properties of 1(3+) have been investigated in CH(3)CN. A series of five distinct and reversible one-electron waves is observed in the -1.0 and +1.50 V potential range, assigned to the Mn(II)(4)Mn(III)/Mn(II)(5), Mn(II)(3)Mn(III)(2)/Mn(II)(4)Mn(III), Mn(II)(2)Mn(III)(3)/Mn(II)(3)Mn(III)(2), Mn(II)Mn(III)(4)/Mn(II)(2)Mn(III)(3), and Mn(III)(5)/Mn(II)Mn(III)(4) redox couples. The two first oxidation processes leading to Mn(II)(3)Mn(III)(2) (1(4+)) and Mn(II)(2)Mn(III)(3) (1(5+)) are related to the oxidation of the Mn(II) ions of the central core and the two higher oxidation waves, close in potential, are thus assigned to the oxidation of the two apical Mn(II) ions. The 1(4+) and 1(5+) oxidized species and the reduced Mn(4)(II) (1(2+)) species are quantitatively generated by bulk electrolyses demonstrating the high stability of the pentanuclear structure in four oxidation states (1(2+) to 1(5+)). The spectroscopic characteristics (X-band electron paramagnetic resonance, EPR, and UV-visible) of these species are also described as well as the magnetic properties of 1(3+) and 1(4+) in solid state. The powder X- and Q-band EPR signature of 1(3+) corresponds to an S = 5/2 spin state characterized by a small zero-field splitting parameter (|D| = 0.071 cm(-1)) attributed to the two apical Mn(II) ions. At 40 K, the magnetic behavior is consistent for 1(3+) with two apical S = 5/2 {Mn(II)(bpp)(3)}(-) and one S

Mn(II) oxidation in Fenton and Fenton type systems : Identification of Reaction Efficiency and Reaction Products

NARCIS (Netherlands)

van Genuchten, C.M.; Peña, Jasquelin

2017-01-01

Efficient and low-cost methods of removing aqueous Mn(II) are required to improve the quality of impacted groundwater supplies. In this work, we show that Fe(0) electrocoagulation (EC) permits the oxidative removal of Mn(II) from solution by reaction with the reactive oxidant species produced

Oxidative Ce"3"+ sequestration by fungal manganese oxides with an associated Mn(II) oxidase activity

International Nuclear Information System (INIS)

Zheng, Haisu; Tani, Yukinori; Naitou, Hirotaka; Miyata, Naoyuki; Tojo, Fuyumi

2016-01-01

Sequestration of Ce"3"+ by biogenic manganese oxides (BMOs) formed by a Mn(II)-oxidizing fungus, Acremonium strictum strain KR21-2, was examined at pH 6.0. In anaerobic Ce"3"+ solution, newly formed BMOs exhibited stoichiometric Ce"3"+ oxidation, where the molar ratio of Ce"3"+ sequestered (Ce_s_e_q) relative to Mn"2"+ released (Mn_r_e_l) was maintained at approximately two throughout the reaction. A similar Ce"3"+ sequestration trend was observed in anaerobic treatment of BMOs in which the associated Mn(II) oxidase was completely inactivated by heating at 85 °C for 1 h or by adding 50 mM NaN_3. Aerobic Ce"3"+ treatment of newly formed BMO (enzymatically active) resulted in excessive Ce"3"+ sequestration over Mn"2"+ release, yielding Ce_s_e_q/Mn_r_e_l > 200, whereas heated or poisoned BMOs released a significant amount of Mn"2"+ with lower Ce"3"+ sequestration efficiency. Consequently, self-regeneration by the Mn(II) oxidase in newly formed BMO effectively suppressed Mn"2"+ release and enhanced oxidative Ce"3"+ sequestration under aerobic conditions. Repeated treatments of heated or poisoned BMOs under aerobic conditions confirmed that oxidative Ce"3"+ sequestration continued even after most Mn oxide was released from the solid phase, indicating auto-catalytic Ce"3"+ oxidation at the solid phase produced through primary Ce"3"+ oxidation by BMO. From X-ray diffraction analysis, the resultant solid phases formed through Ce"3"+ oxidation by BMO under both aerobic and anaerobic conditions consisted of cerianite with crystal sizes of 5.00–7.23 Å. Such nano-sized CeO_2 (CeO_2_,_B_M_O) showed faster auto-catalytic Ce"3"+ oxidation than that on well-crystalized cerianite under aerobic conditions, where the normalized pseudo-first order rate constants for auto-catalytic Ce"3"+ oxidation on CeO_2_,_B_M_O was two orders of magnitude higher. Consequently, we concluded that Ce"3"+ contact with BMOs sequesters Ce"3"+ through two oxidation paths: primary Ce"3

Mn(II), Zn(II) and VO(II) Schiff

Indian Academy of Sciences (India)

Home; Journals; Journal of Chemical Sciences; Volume 113; Issue 3. Synthesis and characterisation of Cu(II), Ni(II), Mn(II), Zn(II) and VO(II) Schiff base complexes derived from o-phenylenediamine and acetoacetanilide. N Raman Y Pitchaikani Raja A Kulandaisamy. Inorganic Volume 113 Issue 3 June 2001 pp 183-189 ...

New Methods of Simulation of Mn(II) EPR Spectra: Single Crystals, Polycrystalline and Amorphous (Biological) Materials

Science.gov (United States)

Misra, Sushil K.

Biological systems exhibit properties of amorphous materials. The Mn(II) ion in amorphous materials is characterized by distributions of spin-Hamiltonian parameters around mean values. It has a certain advantage over other ions, being one of the most abundant elements on the earth. The extent to which living organisms utilize manganese varies from one organism to the other. There is a fairly high concentration of the Mn(II) ion in green plants, which use it in the O2 evolution reaction of photosynthesis (Sauer, 1980). Structure-reactivity relationships in Mn(II)-O2 complexes are given in a review article by Coleman and Taylor (1980). Manganese is a trace requirement in animal nutrition; highly elevated levels of manganese in the diet can be toxic, probably because of an interference with iron homeostasis (Underwood, 1971). On the other hand, animals raised with a dietary deficiency of manganese exhibit severe abnormalities in connective tissue; these problems have been attributed to the obligatory role of Mn(II) in mucopolysaccharide metabolism (Leach, 1971). Mn(II) has been detected unequivocally in living organisms.

Effects of thermo-chemical pretreatment plus microbial fermentation and enzymatic hydrolysis on saccharification and lignocellulose degradation of corn straw.

Science.gov (United States)

Wang, Ping; Chang, Juan; Yin, Qingqiang; Wang, Erzhu; Zhu, Qun; Song, Andong; Lu, Fushan

2015-10-01

In order to increase corn straw degradation, the straw was kept in the combined solution of 15% (w/w) lime supernatant and 2% (w/w) sodium hydroxide with liquid-to-solid ratio of 13:1 (mL/g) at 83.92°C for 6h; and then added with 3% (v/v) H2O2 for reaction at 50°C for 2h; finally cellulase (32.3 FPU/g dry matter) and xylanase (550 U/g dry matter) was added to keep at 50°C for 48 h. The maximal reducing sugars yield (348.77 mg/g) was increased by 126.42% (Pcellulose, hemicellulose and lignin in pretreated corn straw with enzymatic hydrolysis were increased by 40.08%, 45.71% and 52.01%, compared with the native corn straw with enzymatic hydrolysis (P<0.05). The following study indicated that the combined microbial fermentation and enzymatic hydrolysis could further increase straw degradation and reducing sugar yield (442.85 mg/g, P<0.05). Copyright © 2015 Elsevier Ltd. All rights reserved.

Binuclear and tetranuclear Mn(II) clusters in coordination polymers derived from semirigid tetracarboxylate and N‑donor ligands: syntheses, new topology structures and magnetism

Energy Technology Data Exchange (ETDEWEB)

Li, Xiao-Ling [College of Chemistry and Chemical Engineering, and Henan Key Laboratory of Function-Oriented Porous Materials, Luoyang Normal University, Luoyang 471934 (China); Liu, Guang-Zhen, E-mail: gzliuly@126.com [College of Chemistry and Chemical Engineering, and Henan Key Laboratory of Function-Oriented Porous Materials, Luoyang Normal University, Luoyang 471934 (China); Xin, Ling-Yun [College of Chemistry and Chemical Engineering, and Henan Key Laboratory of Function-Oriented Porous Materials, Luoyang Normal University, Luoyang 471934 (China); Wang, Li-Ya [College of Chemistry and Chemical Engineering, and Henan Key Laboratory of Function-Oriented Porous Materials, Luoyang Normal University, Luoyang 471934 (China); College of Chemistry and Pharmacy Engineering, Nanyang Normal University, Nanyang, Henan 473061 (China)

2017-02-15

Two topologically new Mn(II) coordination polymers, namely ([Mn{sub 2}(H{sub 4}ipca)(4,4′-bpy){sub 1.5}(CH{sub 3}CH{sub 2}OH){sub 0.5}(H{sub 2}O){sub 1.5}]·0.5CH{sub 3}CH{sub 2}OH·2.5H{sub 2}O){sub n} (1) and (Mn{sub 4}(H{sub 4}ipca){sub 2}(bze)(H{sub 2}O){sub 4}){sub n} (2) were prepared by the solvothermal reactions of Mn(II) acetate with 5-(2’,3’-dicarboxylphenoxy)isophthalic acid (H{sub 4}ipca) in the presence of different N-donor coligands (4,4′-bpy=4,4′-bipyridyl and bze=1, 4-bis(1-imidazoly)benzene). The single crystal X-ray diffractions reveal that two complexes display 3D metal-organic frameworks with binuclear and tetranuclear Mn(II) units, respectively. Complex 1 features a (3,4,6)-connected porous framework based on dinuclear Mn(II) unit with the (4.5{sup 2}){sub 2}(4{sup 2}.6{sup 8}.8{sup 3}.9{sup 2})(5{sup 2}.8.9{sup 2}.10) new topology, and complex 2 possesses a (3,8)-connected network based on tetranuclear Mn(II) unit with the (4{sup 2}.6){sub 2}(4{sup 4}.6{sup 14}.7{sup 7}.8{sup 2}.9) new topology. Magnetic analyses indicate that both two compounds show weak antiferromagnetic interactions within binuclear and tetranuclear Mn(II) units. - Graphical abstract: Two topologically new Mn(II) metal-organic frameworks with dinuclear and tetranuclear Mn(II) units respectively were assembled by using 5-(2′,3′-Dicarboxylphenoxy)isophthalic acid and N-donor ancillary coligands. Magnetic analysis revealed the existence of dominant antiferromagnetic interactions within the polynuclear Mn(II) units. - Highlights: • Mixed ligand strategy produces two topologically new MOFs with dinuclear and tetranuclear Mn(II) respectively. • Magnetic fitting gives weak antiferromagnetic interactions within the polynuclear Mn(II) units.

Thiol-functionalized polysilsesquioxane as efficient adsorbent for adsorption of Hg(II) and Mn(II) from aqueous solution

International Nuclear Information System (INIS)

Niu, Yuzhong; Qu, Rongjun; Liu, Xiguang; Mu, Lei; Bu, Baihui; Sun, Yuting; Chen, Hou; Meng, Yangfeng; Meng, Lina; Cheng, Lin

2014-01-01

Highlights: • PMPSQ was promising adsorbent for the removal of Hg(II) and Mn(II). • The adsorption kinetics followed the pseudo-second-order model. • The adsorption isotherms can be described by the monolayer Langmuir model. • The adsorption was controlled by film diffusion and chemical ion-exchange mechanism. - Abstract: Thiol-functionalized polysilsesquioxane was synthesized and used for the adsorption of Hg(II) and Mn(II) from aqueous solution. Results showed that the optimal pH was about 6 and 5 for Hg(II) and Mn(II), respectively. Adsorption kinetics showed that the adsorption equilibriums were established within 100 min and followed pseudo-second-order model. Adsorption isotherms revealed that the adsorption capacities increased with the increasing of temperature. The adsorption was found to be well described by the monolayer Langmuir isotherm model and took place by chemical ion-exchange mechanism. The thermodynamic properties indicated the adsorption processes were spontaneous and endothermic nature. Selectively adsorption showed that PMPSQ can selectively adsorb Hg(II) from binary ion systems in the presence of the coexistent ions Mn(II), Cu(II), Pb(II), Co(II), and Ni(II). Based on the results, it is concluded that PMPSQ had comparable high adsorption efficiency and could be potentially used for the removal of Hg(II) and Mn(II) from aqueous solution

Surface Mn(II) oxidation actuated by a multicopper oxidase in a soil bacterium leads to the formation of manganese oxide minerals.

Science.gov (United States)

Zhang, Zhen; Zhang, Zhongming; Chen, Hong; Liu, Jin; Liu, Chang; Ni, Hong; Zhao, Changsong; Ali, Muhammad; Liu, Fan; Li, Lin

2015-06-03

In this manuscript, we report that a bacterial multicopper oxidase (MCO266) catalyzes Mn(II) oxidation on the cell surface, resulting in the surface deposition of Mn(III) and Mn(IV) oxides and the gradual formation of bulky oxide aggregates. These aggregates serve as nucleation centers for the formation of Mn oxide micronodules and Mn-rich sediments. A soil-borne Escherichia coli with high Mn(II)-oxidizing activity formed Mn(III)/Mn(IV) oxide deposit layers and aggregates under laboratory culture conditions. We engineered MCO266 onto the cell surfaces of both an activity-negative recipient and wild-type strains. The results confirmed that MCO266 governs Mn(II) oxidation and initiates the formation of deposits and aggregates. By contrast, a cell-free substrate, heat-killed strains, and intracellularly expressed or purified MCO266 failed to catalyze Mn(II) oxidation. However, purified MCO266 exhibited Mn(II)-oxidizing activity when combined with cell outer membrane component (COMC) fractions in vitro. We demonstrated that Mn(II) oxidation and aggregate formation occurred through an oxygen-dependent biotic transformation process that requires a certain minimum Mn(II) concentration. We propose an approximate electron transfer pathway in which MCO266 transfers only one electron to convert Mn(II) to Mn(III) and then cooperates with other COMC electron transporters to transfer the other electron required to oxidize Mn(III) to Mn(IV).

Redox Reactions between Mn(II) and Hexagonal Birnessite Change Its Layer Symmetry.

Science.gov (United States)

Zhao, Huaiyan; Zhu, Mengqiang; Li, Wei; Elzinga, Evert J; Villalobos, Mario; Liu, Fan; Zhang, Jing; Feng, Xionghan; Sparks, Donald L

2016-02-16

Birnessite, a phyllomanganate and the most common type of Mn oxide, affects the fate and transport of numerous contaminants and nutrients in nature. Birnessite exhibits hexagonal (HexLayBir) or orthogonal (OrthLayBir) layer symmetry. The two types of birnessite contain contrasting content of layer vacancies and Mn(III), and accordingly have different sorption and oxidation abilities. OrthLayBir can transform to HexLayBir, but it is still vaguely understood if and how the reverse transformation occurs. Here, we show that HexLayBir (e.g., δ-MnO2 and acid birnessite) transforms to OrthLayBir after reaction with aqueous Mn(II) at low Mn(II)/Mn (in HexLayBir) molar ratios (5-24%) and pH ≥ 8. The transformation is promoted by higher pH values, as well as smaller particle size, and/or greater stacking disorder of HexLayBir. The transformation is ascribed to Mn(III) formation via the comproportionation reaction between Mn(II) adsorbed on vacant sites and the surrounding layer Mn(IV), and the subsequent migration of the Mn(III) into the vacancies with an ordered distribution in the birnessite layers. This study indicates that aqueous Mn(II) and pH are critical environmental factors controlling birnessite layer structure and reactivity in the environment.

Chlorine-induced assembly of a cationic coordination cage with a μ5-carbonato-bridged Mn(II)24 core.

Science.gov (United States)

Xiong, Ke-Cai; Jiang, Fei-Long; Gai, Yan-Li; Yuan, Da-Qiang; Han, Dong; Ma, Jie; Zhang, Shu-Quan; Hong, Mao-Chun

2012-04-27

Chlorine caged in! The chlorine-induced assembly of six shuttlecock-like tetranuclear Mn(II) building blocks generated in situ based on p-tert-butylthiacalix[4]arene and facial anions gave rise to a novel truncated distorted octahedral cationic coordination cage with a μ(5)-carbonato-bridged Mn(II)(24) core. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Determination of Proton Relaxivities of Mn(II, Cu(II and Cr(III added to Solutions of Serum Proteins

Directory of Open Access Journals (Sweden)

Ali Yilmaz

2009-04-01

Full Text Available Relaxometric studies are still of scientific interest due to their use in medicine and biology. In this study, proton T1 and T2 relaxivities of Mn(II, Cu(II and Cr(III in water were determined in the presence and absence of various proteins (albumin, α-globulin, γ-globulin, lysozyme, fibrinogen. The 1/T1 and 1/T2 in all solutions are linearly proportional to the concentration of the paramagnetic ions. Mn(II has the great influence to alter relaxations in all protein solutions, while Cu(II and Cr(III have a poor influence on the relaxations. In addition, Mn(II and Cu(II are bound to each protein, but Cr(III is not bound to any protein.

Comparison of Enzymatic Assay and Multiple Tube Fermentation Technique in the Assessment of Microbial Quality of the Karoon River

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Mahnaz Nikaeen

2010-09-01

Full Text Available Microbiological monitoring of surface waters designated for use as drinking water is essential by water utilities for the design and operation of drinking water treatment plants. Enzymatic assays have been applied as a rapid alternative approach to assess the microbiological quality of freshwater. In this study, the LMX broth (LMX as an enzymatic assay was compared with the standard method of multiple tube fermentation technique (MTF for the microbial monitoring of the Karoon River. Enumeration of total coliforms and E. coli averaged 9928 and 6684 MPN/ 100 ml by the LMX and 7564 and 6546 MPN/ 100 ml for the MTF, respectively. This difference was statistically significant for TC but the overall analysis revealed no difference between E. coli recoveries on LMX and MTF. In conclusion, LMX can be used for the enumeration of coliforms and E. coli in surface waters as it is less lobar-intensive, yields faster result, and simultaneously detects both total coliforms and E. coli.

Synthesis and Characterization of Multimetallic Fe(II) and Mn(II ...

African Journals Online (AJOL)

Iron(II) and Manganese(II) complexes of the resulting ligand were obtained from its reactions with Fe(II) and Mn(II) salts in absolute methanol for the metal to ligand ratio 2:3. These complexes were characterized by Solubility, Conductivity, IR and UV-VIS spectrometry, elemental analysis and mass spectrometry. Keywords: ...

A novel Mn(II) oxalato-bridged 2D coordination polymer: synthesis ...

Indian Academy of Sciences (India)

Hiba Sehimi

2018-02-28

Feb 28, 2018 ... susceptibility. The title compound exhibits antiferromagnetic coupling between Mn(II) centres. Keywords. ..... to the theoretical dimer model expression (eq. 3) based .... Financial support from the Ministry of Higher Education and. Scientific ... thesis and Charachterisation of (μ-Oxalato)dimetal(II). Complexes ...

Equilibrium, thermodynamic and kinetic studies on biosorption of Mn(II) from aqueous solution by Pseudomonas sp., Staphylococcus xylosus and Blakeslea trispora cells

International Nuclear Information System (INIS)

Gialamouidis, D.; Mitrakas, M.; Liakopoulou-Kyriakides, M.

2010-01-01

Biosorption of Mn(II) from aqueous solutions using Pseudomonas sp., Staphylococcus xylosus and Blakeslea trispora cells was investigated under various experimental conditions of pH, biomass concentration, contact time and temperature. The optimum pH value was determined to 6.0 and the optimum biomass concentration to 1.0 g L -1 for all types of cells. Mn(II) biosorption was found to fit better to the Langmuir model for Pseudomonas sp. and B. trispora and to Freundlich model for S. xylosus. Langmuir model gave maximum Mn(II) uptake capacity 109 mg g -1 for Pseudomonas sp. and much lower, 59 mg g -1 and 40 mg g -1 for S. xylosus and B. trispora, respectively. Pseudo-second-order kinetic model was also found to be in good agreement with the experimental results. Thermodynamic parameters of the adsorption confirmed the endothermic nature of sorption process with positive heat of enthalpy, accompanied by a positive value of entropy change. Interestingly, desorption experiments by treating biomass with 0.1 M HNO 3 solution resulted to more than 88% recovery of the adsorbed Mn(II) from Pseudomonas sp. and almost 95% and 99% from S. xylosus and B. trispora cells respectively, thus indicating that Mn(II) can be easily and quantitatively recovered from biomass.

Enzymatic desulfurization of coal

Energy Technology Data Exchange (ETDEWEB)

Boyer, Y.N.; Crooker, S.C.; Kitchell, J.P.; Nochur, S.V.

1991-05-16

The overall objective of this program was to investigate the feasibility of an enzymatic desulfurization process specifically intended for organic sulfur removal from coal. Toward that end, a series of specific objectives were defined: (1) establish the feasibility of (bio)oxidative pretreatment followed by biochemical sulfate cleavage for representative sulfur-containing model compounds and coals using commercially-available enzymes; (2) investigate the potential for the isolation and selective use of enzyme preparations from coal-utilizing microbial systems for desulfurization of sulfur-containing model compounds and coals; and (3) develop a conceptual design and economic analysis of a process for enzymatic removal of organic sulfur from coal. Within the scope of this program, it was proposed to carry out a portion of each of these efforts concurrently. (VC)

Effects of thermal and enzymatic treatments and harvesting time on the microbial quality and chemical composition of fibre hemp (Cannabis sativa L.)

DEFF Research Database (Denmark)

Nykter, M.; Kymalainen, H.R.; Thomsen, Anne Belinda

2008-01-01

The aim of the present study was to examine the effects of pectinase enzyme treatment followed by thermal treatments (steam explosion and dry heating) on the microbial quality and chemical composition of hemp fibres. Before these treatments, the fibres were separated manually from the stems...... materials. Dry heating had no effect on mould and bacterial counts at temperatures below 120 degrees C and durations less than 60 min. The chemical composition was affected by the enzymatic treatment due to extraction and degradation of water-soluble components, pectin and ash. Thus the cellulose content...... increased by 6% w/w to 67-70% w/w. Steam explosion of the untreated hemp fibres increased the cellulose content to 74% w/w, whereas steam explosion of enzymatically treated hemp increased the cellulose content to 78% w/w. (c) 2007 Elsevier Ltd. All rights reserved....

Physicochemical properties of 3,4,5-trimethoxybenzoates of Mn(II, Co(II, Ni(II and Zn(II

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W. FERENC

2005-09-01

Full Text Available The complexes of Mn(II, Co(II, Ni(II, Cu(II and Zn(II with 3,4,5-trimethoxybenzoic acid anion of the formula: M(C10H11O52·nH2O, where n = 6 for Ni(II, n = 1 for Mn(II, Co(II, Cu(II, and n = 0 for Zn, have been synthesized and characterized by elemental analysis, IR spectroscopy, X–ray diffraction measurements, thermogravimetry and magnetic studies. They are crystalline compounds characterized by various symmetry. They decompose in various ways when heated in air to 1273 K. At first, they dehydrate in one step and form anhydrous salts. The final products of decomposition are oxides of the respective metals (Mn2O3, Co3O4, NiO, CuO, ZnO. The solubilities of the analysed complexes in water at 293 K are in the orders of 10-2 – 10-4 mol dm-3. The magnetic susceptibilities of the Mn(II, Co(II, Ni(II and Cu(II complexes were measured over the range of 76–303 K and the magnetic moments were calculated. The results show that the 3,4,5-trimethoxybenzoates of Mn(II, Co(II and Ni(II are high-spin complexes but that of Cu(II forms a dimer [Cu2(C10H11O54(H2O2]. The carboxylate groups bind as monodentate or bidentate chelating or bridging ligands.

Effects of thermal and enzymatic treatments and harvesting time on the microbial quality and chemical composition of fibre hemp (Cannabis sativa L.)

Energy Technology Data Exchange (ETDEWEB)

Nykter, Minna; Kymaelaeinen, Hanna-Riitta; Sjoeberg, Anna-Maija [Department of Agrotechnology, University of Helsinki, P.O. Box 28, FI-00014 University of Helsinki (Finland); Thomsen, Anne Belinda; Thygesen, Anders [Biosystems Department, Risoe National Laboratory, P.O. Box 49, DK-4000 Roskilde (Denmark); Lilholt, Hans [Materials Research Department, Risoe National Laboratory, P.O. Box 49, DK-4000 Roskilde (Denmark); Koponen, Hilkka [Department of Applied Biology, Section of Plant Pathology, University of Helsinki, P.O. Box 27, FI-00014 University of Helsinki (Finland)

2008-05-15

The aim of the present study was to examine the effects of pectinase enzyme treatment followed by thermal treatments (steam explosion and dry heating) on the microbial quality and chemical composition of hemp fibres. Before these treatments, the fibres were separated manually from the stems harvested after stand retting in the field before frost, after early frost or in the following spring. The enzymatic treatment of hemp promoted growth of moulds on the fibres (500-fold increase in colony-forming units (cfu)), whereas steam explosion reduced the amount of moulds to a relatively constant level of 10{sup 2} cfu/g dw. The amount of bacteria was not markedly affected by enzymatic treatment but was reduced tenfold after steam explosion. Steam explosion is thereby a potentially good process for the production of hemp fibres with low fungal contamination, which can be of importance in insulation materials. Dry heating had no effect on mould and bacterial counts at temperatures below 120 C and durations less than 60 min. The chemical composition was affected by the enzymatic treatment due to extraction and degradation of water-soluble components, pectin and ash. Thus the cellulose content increased by 6% w/w to 67-70% w/w. Steam explosion of the untreated hemp fibres increased the cellulose content to 74% w/w, whereas steam explosion of enzymatically treated hemp increased the cellulose content to 78% w/w. (author)

Removal of Mn(II) from the acid mine wastewaters using coal fired bottom ash

Science.gov (United States)

Mahidin, M.; Sulaiman, T. N.; Muslim, A.; Gani, A.

2017-06-01

Acid mine wastewater (AMW), the wastewater from mining activities which has low pH about 3-5 and contains hazardous heavy metals such as Cu, Fe, Mn, Zn, Pb, etc. Those heavy metals pollution is of prime concern from the environmental view point. Among the heavy metals, Mn occupies the third position in the AMW from one the iron ore mining company in Aceh, Indonesia. In this study, the possibility use of bottom ash from coal fired boiler of steam power plants for the removal of Mn(II) in AMW has been investigated. Experimental has been conducted as follows. Activation of bottom ash was done both by physical and chemical treatments through heating at 270 °C and washing with NaOH activator 0.5 and 1 M. Adsorption test contains two parts observation; preliminary and primary experiments. Preliminary study is addressed to select the best condition of three independent variables i.e.: pH of AMW (3 & 7), bottom ash particle size (40, 60 & 100 mesh) and initial Mn(II) concentrations (100 & 600 mg/l). AMW used was synthetics wastewater. It was found that the best value for NaOH is 1 M, pH is 7, particle size is 100 meshes and initial Mn(II) concentration is 600 mg/l from the adsorption efficiency point of view. The maximum adsorption capacity (q e) is 63.7 mg/g with the efficiency of 85%.

Variations in eco-enzymatic stoichiometric and microbial characteristics in paddy soil as affected by long-term integrated organic-inorganic fertilization

Science.gov (United States)

Lin, Sen; Wang, Shaoxian; Si, Yuanli; Yang, Wenhao; Zhu, Shaowei

2017-01-01

To investigate the effects of different nutrient management regimes on the soil chemical, eco-enzymatic stoichiometric and microbial characteristics, soil samples were collected from a 30-year, long-term field experiment with six plots growing rice. The results showed that as integrated fertilization increased, so did the concentrations of soil total or available nutrients and microbial biomass carbon (MBC). Our results also found enhanced soil basal respiration and cumulative carbon mineralization compared to chemical fertilization alone at the same nutrient doses. The activities of soil protease (Pro), β-glucosidase (βG), N-acetyl-glucosaminidase (NAG) and acid phosphatase (AP) from the integrated fertilization treatments were significantly higher than those of the treatments without organic manure, so did the activities of soil leucyl aminopeptidase (LAP) and urease (Ure) from the treatment with organic manure in addition to farmer practise fertilization (NPKM2). The stoichiometric ratios, expressed as lnβG/ln(NAG+LAP)/lnPro/lnUre/lnAP, ranged from 1:0.94:1.04:0.67:1.01 to 1:0.98:1.10:0.78:1.25, indicating that the acquisition of C, N and P changed consistently and synchronously under different nutrient management strategies. Integrated fertilization was more beneficial to the acquisition and utilization of soil organic carbon compared to low-molecular-weight organic nitrogen. We concluded that protease and urease should be considered in eco-enzymatic stoichiometric assessments for the hydrolysis of proteins, amino acids, carbohydrates and phosphomonoesters in soil, and integrated fertilization with chemical fertilizers and organic manure should be recommended as a preferable nutrient management system for intensive rice cultivation. PMID:29253000

Complete genome sequence of the highly Mn(II) tolerant Staphylococcus sp. AntiMn-1 isolated from deep-sea sediment in the Clarion-Clipperton Zone.

Science.gov (United States)

Wang, Xing; Lin, Danqiu; Jing, Xiaohuan; Zhu, Sidong; Yang, Jifang; Chen, Jigang

2018-01-20

Staphylococcus sp. AntiMn-1 is a deep-sea bacterium inhabiting seafloor sediment in the Clarion-Clipperton Zone (CCZ) that is highly tolerant to Mn(II) and displays efficient Mn(II) oxidation. Herein, we present the assembly and annotation of its genome. Copyright © 2017 Elsevier B.V. All rights reserved.

Synthesis, Hirshfeld surface analyses and magnetism of a 1D Mn(II ...

African Journals Online (AJOL)

A new Mn-based complex of {[Mn(L)2(mi)]·H2O}n (1) (HL = p-hydroxy phenylacetic acid; mi = 1,1'-(1,4-butanediyl)bis(imidazole)), has been synthesized and structurally characterized. Single-crystal X-ray analyses reveal that compound 1 has a dinuclear Mn(II) unit linking by four carboxylate groups. The bridging N-donor ...

Mn(II,III) oxidation and MnO2 mineralization by an expressed bacterial multicopper oxidase

Science.gov (United States)

Butterfield, Cristina N.; Soldatova, Alexandra V.; Lee, Sung-Woo; Spiro, Thomas G.; Tebo, Bradley M.

2013-01-01

Reactive Mn(IV) oxide minerals are ubiquitous in the environment and control the bioavailability and distribution of many toxic and essential elements and organic compounds. Their formation is thought to be dependent on microbial enzymes, because spontaneous Mn(II) to Mn(IV) oxidation is slow. Several species of marine Bacillus spores oxidize Mn(II) on their exosporium, the outermost layer of the spore, encrusting them with Mn(IV) oxides. Molecular studies have identified the mnx (Mn oxidation) genes, including mnxG, encoding a putative multicopper oxidase (MCO), as responsible for this two-electron oxidation, a surprising finding because MCOs only catalyze single-electron transfer reactions. Characterization of the enzymatic mechanism has been hindered by the lack of purified protein. By purifying active protein from the mnxDEFG expression construct, we found that the resulting enzyme is a blue (absorption maximum 590 nm) complex containing MnxE, MnxF, and MnxG proteins. Further, by analyzing the Mn(II)- and (III)-oxidizing activity in the presence of a Mn(III) chelator, pyrophosphate, we found that the complex facilitates both electron transfers from Mn(II) to Mn(III) and from Mn(III) to Mn(IV). X-ray absorption spectroscopy of the Mn mineral product confirmed its similarity to Mn(IV) oxides generated by whole spores. Our results demonstrate that Mn oxidation from soluble Mn(II) to Mn(IV) oxides is a two-step reaction catalyzed by an MCO-containing complex. With the purification of active Mn oxidase, we will be able to uncover its mechanism, broadening our understanding of Mn mineral formation and the bioinorganic capabilities of MCOs. PMID:23818588

Degradation of microbial polyesters.

Science.gov (United States)

Tokiwa, Yutaka; Calabia, Buenaventurada P

2004-08-01

Microbial polyhydroxyalkanoates (PHAs), one of the largest groups of thermoplastic polyesters are receiving much attention as biodegradable substitutes for non-degradable plastics. Poly(D-3-hydroxybutyrate) (PHB) is the most ubiquitous and most intensively studied PHA. Microorganisms degrading these polyesters are widely distributed in various environments. Although various PHB-degrading microorganisms and PHB depolymerases have been studied and characterized, there are still many groups of microorganisms and enzymes with varying properties awaiting various applications. Distributions of PHB-degrading microorganisms, factors affecting the biodegradability of PHB, and microbial and enzymatic degradation of PHB are discussed in this review. We also propose an application of a new isolated, thermophilic PHB-degrading microorganism, Streptomyces strain MG, for producing pure monomers of PHA and useful chemicals, including D-3-hydroxycarboxylic acids such as D-3-hydroxybutyric acid, by enzymatic degradation of PHB.

Recent insights in enzymatic synthesis of fructooligosaccharides from inulin.

Science.gov (United States)

Singh, Ram Sarup; Singh, Rupinder Pal; Kennedy, John F

2016-04-01

In the past few years, people are paying more attention to their dietary habits, and functional foods are playing a key role in maintaining the health of man. Prebiotics are considered as a main component of the functional foods which are usually composed of short chains of carbohydrates. Fructooligosaccharides (FOSs) are considered as one of the main group of prebiotics which have recognisable bifidogenic properties. FOSs are obtained either by extraction from various plant materials or by enzymatic synthesis from different substrates. Enzymatically, these can be obtained either from sucrose using fructosyltransferase or from inulin by endoinulinase. Inulin is a potent substrate for the enzymatic production of FOSs. This review article will provide an overview on the inulin as potent substrate, microbial sources of endoinulinases, enzymatic synthesis of FOSs from inulin, commercial status of FOSs, and their future perspectives. Copyright © 2016 Elsevier B.V. All rights reserved.

Enzymatic vegetable organic extracts as soil biochemical biostimulants and atrazine extenders.

Science.gov (United States)

García-Martínez, Ana María; Tejada, Manuel; Díaz, Ana Isabel; Rodríguez-Morgado, Bruno; Bautista, Juan; Parrado, Juan

2010-09-08

The purpose of this study was to gather information on the potential effects of organic biostimulants on soil activity and atrazine biodegradation. Carob germ enzymatic extract (CGEE) and wheat condensed distiller solubles enzymatic extract (WCDS-EE) have been obtained using an enzymatic process; their main organic components are soluble carbohydrates and proteins in the form of peptides and free amino acids. Their application to soil results in high biostimulation, rapidly increased dehydrogenase, phosphatase and glucosidase activities, and an observed atrazine extender capacity due to inhibition of its mineralization. The extender capacity of both extracts is proportional to the protein/carbohydrate ratio content. As a result, these enzymatic extracts are highly microbially available, leading to two independent phenomena, fertility and an atrazine persistence that is linked to increased soil activity.

Application of Local Adsorbant From Southeast Sulawesi Clay Immobilized Saccharomyces Cerevisiae Bread’s Yeast Biomass for Adsorption Of Mn(Ii) Metal Ion

Science.gov (United States)

R, Halimahtussaddiyah; Mashuni; Budiarni

2017-05-01

Southeast Sulawesi has a great stock of clay. It is probably to use as a source of adsorbent. The adsorbent capacity of clay can be largered with teratment using bread’s yeast as biomass. At this research, study of analysis adsorption of Mn(II) metal ion on clay immobilized Saccharomyces cerevisiae bread’s yeast biomass adsorbent has been conducted. The aims of this research were to determine the effects of contact time, pH and concentration of Mn(II) metal ion and to determine the adsorption capacity of clay immobilized S. cerevisiae biomass for adsorbtion of Mn(II) metal ion. Activated clay was synthesized by reaction of clay with KMnO4, H2SO4 and HCl. S. cerevisiae biomass was result by bread’s yeast mashed. Immobilization of S. cerevisiae biomass into clay was done by mixing of ratio of S. cerevisiae bread’s yeast biomass and clay equal to 1:3 (mass of biomassa : mass of clay). The adsorption capacity was determined by using Freundlich and Langmuir adsorption isoterms. The results of FTIR spectrums showed that the functional groups of clay immobilized S. cerevisiae biomass were Si-OH (wave number 1643 cm-1), Si-O-Si (wave number 1033 cm-1), N-H (wave number 2337 cm-1), O-H (wave number 3441cm-1), and C-H (wave number 2931 cm-1). The result of adsorption capacity from Mn(II) metal ion of contact time optimum 120 minutes, pH optimun at 7 and concentration optimum 50 mg/L were 1,816 mg/g; 0,509 mg/g and 2,624mg/g respectively. The adsorption capacity of Mn(II) metal ion with ratio 1:3 (biomass : clay) was 0,1045 mg/g. Type of isothermal adsorption followed the Freunlich adsorption.

Synthesis and characterisation of Cu(II), Ni(II), Mn(II), Zn(II) and VO(II ...

Indian Academy of Sciences (India)

Unknown

Synthesis and characterisation of Cu(II), Ni(II), Mn(II), Zn(II) and VO(II) Schiff base complexes derived from o-phenylenediamine and acetoacetanilide. N RAMAN*, Y PITCHAIKANI RAJA and A KULANDAISAMY. Department of Chemistry, VHNSN College, Virudhunagar 626 001, India e-mail: ra_man@123india.com.

Synthesis and spectroscopic studies of biologically active tetraazamacrocyclic complexes of Mn(II, Co(II, Ni(II, Pd(II and Pt(II

Directory of Open Access Journals (Sweden)

Monika Tyagi

2014-01-01

Full Text Available Complexes of Mn(II, Co(II, Ni(II, Pd(II and Pt(II were synthesized with the macrocyclic ligand, i.e., 2,3,9,10-tetraketo-1,4,8,11-tetraazacycoletradecane. The ligand was prepared by the [2 + 2] condensation of diethyloxalate and 1,3-diamino propane and characterized by elemental analysis, mass, IR and 1H NMR spectral studies. All the complexes were characterized by elemental analysis, molar conductance, magnetic susceptibility measurements, IR, electronic and electron paramagnetic resonance spectral studies. The molar conductance measurements of Mn(II, Co(II and Ni(II complexes in DMF correspond to non electrolyte nature, whereas Pd(II and Pt(II complexes are 1:2 electrolyte. On the basis of spectral studies an octahedral geometry has been assigned for Mn(II, Co(II and Ni(II complexes, whereas square planar geometry assigned for Pd(II and Pt(II. In vitro the ligand and its metal complexes were evaluated against plant pathogenic fungi (Fusarium odum, Aspergillus niger and Rhizoctonia bataticola and some compounds found to be more active as commercially available fungicide like Chlorothalonil.

Respiration and enzymatic activities as indicators of stabilization of sewage sludge composting.

Science.gov (United States)

Nikaeen, Mahnaz; Nafez, Amir Hossein; Bina, Bijan; Nabavi, BiBi Fatemeh; Hassanzadeh, Akbar

2015-05-01

The objective of this work was to study the evolution of physico-chemical and microbial parameters in the composting process of sewage sludge (SS) with pruning wastes (PW) in order to compare these parameters with respect to their applicability in the evaluation of organic matter (OM) stabilization. To evaluate the composting process and organic matter stability, different microbial activities were compared during composting of anaerobically digested SS with two volumetric ratios, 1:1 and 3:1 of PW:SS and two aeration techniques including aerated static piles (ASP) and turned windrows (TW). Dehydrogenase activity, fluorescein diacetate hydrolysis, and specific oxygen uptake rate (SOUR) were used as microbial activity indices. These indices were compared with traditional parameters, including temperature, pH, moisture content, organic matter, and C/N ratio. The results showed that the TW method and 3:1 (PW:SS) proportion was superior to the ASP method and 1:1 proportion, since the former accelerate the composting process by catalyzing the OM stabilization. Enzymatic activities and SOUR, which reflect microbial activity, correlated well with temperature fluctuations. Based on these results it appears that SOUR and the enzymatic activities are useful parameters to monitor the stabilization of SS compost. Copyright © 2015 Elsevier Ltd. All rights reserved.

Enzymatic transformation of nonfood biomass to starch

Science.gov (United States)

You, Chun; Chen, Hongge; Myung, Suwan; Sathitsuksanoh, Noppadon; Ma, Hui; Zhang, Xiao-Zhou; Li, Jianyong; Zhang, Y.-H. Percival

2013-01-01

The global demand for food could double in another 40 y owing to growth in the population and food consumption per capita. To meet the world’s future food and sustainability needs for biofuels and renewable materials, the production of starch-rich cereals and cellulose-rich bioenergy plants must grow substantially while minimizing agriculture’s environmental footprint and conserving biodiversity. Here we demonstrate one-pot enzymatic conversion of pretreated biomass to starch through a nonnatural synthetic enzymatic pathway composed of endoglucanase, cellobiohydrolyase, cellobiose phosphorylase, and alpha-glucan phosphorylase originating from bacterial, fungal, and plant sources. A special polypeptide cap in potato alpha-glucan phosphorylase was essential to push a partially hydrolyzed intermediate of cellulose forward to the synthesis of amylose. Up to 30% of the anhydroglucose units in cellulose were converted to starch; the remaining cellulose was hydrolyzed to glucose suitable for ethanol production by yeast in the same bioreactor. Next-generation biorefineries based on simultaneous enzymatic biotransformation and microbial fermentation could address the food, biofuels, and environment trilemma. PMID:23589840

Pecan nutshell as biosorbent to remove Cu(II), Mn(II) and Pb(II) from aqueous solutions.

Science.gov (United States)

Vaghetti, Julio C P; Lima, Eder C; Royer, Betina; da Cunha, Bruna M; Cardoso, Natali F; Brasil, Jorge L; Dias, Silvio L P

2009-02-15

In the present study we reported for the first time the feasibility of pecan nutshell (PNS, Carya illinoensis) as an alternative biosorbent to remove Cu(II), Mn(II) and Pb(II) metallic ions from aqueous solutions. The ability of PNS to remove the metallic ions was investigated by using batch biosorption procedure. The effects such as, pH, biosorbent dosage on the adsorption capacities of PNS were studied. Four kinetic models were tested, being the adsorption kinetics better fitted to fractionary-order kinetic model. Besides that, the kinetic data were also fitted to intra-particle diffusion model, presenting three linear regions, indicating that the kinetics of adsorption should follow multiple sorption rates. The equilibrium data were fitted to Langmuir, Freundlich, Sips and Redlich-Peterson isotherm models. Taking into account a statistical error function, the data were best fitted to Sips isotherm model. The maximum biosorption capacities of PNS were 1.35, 1.78 and 0.946mmolg(-1) for Cu(II), Mn(II) and Pb(II), respectively.

Comparative studies on P-vanillin and O-vanillin of 2-hydrazinyl-2-oxo-N-phenylacetamide and their Mn(II) and Co(II) complexes

Science.gov (United States)

Yousef, T. A.; El-Reash, G. M. Abu; El-Tabai, M. N.

2018-05-01

Synthesis of complexes derived from hydrazones derived from both P-vanillin (H2L1) and its isomer O-vanillin (H2L2) of 2-hydrazinyl-2-oxo-N-phenylacetamide that coordinated with high magnetic metal ions of both Mn(II) and Co(II) were performed and characterized by different physicochemical methods, elemental analysis, (1H NMR, IR, and UV-visible spectra), also thermal analysis (TG and DTG) techniques and magnetic measurements. The molecular structures of the ligands and their Mn(II) and Co(II) complexes were optimized theoretically and the quantum chemical parameters were calculated. IR spectra suggest that the H2L1 behaved in a mononegative bidentate manner with both but H2L2 coordinated as mononegative tridentate with both Mn(II) and Co(II). The electronic spectra of the complexes as well as their magnetic moments suggested octahedral geometries for all the isolated complexes. The calculated values of binding energies indicated the stability of complexes is higher than that of ligand. The kinetic and thermodynamic parameters for the different decomposition steps in complexes were calculated using Coats-Redfern and Horowitz-Metzger equations. Moreover, the prepared ligands and their Mn(II) and Co(II) complexes were individually tested against a panel of gram positive Bacillus Subtilis and negative Escherichia coli microscopic organisms. Additionally cytotoxicity assay of two human tumor cell lines namely; hepatocellular carcinoma (liver) HePG-2, and mammary gland (breast) MCF-7 were tested.

Fermentable sugars and microbial inhibitors formation from two ...

African Journals Online (AJOL)

... under low severity factor and its enzymatic degradability was investigated in this ... The highest glucan conversion and recovery at the optimum conditions were ... reduce microbial inhibitors formation and excessive biomass processing cost.

Microbial characteristics of purple paddy soil in response to Pb pollution.

Science.gov (United States)

Jiang, Qiu-Ju; Zhang, Yue-Qiang; Zhang, La-Mei; Zhou, Xin-Bin; Shi, Xiao-Jun

2014-05-01

The study focused on the change of microbial characteristics affected by Plumbum pollution with purple paddy soil in an incubation experiment. The results showed that low concentration of Plumbum had little effect on most of microbial amounts, biological activity and enzymatic activity. However, denitrifying activity was inhibited severely, and inhibition rate was up to 98%. Medium and high concentration of Plumbum significantly reduced the amounts and activity of all microorganisms and enzymatic activity, which increased with incubation time. Negative correlations were found between Plumbum concentrations and microbial amounts, biological activity and enzymatic activities except fungi and actinomyces. Thus they can be used to indicate the Plumbum pollution levels to some extent. LD(50) of denitrifying bacteria (DB) and ED50 of denitrifying activity were 852mg/kg and 33.5mg/kg. Across all test soil microbes, denitrifying bacteria was most sensitive to Plumbum pollution in purple paddy soil. Value of early warning showed that anaerobic cellulose-decomposing bacteria (ACDB) and actinomyces were also sensitive to Plumbum pollution. We concluded that denitrifying activity, actinomyces, ACDB or DB can be chosen as predictor of Plumbum contamination in purple paddy soil.

Stopped Flow Kinetics of MnII Catalysed Periodate Oxidation of 2, 3- dimethylaniline - Evaluation of Stability Constant of the Ternary Intermediate Complex

Directory of Open Access Journals (Sweden)

Rajneesh Dutt Kaushik

2015-03-01

Full Text Available The formation of ternary intermediate unstable complex during the oxidation of aromatic amines by periodate ion catalysed by MnII has been proposed in case of some anilines. This paper is the first report on stopped-flow kinetic study and evaluation of stability constant of ternary complex forming in the MnII - catalysed periodate oxidation of 2, 3-dimethylaniline (D in acetone-water medium. Stop-flow spectrophotometric method was used to study the ternary complex formation and to determine its stability constant. The stop-flow trace shows the reaction to occur in two steps. The first step, which is presumably the formation of ternary complex, is relatively fast while the second stage is relatively quite slow. The stability constant evaluated for D - MnII - IO4- ternary complex by determining  equilibrium absorbance is (2.2 ± 1.0 × 105. Kinetics of ternary complex formation was defined by the rate law(A  under pseudo first order conditions. ln{[C2]eq / ( [C2]eq -[C2]} = kobs . t (A where, kobs is the pseudo first order rate constant, [C2] is concentration of ternary complex at given time t, and [C2]eq is the equilibrium concentration of ternary complex. © 2015 BCREC UNDIP. All rights reservedReceived: 3rd October 2014; Revised: 4th December 2014; Accepted: 15th December 2014How to Cite: Kaushik, R.D., Agarwal, R., Tyagi, P., Singh, O., Singh, J. (2015. Stopped Flow Kinetics of MnII Catalysed Periodate Oxidation of 2,3-dimethylaniline - Evaluation of Stability Constant of the Ternary Intermediate Complex. Bulletin of Chemical Reaction Engineering & Catalysis, 10 (1: 78-87. (doi:10.9767/bcrec.10.1.7621.78-87Permalink/DOI: http://dx.doi.org/10.9767/bcrec.10.1.7621.78-87

Hemp fibres: Enzymatic effect of microbial processing on fibre bundle structure

DEFF Research Database (Denmark)

Thygesen, Anders; Liu, Ming; Meyer, Anne S.

2013-01-01

The effects of microbial pretreatment on hemp fibres were evaluated after microbial retting using the white rot fungi Ceriporiopsis subvermispora and Phlebia radiata Cel 26 and water retting. Based on chemical composition, P. radiata Cel 26 showed the highest selectivity for pectin and lignin...... degradation and lowest cellulose loss (14%) resulting in the highest cellulose content (78.4%) for the treated hemp fibres. The pectin and lignin removal after treatment with P. radiata Cel 26 were of the order 82% and 50%, respectively. Aligned epoxy-matrix composites were made from hemp fibres defibrated...... with the microbial retting to evaluate the effects on their ultrastructure. SEM microscopy of the composites showed low porosity on the fibre surfaces after defibration with P. radiata Cel 26 and C. subvermispora indicating good epoxy polymer impregnation. In contrast, fibres treated by water retting and the raw...

Glycoside Hydrolases across Environmental Microbial Communities.

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Renaud Berlemont

2016-12-01

Full Text Available Across many environments microbial glycoside hydrolases support the enzymatic processing of carbohydrates, a critical function in many ecosystems. Little is known about how the microbial composition of a community and the potential for carbohydrate processing relate to each other. Here, using 1,934 metagenomic datasets, we linked changes in community composition to variation of potential for carbohydrate processing across environments. We were able to show that each ecosystem-type displays a specific potential for carbohydrate utilization. Most of this potential was associated with just 77 bacterial genera. The GH content in bacterial genera is best described by their taxonomic affiliation. Across metagenomes, fluctuations of the microbial community structure and GH potential for carbohydrate utilization were correlated. Our analysis reveals that both deterministic and stochastic processes contribute to the assembly of complex microbial communities.

Constraints on superoxide mediated formation of manganese oxides

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Deric R. Learman

2013-09-01

Full Text Available Manganese (Mn oxides are among the most reactive sorbents and oxidants within the environment, where they play a central role in the cycling of nutrients, metals, and carbon. Recent discoveries have identified superoxide (O2- (both of biogenic and abiogenic origin as an effective oxidant of Mn(II leading to the formation of Mn oxides. Here we examined the conditions under which abiotically produced superoxide led to oxidative precipitation of Mn and the solid-phases produced. Oxidized Mn, as both aqueous Mn(III and Mn(III/IV oxides, was only observed in the presence of active catalase, indicating that hydrogen peroxide, a product of the reaction of O2- with Mn(II, inhibits the oxidation process presumably through the reduction of Mn(III. Citrate and pyrophosphate increased the yield of oxidized Mn but decreased the amount of Mn oxide produced via formation of Mn(III-ligand complexes. While complexing ligands played a role in stabilizing Mn(III, they did not eliminate the inhibition of net Mn(III formation by H2O2. The Mn oxides precipitated were highly disordered colloidal hexagonal birnessite, similar to those produced by biotically generated superoxide. Yet, in contrast to the large particulate Mn oxides formed by biogenic superoxide, abiotic Mn oxides did not ripen to larger, more crystalline phases. This suggests that the deposition of crystalline Mn oxides within the environment requires a biological, or at least organic, influence. This work provides the first direct evidence that, under conditions relevant to natural waters, oxidation of Mn(II by superoxide can occur and lead to formation of Mn oxides. For organisms that oxidize Mn(II by producing superoxide, these findings may also point to other microbially mediated processes, in particular enzymatic hydrogen peroxide degradation and/or production of organic ligand metabolites, that allow for Mn oxide formation.

Self-assembled decanuclear Na(I)2Mn(II)4Mn(III)4 complexes: from discrete clusters to 1-D and 2-D structures, with the Mn(II)4Mn(III)4 unit displaying a large spin ground state and probable SMM behaviour.

Science.gov (United States)

Langley, Stuart K; Chilton, Nicholas F; Moubaraki, Boujemaa; Murray, Keith S

2011-12-07

The synthesis, magnetic characterization and X-ray crystal structures are reported for five new manganese compounds, [Mn(III)(teaH(2))(sal)]·(1/2)H(2)O (1), [Na(I)(2)Mn(II)(4)Mn(III)(4)(teaH)(6)(sal)(4)(N(3))(2)(MeOH)(4)]·6MeOH (2), [Na(I)(2)Mn(II)(4)Mn(III)(4)(teaH)(6)(sal)(4)(N(3))(2)(MeOH)(2)](n)·7MeOH (3), [Na(I)(2)Mn(II)(4)Mn(III)(4)(teaH)(6)(sal)(4)(N(3))(2)(MeOH)(2)](n)·2MeOH·Et(2)O (4) and [K(I)(2)Mn(II)(4)Mn(III)(4)(teaH)(6)(sal)(4)(N(3))(2)(H(2)O)(2)](n)·5MeOH (5). Complex 1 is a mononuclear compound, formed via the reaction of Mn(NO(3))(2)·4H(2)O, triethanolamine (teaH(3)) and salicylic acid (salH(2)) in a basic methanolic solution. Compound 2 is a mixed-valent hetero-metallic cluster made up of a Mn(8)Na(2) decanuclear core and is formed via the reaction of sodium azide (NaN(3)) with 1. Compounds 3-5 are isolated as 1- or 2-D coordination polymers, each containing the decanuclear Mn(8)M(2) (M = Na(+) or K(+)) core building block as the repeating unit. Compound 3 is isolated when 1 is reacted with NaN(3) over a very short reaction time and forms a 1-D coordination polymer. Each unit displays inter-cluster bridges via the O-atoms of teaH(2-) ligands bonding to the sodium ions of an adjacent cluster. Increasing the reaction time appears to drive the formation of 4 which forms 2-D polymeric sheets and is a packing polymorph of 3. The addition of KMnO(4) and NaN(3) to 1 resulted in compound 5, which also forms a 1-D coordination polymer of the decanuclear core unit. The 1-D chains are now linked via inter-cluster potassium and salicylate bridges. Solid state DC susceptibility measurements were performed on compounds 1-5. The data for 1 are as expected for an S = 2 Mn(III) ion, with the isothermal M vs. H data being fitted by matrix diagonalization methods to give values of g and the axial (D) and rhombic (E) zero field splitting parameters of 2.02, -2.70 cm(-1) and 0.36 cm(-1) respectively. The data for 2-5, each with an identical Mn(II)(4)Mn(III)(4

Effect of Soil Amendments on Microbial Resilience Capacity of Acid Soil Under Copper Stress.

Science.gov (United States)

Mounissamy, Vassanda Coumar; Kundu, Samaresh; Selladurai, Rajendiran; Saha, Jayanta Kumar; Biswas, Ashish Kumar; Adhikari, Tapan; Patra, Ashok Kumar

2017-11-01

An incubation study was undertaken to study microbial resilience capacity of acid soil amended with farmyard manure (FYM), charcoal and lime under copper (Cu) perturbation. Copper stress significantly reduced enzymatic activities and microbial biomass carbon (MBC) in soil. Percent reduction in microbial activity of soil due to Cu stress was 74.7% in dehydrogenase activity, 59.9% in MBC, 48.2% in alkaline phosphatase activity and 15.1% in acid phosphatase activity. Soil treated with FYM + charcoal showed highest resistance index for enzymatic activities and MBC. Similarly, the highest resilience index for acid phosphatase activity was observed in soil amended with FYM (0.40), whereas FYM + charcoal-treated soil showed the highest resilience indices for alkaline, dehydrogenase activity and MBC: 0.50, 0.22 and 0.25, respectively. This investigation showed that FYM and charcoal application, either alone or in combination, proved to be better than lime with respect to microbial functional resistance and resilience of acid soil under Cu perturbation.

Microbial Transformations of Actinides and Fission Products in Radioactive Waste

Energy Technology Data Exchange (ETDEWEB)

Francis, A. J. [Pohang Univ. Science and Technology, Pohang (Korea, Republic of)

2011-07-01

The environmental factors that can affect microbial growth and activity include moisture, temperature, ph, Eh, availability of organic and inorganic nutrients, and radiation. The microbial activity in a specific repository is influenced by the ambient environment of the repository, and the materials to be emplaced. For example, a repository in unsaturated igneous rock formations such as volcanic tuff rocks at Yucca Mountain is generally expected to be oxidizing; a repository in a hydrologically expected to be oxidizing; a repository in a hydrologically saturated zone, especially in sedimentary rocks, could be reducing. Sedimentary rocks contain a certain amount of organic matter, which may stimulate microbial activities and, thus maintain the repository and its surrounding areas at reducing conditions. Although the impacts of microbial activity on high-level nuclear waste and the long-term performance of the repository have not fully investigated, little microbial activity is expected in the near-field because of the radiation, lack of nutrients and the harsh conditions. However in the far-field microbial effects could be significant. Much of our understanding of the microbial effects on radionuclides stems from studies conducted with selected transuranic elements and fission products and limited studies with low-level radioactive wastes. Significant aerobic- and anaerobic-microbial activity is expected to occur in the waste because of the presence of electron donors and acceptors. The actinides initially may be present as soluble- or insoluble-forms but, after disposal, may be converted from one to the other by microorganisms. The direct enzymatic or indirect non-enzymatic actions of microbes could alter the speciation, solubility, and sorption properties of the actinides, thereby increasing or decreasing their concentrations in solution.

Microbial transformations of radionuclides released from nuclear fuel reprocessing plants

International Nuclear Information System (INIS)

Francis, A.J.

2007-01-01

Microorganisms can affect the stability and mobility of the actinides U, Pu, Cm, Am, Np, and the fission products Tc, I, Cs, Sr, released from nuclear fuel reprocessing plants. Under appropriate conditions, microorganisms can alter the chemical speciation, solubility and sorption properties and thus could increase or decrease the concentrations of radionuclides in solution and the bioavailability. Dissolution or immobilization of radionuclides is brought about by direct enzymatic action or indirect non-enzymatic action of microorganisms. Although the physical, chemical, and geochemical processes affecting dissolution, precipitation, and mobilization of radionuclides have been investigated, we have only limited information on the effects of microbial processes. The mechanisms of microbial transformations of the major and minor actinides and the fission products under aerobic and anaerobic conditions in the presence of electron donors and acceptors are reviewed. (author)

Production of hydrogen by microbial fermentation

Energy Technology Data Exchange (ETDEWEB)

Roychowdhury, S.; Cox, D.; Levandowsky, M.

1988-01-01

Production of hydrogen by defined and undefined bacterial cultures was studied, using pure sugars (glucose and maltose) or natural sources rich in either pure sugars or polysaccharides. The latter included sugar cane juice, corn pulp (enzymatically treated or untreated), and enzymatically treated paper. Mixed microbial flora from sewage and landfill sediments, as well as pure and mixed cultures of known coliform bacteria produced mixtures of hydrogen and carbon dioxide at 37/sup 0/C and 55/sup 0/C, with hydrogen concentrations as high as 87%. In the case of the pure glucose substrate, an average yield of 0.7 mol hydrogen per mol glucose was obtained.

Understanding and regulation of microbial lignolysis for renewable platform chemicals

Energy Technology Data Exchange (ETDEWEB)

Singh, Seema [Sandia National Lab. (SNL-CA), Livermore, CA (United States); Hudson, Corey [Sandia National Lab. (SNL-CA), Livermore, CA (United States); Turner, Kevin. [Sandia National Lab. (SNL-CA), Livermore, CA (United States); Tran-Gyamfi, Mary Bao [Sandia National Lab. (SNL-CA), Livermore, CA (United States); Williams, Kelly Porter [Sandia National Lab. (SNL-CA), Livermore, CA (United States); Powell, Amy Jo [Sandia National Lab. (SNL-CA), Livermore, CA (United States); Alam, Todd Michael [Sandia National Lab. (SNL-CA), Livermore, CA (United States)

2014-01-01

Lignin is often overlooked in the valorization of lignocellulosic biomass, but lignin-based materials and chemicals represent potential value-added products for biorefineries that could significantly improve the economics of a biorefinery. Fluctuating crude oil prices and changing fuel specifications are some of the driving factors to develop new technologies that could be used to convert polymeric lignin into low molecular weight lignin and or monomeric aromatic feedstocks to assist in the displacement of the current products associated with the conversion of a whole barrel of oil. Our project of understanding microbial lignolysis for renewable platform chemicals aimed to understand microbial and enzymatic lignolysis processes to break down lignin for conversion into commercially viable drop-in fuels. We developed novel lignin analytics to interrogate enzymatic and microbial lignolysis of native polymeric lignin and established a detailed understanding of lignolysis as a function of fungal enzyme, microbes and endophytes. Bioinformatics pipeline was developed for metatranscryptomic analysis of aridland ecosystem for investigating the potential discovery of new lignolysis gene and gene products.

Response of soil microbial activity and biodiversity in soils polluted with different concentrations of cypermethrin insecticide.

Science.gov (United States)

Tejada, Manuel; García, Carlos; Hernández, Teresa; Gómez, Isidoro

2015-07-01

We performed a laboratory study into the effect of cypermethrin insecticide applied to different concentrations on biological properties in two soils [Typic Xerofluvent (soil A) and Xerollic Calciorthid (soil B)]. Two kg of each soil were polluted with cypermethrin at a rate of 60, 300, 600, and 1,200 g ha(-1) (C1, C2, C3, and C4 treatments). A nonpolluted soil was used as a control (C0 treatment). For all treatments and each experimental soil, soil dehydrogenase, urease, β-glucosidase, phosphatase, and arylsulphatase activities and soil microbial community were analysed by phospholipid fatty acids, which were measured at six incubation times (3, 7, 15, 30, 60, and 90 days). The behavior of the enzymatic activities and microbial population were dependent on the dose of insecticide applied to the soil. Compared with the C0 treatment, in soil A, the maximum inhibition of the enzymatic activities was at 15, 30, 45, and 90 days for the C1, C2, C3, and C4 treatments, respectively. However, in soil B, the maximum inhibition occurred at 7, 15, 30, and 45 days for the C1, C2, C3, and C4 treatments, respectively. These results suggest that the cypermethrin insecticide caused a negative effect on soil enzymatic activities and microbial diversity. This negative impact was greater when a greater dose of insecticide was used; this impact was also greater in soil with lower organic matter content. For both soils, and from these respective days onward, the enzymatic activities and microbial populations progressively increased by the end of the experimental period. This is possibly due to the fact that the insecticide or its breakdown products and killed microbial cells, subsequently killed by the insecticide, are being used as a source of energy or as a carbon source for the surviving microorganisms for cell proliferation.

Microbial hydrocarbon degradation - bioremediation of oil spills

Energy Technology Data Exchange (ETDEWEB)

Atlas, R M [Louisville Univ., KY (United States). Dept. of Biology

1991-01-01

Bioremediation has become a major method employed in restoration of oil-polluted environments that makes use of natural microbial biodegradative activities. Bioremediation of petroleum pollutants overcomes the factors limiting rates of microbial hydrocarbon biodegradation. Often this involves using the enzymatic capabilities of the indigenous hydrocarbon-degrading microbial populations and modifying environmental factors, particularly concentrations of molecular oxygen, fixed forms of nitrogen and phosphate to achieve enhanced rates of hydrocarbon biodegradation. Biodegradation of oily sludges and bioremediation of oil-contaminated sites has been achieved by oxygen addition-e.g. by tilling soils in landfarming and by adding hydrogen peroxide or pumping oxygen into oiled aquifers along with addition of nitrogen- and phosphorous-containing fertilizers. The success of seeding oil spills with microbial preparations is ambiguous. Successful bioremediation of a major marine oil spill has been achieved based upon addition of nitrogen and phosphorus fertilizers. (author).

31P and 1H NMR studies of the structure of enzyme-bound substrate complexes of lobster muscle arginine kinase: Relaxation measurements with Mn(II) and Co(II)

International Nuclear Information System (INIS)

Jarori, G.K.; Ray, B.D.; Rao, B.D.N.

1989-01-01

The paramagnetic effects of Mn(II) and Co(II) on the spin-lattice relaxation rates of 31 P nuclei of ATP and ADP and of Mn(II) on the spin-lattice relaxation rate of the δ protons of arginine bound to arginine kinase from lobster tail muscle have been measured. Temperature variation of 31 P relaxation rates in E-MnADP and E-MnATP yields activation energies (ΔE) in the range 6-10 kcal/mol. Thus, the 31 P relaxation rates in these complexes are exchange limited and cannot provide structural information. However, the relaxation rates in E-CoADP and E-CoATP exhibit frequency dependence and ΔE values in the range 1-2 kcal/mol; i.e., these rates depend upon 31 P-Co(II) distances. These distances were calculated to be in the range 3.2-4.5 angstrom, appropriate for direct coordination between Co(II) and the phosphoryl groups. The paramagnetic effect of Mn(II) on the 1 H spin-lattice relaxation rate of the δ protons of arginine in the E-MnADP-Arg complex was also measured at three frequencies. From the frequency dependence of the relaxation rate an effective τ C of 0.6 ns has also been calculated, which is most likely to be the electron spin relaxation rate (τ S1 ) for Mn(II) in this complex. The distance estimated on the basis of the reciprocal sixth root of the average relaxation rate of the δ protons was 10.9 ± 0.3 angstrom

New Mn(II, Ni(II, Cd(II, Pb(II complexes with 2-methylbenzimidazole and other ligands. Synthesis, spectroscopic characterization, crystal structure, magnetic susceptibility and biological activity studies

Directory of Open Access Journals (Sweden)

Shayma A. Shaker

2016-11-01

Full Text Available Synthesis and characterization of Mn(II, Ni(II, Cd(II and Pb(II mixed ligand complexes of 2-methylbenzimidazole with other ligands have been reported. The structure of the ligands and their complexes was investigated using elemental analysis, IR, UV–Vis, (1H, 13C NMR spectroscopy, molar conductivity and magnetic susceptibility measurements. In all the studies of complexes, the 2-methylbenzimidazole behaves as a neutral monodentate ligand which is coordinated with the metal ions through the N atom. While benzotriazole behaves as a neutral bidentate ligand which is coordinated with the Ni(II ion through the two N atoms. Moreover, the N-acetylglycine behaves as a bidentate ligand which is coordinated with the Mn(II, Ni(II and Pb(II ions through the N atom and the terminal carboxyl oxygen atom. The magnetic and spectral data indicate the tetrahedral geometry for Mn(II complex, irregular tetrahedral geometry for Pb(II complex and octahedral geometry for Ni(II complex. The X-ray single crystal diffraction method was used to confirm a centrosymmetric dinuclear Cd(II complex as each two metal ions are linked by a pair of thiocyanate N = S bridge. Two 2-methylbenzimidazole N-atom donors and one terminal thiocyanate N atom complete a highly distorted square pyramid geometry around the Cd atom. Besides, different cell types were used to determine the inhibitory effect of Mn(II, Ni(II, Cd(II and Pb(II complexes on cell growth using MTT assay. Cd(II complex showed cytotoxic effect on various types of cancer cell lines with different EC50 values.

Molecular Species of the Enzymatically Synthesized Polyunsaturated Fatty Acid Rich Triglyceride

OpenAIRE

長田, 恭一; 高橋, 是太郎; 羽田野, 六男; 細川, 雅史

1991-01-01

Enzymatic glyceride synthesis and acid interchange using icosapentaenoic acid (EPA), docosahexaenoic acid (DHA), γ-linolenic acid (GLA), and EPA and DHA concentrated saponified fatty acid mixture obtained from sardine oil were carried out through the use of four kinds of microbial lipases. Lipase TOYO (Chromobacterium viscosum) was the most effective enzyme for glyceride synthesis as well as acid interchange of triglyceride (TG) rich in polyunsaturated fatty acids. There was a general tendenc...

Temperature induced decoupling of enzymatic hydrolysis and carbon remineralization in long-term incubations of Arctic and temperate sediments

DEFF Research Database (Denmark)

Robador, Alberto; Brüchert, Volker; Steen, Andrew

2010-01-01

explored the temperature sensitivity of enzymatic hydrolysis and its connection to subsequent steps in anoxic organic carbon degradation in long-term incubations of sediments from the Arctic and the North Sea. These sediments were incubated under anaerobic conditions for 24 months at temperatures of 0, 10......, and 20 ºC. The short-term temperature response of the active microbial community was tested in temperature gradient block incubations. The temperature optimum of extracellular enzymatic hydrolysis, as measured with a polysaccharide (chondroitin sulfate), differed between Arctic and temperate habitats...

Response of soil microbial activities and microbial community structure to vanadium stress.

Science.gov (United States)

Xiao, Xi-Yuan; Wang, Ming-Wei; Zhu, Hui-Wen; Guo, Zhao-Hui; Han, Xiao-Qing; Zeng, Peng

2017-08-01

High levels of vanadium (V) have long-term, hazardous impacts on soil ecosystems and biological processes. In the present study, the effects of V on soil enzymatic activities, basal respiration (BR), microbial biomass carbon (MBC), and the microbial community structure were investigated through 12-week greenhouse incubation experiments. The results showed that V content affected soil dehydrogenase activity (DHA), BR, and MBC, while urease activity (UA) was less sensitive to V stress. The average median effective concentration (EC 50 ) thresholds of V were predicted using a log-logistic dose-response model, and they were 362mgV/kg soil for BR and 417mgV/kg soil for DHA. BR and DHA were more sensitive to V addition and could be used as biological indicators for soil V pollution. According to a polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) analysis, the structural diversity of the microbial community decreased for soil V contents ranged between 254 and 1104mg/kg after 1 week of incubation. As the incubation time increased, the diversity of the soil microbial community structure increased for V contents ranged between 354 and 1104mg/kg, indicating that some new V-tolerant bacterial species might have replicated under these conditions. Copyright © 2017 Elsevier Inc. All rights reserved.

Speciation of Mn(II), Mn(VII) and total manganese in water and food samples by coprecipitation-atomic absorption spectrometry combination

International Nuclear Information System (INIS)

Citak, Demirhan; Tuzen, Mustafa; Soylak, Mustafa

2010-01-01

A speciation procedure based on the coprecipitation of manganese(II) with zirconium(IV) hydroxide has been developed for the investigation of levels of manganese species. The determination of manganese levels was performed by flame atomic absorption spectrometry (FAAS). Total manganese was determined after the reduction of Mn(VII) to Mn(II) by ascorbic acid. The analytical parameters including pH, amount of zirconium(IV), sample volume, etc., were investigated for the quantitative recoveries of manganese(II). The effects of matrix ions were also examined. The recoveries for manganese(II) were in the range of 95-98%. Preconcentration factor was calculated as 50. The detection limit for the analyte ions based on 3 sigma (n = 21) was 0.75 μg L -1 for Mn(II). The relative standard deviation was found to be lower than 7%. The validation of the presented procedure was performed by analysis of certified reference material having different matrices, NIST SRM 1515 (Apple Leaves) and NIST SRM 1568a (Rice Flour). The procedure was successfully applied to natural waters and food samples.

Novel mode of microbial energy metabolism: organic carbon oxidation coupled to dissimilatory reduction of iron or manganese.

Science.gov (United States)

Lovley, D R; Phillips, E J

1988-06-01

A dissimilatory Fe(III)- and Mn(IV)-reducing microorganism was isolated from freshwater sediments of the Potomac River, Maryland. The isolate, designated GS-15, grew in defined anaerobic medium with acetate as the sole electron donor and Fe(III), Mn(IV), or nitrate as the sole electron acceptor. GS-15 oxidized acetate to carbon dioxide with the concomitant reduction of amorphic Fe(III) oxide to magnetite (Fe(3)O(4)). When Fe(III) citrate replaced amorphic Fe(III) oxide as the electron acceptor, GS-15 grew faster and reduced all of the added Fe(III) to Fe(II). GS-15 reduced a natural amorphic Fe(III) oxide but did not significantly reduce highly crystalline Fe(III) forms. Fe(III) was reduced optimally at pH 6.7 to 7 and at 30 to 35 degrees C. Ethanol, butyrate, and propionate could also serve as electron donors for Fe(III) reduction. A variety of other organic compounds and hydrogen could not. MnO(2) was completely reduced to Mn(II), which precipitated as rhodochrosite (MnCO(3)). Nitrate was reduced to ammonia. Oxygen could not serve as an electron acceptor, and it inhibited growth with the other electron acceptors. This is the first demonstration that microorganisms can completely oxidize organic compounds with Fe(III) or Mn(IV) as the sole electron acceptor and that oxidation of organic matter coupled to dissimilatory Fe(III) or Mn(IV) reduction can yield energy for microbial growth. GS-15 provides a model for how enzymatically catalyzed reactions can be quantitatively significant mechanisms for the reduction of iron and manganese in anaerobic environments.

Synthesis, spectral characterization thermal stability, antimicrobial studies and biodegradation of starch–thiourea based biodegradable polymeric ligand and its coordination complexes with [Mn(II), Co(II), Ni(II), Cu(II), and Zn(II)] metals

OpenAIRE

Nahid Nishat; Ashraf Malik

2016-01-01

A biodegradable polymer was synthesized by the modification reaction of polymeric starch with thiourea which is further modified by transition metals, Mn(II), Co(II), Ni(II), Cu(II) and Zn(II). All the polymeric compounds were characterized by (FT-IR) spectroscopy, 1H NMR spectroscopy, 13C NMR spectroscopy, UV–visible spectra, magnetic moment measurements, thermogravimetric analysis (TGA) and antibacterial activities. Polymer complexes of Mn(II), Co(II) and Ni(II) show octahedral geometry, wh...

Structure and Heme-Independent Peroxidase Activity of a Fully-Coordinated Mononuclear Mn(II) Complex with a Schiff-Base Tripodal Ligand Containing Three Imidazole Groups

Energy Technology Data Exchange (ETDEWEB)

Sarkar, Shuranjan; Lee, Hong In [Kyungpook National University, Daegu (Korea, Republic of); Moon, Do Hyun [Pohang Accelerator Laboratory, Pohang (Korea, Republic of); Lah, Myoung Soo [Ulsan National Institute of Science and Technology, Ulsan (Korea, Republic of)

2010-11-15

New complex [Mn(II)H{sub 1.5}L]{sub 2}[Mn(II)H{sub 3}L]{sub 2}(ClO{sub 4}){sub 5}·3H{sub 2}O, where H{sub 3}L is tris{2-(4-imidazolyl)methyliminoethyl} amine (imtren), has been prepared by reacting manganese(II) perchlorate hexahydrate with the imtren ligand in methanol. X-ray crystallographic study revealed that the imtren ligand hexadentately binds to Mn(II) ion through the three Schiff-base imine N atoms and three imidazole N atoms with a distorted octahedral geometry, and the apical tertiary amine N atom of the ligand pseudo-coordinates to Mn(II), forming overall a pseudo-seven coordination environment. The hydrogen-bonds between imidazole and imidazolate of [Mn(II)H{sub 1.5}L]{sup 0.5+} complex ions are extended to build a 2D puckered network with trigonal voids. [Mn(II)H{sub 3}L]{sup 2+} complex ions constitutes another extended 2D puckered layer without hydrogen bonds. Two layers are wedged each other to constitute overall stack of the crystal. Peroxidase activity of complex 1 was examined by observing the oxidation of 2,2'-azinobis(3-ethylbenzothiazoline)- 6-sulfonic acid (ABTS) with hydrogen peroxide in the presence of complex 1. Generation of ABTS{sup +·} was observed by UV-vis and EPR spectroscopies, indicating that the complex 1, a fully-coordinated mononuclear Mn(II) complex with nitrogen-only ligand, has a heme-independent peroxidase activity.

Synthesis, characterization, anti-microbial, DNA binding and cleavage studies of Schiff base metal complexes

Directory of Open Access Journals (Sweden)

Poomalai Jayaseelan

2016-09-01

Full Text Available A novel Schiff base ligand has been prepared by the condensation between butanedione monoxime with 3,3′-diaminobenzidine. The ligand and metal complexes have been characterized by elemental analysis, UV, IR, 1H NMR, conductivity measurements, EPR and magnetic studies. The molar conductance studies of Cu(II, Ni(II, Co(II and Mn(II complexes showed non-electrolyte in nature. The ligand acts as dibasic with two N4-tetradentate sites and can coordinate with two metal ions to form binuclear complexes. The spectroscopic data of metal complexes indicated that the metal ions are complexed with azomethine nitrogen and oxyimino nitrogen atoms. The binuclear metal complexes exhibit octahedral arrangements. DNA binding properties of copper(II metal complex have been investigated by electronic absorption spectroscopy. Results suggest that the copper(II complex bind to DNA via an intercalation binding mode. The nucleolytic cleavage activities of the ligand and their complexes were assayed on CT-DNA using gel electrophoresis in the presence and absence of H2O2. The ligand showed increased nuclease activity when administered as copper complex and copper(II complex behave as efficient chemical nucleases with hydrogen peroxide activation. The anti-microbial activities and thermal studies have also been studied. In anti-microbial activity all complexes showed good anti-microbial activity higher than ligand against gram positive, gram negative bacteria and fungi.

Preparation, Investigation and the Study of the Effect of Mn(II Complex of Catechol and 2-Aminopyridine on Seed Germination

Directory of Open Access Journals (Sweden)

F. I. El-Moshaty

2011-01-01

Full Text Available The formation of mixed ligand complex of Mn(II with catechol (L1 and 2-aminopyridine (L2 was determined by elemental analyses (C, H and N, molar conductance measurement, thermogravimetric analysis, infrared, electronic and electron paramagnetic resonance spectroscopies. The elemental analysis data show the formation of 1:1:1 [M: L1: L2] complex. The molar conductance measurement shows a non-electrolyte nature. The thermogravimetric analysis data of the complex display the existence of hydrated and coordinated water molecules. The infrared spectral data exhibit the coordination sites that are through -OH,-C=N and –NH2 groups. The electronic spectral data display the electronic transitions of the ligands and suggest an octahedral structure for the complex. The electron paramagnetic resonance spectrum of the complex reveals the existence of paramagnetic phenomena and supports its geometrical structure. Seed germination and root length of grass were also assayed under the effect of MnCl2.4H2O, catechol, 2-aminopyridine and its complex. Mn(II salt was the most effective on germination than its complex which possess the high test effect on root length, while the ligands are the least active of all.

Flow-through Column Experiments and Modeling of Microbially Mediated Cr(VI) Reduction at Hanford 100H

Science.gov (United States)

Yang, L.; Molins, S.; Beller, H. R.; Brodie, E. L.; Steefel, C.; Nico, P. S.; Han, R.

2010-12-01

Fe(II) and Mn(II) released from the sediment could account for the observed Cr(VI) removal. The biogeochemical modeling was employed to test two hypotheses that could explain the release of Fe(II) and Mn(II) from the column sediments: 1) acetate produced by lactate fermentation provided the substrate for the growth of iron(III) and manganese(IV) oxide reducers, and 2) direct reduction of iron(III) and manganese(IV) oxides by hydrogen sulfide generated during sulfate reduction. Overall, experimental and modeling results suggested that Cr(VI) reduction in the sulfate-reducing columns occurred through a complex network of microbial reactions that included fermentation, sulfate reduction, and possibly the stimulated iron-reducing communities.

A New Bis(aquated) High Relaxivity Mn(II) Complex as an Alternative to Gd(III)-Based MRI Contrast Agent.

Science.gov (United States)

Phukan, Bedika; Mukherjee, Chandan; Goswami, Upashi; Sarmah, Amrit; Mukherjee, Subhajit; Sahoo, Suban K; Moi, Sankar Ch

2018-03-05

Disclosed here are a piperazine, a pyridine, and two carboxylate groups containing pentadentate ligand H 2 pmpa and its corresponding water-soluble Mn(II) complex (1). DFT-based structural optimization implied that the complex had pentagonal bipyramidal geometry where the axial positions were occupied by two water molecules, and the equatorial plane was constituted by the ligand ON 3 O donor set. Thus, a bis(aquated) disc-like Mn(II) complex has been synthesized. The complex showed higher stability compared with Mn(II)-EDTA complex [log K MnL = 14.29(3)] and showed a very high r 1 relaxivity value of 5.88 mM -1 s -1 at 1.41 T, 25 °C, and pH = 7.4. The relaxivity value remained almost unaffected by the pH of the medium in the range of 6-10. Although the presence of 200 equiv of fluoride and bicarbonate anions did not affect the relaxivity value appreciably, an increase in the value was noticed in the presence of phosphate anion due to slow tumbling of the complex. Cell viability measurements, as well as phantom MR images using clinical MRI imager, consolidated the possible candidature of complex 1 as a positive contrast agent.

First results on enzymatic activities in two salt marsh soils under different hydromorphic level and vegetation

Directory of Open Access Journals (Sweden)

Carmen Trasar-Cepeda

2015-12-01

Full Text Available Salt-marsh soils are soils characterized by non-permanent hydric saturation that, depending on factors like duration of submersion periods, are dominated by different salt-tolerant plant species. The composition of microbial communities is an essential component in trophic dynamics and biogeochemical processes in salt marshes, and determines the level of enzymatic activities, which catalyze the conversion of complex molecules into simpler ones. Despite of this, the enzymatic activities in marsh-soils has not yet been investigated. The aim of this study was to analyze the enzymatic activities in two soil profiles of marsh-soils under different water saturation level and dominated by different plant species [Juncus maritimus Lam and Spartina maritima (Curtis Fernald (Sp]. In both soils, the enzymatic activities were much lower than the levels typically found in terrestrial ecosystems. The enzymatic activities were measured both in air-dried and in re-moistened and incubated soil samples. In air-dried samples, the enzymatic activities were higher in Juncus than in Spartina soil and tended to decrease with depth, being sharper the decrease in Juncus than in Spartina soil. Re-moistened and pre-incubated soils showed a general increase in all the enzymatic activities and throughout the whole soil profile, especially in Spartina soils. Hydrolase activities showed a strong and positive relationship with organic matter content both in air-dried and in re-moistened soil samples, higher in these latter. In general, oxidoreductase activities only showed this relationship in re-moistened soil samples. More studies, preferably using freshly collected soil samples, are needed to understand the relationship between enzymatic activities and these environmental conditions.

Relationships between waste physicochemical properties, microbial activity and vegetation at coal ash and sludge disposal sites.

Science.gov (United States)

Woch, Marcin W; Radwańska, Magdalena; Stanek, Małgorzata; Łopata, Barbara; Stefanowicz, Anna M

2018-06-11

The aim of the study was to assess the relationships between vegetation, physicochemical and microbial properties of substrate at coal ash and sludge disposal sites. The study was performed on 32 plots classified into 7 categories: dried ash sedimentation ponds, dominated by a grass Calamagrostis epigejos (AH-Ce), with the admixture of Pinus sylvestris (AH-CePs) or Robinia pseudoacacia (AH-CeRp), dry ash landfill dominated by Betula pendula and Pinus sylvestris (AD-BpPs) or Salix viminalis (AD-Sv) and coal sludge pond with drier parts dominated by Tussilago farfara (CS-Tf) and the wetter ones by Cyperus flavescens (CS-Cf). Ash sites were covered with soil layer imported as a part of technical reclamation. Ash had relatively high concentrations of some alkali and alkaline earth metals, Mn and pH, while coal sludge had high water and C, S, P and K contents. Concentrations of heavy metals were lower than allowable limits in all substrate types. Microbial biomass and, particularly, enzymatic activity in ash and sludge were generally low. The only exception were CS-Tf plots characterized by the highest microbial biomass, presumably due to large deposits of organic matter that became available for aerobic microbial biomass when water level fell. The properties of ash and sludge adversely affected microbial biomass and enzymatic activity as indicated by significant negative correlations between the content of alkali/alkaline earth metals, heavy metals, and macronutrients with enzymatic activity and/or microbial biomass, as well as positive correlations of these parameters with metabolic quotient (qCO 2 ). Plant species richness and cover were relatively high, which may be partly associated with alleviating influence of soil covering the ash. The effect of the admixture of R. pseudoacacia or P. sylvestris to stands dominated by C. epigejos was smaller than expected. The former species increased NNH 4 , NNO 3 and arylsulfatase activity, while the latter reduced activity of

Rapid estimation of compost enzymatic activity by spectral analysis method combined with machine learning.

Science.gov (United States)

Chakraborty, Somsubhra; Das, Bhabani S; Ali, Md Nasim; Li, Bin; Sarathjith, M C; Majumdar, K; Ray, D P

2014-03-01

The aim of this study was to investigate the feasibility of using visible near-infrared (VisNIR) diffuse reflectance spectroscopy (DRS) as an easy, inexpensive, and rapid method to predict compost enzymatic activity, which traditionally measured by fluorescein diacetate hydrolysis (FDA-HR) assay. Compost samples representative of five different compost facilities were scanned by DRS, and the raw reflectance spectra were preprocessed using seven spectral transformations for predicting compost FDA-HR with six multivariate algorithms. Although principal component analysis for all spectral pretreatments satisfactorily identified the clusters by compost types, it could not separate different FDA contents. Furthermore, the artificial neural network multilayer perceptron (residual prediction deviation=3.2, validation r(2)=0.91 and RMSE=13.38 μg g(-1) h(-1)) outperformed other multivariate models to capture the highly non-linear relationships between compost enzymatic activity and VisNIR reflectance spectra after Savitzky-Golay first derivative pretreatment. This work demonstrates the efficiency of VisNIR DRS for predicting compost enzymatic as well as microbial activity. Copyright © 2013 Elsevier Ltd. All rights reserved.

Effects of Conservation Agriculture and Fertilization on Soil Microbial Diversity and Activity

Directory of Open Access Journals (Sweden)

Johan Habig

2015-07-01

Full Text Available Soil microbial communities perform critical functions in ecosystem processes. These functions can be used to assess the impact of agricultural practices on sustainable crop production. In this five-year study, the effect of various agricultural practices on soil microbial diversity and activity was investigated in a summer rainfall area under South African dryland conditions. Microbial diversity and activity were measured in the 0–15 cm layer of a field trial consisting of two fertilizer levels, three cropping systems, and two tillage systems. Using the Shannon–Weaver and Evenness diversity indices, soil microbial species richness and abundance were measured. Microbial enzymatic activities: β-glucosidase, phosphatase and urease, were used to evaluate ecosystem functioning. Cluster analysis revealed a shift in soil microbial community diversity and activity over time. Microbial diversity and activity were higher under no-till than conventional tillage. Fertilizer levels seemed to play a minor role in determining microbial diversity and activity, whereas the cropping systems played a more important role in determining the activity of soil microbial communities. Conservation agriculture yielded the highest soil microbial diversity and activity in diversified cropping systems under no-till.

Structural characterization of terrestrial microbial Mn oxides from Pinal Creek, AZ

Science.gov (United States)

Bargar, J.R.; Fuller, C.C.; Marcus, M.A.; Brearley, A.J.; Perez De la Rosa, M.; Webb, S.M.; Caldwell, W.A.

2009-01-01

The microbial catalysis of Mn(II) oxidation is believed to be a dominant source of abundant sorption- and redox-active Mn oxides in marine, freshwater, and subsurface aquatic environments. In spite of their importance, environmental oxides of known biogenic origin have generally not been characterized in detail from a structural perspective. Hyporheic zone Mn oxide grain coatings at Pinal Creek, Arizona, a metals-contaminated stream, have been identified as being dominantly microbial in origin and are well studied from bulk chemistry and contaminant hydrology perspectives. This site thus presents an excellent opportunity to study the structures of terrestrial microbial Mn oxides in detail. XRD and EXAFS measurements performed in this study indicate that the hydrated Pinal Creek Mn oxide grain coatings are layer-type Mn oxides with dominantly hexagonal or pseudo-hexagonal layer symmetry. XRD and TEM measurements suggest the oxides to be nanoparticulate plates with average dimensions on the order of 11 nm thick ?? 35 nm diameter, but with individual particles exhibiting thickness as small as a single layer and sheets as wide as 500 nm. The hydrated oxides exhibit a 10-?? basal-plane spacing and turbostratic disorder. EXAFS analyses suggest the oxides contain layer Mn(IV) site vacancy defects, and layer Mn(III) is inferred to be present, as deduced from Jahn-Teller distortion of the local structure. The physical geometry and structural details of the coatings suggest formation within microbial biofilms. The biogenic Mn oxides are stable with respect to transformation into thermodynamically more stable phases over a time scale of at least 5 months. The nanoparticulate layered structural motif, also observed in pure culture laboratory studies, appears to be characteristic of biogenic Mn oxides and may explain the common occurrence of this mineral habit in soils and sediments. ?? 2008 Elsevier Ltd.

DOTA-Functionalized Polylysine: A High Number of DOTA Chelates Positively Influences the Biodistribution of Enzymatic Conjugated Anti-Tumor Antibody chCE7agl.

OpenAIRE

Grünberg Jürgen; Jeger Simone; Sarko Dikran; Dennler Patrick; Zimmermann Kurt; Mier Walter; Schibli Roger

2013-01-01

Site-specific enzymatic reactions with microbial transglutaminase (mTGase) lead to a homogenous species of immunoconjugates with a defined ligand/antibody ratio. In the present study, we have investigated the influence of different numbers of 1,4,7,10-tetraazacyclododecane-N-N'-N''-N'''-tetraacetic acid (DOTA) chelats coupled to a decalysine backbone on the in vivo behavior of the chimeric monoclonal anti-L1CAM antibody chCE7agl. The enzymatic conjugation of (DOTA)1-decalysine, (DOTA)3-decaly...

Microbial decomposition of keratin in nature—a new hypothesis of industrial relevance

DEFF Research Database (Denmark)

Lange, Lene; Huang, Yuhong; Kamp Busk, Peter

2016-01-01

with the keratinases to loosen the molecular structure, thus giving the enzymes access to their substrate, the protein structure. With such complexity, it is relevant to compare microbial keratin decomposition with the microbial decomposition of well-studied polymers such as cellulose and chitin. Interestingly...... enzymatic and boosting factors needed for keratin breakdown have been used to formulate a hypothesis for mode of action of the LPMOs in keratin decomposition and for a model for degradation of keratin in nature. Testing such hypotheses and models still needs to be done. Even now, the hypothesis can serve...

Photoelectrochemical enzymatic biosensors.

Science.gov (United States)

Zhao, Wei-Wei; Xu, Jing-Juan; Chen, Hong-Yuan

2017-06-15

Enzymatic biosensors have been valuable bioanalytical devices for analysis of diverse targets in disease diagnosis, biological and biomedical research, etc. Photoelectrochemical (PEC) bioanalysis is a recently emerged method that promptly becoming a subject of new research interests due to its attractive potential for future bioanalysis with high sensitivity and specificity. PEC enzymatic biosensors integrate the inherent sensitivities of PEC bioanalysis and the selectivity of enzymes and thus share their both advantages. Currently, PEC enzymatic biosensors have become a hot topic of significant research and the recent impetus has grown rapidly as demonstrated by increased research papers. Given the pace of advances in this area, this review will make a thorough discussion and survey on the fundamentals, sensing strategies, applications and the state of the art in PEC enzymatic biosensors, followed by future prospects based on our own opinions. We hope this work could provide an accessible introduction to PEC enzymatic biosensors for any scientist. Copyright © 2016 Elsevier B.V. All rights reserved.

Surface characterization of pretreated and microbial-treated populus cross-sections

Energy Technology Data Exchange (ETDEWEB)

Tolbert, Allison K. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

2017-05-01

The first objective of this thesis is to illustrate the advantages of surface characterization in biomass utilization studies. The second objective is to gain insight into the workings of potential consolidated bioprocessing microorganisms on the surface of poplar samples. The third objective is to determine the impact biomass recalcitrance has on enzymatic hydrolysis and microbial fermentation in relation to the surface chemistry.

Production of biogenic manganese oxides coupled with methane oxidation in a bioreactor for removing metals from wastewater.

Science.gov (United States)

Matsushita, Shuji; Komizo, Daisuke; Cao, Linh Thi Thuy; Aoi, Yoshiteru; Kindaichi, Tomonori; Ozaki, Noriatsu; Imachi, Hiroyuki; Ohashi, Akiyoshi

2018-03-01

Biogenic manganese oxide (BioMnO x ) can efficiently adsorb various minor metals. The production of BioMnO x in reactors to remove metals during wastewater treatment processes is a promising biotechnological method. However, it is difficult to preferentially enrich manganese-oxidizing bacteria (MnOB) to produce BioMnO x during wastewater treatment processes. A unique method of cultivating MnOB using methane-oxidizing bacteria (MOB) to produce soluble microbial products is proposed here. MnOB were successfully enriched in a methane-fed reactor containing MOB. BioMnO x production during the wastewater treatment process was confirmed. Long-term continual operation of the reactor allowed simultaneous removal of Mn(II), Co(II), and Ni(II). The Co(II)/Mn(II) and Ni(II)/Mn(II) removal ratios were 53% and 19%, respectively. The degree to which Mn(II) was removed indicated that the enriched MnOB used utilization-associated products and/or biomass-associated products. Microbial community analysis revealed that methanol-oxidizing bacteria belonging to the Hyphomicrobiaceae family played important roles in the oxidation of Mn(II) by using utilization-associated products. Methane-oxidizing bacteria were found to be inhibited by MnO 2 , but the maximum Mn(II) removal rate was 0.49 kg m -3  d -1 . Copyright © 2017 Elsevier Ltd. All rights reserved.

Breakthrough Curve Analysis for Column Dynamics Sorption of Mn(II Ions from Wastewater by Using Mangostana garcinia Peel-Based Granular-Activated Carbon

Directory of Open Access Journals (Sweden)

Z. Z. Chowdhury

2013-01-01

Full Text Available The potential of granular-activated carbon (GAC derived from agrowaste of Mangostene (Mangostana garcinia fruit peel was investigated in batch and fixed bed system as a replacement of current expensive methods for treating wastewater contaminated by manganese, Mn(II cations. Batch equilibrium data was analyzed by Langmuir, Freundlich, and Temkin isotherm models at different temperatures. The effect of inlet metal ion concentration (50 mg/L, 70 mg/L, and 100 mg/L, feed flow rate (1 mL/min and 3 mL/min, and activated carbon bed height (4.5 cm and 3 cm on the breakthrough characteristics of the fixed bed sorption system were determined. The adsorption data were fitted with well-established column models, namely, Thomas, Yoon-Nelson, and Adams-Bohart. The results were best-fitted with Thomas and Yoon-Nelson models rather than Adams-Bohart model for all conditions. The column had been regenerated and reused consecutively for five cycles. The results demonstrated that the prepared activated carbon was suitable for removal of Mn(II ions from wastewater using batch as well as fixed bed sorption system.

Enzymatic deconstruction of xylan for biofuel production

Science.gov (United States)

DODD, DYLAN; CANN, ISAAC K. O.

2010-01-01

The combustion of fossil-derived fuels has a significant impact on atmospheric carbon dioxide (CO2) levels and correspondingly is an important contributor to anthropogenic global climate change. Plants have evolved photosynthetic mechanisms in which solar energy is used to fix CO2 into carbohydrates. Thus, combustion of biofuels, derived from plant biomass, can be considered a potentially carbon neutral process. One of the major limitations for efficient conversion of plant biomass to biofuels is the recalcitrant nature of the plant cell wall, which is composed mostly of lignocellulosic materials (lignin, cellulose, and hemicellulose). The heteropolymer xylan represents the most abundant hemicellulosic polysaccharide and is composed primarily of xylose, arabinose, and glucuronic acid. Microbes have evolved a plethora of enzymatic strategies for hydrolyzing xylan into its constituent sugars for subsequent fermentation to biofuels. Therefore, microorganisms are considered an important source of biocatalysts in the emerging biofuel industry. To produce an optimized enzymatic cocktail for xylan deconstruction, it will be valuable to gain insight at the molecular level of the chemical linkages and the mechanisms by which these enzymes recognize their substrates and catalyze their reactions. Recent advances in genomics, proteomics, and structural biology have revolutionized our understanding of the microbial xylanolytic enzymes. This review focuses on current understanding of the molecular basis for substrate specificity and catalysis by enzymes involved in xylan deconstruction. PMID:20431716

Determination and significance of the Mn(II) Zero-Field Splitting (ZFS) interaction in the geochemistry of travertines

Energy Technology Data Exchange (ETDEWEB)

Montegrossi, G. [Istituto di Geoscienze e Georisorse, Consiglio Nazionale delle Ricerche (CNR), via G. La Pira 4, I-50121, Florence (Italy)]. E-mail: giordano@geo.unifi.it; Di Benedetto, F. [Museo di Storia Naturale, Universita di Firenze, via G. La Pira 4, I-50121, Florence (Italy); Minissale, A. [Istituto di Geoscienze e Georisorse, Consiglio Nazionale delle Ricerche (CNR), via G. La Pira 4, I-50121, Florence (Italy); Paladini, M. [Istituto di Geoscienze e Georisorse, Consiglio Nazionale delle Ricerche (CNR), via G. La Pira 4, I-50121, Florence (Italy); Pardi, L.A. [Istituto per i Processi Chimico-Fisici, CNR, via G. Moruzzi 1, I-56124 Pisa (Italy); Romanelli, M. [Dipartimento di Chimica, Universita di Firenze, via della Lastruccia 3, I-50019 Sesto Fiorentino (Italy); Romei, F. [Dipartimento di Biologia Animale e Genetica, Universita di Firenze, Via Romana 17, I-50100 Florence (Italy)

2006-05-15

An analytical approach, based on the electron paramagnetic resonance (EPR) spectroscopy of Mn(II) in travertines, has been developed in order to obtain relevant information about the local inhomogeneity of calcite and about the thermodynamic conditions which control the formation of travertine deposits. This information is crucial to constrain the precipitation of travertine under different geochemical contexts. An empirical correlation between the spectral features and the zero-field splitting (ZFS) interaction has been established through numerical simulations of EPR spectra. The variability of the investigated parameters and the applicability of the method have been tested on several travertines from Central Italy.

Determination and significance of the Mn(II) Zero-Field Splitting (ZFS) interaction in the geochemistry of travertines

International Nuclear Information System (INIS)

Montegrossi, G.; Di Benedetto, F.; Minissale, A.; Paladini, M.; Pardi, L.A.; Romanelli, M.; Romei, F.

2006-01-01

An analytical approach, based on the electron paramagnetic resonance (EPR) spectroscopy of Mn(II) in travertines, has been developed in order to obtain relevant information about the local inhomogeneity of calcite and about the thermodynamic conditions which control the formation of travertine deposits. This information is crucial to constrain the precipitation of travertine under different geochemical contexts. An empirical correlation between the spectral features and the zero-field splitting (ZFS) interaction has been established through numerical simulations of EPR spectra. The variability of the investigated parameters and the applicability of the method have been tested on several travertines from Central Italy

Electron beam combined with hydrothermal treatment for enhancing the enzymatic convertibility of sugarcane bagasse

International Nuclear Information System (INIS)

Duarte, C.L.; Ribeiro, M.A.; Oikawa, H.; Mori, M.N.; Napolitano, C.M.; Galvão, C.A.

2012-01-01

The use of microbial cellulolytic enzymes is the most efficient process to liberate glucose from cellulose in biomass without the formation of fermentation inhibitors. A combination of pretreatment technologies is an alternative way to increase the access of enzymes to cellulose, and consequently, the conversion yield. In this way, the present study reports on the enzymatic hydrolysis of SCB submitted to three kinds of pretreatment: electron beam processing (EBP), and EBP followed by hydrothermal (TH) and diluted acid (AH) treatment. SCB samples were irradiated using a radiation dynamics electron beam accelerator, and then submitted to thermal and acid (0.1% sulfuric acid) hydrolysis for 40 and 60 min at 180 °C. These samples were submitted to enzymatic hydrolysis (EH) using commercial preparations, including Celluclast 1.5 L and beta-glycosidase. The addition of diluted acid improved TH treatment allowing for a shorter application time. EBP with 50 kGy increased the enzymatic hydrolysis yield of cellulose by 20% after TH and 30% after AH. - Highlights: ► We study the enzymatic hydrolysis of cellulose and hemicellulose in sugarcane bagasse. ► We study the combination of three pretreatments: electron beam processing, EBP followed by hydrothermal and by diluted acid treatment. ► The electron beam processing increased the enzymatic hydrolysis from 8% to 15% with 20 kGy. ► The enzymes used were commercial preparations, as Celluclast 1.5 L and β-glycosidase. ► The EBP with 50 kGy increased on 20% the yield of EH of cellulose after TH and 30% after AH.

Extraction studies of Cd(II), Cu(II), Mn(II), Ni(II) and Zn(II) using N, N', N, N' -Bis((2-hydroxy-3,5-di-tert-butylbenzyl) (2-pyridylmethyl)) -ethylenediamine as a novel ligand

International Nuclear Information System (INIS)

Laus, R.; Anjos, A.D.; Naves, A.

2008-01-01

In the present study, the use of N,N',N,N'-bis((2-hydroxy-3,5-di-tert-butylbenzyl) (2- pyridylmethyl))-ethylenediamine (H2L) as ligand was evaluated in the liquid-liquid (water- chloroform) extraction of Cd(II), Cu(II), Mn(II), Ni(II) and Zn(II). Experiments were carried out to determine the pH for maximum extraction for each metal ion by ligand, maximum extraction capacity, extraction kinetics and extraction selectivity. The results revealed that the extraction of metal ions is dependent on the pH: maximum extraction maximum was obtained in the pH range of 4.5 - 6.0 for Cu(II) and 8.0 - 9.0 for Zn(II). Cd(II) and Mn(II) were best extracted at pH 9.0 and Ni(II) at 10.0. The ligand H2L was effective for the extraction of Cd(II), Cu(II) and Zn(II) (extraction efficient, %E equal 100%), whereas %E of 76% and 23.5% were observed for Mn(II) and Ni(II), respectively. The ligand presented high selectivity for the extraction of Cu(II) at pH 4.0. (author)

Unraveling the role of animal heme peroxidases in superoxide mediated Mn oxide formation

Science.gov (United States)

Learman, D. R.; Hansel, C. M.

2013-12-01

Manganese(III,IV) oxides are important in the environment as they can impact the fate of a broad range of nutrients (e.g. carbon and phosphate) and contaminates (e.g. lead and chromium). Bacteria play a valuable role in the production of Mn oxides, yet the mechanisms and physiological reasons remain unclear. Roseobacter sp. AzwK-3b, an organism within the abundant and ubiquitous Roseobacter clade, has recently been shown to oxidize Mn(II) via a novel pathway that involves enzymatic extracellular superoxide production. However, in reactions with only Mn(II) and abiotically generated superoxide, we find superoxide alone is not enough to produce Mn(III,IV) oxides. Scavenging of the byproduct hydrogen peroxide (via the addition of catalase) is required to generate Mn oxides via abiotic reaction of Mn(II) with superoxide. Thus, R. AzwK-3b must produce superoxide and also scavenge hydrogen peroxide to form Mn oxides. Further, in-gel Mn(II) oxidation assay revealed a protein band that could generate Mn oxides in the presence of soluble Mn(II). This Mn(II)-oxidizing protein band was excised from the gel and the peptides identified via mass spectrometry. An animal heme peroxidase (AHP) was the predominant protein found in this band. This protein is homologous to the AHPs previously implicated as a Mn(II)-oxidizing enzyme within the Alphaproteobacteria, Erythrobacter SD-21 and Aurantimonas manganoxydans strain SI85-9A1. Currently, protein expression of the AHPs in R. AzwK-3b is being examined to determine if expression is correlated with Mn(II) concentration or oxidative stress. Our data suggests that AHPs do not directly oxidize Mn(II) but rather plays a role in scavenging hydrogen peroxide and/or producing an organic Mn(III) ligand that complexes Mn(III) and likely aids in Mn oxide precipitation.

Production of wax esters via microbial oil synthesis from food industry waste and by-product streams.

Science.gov (United States)

Papadaki, Aikaterini; Mallouchos, Athanasios; Efthymiou, Maria-Nefeli; Gardeli, Chryssavgi; Kopsahelis, Nikolaos; Aguieiras, Erika C G; Freire, Denise M G; Papanikolaou, Seraphim; Koutinas, Apostolis A

2017-12-01

The production of wax esters using microbial oils was demonstrated in this study. Microbial oils produced from food waste and by-product streams by three oleaginous yeasts were converted into wax esters via enzymatic catalysis. Palm oil was initially used to evaluate the influence of temperature and enzyme activity on wax ester synthesis catalysed by Novozyme 435 and Lipozyme lipases using cetyl, oleyl and behenyl alcohols. The highest conversion yields (up to 79.6%) were achieved using 4U/g of Novozyme 435 at 70°C. Transesterification of microbial oils to behenyl and cetyl esters was achieved at conversion yields up to 87.3% and 69.1%, respectively. Novozyme 435 was efficiently reused for six and three cycles during palm esters and microbial esters synthesis, respectively. The physicochemical properties of microbial oil derived behenyl esters were comparable to natural waxes. Wax esters from microbial oils have potential applications in cosmetics, chemical and food industries. Copyright © 2017 Elsevier Ltd. All rights reserved.

Research on treatment of wastewater containing heavy metal by microbial fuel cell

Science.gov (United States)

Chen, Zixuan; Lu, Xun; Yin, Ruixia; Luo, Yunyi; Mai, Hanjian; Zhang, Nan; Xiong, Jingfang; Zhang, Hongguo; Tang, Jinfeng; Luo, Dinggui

2018-02-01

With rapid development of social economy, serious problem has been caused by wastewater containing heavy metals, which was difficult to be treated by many kinds of traditional treatment methods, such as complex processes, high cost or easy to cause secondary pollution. As a novel biological treatment technology, microbial fuel cells (MFC) can generate electric energy while dealing with wastewater, which was proposed and extensively studied. This paper introduced the working principle of MFC, the classification of cathode, and the research progress on the treatment of wastewater containing Cr(VI), Cu(II), Ag(I), Mn(II) and Cd(II) by MFC. The study found that different cathode, different heavy metals anddifferent hybrid systems would affect the performance of the system and removal effect for heavy metal in MFC. MFC was a highly potential pollution control technology. Until now, the research was still in the laboratory stage. Its industrial application for recovery of heavy metal ion, improving the energy recovery rate and improvement or innovation of system were worthy of further research.

Microbial biodiversity of Sardinian oleic ecosystems.

Science.gov (United States)

Santona, Mario; Sanna, Maria Lina; Multineddu, Chiara; Fancello, Francesco; de la Fuente, Sara Audije; Dettori, Sandro; Zara, Severino

2018-04-01

The olives are rich in microorganisms that, during the extraction process may persist in the oils and can influence their physicochemical and sensory characteristics. In this work, and for the first time, we isolated and identified microbial species, yeast and bacteria, present during the production process in four Sardinian (Italy) oleic ecosystems. Among these varieties, we found that Nera di Gonnos was associated to the highest microbial biodiversity, which was followed by Bosana, Nocellara del Belice and Semidana. Among the different microbial species isolated, some are specific of olive ecological niches, such as Cryptococcus spp and Serratia spp; and others to olive oils such as Candida spp and Saccharomyces. Some other species identified in this work were not found before in oleic ecosystems. The enzymatic analyses of yeast and bacteria showed that they have good β-glucosidase activity and yeast also showed good β-glucanase activity. The majority of bacteria presented lipolytic and catalase activities while in yeast were species-specific. Interestingly, yeast and bacteria isolates presented a high resistance to bile acid, and about 65% of the yeast were able to resist at pH 2.5 for 2 h. Finally, bacteria showed no biofilm activity compared to yeast. Copyright © 2017 Elsevier Ltd. All rights reserved.

Microbial communities and biogeochemistry in an area of Engraulis encrasicolus spawning in the Sicilian Channel

Directory of Open Access Journals (Sweden)

Rosabruna La Ferla

2014-06-01

The rates of production, hydrolysis and degradation activities were quite low, in agreement with the general oligotrophy of the area and in agreement with this findings, picophytoplankton contribution to total production amounted to over than 65%. In terms of metabolic activities, different spatial distributions were observed between the autotrophic and heterotrophic components. In particular, heterotrophic metabolism showed high values in the layer located below the thermocline and above the DCM. Concerning the enzymatic activities, total leucine aminopeptidase activity showed the highest rates, followed by alkaline phosphatase and beta-Glucosidase (Caruso et al., 2014. Distribution of the dissolved enzymatic activities acting on proteins varied widely along the column, accounting for 5 to 90% of the total enzymatic activity and always prevailed on dissolved b-GLU. Total enzymatic activity rates were comparable to those obtained in the oligotrophic zones of Ionian and Mediterranean Sea (Zaccone et al., 2012, while the analysis of the dissolved fraction was the first report for the Mediterranean. In conclusion, the multidisciplinary scientific approach used in this study depicted a complex picture of the study area evidencing a high heterogeneity and dynamism of plankton communities, probably associated to peculiar hydrology of this ecosystem. On the whole, the study area appeared to be characterized by a relatively efficient microbial food web. However, low trophic conditions were stressed by all the biological and biochemical patterns, suggesting an important role of heterotrophic processes in this area in the examined summer period. Consequently, how and how much the microbial web sustains fish reproduction and larval survival need a more comprehensive analysis and will be focused in further research.

Breakthrough Curve Analysis for Column Dynamics Sorption of Mn(II) Ions from Wastewater by Using Mangostana garcinia Peel-Based Granular-Activated Carbon

OpenAIRE

Z. Z. Chowdhury; S. M. Zain; A. K. Rashid; R. F. Rafique; K. Khalid

2013-01-01

The potential of granular-activated carbon (GAC) derived from agrowaste of Mangostene (Mangostana garcinia) fruit peel was investigated in batch and fixed bed system as a replacement of current expensive methods for treating wastewater contaminated by manganese, Mn(II) cations. Batch equilibrium data was analyzed by Langmuir, Freundlich, and Temkin isotherm models at different temperatures. The effect of inlet metal ion concentration (50 mg/L, 70 mg/L, and 100 mg/L), feed flow rate (1 mL/min...

Transitory microbial habitat in the hyperarid Atacama Desert

Science.gov (United States)

Schulze-Makuch, Dirk; Wagner, Dirk; Kounaves, Samuel P.; Mangelsdorf, Kai; Devine, Kevin G.; de Vera, Jean-Pierre; Schmitt-Kopplin, Philippe; Grossart, Hans-Peter; Parro, Victor; Kaupenjohann, Martin; Galy, Albert; Schneider, Beate; Airo, Alessandro; Frösler, Jan; Davila, Alfonso F.; Arens, Felix L.; Cáceres, Luis; Solís Cornejo, Francisco; Carrizo, Daniel; Dartnell, Lewis; DiRuggiero, Jocelyne; Flury, Markus; Ganzert, Lars; Gessner, Mark O.; Grathwohl, Peter; Guan, Lisa; Heinz, Jacob; Hess, Matthias; Keppler, Frank; Maus, Deborah; McKay, Christopher P.; Meckenstock, Rainer U.; Montgomery, Wren; Oberlin, Elizabeth A.; Probst, Alexander J.; Sáenz, Johan S.; Sattler, Tobias; Schirmack, Janosch; Sephton, Mark A.; Schloter, Michael; Uhl, Jenny; Valenzuela, Bernardita; Vestergaard, Gisle; Wörmer, Lars; Zamorano, Pedro

2018-03-01

Traces of life are nearly ubiquitous on Earth. However, a central unresolved question is whether these traces always indicate an active microbial community or whether, in extreme environments, such as hyperarid deserts, they instead reflect just dormant or dead cells. Although microbial biomass and diversity decrease with increasing aridity in the Atacama Desert, we provide multiple lines of evidence for the presence of an at times metabolically active, microbial community in one of the driest places on Earth. We base this observation on four major lines of evidence: (i) a physico-chemical characterization of the soil habitability after an exceptional rain event, (ii) identified biomolecules indicative of potentially active cells [e.g., presence of ATP, phospholipid fatty acids (PLFAs), metabolites, and enzymatic activity], (iii) measurements of in situ replication rates of genomes of uncultivated bacteria reconstructed from selected samples, and (iv) microbial community patterns specific to soil parameters and depths. We infer that the microbial populations have undergone selection and adaptation in response to their specific soil microenvironment and in particular to the degree of aridity. Collectively, our results highlight that even the hyperarid Atacama Desert can provide a habitable environment for microorganisms that allows them to become metabolically active following an episodic increase in moisture and that once it decreases, so does the activity of the microbiota. These results have implications for the prospect of life on other planets such as Mars, which has transitioned from an earlier wetter environment to today’s extreme hyperaridity.

Fungal oxidative dissolution of the Mn(II)-bearing mineral rhodochrosite and the role of metabolites in manganese oxide formation.

Science.gov (United States)

Tang, Yuanzhi; Zeiner, Carolyn A; Santelli, Cara M; Hansel, Colleen M

2013-04-01

Microbially mediated oxidation of Mn(II) to Mn(III/IV) oxides influences the cycling of metals and remineralization of carbon. Despite the prevalence of Mn(II)-bearing minerals in nature, little is known regarding the ability of microbes to oxidize mineral-hosted Mn(II). Here, we explored oxidation of the Mn(II)-bearing mineral rhodochrosite (MnCO3 ) and characteristics of ensuing Mn oxides by six Mn(II)-oxidizing Ascomycete fungi. All fungal species substantially enhanced rhodochrosite dissolution and surface modification. Mineral-hosted Mn(II) was oxidized resulting in formation of Mn(III/IV) oxides that were all similar to δ-MnO2 but varied in morphology and distribution in relation to cellular structures and the MnCO3 surface. For four fungi, Mn(II) oxidation occurred along hyphae, likely mediated by cell wall-associated proteins. For two species, Mn(II) oxidation occurred via reaction with fungal-derived superoxide produced at hyphal tips. This pathway ultimately resulted in structurally unique Mn oxide clusters formed at substantial distances from any cellular structure. Taken together, findings for these two fungi strongly point to a role for fungal-derived organic molecules in Mn(III) complexation and Mn oxide templation. Overall, this study illustrates the importance of fungi in rhodochrosite dissolution, extends the relevance of biogenic superoxide-based Mn(II) oxidation and highlights the potential role of mycogenic exudates in directing mineral precipitation. © 2012 Society for Applied Microbiology and Blackwell Publishing Ltd.

Assessment of soil microbial diversity with functional multi-endpoint methods

DEFF Research Database (Denmark)

Winding, Anne; Creamer, R. E.; Rutgers, M.

on CO2 development by the microbes such as substrate induced respiration (SIR) on specific substrates have lead to the development of MicroResp™ and Community Level Physiological Profile (CLPP) with Biolog™ plates, and soil enzymatic activity assayed by Extracellular Enzyme Activity (EEA) based on MUF......Soil microbial diversity provides the cornerstone for support of soil ecosystem services by key roles in soil organic matter turnover, carbon sequestration and water infiltration. However, standardized methods to quantify the multitude of microbial functions in soils are lacking. Methods based...... to the lack of principle methods, the data obtained from these substitute methods are currently not used in classification and assessment schemes, making quantification of natural capital and ecosystems services of the soil a difficult venture. In this contribution, we compare and contrast the three...

Kinetic modelling of enzymatic starch hydrolysis

NARCIS (Netherlands)

Bednarska, K.A.

2015-01-01

Kinetic modelling of enzymatic starch hydrolysis – a summary

K.A. Bednarska

The dissertation entitled ‘Kinetic modelling of enzymatic starch hydrolysis’ describes the enzymatic hydrolysis and kinetic modelling of liquefaction and saccharification of wheat starch.

Characterization of microbial metabolism of Syrah grape products in an in vitro colon model using targeted and non-targeted analytical approaches

OpenAIRE

Aura, Anna-Marja; Mattila, Ismo; Hyötyläinen, Tuulia; Gopalacharyulu, Peddinti; Cheynier, Veronique; Souquet, Jean-Marc; Bes, Magali; Le Bourvellec, Carine; Guyot, Sylvain; Orešič, Matej

2012-01-01

Purpose Syrah red grapes are used in the production of tannin-rich red wines. Tannins are high molecular weight molecules, proanthocyanidins (PAs), and poorly absorbed in the upper intestine. In this study, gut microbial metabolism of Syrah grape phenolic compounds was investigated. Methods Syrah grape pericarp was subjected to an enzymatic in vitro digestion model, and red wine and grape skin PA fraction were prepared. Microbial conversion was screened using an in vitro colon model with faec...

Chromophoric dissolved organic matter and microbial enzymatic activity. A biophysical approach to understand the marine carbon cycle.

Science.gov (United States)

Gonnelli, Margherita; Vestri, Stefano; Santinelli, Chiara

2013-12-01

This study reports the first information on extracellular enzymatic activity (EEA) combined with a study of DOM dynamics at the Arno River mouth. DOM dynamics was investigated from both a quantitative (dissolved organic carbon, DOC) and a qualitative (absorption and fluorescence of chromophoric DOM, CDOM) perspective. The data here reported highlight that the Arno River was an important source of both DOC and CDOM for this coastal area. CDOM optical properties suggested that terrestrial DOM did not undergo simple dilution at the river mouth but, other physical-chemical and biological processes were probably at work to change its molecular characteristics. This observation was further supported by the "potential" enzymatic activity of β-glucosidase (BG) and leucine aminopeptidase (LAP). Their Vmax values were markedly higher in the river water than in the seawater and their ratio suggested that most of the DOM used by microbes in the Arno River was polysaccharide-like, while in the seawater it was mainly protein-like. © 2013. Published by Elsevier B.V. All rights reserved.

The effect of microbial starter composition on cassava chips fermentation for the production of fermented cassava flour

Science.gov (United States)

Kresnowati, M. T. A. P.; Listianingrum, Zaenudin, Ahmad; Trihatmoko, Kharisrama

2015-12-01

The processing of cassava into fermented cassava flour (fercaf) or the widely known as modified cassava flour (mocaf) presents an alternative solution to improve the competitiveness of local foods and to support national food security. However, the mass production of fercaf is being limited by several problems, among which is the availability of starter cultures. This paper presents the mapping of the effect of microbial starter compositions on the nutritional content of fercaf in order to obtain the suitable nutritional composition. Based on their enzymatic activities, the combination of Lactobacillus plantarum, Bacillus subtilis, and Aspergillus oryzae were tested during the study. In addition, commercial starter was also tested. During the fermentation, the dynamics in microbial population were measured as well as changes in cyanogenic glucoside content. The microbial starter composition was observed to affect the dynamics in microbial populationcynaogenic glucoside content of the produced fercaf. In general, steady state microbial population was reached within 12 hours of fermentation. Cyanogenic glucoside was observed to decrease along the fermentation.

Microbial transformation of coal and coal relevant structures - presentation of a BMBF joint research project

Energy Technology Data Exchange (ETDEWEB)

Sinder, C.; Schacht, S.; Pfeifer, F.; Klein, J. [DMT-Gesellschaft fuer Forschung und Pruefung mbH, Essen (Germany)

1997-12-31

Investigations in the joint research project `Microbial transformation of coal and coal relevant structures` supported by the Ministry of Education, Science, Research and Technology (BMBF) of the Federal Republic of Germany and coordinated by the DMT-Gesellschaft fuer Forschung und Pruefung mbH (DMT) are focussed on research and development of biotechnological coal conversion processes. Up to now investigations carried out in the project lead to a number of important results. During work on the project a great number of different microorganisms was found able to degrade or solubilize coal or lignite. Enzymatic as well as regulation mechanisms of the microbial depolymerization processes have been characterized successfully. (orig.)

Some non-thermal microbial inactivation methods in dairy products

International Nuclear Information System (INIS)

Yangilar, F.; Kabil, E.

2013-01-01

During the production of dairy products, some thermal processes such as pasteurization and sterilization are used commonly to inactive microorganisms. But as a result of thermal processes, loss of nutrient and aroma, non-enzymatic browning and organoleptic differentiation especially in dairy products are seen. Because of this, alternative methods are needed to provide microbial inactivation and as major problems are caused by high temperatures, non-thermal processes are focused on. For this purpose, some methods such as high pressure (HP), pulsed light (PL), ultraviolet radiation (UV), supercritical carbon dioxide (SC-CO2) or pulsed electric field (PEF) are used in food. These methods products are processed in ambient temperature and so not only mentioned losses are minimized but also freshness and naturality of products can be preserved. In this work, we will try to be given information about methods of non-thermal microbial inactivation of dairy products. (author) [tr

Biohydrogen production from enzymatic hydrolysis of food waste in batch and continuous systems

Science.gov (United States)

Han, Wei; Yan, Yingting; Shi, Yiwen; Gu, Jingjing; Tang, Junhong; Zhao, Hongting

2016-01-01

In this study, the feasibility of biohydrogen production from enzymatic hydrolysis of food waste was investigated. Food waste (solid-to-liquid ratio of 10%, w/v) was first hydrolyzed by commercial glucoamylase to release glucose (24.35 g/L) in the food waste hydrolysate. Then, the obtained food waste hydrolysate was used as substrate for biohydrogen production in the batch and continuous (continuous stirred tank reactor, CSTR) systems. It was observed that the maximum cumulative hydrogen production of 5850 mL was achieved with a yield of 245.7 mL hydrogen/g glucose (1.97 mol hydrogen/mol glucose) in the batch system. In the continuous system, the effect of hydraulic retention time (HRT) on biohydrogen production from food waste hydrolysate was investigated. The optimal HRT obtained from this study was 6 h with the highest hydrogen production rate of 8.02 mmol/(h·L). Ethanol and acetate were the major soluble microbial products with low propionate production at all HRTs. Enzymatic hydrolysis of food waste could effectively accelerate hydrolysis speed, improve substrate utilization rate and increase hydrogen yield. PMID:27910937

Enzymatic activity of the cellulolytic complex produced by trichoderma reesei. Enzymatic hydrolysis of cellulose

International Nuclear Information System (INIS)

Alfonsel Jaen, M.; Negro, M.J.; Saez, R.; Martin Moreno, C.

1986-01-01

The enzymatic activity characterization of the cellulolytic complex obtained from Trichoderma reese QM 9414 and the influence of the enzymatic hydrolysis conditions on the hydrolysis yield are studied. Pure cellulose and native or alkali pretreated biomass from Onopordum nervosum have been used as substrates. The values of pH, temperature, substrate concentration and enzyme-substrate ratio for the optimum activity of that complex, evaluated as glucose and reducing sugars productions, have been selected. Previous studies on enzymatic hydrolysis of O. nervosum have shown a remarkable effect of the alkaline pretreatments on the final hydrolysis yield. (author). 10 figs.; 10 refs

Enzymatic activity of the cellulolytic complex produced by Trichoderma reesei. Enzymatic hydrolysis of cellulose

International Nuclear Information System (INIS)

Alfonsel J, M.; Negro A, M. J.; Saez A, R.; Martin M, C.

1986-01-01

The enzymatic activity characterization of the cellulolytic complex obtained from Trichoderma reesei QM 9414 and the influence of the enzymatic hydrolysis conditions on the hydrolysis yield are studied. Pure cellulose and native or alkali pretreated biomass Onopordum nervosum have been used as substrates. The values of pH, temperature, substrate concentration and enzyme-substrate ratio for the optimum activity of that complex, evaluated as glucose and reducing sugars production, have been selected. Previous studies on enzymatic hydrolysis of 0. nervosum have shown a remarkable effect of the alkaline pretreatments on the final hydrolysis yield. (Author) 10 refs

Are Microbial Nanowires Responsible for Geoelectrical Changes at Hydrocarbon Contaminated Sites?

Science.gov (United States)

Hager, C.; Atekwana, E. A.; Gorby, Y. A.; Duris, J. W.; Allen, J. P.; Atekwana, E. A.; Ownby, C.; Rossbach, S.

2007-05-01

Significant advances in near-surface geophysics and biogeophysics in particular, have clearly established a link between geoelectrical response and the growth and enzymatic activities of microbes in geologic media. Recent studies from hydrocarbon contaminated sites suggest that the activities of distinct microbial populations, specifically syntrophic, sulfate reducing, and dissimilatory iron reducing microbial populations are a contributing factor to elevated sediment conductivity. However, a fundamental mechanistic understanding of the processes and sources resulting in the measured electrical response remains uncertain. The recent discovery of bacterial nanowires and their electron transport capabilities suggest that if bacterial nanowires permeate the subsurface, they may in part be responsible for the anomalous conductivity response. In this study we investigated the microbial population structure, the presence of nanowires, and microbial-induced alterations of a hydrocarbon contaminated environment and relate them to the sediments' geoelectrical response. Our results show that microbial communities varied substantially along the vertical gradient and at depths where hydrocarbons saturated the sediments, ribosomal intergenic spacer analysis (RISA) revealed signatures of microbial communities adapted to hydrocarbon impact. In contrast, RISA profiles from a background location showed little community variations with depth. While all sites showed evidence of microbial activity, a scanning electron microscope (SEM) study of sediment from the contaminated location showed pervasive development of "nanowire-like structures" with morphologies consistent with nanowires from laboratory experiments. SEM analysis suggests extensive alteration of the sediments by microbial Activity. We conclude that, excess organic carbon (electron donor) but limited electron acceptors in these environments cause microorganisms to produce nanowires to shuttle the electrons as they seek for

High turnover catalysis of water oxidation by Mn(II) complexes of monoanionic pentadentate ligands

DEFF Research Database (Denmark)

Seidler-Egdal, Rune Kirk; Nielsen, Anne; Bond, Andrew

2011-01-01

-pyridylmethyl)ethane-1,2-diamine (bcbpen(-)), show the presence of a mixture of closely related Mn(II) species, assigned to the mono, di-, tri- and poly-cationic complexes [Mn(II)(L)(H(2)O)](n)(n+), L = mcbpen(-) or bcbpen(-) with n = 1, 2, 3, etc. In solution, these complexes are reversibly oxidized by tert......:1 reaction of TBHP with [Mn] is rate determining and the resultant species is proposed to be the mononuclear, catalytically competent, [Mn(IV)(O)(mcbpen)](+). At very close m/z values [Mn(III)(OH)(mcbpen)](+), [Mn(2)(III/IV)(O)(2)(mcbpen)(2)](+) and [Mn(IV)(2)(O)(2)(mcbpen)(2)](2+) are detected by ESI MS......-butyl hydrogen peroxide (TBHP), (NH(4))(2)[Ce(NO(3))(6)], Ce(ClO(4))(4), oxone and [Ru(bipy)(3)](3+) to form metastable (t(½) = min to h) higher valent (hydr)oxide species, showing a collective maximum absorbance at 430 nm. The same species can be produced by [Ru(bipy)(3)](2+)-mediated photooxidization...

High Turnover Catalysis of Water Oxidation by Mn(II) complexes of Monoanionic Pentadentate Ligands

DEFF Research Database (Denmark)

Seidler-Egdal, Rune Kirk; Nielsen, Anne; Bond, Andrew

2011-01-01

-pyridylmethyl)ethane-1,2-diamine (bcbpen−), show the presence of a mixture of closely related Mn(II) species, assigned to the mono, di-, tri- and poly-cationic complexes [MnII(L)(H2O)]nn+, L = mcbpen− or bcbpen− with n = 1, 2, 3, etc. In solution, these complexes are reversibly oxidized by tert-butyl hydrogen...... determining and the resultant species is proposed to be the mononuclear, catalytically competent, [MnIV(O)(mcbpen)]+. At very close m/z values [MnIII(OH)(mcbpen)]+, [Mn2III/IV(O)2(mcbpen)2]+ and [MnIV2(O)2(mcbpen)2]2+are detected by ESI MS and CE when the concentration of TBHP is comparable to or lower than...... peroxide (TBHP), (NH4)2[Ce(NO3)6], Ce(ClO4)4, oxone and [Ru(bipy)3]3+ to form metastable (t½ = min to h) higher valent (hydr)oxide species, showing a collective maximum absorbance at 430 nm. The same species can be produced by [Ru(bipy)3]2+-mediated photooxidization in the presence of an electron acceptor...

Plant stimulation of soil microbial community succession: how sequential expression mediates soil carbon stabilization and turnover

Energy Technology Data Exchange (ETDEWEB)

Firestone, Mary [Univ. of California, Berkeley, CA (United States)

2015-03-31

It is now understood that most plant C is utilized or transformed by soil microorganisms en route to stabilization. Hence the composition of microbial communities that mediate decomposition and transformation of root C is critical, as are the metabolic capabilities of these communities. The change in composition and function of the C-transforming microbial communities over time in effect defines the biological component of soil C stabilization. Our research was designed to test 2 general hypotheses; the first two hypotheses are discussed first; H1: Root-exudate interactions with soil microbial populations results in the expression of enzymatic capacities for macromolecular, complex carbon decomposition; and H2: Microbial communities surrounding roots undergo taxonomic succession linked to functional gene activities as roots grow, mature, and decompose in soil. Over the term of the project we made significant progress in 1) quantifying the temporal pattern of root interactions with the soil decomposing community and 2) characterizing the role of root exudates in mediating these interactions.

Biological Superoxide In Manganese Oxide Formation

Science.gov (United States)

Hansel, C.; Learman, D.; Zeiner, C.; Santelli, C. M.

2011-12-01

Manganese (Mn) oxides are among the strongest sorbents and oxidants within the environment, controlling the fate and transport of numerous elements and the degradation of recalcitrant carbon. Both bacteria and fungi mediate the oxidation of Mn(II) to Mn(III/IV) oxides but the genetic and biochemical mechanisms responsible remain poorly understood. Furthermore, the physiological basis for microbial Mn(II) oxidation remains an enigma. We have recently reported that a common marine bacterium (Roseobacter sp. AzwK-3b) oxidizes Mn(II) via reaction with extracellular superoxide (O2-) produced during exponential growth. Here we expand this superoxide-mediated Mn(II) oxidation pathway to fungi, introducing a surprising homology between prokaryotic and eukaryotic metal redox processes. For instance, Stibella aciculosa, a common soil Ascomycete filamentous fungus, precipitates Mn oxides at the base of asexual reproductive structures (synnemata) used to support conidia (Figure 1). This distribution is a consequence of localized production of superoxide (and it's dismutation product hydrogen peroxide, H2O2), leading to abiotic oxidation of Mn(II) by superoxide. Disruption of NADPH oxidase activity using the oxidoreductase inhibitor DPI leads to diminished cell differentiation and subsequent Mn(II) oxidation inhibition. Addition of Cu(II) (an effective superoxide scavenger) leads to a concentration dependent decrease in Mn oxide formation. We predict that due to the widespread production of extracellular superoxide within the fungal and likely bacterial kingdoms, biological superoxide may be an important contributor to the cycling of Mn, as well as other metals (e.g., Hg, Fe). Current and future explorations of the genes and proteins involved in superoxide production and Mn(II) oxidation will ideally lend insight into the physiological and biochemical basis for these processes.

Microbial activities in forest soils exposed to chronic depositions from a lignite power plant

Energy Technology Data Exchange (ETDEWEB)

Klose, S.; Wernecke, K.D.; Makeschin, F. [Technical University of Dresden, Tharandt (Germany)

2004-12-01

Atmospheric emissions of fly ash and SO{sub 2} from lignite-fired power plants strongly affect large forest areas in Germany. The impact of different deposition loads on the microbial biomass and enzyme activities was studied at three forest sites (Picea abies (L.) Karst.) along an emission gradient of 3, 6, and 15 km downwind of a coal-fired power plant, representing high, moderate and low emission rates. An additional site at a distance of 3 km from the power plant was chosen to study the influence of forest type on microbial parameters in coniferous forest soils under fly ash and SO{sub 2} emissions. Soil microbial biomass C and N, CO{sub 2} evolved and activities of L-asparaginase, L-glutaminase, beta-glucosidase, acid phosphatase and arylsulfatase (expressed on dry soil and organic C basis) were determined in the forest floor (L, Of and Oh horizon) and mineral top soil (0-10 cm). It is concluded that chronic fly ash depositions decrease litter decomposition by influencing specific microbial and enzymatic processes in forest soils.

Microbial production host selection for converting second-generation feedstocks into bioproducts

Directory of Open Access Journals (Sweden)

van Groenestijn Johan W

2009-12-01

Full Text Available Abstract Background Increasingly lignocellulosic biomass hydrolysates are used as the feedstock for industrial fermentations. These biomass hydrolysates are complex mixtures of different fermentable sugars, but also inhibitors and salts that affect the performance of the microbial production host. The performance of six industrially relevant microorganisms, i.e. two bacteria (Escherichia coli and Corynebacterium glutamicum, two yeasts (Saccharomyces cerevisiae and Pichia stipitis and two fungi (Aspergillus niger and Trichoderma reesei were compared for their (i ability to utilize monosaccharides present in lignocellulosic hydrolysates, (ii resistance against inhibitors present in lignocellulosic hydrolysates, (iii their ability to utilize and grow on different feedstock hydrolysates (corn stover, wheat straw, sugar cane bagasse and willow wood. The feedstock hydrolysates were generated in two manners: (i thermal pretreatment under mild acid conditions followed by enzymatic hydrolysis and (ii a non-enzymatic method in which the lignocellulosic biomass is pretreated and hydrolyzed by concentrated sulfuric acid. Moreover, the ability of the selected hosts to utilize waste glycerol from the biodiesel industry was evaluated. Results Large differences in the performance of the six tested microbial production hosts were observed. Carbon source versatility and inhibitor resistance were the major discriminators between the performances of these microorganisms. Surprisingly all 6 organisms performed relatively well on pretreated crude feedstocks. P. stipitis and A. niger were found to give the overall best performance C. glutamicum and S. cerevisiae were shown to be the least adapted to renewable feedstocks. Conclusion Based on the results obtained we conclude that a substrate oriented instead of the more commonly used product oriented approach towards the selection of a microbial production host will avoid the requirement for extensive metabolic

Improving chocolate flavor in poor-quality cocoa almonds by enzymatic treatment.

Science.gov (United States)

Oliveira, Hilana Salete Silva; Mamede, Maria Eugênia Oliveira; Góes-Neto, Aristóteles; Koblitz, Maria Gabriela Bello

2011-01-01

This paper proposes a method to enzymatically treat poor-quality cocoa almonds (known as "slate") to ensure the formation of chocolate flavor precursors. The production of flavor precursors improves the quality of these almonds, which are usually responsible for the low quality of the liquor produced. Proteases and carboxypeptidases from different sources were tested under various conditions. The different treatments were evaluated by chemical analysis (hydrolysis efficiency) and sensory analysis of the treated material compared to good-quality cocoa almonds. The results show that it is possible, through the use of microbial enzymes, to generate the mixture of compounds that will release, after roasting, the characteristic chocolate flavor in poor-quality almonds. However, it is necessary to optimize the conditions of enzymatic treatment to obtain better results and thus establish a process that can be used for industrial purposes for manufacturing cocoa and chocolate. The basidiomycete Moniliophtora perniciosa is the causative agent of witches' broom disease (WBD) of the cocoa tree, whose seeds are the source of chocolate. It is the most important phytopathological problem of cocoa-producing areas of the American continent, and has decimated the Brazilian cocoa industry. In Bahia (Brazil), M. perniciosa was identified in 1989 and, as a consequence of its spreading, the annual production of cocoa almonds dropped from 450,000 to 90,000 tons within 12 y, reducing export values from an all-time high of about US$ 1 billion to 110 million. The high incidence of WBD incapacitates Brazil to produce enough cocoa almonds even for the internal market, leading the country to import low-quality cocoa almonds mainly from African countries. Our work proposes an enzymatic treatment to increase the quality of that cocoa almonds and, consequently, to improve the quality of the chocolate produced and consumed in the country. © 2011 Institute of Food Technologists®

Microbial brokers of insect-plant interactions revisited.

Science.gov (United States)

Douglas, Angela E

2013-07-01

Recent advances in sequencing methods have transformed the field of microbial ecology, making it possible to determine the composition and functional capabilities of uncultured microorganisms. These technologies have been instrumental in the recognition that resident microorganisms can have profound effects on the phenotype and fitness of their animal hosts by modulating the animal signaling networks that regulate growth, development, behavior, etc. Against this backdrop, this review assesses the impact of microorganisms on insect-plant interactions, in the context of the hypothesis that microorganisms are biochemical brokers of plant utilization by insects. There is now overwhelming evidence for a microbial role in insect utilization of certain plant diets with an extremely low or unbalanced nutrient content. Specifically, microorganisms enable insect utilization of plant sap by synthesizing essential amino acids. They also can broker insect utilization of plant products of extremely high lignocellulose content, by enzymatic breakdown of complex plant polysaccharides, nitrogen fixation, and sterol synthesis. However, the experimental evidence for microbial-mediated detoxification of plant allelochemicals is limited. The significance of microorganisms as brokers of plant utilization by insects is predicted to vary, possibly widely, as a result of potentially complex interactions between the composition of the microbiota and the diet and insect developmental age or genotype. For every insect species feeding on plant material, the role of resident microbiota as biochemical brokers of plant utilization is a testable hypothesis.

Comparison of the role that entropy has played in processes of non-enzymatic and enzymatic catalysis

International Nuclear Information System (INIS)

Dixon Pineda, Manuel Tomas

2012-01-01

The function that entropy has played is compared in processes of non-enzymatic and enzymatic catalysis. The processes followed are showed: the kinetics of the acid hydrolysis of 3-pentyl acetate and cyclopentyl acetate catalyzed by hydrochloric acid and enzymatic hydrolysis of ethyl acetate and γ-butyrolactone catalyzed by pig liver esterase. The activation parameters of Eyring were determined for each process and interpreted the contribution of the entropy of activation for catalysis in this type of model reactions. (author) [es

The Role of Microbial Community Composition in Controlling Soil Respiration Responses to Temperature.

Science.gov (United States)

Auffret, Marc D; Karhu, Kristiina; Khachane, Amit; Dungait, Jennifer A J; Fraser, Fiona; Hopkins, David W; Wookey, Philip A; Singh, Brajesh K; Freitag, Thomas E; Hartley, Iain P; Prosser, James I

2016-01-01

Rising global temperatures may increase the rates of soil organic matter decomposition by heterotrophic microorganisms, potentially accelerating climate change further by releasing additional carbon dioxide (CO2) to the atmosphere. However, the possibility that microbial community responses to prolonged warming may modify the temperature sensitivity of soil respiration creates large uncertainty in the strength of this positive feedback. Both compensatory responses (decreasing temperature sensitivity of soil respiration in the long-term) and enhancing responses (increasing temperature sensitivity) have been reported, but the mechanisms underlying these responses are poorly understood. In this study, microbial biomass, community structure and the activities of dehydrogenase and β-glucosidase enzymes were determined for 18 soils that had previously demonstrated either no response or varying magnitude of enhancing or compensatory responses of temperature sensitivity of heterotrophic microbial respiration to prolonged cooling. The soil cooling approach, in contrast to warming experiments, discriminates between microbial community responses and the consequences of substrate depletion, by minimising changes in substrate availability. The initial microbial community composition, determined by molecular analysis of soils showing contrasting respiration responses to cooling, provided evidence that the magnitude of enhancing responses was partly related to microbial community composition. There was also evidence that higher relative abundance of saprophytic Basidiomycota may explain the compensatory response observed in one soil, but neither microbial biomass nor enzymatic capacity were significantly affected by cooling. Our findings emphasise the key importance of soil microbial community responses for feedbacks to global change, but also highlight important areas where our understanding remains limited.

Antibody against Microbial Neuraminidases Recognizes Human Sialidase 3 (NEU3: the Neuraminidase/Sialidase Superfamily Revisited

Directory of Open Access Journals (Sweden)

Chiguang Feng

2017-06-01

Full Text Available Neuraminidases (NAs are critical virulence factors for several microbial pathogens. With a highly conserved catalytic domain, a microbial NA “superfamily” has been proposed. We previously reported that murine polymorphonuclear leukocyte (PMN sialidase activity was important in leukocyte trafficking to inflamed sites and that antibodies to Clostridium perfringens NA recognized a cell surface molecule(s, presumed to be a sialidase of eukaryotic origin on interleukin-8-stimulated human and murine PMNs. These antibodies also inhibited cell sialidase activity both in vitro and, in the latter instance, in vivo. We therefore hypothesized that mammalian sialidases share structural homology and epitopes with microbial NAs. We now report that antibodies to one of the isoforms of C. perfringens NA, as well as anti-influenza virus NA serum, recognize human NEU3 but not NEU1 and that antibodies to C. perfringens NA inhibit NEU3 enzymatic activity. We conclude that the previously described microbial NA superfamily extends to human sialidases. Strategies designed to therapeutically inhibit microbial NA may need to consider potential compromising effects on human sialidases, particularly those expressed in cells of the immune system.

Crystal structure and spectroscopic analysis of a new oxalate-bridged MnII compound: catena-poly[guanidinium [[aquachloridomanganese(II]-μ2-oxalato-κ4O1,O2:O1′,O2′] monohydrate

Directory of Open Access Journals (Sweden)

Hiba Sehimi

2016-05-01

Full Text Available As part of our studies on the synthesis and the characterization of oxalate-bridged compounds M–ox–M (ox = oxalate dianion and M = transition metal ion, we report the crystal structure of a new oxalate-bridged MnII phase, {(CH6N3[Mn(C2O4Cl(H2O]·H2O}n. In the compound, a succession of MnII ions (situated on inversion centers adopting a distorted octahedral coordination and bridged by oxalate ligands forms parallel zigzag chains running along the c axis. These chains are interconnected through O—H...O hydrogen-bonding interactions to form anionic layers parallel to (010. Individual layers are held together via strong hydrogen bonds involving the guanidinium cations (N—H...O and N—H...Cl and the disordered non-coordinating water molecule (O—H...O and O—H...Cl, as well as by guanidinium π–π stacking. The structural data were confirmed by IR and UV–Visible spectroscopic analysis.

Mechano-Enzymatic Deconstruction with a New Enzymatic Cocktail to Enhance Enzymatic Hydrolysis and Bioethanol Fermentation of Two Macroalgae Species

Directory of Open Access Journals (Sweden)

Sameh Amamou

2018-01-01

Full Text Available The aim of this study was to explore the efficiency of a mechano-enzymatic deconstruction of two macroalgae species for sugars and bioethanol production, by using a new enzymatic cocktail (Haliatase and two types of milling modes (vibro-ball: VBM and centrifugal milling: CM. By increasing the enzymatic concentration from 3.4 to 30 g/L, the total sugars released after 72 h of hydrolysis increased (from 6.7 to 13.1 g/100 g TS and from 7.95 to 10.8 g/100 g TS for the green algae U. lactuca and the red algae G. sesquipedale, respectively. Conversely, total sugars released from G. sesquipedale increased (up to 126% and 129% after VBM and CM, respectively. The best bioethanol yield (6 geth/100 g TS was reached after 72 h of fermentation of U. lactuca and no increase was obtained after centrifugal milling. The latter led to an enhancement of the ethanol yield of G. sesquipedale (from 2 to 4 g/100 g TS.

Production of human milk oligosaccharides by enzymatic and whole-cell microbial biotransformations.

Science.gov (United States)

Sprenger, Georg A; Baumgärtner, Florian; Albermann, Christoph

2017-09-20

Human milk oligosaccharides (HMO) are almost unique constituents of breast milk and are not found in appreciable amounts in cow milk. Due to several positive aspects of HMO for the development, health, and wellbeing of infants, production of HMO would be desirable. As a result, scientists from different disciplines have developed methods for the preparation of single HMO compounds. Here, we review approaches to HMO preparation by (chemo-)enzymatic syntheses or by whole-cell biotransformation with recombinant bacterial cells. With lactose as acceptor (in vitro or in vivo), fucosyltransferases can be used for the production of 2'-fucosyllactose, 3-fucosyllactose, or more complex fucosylated core structures. Sialylated HMO can be produced by sialyltransferases and trans-sialidases. Core structures as lacto-N-tetraose can be obtained by glycosyltransferases from chemical donor compounds or by multi-enzyme cascades; recent publications also show production of lacto-N-tetraose by recombinant Escherichia coli bacteria and approaches to obtain fucosylated core structures. In view of an industrial production of HMOs, the whole cell biotransformation is at this stage the most promising option to provide human milk oligosaccharides as food additive. Copyright © 2017 Elsevier B.V. All rights reserved.

Product quality and microbial dynamics during vermicomposting and maturation of compost from pig manure.

Science.gov (United States)

Villar, Iria; Alves, David; Mato, Salustiano

2017-11-01

This research evaluates, through microbial dynamics, the use of earthworms Eisenia andrei for maturation of pre-composted pig manure in comparison with maturation under static conditions and with vermicomposting of fresh pig manure. Therefore, two substrates were used (fresh and pre-composted pig manure) and four treatments were developed: fresh manure vermicomposting, control of fresh manure without earthworms, pre-composting followed by vermicomposting and static maturation of pre-composted manure. In order to determine the microbial dynamics, the enzymatic activities and profiles of phospholipid fatty acids (PLFAs) were evaluated over a 112-days period. Physicochemical and biological parameters of the obtained products were also analyzed. The presence of earthworms significantly reduced (pquality values, it is necessary to optimize the vermicompost aging phase period to improve the stability. Static maturation presented stability on microbial dynamics that indicated a slow degradation of organic compounds so that, maturation of pre-composted manure through vermicomposting is better option. Copyright © 2017 Elsevier Ltd. All rights reserved.

Biohydrogen production in the suspended and attached microbial growth systems from waste pastry hydrolysate.

Science.gov (United States)

Han, Wei; Hu, Yunyi; Li, Shiyi; Li, Feifei; Tang, Junhong

2016-10-01

Waste pastry was hydrolyzed by glucoamylase and protease which were obtained from solid state fermentation of Aspergillus awamori and Aspergillus oryzae to produce waste pastry hydrolysate. Then, the effects of hydraulic retention times (HRTs) (4-12h) on hydrogen production rate (HPR) in the suspended microbial growth system (continuous stirred tank reactor, CSTR) and attached microbial growth system (continuous mixed immobilized sludge reactor, CMISR) from waste pastry hydrolysate were investigated. The maximum HPRs of CSTR (201.8mL/(h·L)) and CMISR (255.3mL/(h·L)) were obtained at HRT of 6h and 4h, respectively. The first-order reaction could be used to describe the enzymatic hydrolysis of waste pastry. The carbon content of the waste pastry remained 22.8% in the undigested waste pastry and consumed 77.2% for carbon dioxide and soluble microbial products. To our knowledge, this is the first study which reports biohydrogen production from waste pastry. Copyright © 2016 Elsevier Ltd. All rights reserved.

Physico-chemical, spectroscopical and thermal characterization of bio diesel obtained by enzymatic route as a tool to select the most efficient immobilized lipase

International Nuclear Information System (INIS)

Silva, G.A.M.; Ros, P.C.M. da; Souza, L.T.A.; Costa, A.P.O.; Castro, H.F. de

2012-01-01

Two microbial lipases from Burkholderia cepacia and Pseudomonas fluorescens were evaluated as catalysts for the enzymatic transesterification of beef tallow with ethanol and the most efficient lipase source was selected by taking into account the properties of the product to be used as fuel. Both lipases were immobilized on an epoxy silica-polyvinyl alcohol composite by covalent immobilization and used to perform the reactions under the following operational conditions: beef tallow-to-ethanol molar ratio of 1:9, 45 degree C and 400 units of enzymatic activity per gram of fat. Products, characterized using Fourier Transform Infrared spectroscopy (FTIR), viscosimetry, thermogravimetry and 1 H NMR spectroscopy, suggested that the bio diesel sample obtained in the reaction catalyzed by Burkholderia cepacia lipase has the best set of properties for fuel usage. (author)

Physico-chemical, spectroscopical and thermal characterization of bio diesel obtained by enzymatic route as a tool to select the most efficient immobilized lipase

Energy Technology Data Exchange (ETDEWEB)

Silva, G.A.M.; Ros, P.C.M. da; Souza, L.T.A.; Costa, A.P.O.; Castro, H.F. de, E-mail: heizir@dequi.eel.usp.br [Engineering School of Lorena. University of Sao Paulo (EEL/USP), Lorena, SP (Brazil)

2012-01-15

Two microbial lipases from Burkholderia cepacia and Pseudomonas fluorescens were evaluated as catalysts for the enzymatic transesterification of beef tallow with ethanol and the most efficient lipase source was selected by taking into account the properties of the product to be used as fuel. Both lipases were immobilized on an epoxy silica-polyvinyl alcohol composite by covalent immobilization and used to perform the reactions under the following operational conditions: beef tallow-to-ethanol molar ratio of 1:9, 45 degree C and 400 units of enzymatic activity per gram of fat. Products, characterized using Fourier Transform Infrared spectroscopy (FTIR), viscosimetry, thermogravimetry and {sup 1}H NMR spectroscopy, suggested that the bio diesel sample obtained in the reaction catalyzed by Burkholderia cepacia lipase has the best set of properties for fuel usage. (author)

Enzymatic Modification of Corn Starch Influences Human Fecal Fermentation Profiles.

Science.gov (United States)

Dura, Angela; Rose, Devin J; Rosell, Cristina M

2017-06-14

Enzymatically modified starches have been widely used in food applications to develop new products, but information regarding digestion and fecal fermentation of these products is sparse. The objective of this study was to determine the fermentation properties of corn starch modified with α-amylase, amyloglucosidase, or cyclodextrin glycosyltransferase and the possible role of hydrolysis products. Samples differed in their digestibility and availability to be fermented by the microbiota, resulting in differences in microbial metabolites produced during in vitro fermentation. The presence or absence of hydrolysis products and gelatinization affected starch composition and subsequent metabolite production by the microbiota. Amyloglucosidase-treated starch led to the greatest production of short- and branched-chain fatty acid production by the microbiota. Results from this study could be taken into consideration to confirm the possible nutritional claims and potential health benefits of these starches as raw ingredients for food development.

Colorimetric method for enzymatic screening assay of ATP using Fe(III)-xylenol orange complex formation.

Science.gov (United States)

Ishida, Akihiko; Yamada, Yasuko; Kamidate, Tamio

2008-11-01

In hygiene management, recently there has been a significant need for screening methods for microbial contamination by visual observation or with commonly used colorimetric apparatus. The amount of adenosine triphosphate (ATP) can serve as the index of a microorganism. This paper describes the development of a colorimetric method for the assay of ATP, using enzymatic cycling and Fe(III)-xylenol orange (XO) complex formation. The color characteristics of the Fe(III)-XO complexes, which show a distinct color change from yellow to purple, assist the visual observation in screening work. In this method, a trace amount of ATP was converted to pyruvate, which was further amplified exponentially with coupled enzymatic reactions. Eventually, pyruvate was converted to the Fe(III)-XO complexes through pyruvate oxidase reaction and Fe(II) oxidation. As the assay result, yellow or purple color was observed: A yellow color indicates that the ATP concentration is lower than the criterion of the test, and a purple color indicates that the ATP concentration is higher than the criterion. The method was applied to the assay of ATP extracted from Escherichia coli cells added to cow milk.

Zeolite-encapsulated Co(II), Mn(II), Cu(II) and Cr(III) salen complexes as catalysts for efficient selective oxidation of benzyl alcohol

Science.gov (United States)

Li, F. H.; Bi, H.; Huang, D. X.; Zhang, M.; Song, Y. B.

2018-01-01

Co(II), Mn(II), Cu(II) and Cr(III) salen type complexes were synthesized in situ in Y zeolite by the reaction of ion-exchanged metal ions with the flexible ligand molecules that had diffused into the cavities. Data of characterization indicates the formation of metal salen complexes in the pores without affecting the zeolite framework structure, the absence of any extraneous species and the geometry of encapsulated complexes. The catalytic activity results show that Cosalcyen Y exhibited higher catalytic activity in the water phase selective oxidation of benzyl alcohol, which could be attributed to their geometry and the steric environment of the metal actives sites.

Organic carboxylate anions effect on the structures of a series of Mn(II) complexes based on 2-phenylimidazo[4,5-f]1,10-phenanthroline ligand

International Nuclear Information System (INIS)

Wang Xiuli; Chen Yongqiang; Liu Guocheng; Lin Hongyan; Zhang Jinxia

2009-01-01

In our efforts to tune the structures of Mn(II) complexes by selection of organic carboxylic acid ligands, six new complexes [Mn(PIP) 2 Cl 2 ] (1), [Mn(PIP) 2 (4,4'-bpdc)(H 2 O)].2H 2 O (2), [Mn(PIP) 2 (1,4-bdc)] (3), [Mn(PIP)(1,3-bdc)] (4), [Mn(PIP) 2 (2,6-napdc)].H 2 O (5), and [Mn(PIP)(1,4-napdc)].H 2 O (6) were obtained, where PIP=2-phenylimidazo[4,5-f]1,10-phenanthroline, 4,4'-H 2 bpdc=biphenyl-4,4'-dicarboxylic acid, 1,4-H 2 bdc=benzene-1,4-dicarboxylic acid, 1,3-H 2 bdc=benzene-1,3-dicarboxylic acid, 2,6-H 2 napdc=2,6-naphthalenedicarboxylic acid, 1,4-H 2 napdc=1,4-naphthalenedicarboxylic acid. All complexes have been structurally characterized by IR, elemental analyses, and single crystal X-ray diffraction. Structural analyses show that complexes 1 and 2 possess mononuclear structures, complexes 3, 4, and 5 feature chain structures, and complex 6 exhibits a 2D (4,4) network. The structural difference of 1-6 indicates that organic carboxylate anions play important roles in the formation of such coordination architectures. Furthermore, the thermal properties of complexes 1-6 and the magnetic property of 4 have been investigated. - Graphical Abstract: Through selecting organic carboxylate anions, six Mn(II) complexes have been synthesized under hydrothermal conditions and characterized by single crystal X-ray diffraction.

Interactive effects of vertical mixing, solar radiation and microbial activity on oceanic dimethylated sulfur cycling

OpenAIRE

Galí Tàpias, Martí

2012-01-01

The production and subsequent emission of volatile compounds is one of the numerous ways by which microbial plankton participate in the cycling of elements and influence the Earth's climate. Dimethylsulfide (DMS), produced by enzymatic decomposition of the algal intracellular compound dimethylsulfoniopropionate (DMSP), is the more abundant organic volatile in the upper ocean. Its global emission amounts ca. 28 Tg S per year, and represents the main biogenic source of sulfur to the troposphere...

Microorganisms with a Taste for Vanilla: Microbial Ecology of Traditional Indonesian Vanilla Curing

Science.gov (United States)

Röling, Wilfred F. M.; Kerler, Josef; Braster, Martin; Apriyantono, Anton; Stam, Hein; van Verseveld, Henk W.

2001-01-01

The microbial ecology of traditional postharvesting processing of vanilla beans (curing) was examined using a polyphasic approach consisting of conventional cultivation, substrate utilization-based and molecular identification of isolates, and cultivation-independent community profiling by 16S ribosomal DNA based PCR-denaturing gradient gel electrophoresis. At two different locations, a batch of curing beans was monitored. In both batches a major shift in microbial communities occurred after short-term scalding of the beans in hot water. Fungi and yeast disappeared, although regrowth of fungi occurred in one batch during a period in which process conditions were temporarily not optimal. Conventional plating showed that microbial communities consisting of thermophilic and thermotolerant bacilli (mainly closely related to Bacillus subtilis, B. licheniformis,, and B. smithii) developed under the high temperatures (up to 65°C) that were maintained for over a week after scalding. Only small changes in the communities of culturable bacteria occurred after this period. Molecular analysis revealed that a proportion of the microbial communities could not be cultured on conventional agar medium, especially during the high-temperature period. Large differences between both batches were observed in the numbers of microorganisms, in species composition, and in the enzymatic abilities of isolated bacteria. These large differences indicate that the effects of microbial activities on the development of vanilla flavor could be different for each batch of cured vanilla beans. PMID:11319073

Microbial Proteases in Baked Goods: Modification of Gluten and Effects on Immunogenicity and Product Quality

Directory of Open Access Journals (Sweden)

Nina G. Heredia-Sandoval

2016-08-01

Full Text Available Gluten-related diseases are a range of inflammatory disorders of the small intestine, characterized by an adverse response to gluten ingestion; therefore, the treatment is a gluten withdrawal. In spite of the increased market of gluten-free products, widely available breads with high acceptability are still missing due to the technological challenge of substituting the special gluten properties. Instead of using alternative ingredients for baking, some attempts have been done to decrease gluten immunogenicity by its enzymatic degradation with microbial proteases. Although the gluten immunogenicity reduction has been reached to an acceptable level, some quality parameters of the products are affected. This review focus on the use of microbial peptidases to prepare less immunogenic baked goods and their effect on product quality.

Microbial Proteases in Baked Goods: Modification of Gluten and Effects on Immunogenicity and Product Quality.

Science.gov (United States)

Heredia-Sandoval, Nina G; Valencia-Tapia, Maribel Y; Calderón de la Barca, Ana M; Islas-Rubio, Alma R

2016-08-30

Gluten-related diseases are a range of inflammatory disorders of the small intestine, characterized by an adverse response to gluten ingestion; therefore, the treatment is a gluten withdrawal. In spite of the increased market of gluten-free products, widely available breads with high acceptability are still missing due to the technological challenge of substituting the special gluten properties. Instead of using alternative ingredients for baking, some attempts have been done to decrease gluten immunogenicity by its enzymatic degradation with microbial proteases. Although the gluten immunogenicity reduction has been reached to an acceptable level, some quality parameters of the products are affected. This review focus on the use of microbial peptidases to prepare less immunogenic baked goods and their effect on product quality.

Pretreatment of wheat straw with potassium hydroxide for increasing enzymatic and microbial degradability.

Science.gov (United States)

Liu, Xiaoying; Zicari, Steven M; Liu, Guangqing; Li, Yeqing; Zhang, Ruihong

2015-06-01

The pretreatment of wheat straw with potassium hydroxide (KOH) at ambient temperature (20°C) was investigated. The pretreatment effects on chemical composition and physical structures, and subsequent enzymatic hydrolysis and anaerobic digestion were evaluated. Wheat straw at 10% total solids (TS) was treated with KOH solution for 24h at a wide range of KOH loadings from 2% to 50% (w/w dry basis). Higher KOH loading resulted in higher lignin reduction from the straw and chemical oxygen demand (COD) in the resulting black liquor. Maximum lignin reduction of 54.7% was observed at 50% KOH loading. In comparison to untreated straw, specific hydrolysis yields achieved 14.0-92.3% over the range of 2-50% KOH loading, and methane yields increased 16.7-77.5% for KOH loadings of 10-50%, respectively. Accounting for losses during pretreatment, 20% KOH loading resulted in maximum overall reducing sugar yield and methane yield and therefore is the recommended loading for pretreatment under these conditions. Copyright © 2015 Elsevier Ltd. All rights reserved.

Process technology for multi-enzymatic reaction systems

DEFF Research Database (Denmark)

Xue, Rui; Woodley, John M.

2012-01-01

In recent years, biocatalysis has started to provide an important green tool in synthetic organic chemistry. Currently, the idea of using multi-enzymatic systems for industrial production of chemical compounds becomes increasingly attractive. Recent examples demonstrate the potential of enzymatic...... synthesis and fermentation as an alternative to chemical-catalysis for the production of pharmaceuticals and fine chemicals. In particular, the use of multiple enzymes is of special interest. However, many challenges remain in the scale-up of a multi-enzymatic system. This review summarizes and discusses...... the technology options and strategies that are available for the development of multi-enzymatic processes. Some engineering tools, including kinetic models and operating windows, for developing and evaluating such processes are also introduced....

The Enzymatic Conversion of Major Algal and Cyanobacterial Carbohydrates to Bioethanol

International Nuclear Information System (INIS)

Al Abdallah, Qusai; Nixon, B. Tracy; Fortwendel, Jarrod R.

2016-01-01

fermentable sugars before entering glycolysis. In contrast, microbial wild-type strains are not capable of producing ethanol from alginate, and therefore the production of bioethanol from alginate was achieved by using genetically engineered microbial strains, which can simultaneously hydrolyze and ferment alginate to ethanol. In this review, we emphasize the enzymatic hydrolysis processes of different algal polysaccharides. Additionally, we highlight the major metabolic pathways that are employed to ferment different algal monosaccharides to ethanol.

The enzymatic conversion of major algal and cyanobacterial carbohydrates to bioethanol

Directory of Open Access Journals (Sweden)

Qusai Al Abdallah

2016-11-01

converted to fermentable sugars before entering glycolysis. In contrast, microbial wild type strains are not capable of producing ethanol from alginate, and therefore the production of bioethanol from alginate was achieved by using genetically engineered microbial strains, which can simultaneously hydrolyze and ferment alginate to ethanol. In this review, we emphasize the enzymatic hydrolysis processes of different algal polysaccharides. Additionally, we highlight the major metabolic pathways that are employed to ferment different algal monosaccharides to ethanol.

The Enzymatic Conversion of Major Algal and Cyanobacterial Carbohydrates to Bioethanol

Energy Technology Data Exchange (ETDEWEB)

Al Abdallah, Qusai, E-mail: qalabdal@uthsc.edu [Department of Clinical Pharmacy, University of Tennessee Health Science Center, Memphis, TN (United States); Nixon, B. Tracy [Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA (United States); Fortwendel, Jarrod R. [Department of Clinical Pharmacy, University of Tennessee Health Science Center, Memphis, TN (United States)

2016-11-04

fermentable sugars before entering glycolysis. In contrast, microbial wild-type strains are not capable of producing ethanol from alginate, and therefore the production of bioethanol from alginate was achieved by using genetically engineered microbial strains, which can simultaneously hydrolyze and ferment alginate to ethanol. In this review, we emphasize the enzymatic hydrolysis processes of different algal polysaccharides. Additionally, we highlight the major metabolic pathways that are employed to ferment different algal monosaccharides to ethanol.

High activity and low temperature optima of extracellular enzymes in Arctic sediments: implications for carbon cycling by heterotrophic microbial communities

DEFF Research Database (Denmark)

Arnosti, C.; Jørgensen, BB

2003-01-01

The rate of the initial step in microbial remineralization of organic carbon, extracellular enzymatic hydrolysis, was investigated as a function of temperature in permanently cold sediments from 2 fjords on the west coast of Svalbard (Arctic Ocean). We used 4 structurally distinct polysaccharides...... hydrolysis in order to determine the relative temperature responses of the initial and terminal steps in microbial remineralization of carbon. The temperature optimum of sulfate reduction, 21degreesC, was considerably lower than previous reports of sulfate reduction in marine sediments, but is consistent...... with recent studies of psychrophilic sulfate reducers isolated from Svalbard sediments. A calculation of potential carbon flow into the microbial food chain demonstrated that the activity of just one type of polysaccharide-hydrolyzing enzyme could in theory supply 21 to 100% of the carbon consumed via sulfate...

Investigations of the microbial transformation of cortisol to prednisolone in urine samples.

Science.gov (United States)

Bredehöft, Michael; Baginski, Rainer; Parr, Maria-Kristina; Thevis, Mario; Schänzer, Wilhelm

2012-03-01

Doping control samples are normally collected under non-sterile conditions and sometimes, storage and transportation are influenced by parameters such as the temperature. Therefore, microbial contamination and subsequent alteration of a sample's composition are possible. Studies regarding sample collection in cattle breeding have already shown enzymatic transformation of endogenous testosterone to boldenone causing false-positive findings. The aim of the present study was to investigate whether positive doping cases with the synthetic corticosteroids prednisolone and prednisone may result from microbial transformation of the endogenous corticosteroids cortisol and cortisone, respectively. A method comprising parameters such as pH values and screening results for synthetic glucocorticosteroids as well as incubation experiments followed by liquid chromatographic and mass spectrometric analysis was employed to test for contaminating germs with Δ(1)-dehydrogenase activity. Over 700 urine samples comprising inpatient and doping control specimens were investigated. In none of them, 1,2-dehydrogenating activity was confirmed. These findings are in accordance with other studies. However, the problem of microbial alteration of doping control specimens with special respect to 1,2-dehydrogenation must not be underestimated. Article from a special issue on steroids and microorganisms. Copyright © 2010 Elsevier Ltd. All rights reserved.

Lignin depolymerization by fungal secretomes and a microbial sink

Energy Technology Data Exchange (ETDEWEB)

Salvachúa, Davinia; Katahira, Rui; Cleveland, Nicholas S.; Khanna, Payal; Resch, Michael G.; Black, Brenna A.; Purvine, Samuel O.; Zink, Erika M.; Prieto, Alicia; Martínez, María J.; Martínez, Angel T.; Simmons, Blake A.; Gladden, John M.; Beckham, Gregg T.

2016-08-25

In Nature, powerful oxidative enzymes secreted by white rot fungi and some bacteria catalyze lignin depolymerization and some microbes are able to catabolize the resulting aromatic compounds as carbon and energy sources. Taken together, these two processes offer a potential route for microbial valorization of lignin. However, many challenges remain in realizing this concept, including that oxidative enzymes responsible for lignin depolymerization also catalyze polymerization of low molecular weight (LMW) lignin. Here, multiple basidiomycete secretomes were screened for ligninolytic enzyme activities in the presence of a residual lignin solid stream from a corn stover biorefinery, dubbed DMR-EH (Deacetylation, Mechanical Refining, and Enzymatic Hydrolysis) lignin. Two selected fungal secretomes, with high levels of laccases and peroxidases, were utilized for DMR-EH lignin depolymerization assays. The secretome from Pleurotus eryngii, which exhibited the highest laccase activity, reduced the lignin average molecular weight by 63% and 75% at pH 7 compared to the Mw of the control treated at the same conditions and the initial DMR-EH lignin, respectively, and was applied in further depolymerization assays as a function of time. As repolymerization was observed after 3 days of incubation, an aromatic-catabolic microbe (Pseudomonas putida KT2440) was incubated with the fungal secretome and DMR-EH lignin. These experiments demonstrated that the presence of the bacterium enhances lignin depolymerization, likely due to bacterial catabolism of LMW lignin, which may partially prevent repolymerization. In addition, proteomics was also applied to the P. eryngii secretome to identify the enzymes present in the fungal cocktail utilized for the depolymerization assays, which highlighted a significant number of glucose/ methanol/choline (GMC) oxidoreductases and laccases. Overall, this study demonstrates that ligninolytic enzymes can be used to partially depolymerize a solid, high

Synthesis and characterization of polychelates of Cu(II), Ni(II), Co(II), Mn(II), Zn(II), oxovanadium(IV) and dioxouranium(VI) with 2,4-dihydroxybenzaldehyde-urea-formaldehyde polymer

International Nuclear Information System (INIS)

Patel, G.C.; Pancholi, H.B.; Patel, M.M.

1991-01-01

Polychelates of Cu(II), Ni(II), Co(II), Mn(II), Zn(II), oxovandium(IV) and dioxouranium(VI) with 2,4-dihydroxybenzaldehyde (2,4-DB)-urea(U)-formaldehyde(F) polymer (2,4-DBUF) have been prepared. Elemental analyses of the polychelates indicate a metal:ligand ratio of 1:2. The structures of the polychelates have been assigned on the basis of their elemental analyses, IR, reflectance spectra, magnetic moment, thermal data and their electrical conductivity behaviour. (author). 1 tab., 18 refs

Enzymatic hydrolysis of pretreated soybean straw

International Nuclear Information System (INIS)

Xu Zhong; Wang Qunhui; Jiang Zhaohua; Yang Xuexin; Ji Yongzhen

2007-01-01

In order to produce lactic acid, from agricultural residues such as soybean straw, which is a raw material for biodegradable plastic production, it is necessary to decompose the soybean straw into soluble sugars. Enzymatic hydrolysis is one of the methods in common use, while pretreatment is the effective way to increase the hydrolysis rate. The optimal conditions of pretreatment using ammonia and enzymatic hydrolysis of soybean straw were determined. Compared with the untreated straw, cellulose in straw pretreated by ammonia liquor (10%) soaking for 24 h at room temperature increased 70.27%, whereas hemicellulose and lignin in pretreated straw decreased to 41.45% and 30.16%, respectively. The results of infrared spectra (IR), scanning electron microscope (SEM) and X-ray diffraction (XRD) analysis also showed that the structure and the surface of the straw were changed through pretreatment that is in favor of the following enzymatic hydrolysis. maximum enzymatic hydrolysis rate of 51.22% was achieved at a substrate concentration of 5% (w/v) at 50 deg. C and pH 4.8 using cellulase (50 fpu/g of substrate) for 36 h

Enzymatic approaches to rare sugar production.

Science.gov (United States)

Zhang, Wenli; Zhang, Tao; Jiang, Bo; Mu, Wanmeng

Rare sugars have recently attracted much attention because of their potential applications in the food, nutraceutical, and pharmaceutical industries. A systematic strategy for enzymatic production of rare sugars, named Izumoring, was developed >10years ago. The strategy consists of aldose-ketose isomerization, ketose C-3 epimerization, and monosaccharide oxidation-reduction. Recent development of the Izumoring strategy is reviewed herein, especially the genetic approaches to the improvement of rare sugar-producing enzymes and the applications of target-oriented bioconversion. In addition, novel non-Izumoring enzymatic approaches are also summarized, including enzymatic condensation, phosphorylation-dephosphorylation cascade reaction, aldose epimerization, ulosonic acid decarboxylation, and biosynthesis of rare disaccharides. Copyright © 2017 Elsevier Inc. All rights reserved.

Functional breadth and home-field advantage generate functional differences among soil microbial decomposers.

Science.gov (United States)

Fanin, Nicolas; Fromin, Nathalie; Bertrand, Isabelle

2016-04-01

correlated with those calculated on enzymatic activity, confirming the idea that the interaction between litter quality and microbial community structure may modify the trajectory of carbon mineralization via enzymatic synthesis. We conclude that although litter quality was the predominant factor controlling litter mineralization, the local microbial communities and interactions with their substrates can explain a small (< 5%) but noticeable portion of carbon fluxes.

Microbial Production of l-Serine from Renewable Feedstocks.

Science.gov (United States)

Zhang, Xiaomei; Xu, Guoqiang; Shi, Jinsong; Koffas, Mattheos A G; Xu, Zhenghong

2018-07-01

l-Serine is a non-essential amino acid that has wide and expanding applications in industry with a fast-growing market demand. Currently, extraction and enzymatic catalysis are the main processes for l-serine production. However, such approaches limit the industrial-scale applications of this important amino acid. Therefore, shifting to the direct fermentative production of l-serine from renewable feedstocks has attracted increasing attention. This review details the current status of microbial production of l-serine from renewable feedstocks. We also summarize the current trends in metabolic engineering strategies and techniques for the typical industrial organisms Corynebacterium glutamicum and Escherichia coli that have been developed to address and overcome major challenges in the l-serine production process. Copyright © 2018 Elsevier Ltd. All rights reserved.

Synthesis, spectral characterization thermal stability, antimicrobial studies and biodegradation of starch–thiourea based biodegradable polymeric ligand and its coordination complexes with [Mn(II, Co(II, Ni(II, Cu(II, and Zn(II] metals

Directory of Open Access Journals (Sweden)

Nahid Nishat

2016-09-01

Full Text Available A biodegradable polymer was synthesized by the modification reaction of polymeric starch with thiourea which is further modified by transition metals, Mn(II, Co(II, Ni(II, Cu(II and Zn(II. All the polymeric compounds were characterized by (FT-IR spectroscopy, 1H NMR spectroscopy, 13C NMR spectroscopy, UV–visible spectra, magnetic moment measurements, thermogravimetric analysis (TGA and antibacterial activities. Polymer complexes of Mn(II, Co(II and Ni(II show octahedral geometry, while polymer complexes of Cu(II and Zn(II show square planar and tetrahedral geometry, respectively. The TGA revealed that all the polymer metal complexes are more thermally stable than their parental ligand. In addition, biodegradable studies of all the polymeric compounds were also carried out through ASTM-D-5338-93 standards of biodegradable polymers by CO2 evolution method which says that coordination decreases biodegradability. The antibacterial activity was screened with the agar well diffusion method against some selected microorganisms. Among all the complexes, the antibacterial activity of the Cu(II polymer–metal complex showed the highest zone of inhibition because of its higher stability constant.

Syntheses, X-ray structures, solid state high-field electron paramagnetic resonance, and density-functional theory investigations on chloro and aqua Mn(II) mononuclear complexes with amino-pyridine pentadentate ligands.

Science.gov (United States)

Hureau, Christelle; Groni, Sihem; Guillot, Régis; Blondin, Geneviève; Duboc, Carole; Anxolabéhère-Mallart, Elodie

2008-10-20

The two pentadentate amino-pyridine ligands L5(2) and L5(3) (L5(2) and L5(3) stand for the N-methyl-N,N',N'-tris(2-pyridylmethyl)ethane-1,2-diamine and the N-methyl-N,N',N'-tris(2-pyridylmethyl)propane-1,3-diamine, respectively) were used to synthesize four mononuclear Mn(II) complexes, namely [(L5(2))MnCl](PF6) (1(PF6)), [(L5(3))MnCl](PF6) (2(PF6)), [(L5(2))Mn(OH2)](BPh4)2 (3(BPh4)2), and [(L5(3))Mn(OH2)](BPh4)2 (4(BPh4)2). The X-ray diffraction studies revealed different configurations for the ligand L5(n) (n = 2, 3) depending on the sixth exogenous ligand and/or the counterion. Solid state high-field electron paramagnetic resonance spectra were recorded on complexes 1-4 as on previously described mononuclear Mn(II) systems with tetra- or hexadentate amino-pyridine ligands. Positive and negative axial zero-field splitting (ZFS) parameters D were determined whose absolute values ranged from 0.090 to 0.180 cm(-1). Density-functional theory calculations were performed unraveling that, in contrast with chloro systems, the spin-spin and spin-orbit coupling contributions to the D-parameter are comparable for mixed N,O-coordination sphere complexes.

A wheel-shaped single-molecule magnet of [MnII 3MnIII 4]: quantum tunneling of magnetization under static and pulse magnetic fields.

Science.gov (United States)

Koizumi, Satoshi; Nihei, Masayuki; Shiga, Takuya; Nakano, Motohiro; Nojiri, Hiroyuki; Bircher, Roland; Waldmann, Oliver; Ochsenbein, Stefan T; Güdel, Hans U; Fernandez-Alonso, Felix; Oshio, Hiroki

2007-01-01

The reaction of N-(2-hydroxy-5-nitrobenzyl)iminodiethanol (=H3(5-NO2-hbide)) with Mn(OAc)2* 4 H2O in methanol, followed by recrystallization from 1,2-dichloroethane, yielded a wheel-shaped single-molecule magnet (SMM) of [MnII 3MnIII 4(5-NO2-hbide)6].5 C2H4Cl2 (1). In 1, seven manganese ions are linked by six tri-anionic ligands and form the wheel in which the two manganese ions on the rim and the one in the center are MnII and the other four manganese ions are MnIII ions. Powder magnetic susceptibility measurements showed a gradual increase with chimT values as the temperature was lowered, reaching a maximum value of 53.9 emu mol(-1) K. Analyses of magnetic susceptibility data suggested a spin ground state of S=19/2. The zero-field splitting parameters of D and B 0 4 were estimated to be -0.283(1) K and -1.64(1)x10(-5) K, respectively, by high-field EPR measurements (HF-EPR). The anisotropic parameters agreed with those estimated from magnetization and inelastic neutron scattering experiments. AC magnetic susceptibility measurements showed frequency-dependent in- and out-of-phase signals, characteristic data for an SMM, and an Arrhenius plot of the relaxation time gave a re-orientation energy barrier (DeltaE) of 18.1 K and a pre-exponential factor of 1.63x10(-7) s. Magnetization experiments on aligned single crystals below 0.7 K showed a stepped hysteresis loop, confirming the occurrence of quantum tunneling of the on magnetization (QTM). QTM was, on the other hand, suppressed by rapid sweeps of the magnetic field even at 0.5 K. The sweep-rate dependence of the spin flips can be understood by considering the Landau-Zener-Stückelberg (LZS) model.

Biotechnological Applications of Microbial (Per)chlorate Reduction.

Science.gov (United States)

Wang, Ouwei; Coates, John D

2017-11-24

While the microbial degradation of a chloroxyanion-based herbicide was first observed nearly ninety years ago, only recently have researchers elucidated the underlying mechanisms of perchlorate and chlorate [collectively, (per)chlorate] respiration. Although the obvious application of these metabolisms lies in the bioremediation and attenuation of (per)chlorate in contaminated environments, a diversity of alternative and innovative biotechnological applications has been proposed based on the unique metabolic abilities of dissimilatory (per)chlorate-reducing bacteria (DPRB). This is fueled in part by the unique ability of these organisms to generate molecular oxygen as a transient intermediate of the central pathway of (per)chlorate respiration. This ability, along with other novel aspects of the metabolism, have resulted in a wide and disparate range of potential biotechnological applications being proposed, including enzymatic perchlorate detection; gas gangrene therapy; enhanced xenobiotic bioremediation; oil reservoir bio-souring control; chemostat hygiene control; aeration enhancement in industrial bioreactors; and, biogenic oxygen production for planetary exploration. While previous reviews focus on the fundamental science of microbial (per)chlorate reduction (for example see Youngblut et al., 2016), here, we provide an overview of the emerging biotechnological applications of (per)chlorate respiration and the underlying organisms and enzymes to environmental and biotechnological industries.

Evaluation of microbial dynamics during post-consumption food waste composting.

Science.gov (United States)

Awasthi, Sanjeev Kumar; Wong, Jonathan W C; Li, Jiao; Wang, Quan; Zhang, Zengqiang; Kumar, Sunil; Awasthi, Mukesh Kumar

2018-03-01

The objective of present study was to evaluate the efficacy of bacterial consortium to boost the microbial population and enzyme activities during post-consumption food waste (PCFWs) composting. Three treatments of PCFWs mixed with saw dust and 10% zeolite (dry weight basis) was design, where treatments T-2 and T-3 were applied with two distinctive bacterial consortium, respectively, while T-1 was served as control. The results showed that total aerobic proteolytic, amylolytic, cellulolytic, oil degrading and total aerobic bacteria populations were significantly higher in treatment T2 and T3 than T1. Consequently, the selected hydrolytic enzymes were also higher in T2 and T3 than T1, whose apparently gave the interesting information about rate of decomposition and end product stability. Furthermore, T2 and T3 showed significant correlations between the enzymatic activities and microbial population with other physico-chemical parameters. Based on germination assays and CO 2 -C evolution rate, T2 and T3 were considered phytotoxic free and highly stable final compost on day 56. Copyright © 2017 Elsevier Ltd. All rights reserved.

Enzymatic hydrolysis of biomimetic bacterial cellulose-hemicellulose composites.

Science.gov (United States)

Penttilä, Paavo A; Imai, Tomoya; Hemming, Jarl; Willför, Stefan; Sugiyama, Junji

2018-06-15

The production of biofuels and other chemicals from lignocellulosic biomass is limited by the inefficiency of enzymatic hydrolysis. Here a biomimetic composite material consisting of bacterial cellulose and wood-based hemicelluloses was used to study the effects of hemicelluloses on the enzymatic hydrolysis with a commercial cellulase mixture. Bacterial cellulose synthesized in the presence of hemicelluloses, especially xylan, was found to be more susceptible to enzymatic hydrolysis than hemicellulose-free bacterial cellulose. The reason for the easier hydrolysis could be related to the nanoscale structure of the substrate, particularly the packing of cellulose microfibrils into ribbons or bundles. In addition, small-angle X-ray scattering was used to show that the average nanoscale morphology of bacterial cellulose remained unchanged during the enzymatic hydrolysis. The reported easier enzymatic hydrolysis of bacterial cellulose produced in the presence of wood-based xylan offers new insights to overcome biomass recalcitrance through genetic engineering. Copyright © 2018 Elsevier Ltd. All rights reserved.

Zn(II, Mn(II and Sr(II Behavior in a Natural Carbonate Reservoir System. Part I: Impact of Salinity, Initial pH and Initial Zn(II Concentration in Atmospheric Conditions

Directory of Open Access Journals (Sweden)

Auffray B.

2016-07-01

Full Text Available The sorption of inorganic elements on carbonate minerals is well known in strictly controlled conditions which limit the impact of other phenomena such as dissolution and/or precipitation. In this study, we evidence the behavior of Zn(II (initially in solution and two trace elements, Mn(II and Sr(II (released by carbonate dissolution in the context of a leakage from a CO2 storage site. The initial pH chosen are either equal to the pH of the water-CO2 equilibrium (~ 2.98 or equal to the pH of the water-CO2-calcite system (~ 4.8 in CO2 storage conditions. From this initial influx of liquid, saturated or not with respect to calcite, the batch experiments evolve freely to their equilibrium, as it would occur in a natural context after a perturbation. The batch experiments are carried out on two natural carbonates (from Lavoux and St-Emilion with PCO2 = 10−3.5 bar, with different initial conditions ([Zn(II]i from 10−4 to 10−6 M, either with pure water or 100 g/L NaCl brine. The equilibrium regarding calcite dissolution is confirmed in all experiments, while the zinc sorption evidenced does not always correspond to the two-step mechanism described in the literature. A preferential sorption of about 10% of the concentration is evidenced for Mn(II in aqueous experiments, while Sr(II is more sorbed in saline conditions. This study also shows that this preferential sorption, depending on the salinity, is independent of the natural carbonate considered. Then, the simulations carried out with PHREEQC show that experiments and simulations match well concerning the equilibrium of dissolution and the sole zinc sorption, with log KZn(II ~ 2 in pure water and close to 4 in high salinity conditions. When the simulations were possible, the log K values for Mn(II and Sr(II were much different from those in the literature obtained by sorption in controlled conditions. It is shown that a new conceptual model regarding multiple Trace Elements (TE sorption is

Use of ion chromatography for monitoring microbial spoilage in the fruit juice industry.

Science.gov (United States)

Trifirò, A; Saccani, G; Gherardi, S; Vicini, E; Spotti, E; Previdi, M P; Ndagijimana, M; Cavalli, S; Reschiotto, C

1997-05-16

Fruit juices and purees are defined as fermentable, but unfermented, products obtained by mechanical processing of fresh fruits. The presence of undesired metabolites derived from microbial growth can arise from the use of unsuitable fruit or from defects in the production line or subsequent contamination. This involves a loss in the overall quality that cannot be resolved by thermal treatment following the start of fermentation. With these considerations, together with microbiological control, the analysis of different metabolites, which can be considered as microbial growth markers, such as alcohols (i.e. ethanol, etc.), acids (i.e. acetic, fumaric, lactic, etc.) is fundamental in order to achieve a better evaluation of product quality. Enzymatic determination and other single-component analytical techniques are often used for the determination of these metabolites. When the microbial spoilage is not well known, this results in a long and cumbersome procedure. A versatile technique that is capable of determining many metabolites in one analysis could be helpful in improving routine quality control. For this purpose, an ion chromatographic technique, such as ion exclusion, for separation, and diode array spectrophotometry and conductivity, for detection, were evaluated. Both different industrial samples and inoculated samples were analyzed.

Efficacy of Denture Cleansers in Reducing Microbial Counts from Removable Partial Dentures: A Short-Term Clinical Evaluation

OpenAIRE

Lucena-Ferreira,Silvia Carneiro de; Cavalcanti,Indira Moraes Gomes; Cury,Altair Antoninha Del Bel

2013-01-01

This clinical study investigated if daily immersion in denture cleansers reduces microbial counts on removable partial denture's (RPD) biofilm. Twenty-five RPD wearer volunteers were selected and instructed to complement the hygiene of their dentures by immersing them in an enzymatic peroxide-based denture cleanser (Polident® 3 minute) once a day for 3 min for a period of 15 days. The biofilm was collected from RPD surfaces with a swab immediately before (baseline) and after the experimental ...

Inhibition of tyrosinase-mediated enzymatic browning by sulfite and natural alternatives

NARCIS (Netherlands)

Kuijpers, T.F.M.; Vincken, J.P.

2013-01-01

Although sulfite is widely used to counteract enzymatic browning, its mechanism has remained largely unknown. We describe a double inhibitory mechanism of sulfite on enzymatic browning, affecting both the enzymatic oxidation of phenols into o‑quinones, as well as the non‑enzymatic

Bioelectrocatalytic NAD+/NADH inter-conversion: transformation of an enzymatic fuel cell into an enzymatic redox flow battery.

Science.gov (United States)

Quah, Timothy; Milton, Ross D; Abdellaoui, Sofiene; Minteer, Shelley D

2017-07-25

Diaphorase and a benzylpropylviologen redox polymer were combined to create a bioelectrode that can both oxidize NADH and reduce NAD + . We demonstrate how bioelectrocatalytic NAD + /NADH inter-conversion can transform a glucose/O 2 enzymatic fuel cell (EFC) with an open circuit potential (OCP) of 1.1 V into an enzymatic redox flow battery (ERFB), which can be rapidly recharged by operation as an EFC.

Reproducible analyses of microbial food for advanced life support systems

Science.gov (United States)

Petersen, Gene R.

1988-01-01

The use of yeasts in controlled ecological life support systems (CELSS) for microbial food regeneration in space required the accurate and reproducible analysis of intracellular carbohydrate and protein levels. The reproducible analysis of glycogen was a key element in estimating overall content of edibles in candidate yeast strains. Typical analytical methods for estimating glycogen in Saccharomyces were not found to be entirely aplicable to other candidate strains. Rigorous cell lysis coupled with acid/base fractionation followed by specific enzymatic glycogen analyses were required to obtain accurate results in two strains of Candida. A profile of edible fractions of these strains was then determined. The suitability of yeasts as food sources in CELSS food production processes is discussed.

Chemical characterization and hydrothermal pretreatment of Salicornia bigelovii straw for enhanced enzymatic hydrolysis and bioethanol potential

DEFF Research Database (Denmark)

Cybulska, Iwona; Chaturvedi, Tanmay; Brudecki, Grzegorz P.

2014-01-01

equipment and avoid inhibition of enzymes and yeast. Composition of the washed biomass was comparable to traditional lignocellulosic biomasses with relatively high glucan and xylan content (26 and 22. g/100. gDM, respectively) but with lower lignin content (7. g/100. gDM). The washed feedstock was subjected...... to hydrothermal pretreatment, producing highly digestible (up to 92% glucan-to-glucose conversion) and fermentable (up to 100% glucose-to-ethanol conversion) fiber fractions. Liquid fractions obtained in the pretreatment did not show inhibition towards Saccharomyces cerevisiae. No significant differences among...... the enzymatic convertibility and microbial fermentability of the fibers as well as low xylose recoveries suggest that lower severity pretreatment conditions could be exploited for S. bigelovii. © 2013 Elsevier Ltd....

Improved enzymatic production of phenolated glycerides through alkyl phenolate intermediate

DEFF Research Database (Denmark)

Yang, Zhiyong; Feddern, Vivian; Glasius, Marianne

2011-01-01

This work reported a novel approach for synthesis of dihydrocaffoylated glycerides, consisting of 2 steps: enzymatic synthesis of octyl dihydrocaffeate (as a synthetic intermediate) from octanol and dihydrocaffeic acid (DHCA), and enzymatic interesterification of triglycerides with octyl dihydroc......This work reported a novel approach for synthesis of dihydrocaffoylated glycerides, consisting of 2 steps: enzymatic synthesis of octyl dihydrocaffeate (as a synthetic intermediate) from octanol and dihydrocaffeic acid (DHCA), and enzymatic interesterification of triglycerides with octyl...

Microbial Mineralization of cis-Dichloroethene and Vinyl Chloride as a Component of Natural Attenuation of Chloroethene Contaminants under Conditions Identified in the Field as Anoxic

Science.gov (United States)

2012-01-01

16 2. cis-DCE mineralization kinetics under hypoxic and anoxic conditions .............................17 Conversion Factors Inch/Pound...situ conditions. Vmax is influenced by micro- bial biomass , metabolic activity, and the availability of nutri- ents and substrates that support...were incapable of growth at atmospheric oxygen levels (Morris 1976). Enzymatic defenses against oxygen radicals have been documented 20 Microbial

Role of Ergothioneine in Microbial Physiology and Pathogenesis.

Science.gov (United States)

Cumming, Bridgette M; Chinta, Krishna C; Reddy, Vineel P; Steyn, Adrie J C

2018-02-20

L-ergothioneine is synthesized in actinomycetes, cyanobacteria, methylobacteria, and some fungi. In contrast to other low-molecular-weight redox buffers, glutathione and mycothiol, ergothioneine is primarily present as a thione rather than a thiol at physiological pH, which makes it resistant to autoxidation. Ergothioneine regulates microbial physiology and enables the survival of microbes under stressful conditions encountered in their natural environments. In particular, ergothioneine enables pathogenic microbes, such as Mycobacterium tuberculosis (Mtb), to withstand hostile environments within the host to establish infection. Recent Advances: Ergothioneine has been reported to maintain bioenergetic homeostasis in Mtb and protect Mtb against oxidative stresses, thereby enhancing the virulence of Mtb in a mouse model. Furthermore, ergothioneine augments the resistance of Mtb to current frontline anti-TB drugs. Recently, an opportunistic fungus, Aspergillus fumigatus, which infects immunocompromised individuals, has been found to produce ergothioneine, which is important in conidial health and germination, and contributes to the fungal resistance against redox stresses. The molecular mechanisms of the functions of ergothioneine in microbial physiology and pathogenesis are poorly understood. It is currently not known if ergothioneine is used in detoxification or antioxidant enzymatic pathways. As ergothioneine is involved in bioenergetic and redox homeostasis and antibiotic susceptibility of Mtb, it is of utmost importance to advance our understanding of these mechanisms. A clear understanding of the role of ergothioneine in microbes will advance our knowledge of how this thione enhances microbial virulence and resistance to the host's defense mechanisms to avoid complete eradication. Antioxid. Redox Signal. 28, 431-444.

The degradation of phytate by microbial and wheat phytases is dependent on the phytate matrix and the phytase origin

DEFF Research Database (Denmark)

Brejnholt, Sarah M; Dionisio, Giuseppe; Glitsoe, Vibe

2011-01-01

BACKGROUND: Phytases increase utilization of phytate phosphorus in feed. Since wheat is rich in endogenous phytase activity it was examined whether wheat phytases could improve phytate degradation compared to microbial phytases. Moreover, it was investigated whether enzymatic degradation of phytate...... is influenced by the matrix surrounding it. Phytate degradation was defined as the decrease in the sum of InsP6 + InsP5. RESULTS: Endogenous wheat phytase effectively degraded wheat InsP6 + InsP5 at pH 4 and pH 5, while this was not true for a recombinant wheat phytase or phytase extracted from wheat bran. Only...... microbial phytases were able to degrade InsP6 + InsP5 in the entire pH range from 3 to 5, which is relevant for feed applications. A microbial phytase was efficient towards InsP6 + InsP5 in different phytate samples, whereas the ability to degrade InsP6 + InsP5 in the different phytate samples ranged from...

Combinational effects of sulfomethoxazole and copper on soil microbial community and function.

Science.gov (United States)

Liu, Aiju; Cao, Huansheng; Yang, Yan; Ma, Xiaoxuan; Liu, Xiao

2016-03-01

Sulfonamides and Cu are largely used feed additives in poultry farm. Subsequently, they are spread onto agricultural soils together with contaminated manure used as fertilizer. Both sulfonamides and Cu affect the soil microbial community. However, an interactive effect of sulfonamides and Cu on soil microorganisms is not well understood. Therefore, a short-time microcosm experiment was conducted to investigate the interaction of veterinary antibiotic sulfomethoxazole (SMX) and Cu on soil microbial structure composition and functions. To this end, selected concentrations of SMX (0, 5, and 50 mg kg(-1)) and Cu (0, 300, and 500 mg kg(-1)) were combined, respectively. Clear dose-dependent effects of SMX on microbial biomass and basal respiration were determined, and these effects were amplified in the presence of additional Cu. For activities of soil enzymes including β-glucosidase, urease, and protease, clear reducing effects were determined in soil samples containing 5 or 50 mg kg(-1) of SMX, and the interaction of SMX and Cu was significant, particularly in soil samples containing 50 mg kg(-1) SMX or 500 mg kg(-1) Cu. SMX amendments, particularly in combination with Cu, significantly reduced amounts of the total, bacterial, and fungal phospholipid fatty acids (PLFAs) in soil. Moreover, the derived ratio of bacteria to fungi decreased significantly with incremental SMX and Cu, and principal component analysis of the PLFAs showed that soil microbial composition was significantly affected by SMX interacted with Cu at 500 mg kg(-1). All of these results indicated that the interaction of SMX and Cu was synergistic to amplify the negative effect of SMX on soil microbial biomass, structural composition, and even the enzymatic function.

Thermal and enzymatic pretreatment of sludge containing phthalate esters prior to mesophilic anaerobic digestion

DEFF Research Database (Denmark)

Gavala, Hariklia N.; Yenal, U.; Ahring, Birgitte Kiær

2004-01-01

The present study aimed at investigating the effect of thermal pretreatment of sludge at 70degreesC on the anaerobic degradation of three commonly found phthalic acid esters (PAE): di-ethyl phthalate (DEP), di-butyl phthalate (DBP), and di-ethylhexyl phthalate (DEHP). Also, the enzymatic treatment...... at 28degreesC with a commercial lipase was studied as a way to enhance PAE removal. Pretreatment at 70degreesC of the sludge containing PAE negatively influenced the anaerobic biodegradability of phthalate esters at 37degreesC. The observed reduction of PAE biodegradation rates after the thermal...... pretreatment was found to be proportional to the PAE solubility in water: the higher the solubility, the higher the percentage of the reduction (DEP > DBP > DEHP). PAE were slowly degraded during the pretreatment at 70degreesC, yet this was probably due to physicochemical reactions than to microbial...

Sediment microbial activity and its relation to environmental variables along the eastern Gulf of Finland coastline

Science.gov (United States)

Polyak, Yulia; Shigaeva, Tatyana; Gubelit, Yulia; Bakina, Ludmila; Kudryavtseva, Valentina; Polyak, Mark

2017-07-01

Sediment microbial activity and its relationship with the main environmental factors and pollutants were examined in the coastal area of the eastern Gulf of Finland, Baltic Sea. The activity of two common oxidoreductase enzymes: dehydrogenase (DA) and catalase (CA) varied significantly between 13 study sites. In the Neva Bay the highest microbial activities (DA: 2.64 mg TFF (10 g- 1) day- 1, CA: 6.29 mg H2O2 g- 1) were recorded, while in the outer estuary the minimum values of dehydrogenase and catalase were measured. DA, CA, and abundances of culturable heterotrophic bacteria (CHB) were positively correlated with each other, while biomass of green opportunistic algae was independent of both microbial activities and CHB. Enzymatic activity was found to be strongly positively correlated with sediment particle size and organic matter content, but unrelated to the other studied environmental parameters (temperature, pH, and salinity). Principal components analysis (PCA), controlling for environmental variables, supported direct effects of metal and oil contamination on sediment microbial activity. Also it had shown the similar patterns for algal biomass and metals. Our results suggest that copper and hydrocarbons are the main anthropogenic variables influencing enzyme distribution along the eastern Gulf of Finland coastline.

MICROBIAL CHARACTERISTICS OF SOILS UNDER AN INTEGRATED CROP-LIVESTOCK SYSTEM

Directory of Open Access Journals (Sweden)

Andréa Scaramal da Silva

2015-02-01

Full Text Available Integrated crop-livestock systems (ICLs are a viable strategy for the recovery and maintenance of soil characteristics. In the present study, an ICL experiment was conducted by the Instituto Agronômico do Paraná in the municipality of Xambre, Parana (PR, Brazil, to evaluate the effects of various grazing intensities. The objective of the present study was to quantify the levels of microbial biomass carbon (MBC and soil enzymatic activity in an ICL of soybean (summer and Brachiaria ruziziensis (winter, with B. ruziziensis subjected to various grazing intensities. Treatments consisted of varying pasture heights and grazing intensities (GI: 10, 20, 30, and 40 cm (GI-10, GI-20, GI-30, and GI-40, respectively and a no grazing (NG control. The microbial characteristics analysed were MBC, microbial respiration (MR, metabolic quotient (qCO2, the activities of acid phosphatase, β-glucosidase, arylsuphatase, and cellulase, and fluorescein diacetate (FDA hydrolysis. Following the second grazing cycle, the GI-20 treatment (20-cm - moderate grazing intensity contained the highest MBC concentrations and lowest qCO2 concentrations. Following the second soybean cycle, the treatment with the highest grazing intensity (GI-10 contained the lowest MBC concentration. Soil MBC concentrations in the pasture were favoured by the introduction of animals to the system. High grazing intensity (10-cm pasture height during the pasture cycle may cause a decrease in soil MBC and have a negative effect on the microbial biomass during the succeeding crop. Of all the enzymes analyzed, only arylsuphatase and cellulase activities were altered by ICL management, with differences between the moderate grazing intensity (GI-20 and no grazing (NG treatments.

Enzymatic Browning: a practical class

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Maria Teresa Pedrosa Silva Clerici

2014-10-01

Full Text Available This paper presents a practical class about the enzymes polyphenol oxidases, which have been shown to be responsible for the enzymatic browning of fruits and vegetables. Vegetables samples were submitted to enzymatic inactivation process with chemical reagents, as well as by bleaching methods of applying heat by conventional oven and microwave oven. Process efficiency was assessed qualitatively by both observing the guaiacol peroxidase activity and after the storage period under refrigeration or freezing. The practical results obtained in this class allow exploring multidisciplinary knowledge in food science, with practical applications in everyday life.

Enzymatic biodiesel production: Technical and economical considerations

DEFF Research Database (Denmark)

Munk Nielsen, Per; Brask, Jesper; Fjerbæk, Lene

2008-01-01

It is well documented in the literature that enzymatic processing of oils and fats for biodiesel is technically feasible. However, with very few exceptions, enzyme technology is not currently used in commercial-scale biodiesel production. This is mainly due to non-optimized process design...... and a lack of available costeffective enzymes. The technology to re-use enzymes has typically proven insufficient for the processes to be competitive. However, literature data documenting the productivity of enzymatic biodiesel together with the development of new immobilization technology indicates...... that enzyme catalysts can become cost effective compared to chemical processing. This work reviews the enzymatic processing of oils and fats into biodiesel with focus on process design and economy....

Soil microbial communities as suitable bioindicators of trace metal pollution in agricultural volcanic soils

Science.gov (United States)

Parelho, Carolina; dos Santos Rodrigues, Armindo; do Carmo Barreto, Maria; Gonçalo Ferreira, Nuno; Garcia, Patrícia

2015-04-01

Summary: The biological, chemical and physical properties of soil confer unique characteristics that enhance or influence its overall biodiversity. The adaptive character of soil microbial communities (SMCs) to metal pollution allows discriminating soil health, since changes in microbial populations and activities may function as excellent indicators of soil pollutants. Volcanic soils are unique naturally fertile resources, extensively used for agricultural purposes and with particular physicochemical properties that may result in accumulation of toxic substances, such as trace metals (TM). In our previous works, we identified priority TM affecting agricultural Andosols under different agricultural land uses. Within this particular context, the objectives of this study were to (i) assess the effect of soil TM pollution in different agricultural systems (conventional, traditional and organic) on the following soil properties: microbial biomass carbon, basal soil respiration, metabolic quotient, enzymatic activities (β-glucosidase, acid phosphatase and dehydrogenase) and RNA to DNA ratio; and (ii) evaluate the impact of TM in the soil ecosystem using the integrated biomarker response (IBR) based on a set of biochemical responses of SMCs. This multi-biomarker approach will support the development of the "Trace Metal Footprint" for different agricultural land uses in volcanic soils. Methods: The study was conducted in S. Miguel Island (Azores, Portugal). Microbial biomass carbon was measured by chloroform-fumigation-incubation-assay (Vance et al., 1987). Basal respiration was determined by the Jenkinson & Powlson (1976) technique. Metabolic quotient was calculated as the ratio of basal respiration to microbial biomass C (Sparkling & West, 1988). The enzymatic activities of β-glucosidase and acid phosphatase were determined by the Dick et al. (1996) method and dehydrogenase activity by the Rossel et al. (1997) method. The RNA and DNA were co-extracted from the same

Effect of elevated CO2 on chlorpyriphos degradation and soil microbial activities in tropical rice soil.

Science.gov (United States)

Adak, Totan; Munda, Sushmita; Kumar, Upendra; Berliner, J; Pokhare, Somnath S; Jambhulkar, N N; Jena, M

2016-02-01

Impact of elevated CO2 on chlorpyriphos degradation, microbial biomass carbon, and enzymatic activities in rice soil was investigated. Rice (variety Naveen, Indica type) was grown under four conditions, namely, chambered control, elevated CO2 (550 ppm), elevated CO2 (700 ppm) in open-top chambers and open field. Chlorpyriphos was sprayed at 500 g a.i. ha(-1) at maximum tillering stage. Chlorpyriphos degraded rapidly from rice soils, and 88.4% of initially applied chlorpyriphos was lost from the rice soil maintained under elevated CO2 (700 ppm) by day 5 of spray, whereas the loss was 80.7% from open field rice soil. Half-life values of chlorpyriphos under different conditions ranged from 2.4 to 1.7 days with minimum half-life recorded with two elevated CO2 treatments. Increased CO2 concentration led to increase in temperature (1.2 to 1.8 °C) that played a critical role in chlorpyriphos persistence. Microbial biomass carbon and soil enzymatic activities specifically, dehydrogenase, fluorescien diacetate hydrolase, urease, acid phosphatase, and alkaline phosphatase responded positively to elevated CO2 concentrations. Generally, the enzyme activities were highly correlated with each other. Irrespective of the level of CO2, short-term negative influence of chlorpyriphos was observed on soil enzymes till day 7 of spray. Knowledge obtained from this study highlights that the elevated CO2 may negatively influence persistence of pesticide but will have positive effects on soil enzyme activities.

Biosensing strategies based on enzymatic reactions and nanoparticles.

Science.gov (United States)

Díez-Buitrago, Beatriz; Briz, Nerea; Liz-Marzán, Luis M; Pavlov, Valeri

2018-04-16

Enzymes are pivotal elements in bioanalysis due to their specificity and extremely high catalytic activity. The sensitivity of bioanalytical assays depends mainly on the capacity of an observer to detect the product(s) of a biocatalytic reaction. Both natural and artificial compounds have been traditionally used to evaluate enzymatic activities. The drawbacks of chromogenic and fluorogenic organic enzymatic substrates are their high cost and low stability, resulting in high background signals. We review here state of the art assays in the detection of enzymatic activities using recent advances in nanoscience. Novel methods based on the use of nanoparticles lead to increased sensitivity and decreased costs for bioanalysis based on enzymes as recognition elements and signal amplifiers in Enzyme-Linked Immunosorbent Assays (ELISA). Novel approaches toward the detection of enzymatic activities are based on biocatalytic synthesis, modulation, etching, and aggregation of nanoparticles under physiological conditions.

Enzymatic Inverse Opal Hydrogel Particles for Biocatalyst.

Science.gov (United States)

Wang, Huan; Gu, Hongcheng; Chen, Zhuoyue; Shang, Luoran; Zhao, Ze; Gu, Zhongze; Zhao, Yuanjin

2017-04-19

Enzymatic carriers have a demonstrated value for chemical reactions and industrial applications. Here, we present a novel kind of inverse opal hydrogel particles as the enzymatic carriers. The particles were negatively replicated from spherical colloidal crystal templates by using magnetic nanoparticles tagged acrylamide hydrogel. Thus, they were endowed with the features of monodispersity, small volume, complete penetrating structure, and controllable motion, which are all beneficial for improving the efficiency of biocatalysis. In addition, due to the ordered porous nanostructure, the inverse opal hydrogel particles were imparted with unique photonic band gaps (PBGs) and vivid structural colors for encoding varieties of immobilized enzymes and for constructing a multienzymes biocatalysis system. These features of the inverse opal hydrogel particles indicate that they are ideal enzymatic carriers for biocatalysis.

Enzymatic Processes in Marine Biotechnology.

Science.gov (United States)

Trincone, Antonio

2017-03-25

In previous review articles the attention of the biocatalytically oriented scientific community towards the marine environment as a source of biocatalysts focused on the habitat-related properties of marine enzymes. Updates have already appeared in the literature, including marine examples of oxidoreductases, hydrolases, transferases, isomerases, ligases, and lyases ready for food and pharmaceutical applications. Here a new approach for searching the literature and presenting a more refined analysis is adopted with respect to previous surveys, centering the attention on the enzymatic process rather than on a single novel activity. Fields of applications are easily individuated: (i) the biorefinery value-chain, where the provision of biomass is one of the most important aspects, with aquaculture as the prominent sector; (ii) the food industry, where the interest in the marine domain is similarly developed to deal with the enzymatic procedures adopted in food manipulation; (iii) the selective and easy extraction/modification of structurally complex marine molecules, where enzymatic treatments are a recognized tool to improve efficiency and selectivity; and (iv) marine biomarkers and derived applications (bioremediation) in pollution monitoring are also included in that these studies could be of high significance for the appreciation of marine bioprocesses.

Influence of enzymatic reactions on the electrochemical behavior of EN X2CrNiMo17-11-2 (AISI 316L) stainless steel in bio-corrosion: role of interfacial processes on the modification of the passive layer

International Nuclear Information System (INIS)

Landoulsi, J.

2008-01-01

The outstanding corrosion behavior of stainless steels (SS) results from the presence of thin oxide layer (some nanometers). In non sterile aqueous media, stainless steels may exhibit a non stable behavior resulting from interactions between microbial species and passive film. In fact, microorganisms can be deeply involved in the corrosion processes usually reported as Microbial Influenced Corrosion (MIC). They can induce the initiation or the acceleration of this phenomenon and they do so when organized in bio-films. From the electrochemical point of view, stainless steels showed an increase of the free corrosion potential (Ecorr) attributed to the bio-film settlement. The Eco' ennoblement was broadly reported in seawater and seems to be confirmed in fresh water according to recent findings. A considerable progress in the comprehension of MIC processes was related to the role of extracellular species, essentially enzymes. Many enzymatic reactions occurring in bio-films consist on using oxygen as electron acceptor to generate hydrogen peroxide and related species. The aim of this work is to understand the mechanisms involved in the electrochemical behavior of stainless steel according to an enzymatic approach in medium simulating fresh water. To this end, glucose oxidase was chosen to globalize aerobic activities of bio-films. Electrochemical measurements in situ and surface analysis allow the comprehension of the role and the nature of interfacial processes. Surface characterization was performed with the help of a new quantitative utilization of XPS analysis and AFM. Results show a significant evolution in term of morphology (surface organization), (ii) chemical composition (passive layer, adsorbed organic species) and (iii) chemical reaction (oxidation, dissolution, effect of enzyme). Finally, a new enzymatic system is proposed to mimic specific physicochemical conditions at the SS / bio-film interface, in particular enzymatic generation of oxidant species in

Synthesis, Characterization and Thermal Decomposition Studies of Cr(III, Mn(II and Fe(III Complexes of N, N '-Bis[1,3-benzodioxol-5-ylmethylene]butane-1,4-diamine

Directory of Open Access Journals (Sweden)

Prasad M. Alex

2009-01-01

Full Text Available A bidentate Schiff base ligand namely, N,N'-bis-1,3-benzodioxol-5-ylmethylene]butane-1,4-diamine was synthesised by condensing piperonal (3,4-dioxymethylenebenzaldehyde with butane-1,4-diamine. Cr(III, Mn(II, Fe(III complexes of this chelating ligand were synthesised using acetates, chlorides, bromides, nitrates and perchlorates of these metals. The ligand and the complexes were characterised by elemental analysis, 1H NMR, UV-Vis and IR spectra, conductance and magnetic susceptibility measurements and thermogravimetric analysis. The thermograms of three complexes were analysed and the kinetic parameters for the different stages of decompositions were determined.

Enzymatic Synthesis of Psilocybin.

Science.gov (United States)

Fricke, Janis; Blei, Felix; Hoffmeister, Dirk

2017-09-25

Psilocybin is the psychotropic tryptamine-derived natural product of Psilocybe carpophores, the so-called "magic mushrooms". Although its structure has been known for 60 years, the enzymatic basis of its biosynthesis has remained obscure. We characterized four psilocybin biosynthesis enzymes, namely i) PsiD, which represents a new class of fungal l-tryptophan decarboxylases, ii) PsiK, which catalyzes the phosphotransfer step, iii) the methyltransferase PsiM, catalyzing iterative N-methyl transfer as the terminal biosynthetic step, and iv) PsiH, a monooxygenase. In a combined PsiD/PsiK/PsiM reaction, psilocybin was synthesized enzymatically in a step-economic route from 4-hydroxy-l-tryptophan. Given the renewed pharmaceutical interest in psilocybin, our results may lay the foundation for its biotechnological production. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Operation and Control of Enzymatic Biodiesel Production

DEFF Research Database (Denmark)

Price, Jason Anthony; Huusom, Jakob Kjøbsted; Nordblad, Mathias

This work explores the control of biodiesel production via an enzymatic catalyst. The process involves the transesterification of oils/fats with an alcohol (usually methanol or ethanol), using enzymatic catalysts to generate mono-alkyl esters (the basis of biodiesel) and glycerol as by......-product. Current literature indicates that enzymatic processing of oils and fats to produce biodiesel is technically feasible and developments in immobilization technology indicate that enzyme catalysts can become cost effective compared to chemical processing. However, with very few exceptions, enzyme technology...... is not currently used in commercial-scale biodiesel production. This is mainly due to non-optimized process designs, which do not use the full potential of the catalysts in a cost-efficient way. Furthermore is it unclear what process variables need to be monitored and controlled to ensure optimal economics...

Biological pretreatment of corn stover with ligninolytic enzyme for high efficient enzymatic hydrolysis.

Science.gov (United States)

Wang, Feng-Qin; Xie, Hui; Chen, Wei; Wang, En-Tao; Du, Feng-Guang; Song, An-Dong

2013-09-01

Aiming at increasing the efficiency of transferring corn stover into sugars, a biological pretreatment was developed and investigated in this study. The protocol was characterized by the pretreatment with crude ligninolytic enzymes from Phanerochete chrysosporium and Coridus versicolor to break the lignin structure in corn stover, followed by a washing procedure to eliminate the inhibition of ligninolytic enzyme on cellulase. By a 2 d-pretreatment, sugar yield from corn stover hydrolysis could be increased by 50.2% (up to 323 mg/g) compared with that of the control. X-ray diffractometry and FT-IR analysis revealed that biological pretreatment could partially remove the lignin of corn stover, and consequently enhance the enzymatic hydrolysis efficiency of cellulose and hemeicellulose. In addition, the amount of microbial inhibitors, such as acetic acid and furfural, were much lower in biological pretreatment than that in acid pretreatment. This study provided a promising pretreatment method for biotransformation of corn stovers. Copyright © 2013 Elsevier Ltd. All rights reserved.

Potential for microbial oxidation of ferrous iron in basaltic glass.

Science.gov (United States)

Xiong, Mai Yia; Shelobolina, Evgenya S; Roden, Eric E

2015-05-01

Basaltic glass (BG) is an amorphous ferrous iron [Fe(II)]-containing material present in basaltic rocks, which are abundant on rocky planets such as Earth and Mars. Previous research has suggested that Fe(II) in BG can serve as an energy source for chemolithotrophic microbial metabolism, which has important ramifications for potential past and present microbial life on Mars. However, to date there has been no direct demonstration of microbially catalyzed oxidation of Fe(II) in BG. In this study, three different culture systems were used to investigate the potential for microbial oxidation of Fe(II) in BG, including (1) the chemolithoautotrophic Fe(II)-oxidizing, nitrate-reducing "Straub culture"; (2) the mixotrophic Fe(II)-oxidizing, nitrate-reducing organism Desulfitobacterium frappieri strain G2; and (3) indigenous microorganisms from a streambed Fe seep in Wisconsin. The BG employed consisted of clay and silt-sized particles of freshly quenched lava from the TEB flow in Kilauea, Hawaii. Soluble Fe(II) or chemically reduced NAu-2 smectite (RS) were employed as positive controls to verify Fe(II) oxidation activity in the culture systems. All three systems demonstrated oxidation of soluble Fe(II) and/or structural Fe(II) in RS, whereas no oxidation of Fe(II) in BG material was observed. The inability of the Straub culture to oxidize Fe(II) in BG was particularly surprising, as this culture can oxidize other insoluble Fe(II)-bearing minerals such as biotite, magnetite, and siderite. Although the reason for the resistance of the BG toward enzymatic oxidation remains unknown, it seems possible that the absence of distinct crystal faces or edge sites in the amorphous glass renders the material resistant to such attack. These findings have implications with regard to the idea that Fe(II)-Si-rich phases in basalt rocks could provide a basis for chemolithotrophic microbial life on Mars, specifically in neutral-pH environments where acid-promoted mineral dissolution and

High activity and low temperature optima of extracellular enzymes in Arctic sediments: implications for carbon cycling by heterotrophic microbial communities

DEFF Research Database (Denmark)

Arnosti, C.; Jørgensen, BB

2003-01-01

(chondroitin sulfate, fucoidan, xylan and pullulan) to determine the temperature-activity responses of hydrolysis of a related class of compounds. All 4 enzyme activities showed similarly low temperature optima in the range of 15 to 18degreesC. These temperature optima are considerably lower than most previous......The rate of the initial step in microbial remineralization of organic carbon, extracellular enzymatic hydrolysis, was investigated as a function of temperature in permanently cold sediments from 2 fjords on the west coast of Svalbard (Arctic Ocean). We used 4 structurally distinct polysaccharides...... reports of temperature optima for enzyme activities in marine sediments. At 0degreesC, close to the in situ temperature, these enzyme activities achieved 13 to 38% of their rates at optimum temperatures. In one experiment, sulfate reduction rates were measured in parallel with extracellular enzymatic...

Increased microbial functional diversity under long-term organic and integrated fertilization in a paddy soil.

Science.gov (United States)

Ding, Long-Jun; Su, Jian-Qiang; Sun, Guo-Xin; Wu, Jin-Shui; Wei, Wen-Xue

2018-02-01

Microbes play key roles in diverse biogeochemical processes including nutrient cycling. However, responses of soil microbial community and functional genes to long-term integrated fertilization (chemical combined with organic fertilization) remain unclear. Here, we used pyrosequencing and a microarray-based GeoChip to explore the shifts of microbial community and functional genes in a paddy soil which received over 21-year fertilization with various regimes, including control (no fertilizer), rice straw (R), rice straw plus chemical fertilizer nitrogen (NR), N and phosphorus (NPR), NP and potassium (NPKR), and reduced rice straw plus reduced NPK (L-NPKR). Significant shifts of the overall soil bacterial composition only occurred in the NPKR and L-NPKR treatments, with enrichment of certain groups including Bradyrhizobiaceae and Rhodospirillaceae families that benefit higher productivity. All fertilization treatments significantly altered the soil microbial functional structure with increased diversity and abundances of genes for carbon and nitrogen cycling, in which NPKR and L-NPKR exhibited the strongest effect, while R exhibited the least. Functional gene structure and abundance were significantly correlated with corresponding soil enzymatic activities and rice yield, respectively, suggesting that the structural shift of the microbial functional community under fertilization might promote soil nutrient turnover and thereby affect yield. Overall, this study indicates that the combined application of rice straw and balanced chemical fertilizers was more pronounced in shifting the bacterial composition and improving the functional diversity toward higher productivity, providing a microbial point of view on applying a cost-effective integrated fertilization regime with rice straw plus reduced chemical fertilizers for sustainable nutrient management.

Unraveling the enzymatic basis of wine flavorome: a phylo-functional study of wine related yeast species

Directory of Open Access Journals (Sweden)

Ignacio eBelda

2016-01-01

Full Text Available Non-Saccharomyces yeasts are a heterogeneous microbial group involved in the early stages of wine fermentation. The high enzymatic potential of these yeasts makes them a useful tool for increasing the final organoleptic characteristics of wines in spite of their low fermentative power. Their physiology and contribution to wine quality are still poorly understood, with most current knowledge being acquired empirically and in most cases based in single species and strains. This work analyzed the metabolic potential of 770 yeast isolates from different enological origins and representing 15 different species, by studying their production of enzymes of enological interest and linking phylogenetic and enzymatic data. The isolates were screened for glycosidase enzymes related to terpene aroma release, the β-lyase activity responsible for the release of volatile thiols, and sulfite reductase. Apart from these aroma-related activities, protease, polygalacturonase and cellulase activities were also studied in the entire yeast collection, being related to the improvement of different technological and sensorial features of wines. In this context, and in terms of abundance, two different groups were established, with α-L-arabinofuranosidase, polygalacturonase and cellulase being the less abundant activities. By contrast, β-glucosidase and protease activities were widespread in the yeast collection studied.A classical phylogenetic study involving the partial sequencing of 26S rDNA was conducted in conjunction with the enzymatic profiles of the 770 yeast isolates for further typing, complementing the phylogenetic relationships established by using 26S rDNA. This has rendered it possible to foresee the contribution different yeast species make to wine quality and their potential applicability as pure inocula, establishing species-specific behavior. These consistent results allowed us to design future targeted studies on the impact different non

Glucose obtained from rice bran by ultrasound-assisted enzymatic hydrolysis

Directory of Open Access Journals (Sweden)

Raquel Cristine Kuhn

2015-05-01

Full Text Available In this work ultrasound-assisted solid-state enzymatic hydrolysis of rice bran to obtain fermentable sugars was investigated. For this purpose, process variables such as temperature, enzyme concentration and moisture content were evaluated during the enzymatic hydrolysis with and without ultrasound irradiation. The enzyme used is a blend of amylases derived from genetically modified strains of Trichoderma reesei. Kinetic of the enzymatic hydrolysis of rice bran at the constant-reaction rate period were measured. The best results for the ultrasound-assisted enzymatic hydrolysis was obtained using 3 wt% of enzyme, 60 oC and moisture content of 65 wt%, yielding 0.38 g sugar/g rice bran, whereas for the hydrolysis in the absence of ultrasound the highest yield was 0.20 g sugar/g rice bran using 3 wt% of enzyme, 60 oC and moisture content of 50 wt%. The use of ultrasound-assisted enzymatic hydrolysis of rice bran was intensified, obtaining around 74% more fermentable sugar than in the absence, showing that the use of ultrasound is a promising technology to be used in enzymatic reaction as an alternative of process intensification.

Enzymatic hydrolysis of plant extracts containing inulin

Energy Technology Data Exchange (ETDEWEB)

Guiraud, J.P.; Galzy, P.

1981-10-01

Inulin-rich extracts of chicory and Jerusalem artichoke are a good potential source of fructose. Total enzymatic hydrolysis of these extracts can be effected by yeast inulinases (EC 3.2.1.7). Chemical prehydrolysis is unfavourable. Enzymatic hydrolysis has advantages over chemical hydrolysis: it does not produce a dark-coloured fraction or secondary substances. It is possible to envisage the preparation of high fructose syrups using this process. (Refs. 42).

Effect of Microwave Treatment on Microbial Contamination of Honeys and on Their Physicochemical and Thermal Properties

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Paz Moliné María de la

2015-06-01

Full Text Available In recent years, microwave heating has become a common method for pasteurization and sterilization of food. Honey is a sweet substance produced by worker honeybees from nectar of flowers. The major microbial contaminants include moulds and yeasts, as well as the spore-forming bacteria, being their counts indicative of honeys’ commercial quality and safety. Paenibacillus larvae is also of interest since it causes American foulbrood (AFB in honeybee larvae. The main quality factors that are used in the honey international trade are moisture, hydroxymethylfurfural content (HMF, and enzymatic indices. Moreover, honey exhibits several thermal events, the most important being the glass transition temperature (Tg. The aim of this work was to evaluate microwave effect (800 watts during 45 and 90 seconds on microbial content in particular over P. larvae spores retained in honey, and on physicochemical and thermal properties. Microwave promoted a decrease of microbial count with time of exposure, including P. larvae. Moisture content diminished after treatment, while Tg increased linearly, and acidity decremented in the majority of cases. Honeys darkened and HMF exceeded the permissible value. Diastase and glucose-oxidase enzymes were totally inactivated by microwave treatment.

Tracking dynamics of plant biomass composting by changes in substrate structure, microbial community, and enzyme activity

Science.gov (United States)

2012-01-01

Background Understanding the dynamics of the microbial communities that, along with their secreted enzymes, are involved in the natural process of biomass composting may hold the key to breaking the major bottleneck in biomass-to-biofuels conversion technology, which is the still-costly deconstruction of polymeric biomass carbohydrates to fermentable sugars. However, the complexity of both the structure of plant biomass and its counterpart microbial degradation communities makes it difficult to investigate the composting process. Results In this study, a composter was set up with a mix of yellow poplar (Liriodendron tulipifera) wood-chips and mown lawn grass clippings (85:15 in dry-weight) and used as a model system. The microbial rDNA abundance data obtained from analyzing weekly-withdrawn composted samples suggested population-shifts from bacteria-dominated to fungus-dominated communities. Further analyses by an array of optical microscopic, transcriptional and enzyme-activity techniques yielded correlated results, suggesting that such population shifts occurred along with early removal of hemicellulose followed by attack on the consequently uncovered cellulose as the composting progressed. Conclusion The observed shifts in dominance by representative microbial groups, along with the observed different patterns in the gene expression and enzymatic activities between cellulases, hemicellulases, and ligninases during the composting process, provide new perspectives for biomass-derived biotechnology such as consolidated bioprocessing (CBP) and solid-state fermentation for the production of cellulolytic enzymes and biofuels. PMID:22490508

Functional patterns of microbial communities of rhizospheric soils across the development stages of a young mangrove in French Guiana.

Science.gov (United States)

Luglia, Mathieu; Criquet, Stéven; Sarrazin, Max; Ziarelli, Fabio; Guiral, Daniel

2014-02-01

The functional patterns of microbial communities (microbial respiration, enzyme activities, functional diversity) and the relevant physico-chemical characteristics of rhizospheric soils were studied during the process of mudflat colonization by mangrove. The study site is a fringe mangrove stand located in Montabo Bay at Cayenne (French Guiana). It is characterized by different vegetation development stages dominated by an assemblage of Avicennia germinans and Laguncularia racemosa. Rhizospheric and surface soils were collected from three stations based on successional stages of mangrove colonization: pioneer (P), coppice (C), and young forest (F). The microbial functional patterns showed significant progressive shifts along the mangrove vegetation profile. The P stages, those most influenced by tide currents, were macroscopically characterized by hydro-sedimentary instability and micro-phytobenthic colonization of mudflat. This stage, characterized by low total organic carbon (TOC) content and quality, showed the lowest extracellular enzymatic activities and the highest functional metabolic diversities. TOC quality analyses by (13)C CPMAS NMR provided evidence of progressive TOC enrichment and an increasing imprint of aboveground vegetation on C quality as succession occurs. These differences in the origin, amount, and quality of soil organic matter (SOM) of older stages exerted both a quantitative and qualitative control over microbial functional responses. This indicated the enhancement of aboveground-belowground functional linkages, leading to the expression of high decomposition activities and a functional loss and specialization of rhizospheric microbial communities.

Increased resiliency and activity of microbial mediated carbon cycling enzymes in diversified bioenergy cropping systems

Science.gov (United States)

Upton, R.; Bach, E.; Hofmockel, K. S.

2017-12-01

Microbes are mediators of soil carbon (C) and are influenced in membership and activity by nitrogen (N) fertilization and inter-annual abiotic factors. Microbial communities and their extracellular enzyme activities (EEA) are important parameters that influence ecosystem C cycling properties and are often included in microbial explicit C cycling models. In an effort to generate model relevant, empirical findings, we investigated how both microbial community structure and C degrading enzyme activity are influenced by inter-annual variability and N inputs in bioenergy crops. Our study was performed at the Comparison of Biofuel Systems field-site from 2011 to 2014, in three bioenergy cropping systems, continuous corn (CC) and two restored prairies, both fertilized (FP) and unfertilized (P). We hypothesized microbial community structure would diverge during the prairie restoration, leading to changes in C cycling enzymes over time. Using a sequencing approach (16S and ITS) we determined the bacterial and fungal community structure response to the cropping system, fertilization, and inter-annual variability. Additionally, we used EEA of β-glucosidase, cellobiohydrolase, and β-xylosidase to determine inter-annual and ecosystem impacts on microbial activity. Our results show cropping system was a main effect for microbial community structure, with corn diverging from both prairies to be less diverse. Inter-annual changes showed that a drought occurring in 2012 significantly impacted microbial community structure in both the P and CC, decreasing microbial richness. However, FP increased in microbial richness, suggesting the application of N increased resiliency to drought. Similarly, the only year in which C cycling enzymes were impacted by ecosystem was 2012, with FP supporting higher potential enzymatic activity then CC and P. The highest EEA across all ecosystems occurred in 2014, suggesting the continued root biomass and litter build-up in this no till system

The Oxidative Metabolism of Fossil Hydrocarbons and Sulfide Minerals by the Lithobiontic Microbial Community Inhabiting Deep Subterrestrial Kupferschiefer Black Shale

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Agnieszka Włodarczyk

2018-05-01

Full Text Available Black shales are one of the largest reservoirs of fossil organic carbon and inorganic reduced sulfur on Earth. It is assumed that microorganisms play an important role in the transformations of these sedimentary rocks and contribute to the return of organic carbon and inorganic sulfur to the global geochemical cycles. An outcrop of deep subterrestrial ~256-million-year-old Kupferschiefer black shale was studied to define the metabolic processes of the deep biosphere important in transformations of organic carbon and inorganic reduced sulfur compounds. This outcrop was created during mining activity 12 years ago and since then it has been exposed to the activity of oxygen and microorganisms. The microbial processes were described based on metagenome and metaproteome studies as well as on the geochemistry of the rock. The microorganisms inhabiting the subterrestrial black shale were dominated by bacterial genera such as Pseudomonas, Limnobacter, Yonghaparkia, Thiobacillus, Bradyrhizobium, and Sulfuricaulis. This study on black shale was the first to detect archaea and fungi, represented by Nitrososphaera and Aspergillus genera, respectively. The enzymatic oxidation of fossil aliphatic and aromatic hydrocarbons was mediated mostly by chemoorganotrophic bacteria, but also by archaea and fungi. The dissimilative enzymatic oxidation of primary reduced sulfur compounds was performed by chemolithotrophic bacteria. The geochemical consequences of microbial activity were the oxidation and dehydrogenation of kerogen, as well as oxidation of sulfide minerals.

Kinetics of enzymatic hydrolysis of methyl ricinoleate

OpenAIRE

Neeharika, T. S.V.R.; Lokesh, P.; Prasanna Rani, K. N.; Prathap Kumar, T.; Prasad, R. B.N.

2015-01-01

Ricinoleic acid is an unsaturated hydroxy fatty acid that naturally occurs in castor oil in proportions of up to 85–90%. Ricinoleic acid is a potential raw material and finds several applications in coatings, lubricant formulations and pharmaceutical areas. Enzymatic hydrolysis of castor oil is preferred over conventional hydrolysis for the preparation of ricinoleic acid to avoid estolide formation. A kinetics analysis of the enzymatic hydrolysis of Methyl Ricinoleate in the presence of Candi...

Effects of microbial enzymes on starch and hemicellulose degradation in total mixed ration silages

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Tingting Ning

2017-02-01

Full Text Available Objective This study investigated the association of enzyme-producing microbes and their enzymes with starch and hemicellulose degradation during fermentation of total mixed ration (TMR silage. Methods The TMRs were prepared with soybean curd residue, alfalfa hay (ATMR or Leymus chinensis hay (LTMR, corn meal, soybean meal, vitamin-mineral supplements, and salt at a ratio of 25:40:30:4:0.5:0.5 on a dry matter basis. Laboratory-scale bag silos were randomly opened after 1, 3, 7, 14, 28, and 56 days of ensiling and subjected to analyses of fermentation quality, carbohydrates loss, microbial amylase and hemicellulase activities, succession of dominant amylolytic or hemicellulolytic microbes, and their microbial and enzymatic properties. Results Both ATMR and LTMR silages were well preserved, with low pH and high lactic acid concentrations. In addition to the substantial loss of water soluble carbohydrates, loss of starch and hemicellulose was also observed in both TMR silages with prolonged ensiling. The microbial amylase activity remained detectable throughout the ensiling in both TMR silages, whereas the microbial hemicellulase activity progressively decreased until it was inactive at day 14 post-ensiling in both TMR silages. During the early stage of fermentation, the main amylase-producing microbes were Bacillus amyloliquefaciens (B. amyloliquefaciens, B. cereus, B. licheniformis, and B. subtilis in ATMR silage and B. flexus, B. licheniformis, and Paenibacillus xylanexedens (P. xylanexedens in LTMR silage, whereas Enterococcus faecium was closely associated with starch hydrolysis at the later stage of fermentation in both TMR silages. B. amyloliquefaciens, B. licheniformis, and B. subtilis and B. licheniformis, B. pumilus, and P. xylanexedens were the main source of microbial hemicellulase during the early stage of fermentation in ATMR and LTMR silages, respectively. Conclusion The microbial amylase contributes to starch hydrolysis during the

Enzymatic synthesis of vanillin

NARCIS (Netherlands)

van den Heuvel, RHH; Fraaije, MW; Laane, C; van Berkel, WJH; Heuvel, Robert H.H. van den; Berkel, Willem J.H. van

Due to increasing interest in natural vanillin, two enzymatic routes for the synthesis of vanillin were developed. The flavoprotein vanillyl alcohol oxidase (VAO) acts on a wide range of phenolic compounds and converts both creosol and vanillylamine to vanillin with high yield. The VAO-mediated

Enzymatic synthesis of vanillin

NARCIS (Netherlands)

Heuvel, van den R.H.H.; Fraaije, M.W.; Laane, C.; Berkel, van W.J.H.

2001-01-01

Due to increasing interest in natural vanillin, two enzymatic routes for the synthesis of vanillin were developed. The flavoprotein vanillyl alcohol oxidase (VAO) acts on a wide range of phenolic compounds and converts both creosol and vanillylamine to vanillin with high yield. The VAO-mediated

Development of optimal enzymatic and microbial conversion systems for biofuel production

Science.gov (United States)

Aramrueang, Natthiporn

The increase in demand for fuels, along with the concerns over the depletion of fossil fuels and the environmental problems associated with the use of the petroleum-based fuels, has driven the exploitation of clean and renewable energy. Through a collaboration project with Mendota Bioenergy LLC to produce advanced biofuel from sugar beet and other locally grown crops in the Central Valley of California through demonstration and commercial-scale biorefineries, the present study focused on the investigation of selected potential biomass as biofuel feedstock and development of bioconversion systems for sustainable biofuel production. For an efficient biomass-to-biofuel conversion process, three important steps, which are central to this research, must be considered: feedstock characterization, enzymatic hydrolysis of the feedstock, and the bioconversion process. The first part of the research focused on the characterization of various lignocellulosic biomass as feedstocks and investigated their potential ethanol yields. Physical characteristics and chemical composition were analyzed for four sugar beet varieties, three melon varieties, tomato, Jose tall wheatgrass, wheat hay, and wheat straw. Melons and tomato are those products discarded by the growers or processors due to poor quality. The mass-based ethanol potential of each feedstock was determined based on the composition. The high sugar-containing feedstocks are sugar beet roots, melons, and tomato, containing 72%, 63%, and 42% average soluble sugars on a dry basis, respectively. Thus, for these crops, the soluble sugars are the main substrate for ethanol production. The potential ethanol yields, on average, for sugar beet roots, melons, and tomato are 591, 526, and 448 L ethanol/metric ton dry basis (d.b.), respectively. Lignocellulosic biomass, including Jose Tall wheatgrass and wheat straw, are composed primarily of cellulose (27-39% d.b.) and hemicellulose (26-30% d.b.). The ethanol yields from these

First Evidence of an Important Organic Matter Trophic Pathway between Temperate Corals and Pelagic Microbial Communities.

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J A Fonvielle

Full Text Available Mucus, i.e., particulate and dissolved organic matter (POM, DOM released by corals, acts as an important energy carrier in tropical ecosystems, but little is known on its ecological role in temperate environments. This study assessed POM and DOM production by the temperate coral Cladocora caespitosa under different environmental conditions. The subsequent enzymatic degradation, growth of prokaryotes and virus-like particles (VLPs as well as changes in the structure of the prokaryotic communities were also monitored. C. caespitosa produced an important quantity of mucus, which varied according to the environmental conditions (from 37.8 to 67.75 nmol carbon h-1 cm-2, but remained higher or comparable to productions observed in tropical corals. It has an important nutritional value, as highlighted by the high content in dissolved nitrogen (50% to 90% of the organic matter released. Organic matter was rapidly degraded by prokaryotes' enzymatic activities, and due to its nitrogen content, aminopeptidase activity was 500 fold higher than the α-glucosidase activity. Prokaryotes, as well as VLPs, presented a rapid growth in the mucus, with prokaryote production rates as high as 0.31 μg h-1 L-1. Changes in bacterial and archaeal communities were observed in the ageing mucus and between mucus and the water column, suggesting a clear impact of mucus on microorganism diversity. Overall, our results show that the organic matter released by temperate corals, such as C. caespitosa, which can form reef structures in the Mediterranean Sea, stimulates microbial activity and thereby functions as a significant carbon and nitrogen supplier to the microbial loop.

Enzymatic network for production of ether amines from alcohols

NARCIS (Netherlands)

Palacio, Cyntia M.; Crismaru, Gica Ciprian; Bartsch, Sebastian; Navickas, Vaidotas; Ditrich, Klaus; Breuer, Michael; Abu, Rohana; Woodley, John; Baldenius, Kai-Uwe; Wu, Bian; Janssen, Dick

We constructed an enzymatic network composed of three different enzymes for the synthesis of valuable ether amines. The enzymatic reactions are interconnected to catalyze the oxidation and subsequent transamination of the substrate and to provide cofactor recycling. This allows production of the

A multi-parametric approach assessing microbial viability and organic matter characteristics during managed aquifer recharge.

Science.gov (United States)

Kim, Hyun-Chul; Noh, Jin Hyung; Chae, So-Ryong; Choi, Jaewon; Lee, Yunho; Maeng, Sung Kyu

2015-08-15

Soil column (SC) experiments were conducted to investigate the feasibility of using silver nanoparticles (AgNPs) as microbial inhibitors; the microbial viability affecting the degradation of pharmaceutically active compounds (PhACs) and the characteristics of organic matter during managed aquifer recharge were specifically evaluated. Natural surface water samples treated with AgNPs (0, 2.5, 5, and 10 mg L(-1)) were continually fed into the soil columns for 2 years. The adverse impact of AgNPs on the cell membrane integrity and microbial enzymatic activity was quantitatively determined using flow cytometry and adenosine triphosphate analysis. The increase in AgNP concentration in the feed water (up to 10 mg L(-1)) resulted in a corresponding deterioration in the performance of the managed aquifer recharge (MAR), with respect to the removal of organic carbon, oxidation of nitrogenous compounds, and PhAC attenuation. The fluorescence excitation-emission matrices of feed water and treated water showed the favorable removal of protein-like substances compared to humic-like substances regardless of the AgNP concentrations; however, the extent of removed fractions decreased noticeably when the microbial viability was lowered via AgNP treatment. The biological oxidation of organic nitrogen was almost completely inhibited when 10 mg L(-1) AgNP was added during soil passage. The attenuation of bezafibrate, ketoprofen, diclofenac, clofibric acid, and gemfibrozil was strongly associated with the significant deterioration in biodegradation as a result of AgNP activity. Copyright © 2015 Elsevier B.V. All rights reserved.

Conditions for the formation of pure birnessite during the oxidation of Mn(II) cations in aqueous alkaline medium

Energy Technology Data Exchange (ETDEWEB)

Boumaiza, Hella [Laboratoire de Chimie des Matériaux et Catalyse, Faculté des Sciences de Tunis, Université El Manar (Tunisia); Laboratoire de Chimie Physique et Microbiologie pour l' Environnement (LCPME)-UMR 7564, CNRS-Université de Lorraine, 405, rue de Vandoeuvre, 54600 Villers-lès-Nancy (France); Département de Génie Biologique et Chimique, Institut National des Sciences Appliquées et de Technologies (INSAT), Université de Carthage, Tunis (Tunisia); Coustel, Romain [Laboratoire de Chimie Physique et Microbiologie pour l' Environnement (LCPME)-UMR 7564, CNRS-Université de Lorraine, 405, rue de Vandoeuvre, 54600 Villers-lès-Nancy (France); Medjahdi, Ghouti [Institut Jean Lamour, Centre de Compétences Rayons X et Spectroscopie (X-Gamma), UMR 7198 CNRS-Université de Lorraine (France); Ruby, Christian, E-mail: Christian.ruby@univ-lorraine.fr [Laboratoire de Chimie Physique et Microbiologie pour l' Environnement (LCPME)-UMR 7564, CNRS-Université de Lorraine, 405, rue de Vandoeuvre, 54600 Villers-lès-Nancy (France); and others

2017-04-15

Birnessite was synthetized through redox reaction by mixing MnO{sub 4}{sup -}, Mn{sup 2+} and OH{sup -} solutions. The Mn(VII): Mn(II) ratio of 0.33 was chosen and three methods were used consisting in a quick mixing under vigorous stirring of two of the three reagents and then on the dropwise addition of the third one. The obtained solids were characterized by XRD, FTIR and XPS spectroscopies. Their average oxidation states were determined from ICP and CEC measurements while their surface properties were investigated by XPS. This study provides an increased understanding of the importance of dissolved oxygen in the formation of birnessite and hausmannite and shows the ways to obtain pure birnessite. The role of counter-ion ie. Na{sup +} or K{sup +} was also examined. - Graphical abstract: Pathways of birnessite formation. - Highlights: • Pure birnessite is prepared through a redox reaction. • Hausmannite formation is prevented by controlling dissolved O2. • The employed counterion influences the purity of birnessite. • Initial Mn(OH){sub 2} is oxidized by both MnO{sub 4}{sup -} and dissolved O{sub 2}.

Anaerobic Microbial Degradation of Hydrocarbons: From Enzymatic Reactions to the Environment.

Science.gov (United States)

Rabus, Ralf; Boll, Matthias; Heider, Johann; Meckenstock, Rainer U; Buckel, Wolfgang; Einsle, Oliver; Ermler, Ulrich; Golding, Bernard T; Gunsalus, Robert P; Kroneck, Peter M H; Krüger, Martin; Lueders, Tillmann; Martins, Berta M; Musat, Florin; Richnow, Hans H; Schink, Bernhard; Seifert, Jana; Szaleniec, Maciej; Treude, Tina; Ullmann, G Matthias; Vogt, Carsten; von Bergen, Martin; Wilkes, Heinz

2016-01-01

Hydrocarbons are abundant in anoxic environments and pose biochemical challenges to their anaerobic degradation by microorganisms. Within the framework of the Priority Program 1319, investigations funded by the Deutsche Forschungsgemeinschaft on the anaerobic microbial degradation of hydrocarbons ranged from isolation and enrichment of hitherto unknown hydrocarbon-degrading anaerobic microorganisms, discovery of novel reactions, detailed studies of enzyme mechanisms and structures to process-oriented in situ studies. Selected highlights from this program are collected in this synopsis, with more detailed information provided by theme-focused reviews of the special topic issue on 'Anaerobic biodegradation of hydrocarbons' [this issue, pp. 1-244]. The interdisciplinary character of the program, involving microbiologists, biochemists, organic chemists and environmental scientists, is best exemplified by the studies on alkyl-/arylalkylsuccinate synthases. Here, research topics ranged from in-depth mechanistic studies of archetypical toluene-activating benzylsuccinate synthase, substrate-specific phylogenetic clustering of alkyl-/arylalkylsuccinate synthases (toluene plus xylenes, p-cymene, p-cresol, 2-methylnaphthalene, n-alkanes), stereochemical and co-metabolic insights into n-alkane-activating (methylalkyl)succinate synthases to the discovery of bacterial groups previously unknown to possess alkyl-/arylalkylsuccinate synthases by means of functional gene markers and in situ field studies enabled by state-of-the-art stable isotope probing and fractionation approaches. Other topics are Mo-cofactor-dependent dehydrogenases performing O2-independent hydroxylation of hydrocarbons and alkyl side chains (ethylbenzene, p-cymene, cholesterol, n-hexadecane), degradation of p-alkylated benzoates and toluenes, glycyl radical-bearing 4-hydroxyphenylacetate decarboxylase, novel types of carboxylation reactions (for acetophenone, acetone, and potentially also benzene and

Impact of enzymatic hydrolyzed lactose on fermentation and growth of probiotic bacteria in whey

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Katarina Lisak

2011-06-01

Full Text Available Taking in consideration the long time for whey fermentation using probiotic bacteria, the aim of this research was to determine if prior enzymatic hydrolysis of lactose influences microbial activities of Lactobacillus acidophilus La-5 or Bifidobacterium animalis subsp. lactis BB-12 in reconstituted sweet whey. During fermentation (at 37 °C, pH-value and viable cell counts were monitored. The fermented samples were sensory profiled. Lactose hydrolysis shortened the fermentation time of Lactobacillus acidophilus La-5 by 2 h, and viable cell count at the end of fermentation time was greater in hydrolyzed whey sample (~9.45 log10 CFU/mL when compared with the control sample (~8.91 log10 CFU/mL. In contrast, lactose hydrolysis in whey did not enhance the activity of Bifidobacterium animalis subsp. lactis BB-12. Lactose hydrolysis had slightly influence on sensory score of fermented samples, probably due to sweetness that masked the acidic taste of the product.

Enzymatic activity of proteases and its isoenzymes in fermentation process in cultivars of cocoa (Theobroma cacao L. produced in southern Bahia, Brazil

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Luciane Santos SOUSA

Full Text Available Abstract The fermentation of cocoa seeds envolves microbial processes and the action of enzymes. To identify the possible differences in the cocoa fermentation process, with regards to proteolysis, this study has the objective of determining protease activity (under predetermined conditions and its isoenzymes in two cocoa cultivars (PH-16 and HRT-1188 in different cocoa fermentation times, in addition to establishing the microbial load (molds and yeasts and aerobic mesophilic. Protease and its isoenzymes were extracted and partially purified and the enzymatic activities determined by spectrophotometry. The results showed that the proteases activity was higher at 66h of fermentation for both cultivars. When the isoenzymes activity was evaluated, the results demonstrated similar activity behavior for both cultivars, with regards to the isoenzymes aminopeptidase and carboxypeptidase, although the behavior of the endoprotease isoenzyme activity proved to be a little different for TSH-1188 cultivar. Concerning microbiological analyses, the results indicate that the period after molds and yeast counting reduction is consistent with the period of protease activity increase.

Manganese acquisition by Lactobacillus plantarum

Energy Technology Data Exchange (ETDEWEB)

Archibald, F.S.; Duong, M.N.

1984-04-01

Lactobacillus plantarum has an unusually high Mn(II) requirement for growth and accumulated over 30 mM intracellular Mn(II). The acquisition of Mn(II) by L. plantarum occurred via a specific active transport system powered by the transmembrane proton gradient. The Mn(II) uptake system has a K/sub m/ of 0.2 ..mu..M and a V/sub max/ of 24 nmol mg/sup -1/ of protein min/sup -1/. Above a medium Mn(II) concentration of 200 ..mu..M, the intracellular Mn(II) level was independent of the medium Mn(II) and unresponsive to oxygen stresses but was reduced by phosphate limitation. At a pH of 5.5, citrate, isocitrate, and cis-aconitate effectively promoted MN(II) uptake, although measurable levels of 1,5-(/sup 14/C)citrate were not accumulated. When cells were presented with equimolar Mn(II) and Cd(II), Cd(II) was preferentially taken up by the Mn(II) transport system. Both Mn(II) and Cd(II) uptake were greatly increased by Mn(II) starvation. Mn(II) uptake by Mn(II)-starved cells was subject to a negative feedback regulatory mechanism functioning less than 1 min after exposure of the cells to Mn(II) and independent of protein synthesis. When presented with a relatively large amount of exogenous Mn(II), Mn(II)-starved cells exhibited a measurable efflux of their internal Mn(II), but the rate was only a small fraction of the maximal Mn(II) uptake rate.

Subtle shifts in microbial communities occur alongside the release of carbon induced by drought and rewetting in contrasting peatland ecosystems.

Science.gov (United States)

Potter, Caitlin; Freeman, Chris; Golyshin, Peter N; Ackermann, Gail; Fenner, Nathalie; McDonald, James E; Ehbair, Abdassalam; Jones, Timothy G; Murphy, Loretta M; Creer, Simon

2017-09-12

Peat represents a globally significant pool of sequestered carbon. However, peatland carbon stocks are highly threatened by anthropogenic climate change, including drought, which leads to a large release of carbon dioxide. Although the enzymatic mechanisms underlying drought-driven carbon release are well documented, the effect of drought on peatland microbial communities has been little studied. Here, we carried out a replicated and controlled drought manipulation using intact peat 'mesocosm cores' taken from bog and fen habitats, and used a combination of community fingerprinting and sequencing of marker genes to identify community changes associated with drought. Community composition varied with habitat and depth. Moreover, community differences between mesocosm cores were stronger than the effect of the drought treatment, emphasising the importance of replication in microbial marker gene studies. While the effect of drought on the overall composition of prokaryotic and eukaryotic communities was weak, a subset of the microbial community did change in relative abundance, especially in the fen habitat at 5 cm depth. 'Drought-responsive' OTUs were disproportionately drawn from the phyla Bacteroidetes and Proteobacteria. Collectively, the data provide insights into the microbial community changes occurring alongside drought-driven carbon release from peatlands, and suggest a number of novel avenues for future research.

Impact of enzymatic digestion on bacterial community composition in CF airway samples.

Science.gov (United States)

Williamson, Kayla M; Wagner, Brandie D; Robertson, Charles E; Johnson, Emily J; Zemanick, Edith T; Harris, J Kirk

2017-01-01

Previous studies have demonstrated the importance of DNA extraction methods for molecular detection of Staphylococcus, an important bacterial group in cystic fibrosis (CF). We sought to evaluate the effect of enzymatic digestion (EnzD) prior to DNA extraction on bacterial communities identified in sputum and oropharyngeal swab (OP) samples from patients with CF. DNA from 81 samples (39 sputum and 42 OP) collected from 63 patients with CF was extracted in duplicate with and without EnzD. Bacterial communities were determined by rRNA gene sequencing, and measures of alpha and beta diversity were calculated. Principal Coordinate Analysis (PCoA) was used to assess differences at the community level and Wilcoxon Signed Rank tests were used to compare relative abundance (RA) of individual genera for paired samples with and without EnzD. Shannon Diversity Index (alpha-diversity) decreased in sputum and OP samples with the use of EnzD. Larger shifts in community composition were observed for OP samples (beta-diversity, measured by Morisita-Horn), whereas less change in communities was observed for sputum samples. The use of EnzD with OP swabs resulted in significant increase in RA for the genera Gemella ( p  microbial community composition. We show that the application of EnzD to CF airway samples, particularly OP swabs, results in differences in microbial communities detected by sequencing. Use of EnzD can result in large changes in bacterial community composition, and is particularly useful for detection of Staphylococcus in CF OP samples. The enhanced identification of Staphylococcus aureus is a strong indication to utilize EnzD in studies that use OP swabs to monitor CF airway communities.

Tracking dynamics of plant biomass composting by changes in substrate structure, microbial community, and enzyme activity

Directory of Open Access Journals (Sweden)

Wei Hui

2012-04-01

Full Text Available Abstract Background Understanding the dynamics of the microbial communities that, along with their secreted enzymes, are involved in the natural process of biomass composting may hold the key to breaking the major bottleneck in biomass-to-biofuels conversion technology, which is the still-costly deconstruction of polymeric biomass carbohydrates to fermentable sugars. However, the complexity of both the structure of plant biomass and its counterpart microbial degradation communities makes it difficult to investigate the composting process. Results In this study, a composter was set up with a mix of yellow poplar (Liriodendron tulipifera wood-chips and mown lawn grass clippings (85:15 in dry-weight and used as a model system. The microbial rDNA abundance data obtained from analyzing weekly-withdrawn composted samples suggested population-shifts from bacteria-dominated to fungus-dominated communities. Further analyses by an array of optical microscopic, transcriptional and enzyme-activity techniques yielded correlated results, suggesting that such population shifts occurred along with early removal of hemicellulose followed by attack on the consequently uncovered cellulose as the composting progressed. Conclusion The observed shifts in dominance by representative microbial groups, along with the observed different patterns in the gene expression and enzymatic activities between cellulases, hemicellulases, and ligninases during the composting process, provide new perspectives for biomass-derived biotechnology such as consolidated bioprocessing (CBP and solid-state fermentation for the production of cellulolytic enzymes and biofuels.

Enzymatic biosensors based on the use of metal oxide nanoparticles

International Nuclear Information System (INIS)

Shi, Xinhao; Gu, Wei; Li, Bingyu; Chen, Ningning; Zhao, Kai; Xian, Yuezhong

2014-01-01

Over the past decades, various techniques have been developed to obtain materials at a nanoscale level to design biosensors with high sensitivity, selectivity and efficiency. Metal oxide nanoparticles (MONPs) are of particular interests and have received much attention because of their unique physical, chemical and catalytic properties. This review summarizes the progress made in enzymatic biosensors based on the use of MONPs. Synthetic methods, strategies for immobilization, and the functions of MONPs in enzymatic biosensing systems are reviewed and discussed. The article is subdivided into sections on enzymatic biosensors based on (a) zinc oxide nanoparticles, (b) titanium oxide nanoparticles, (c) iron oxide nanoparticles, and (d) other metal oxide nanoparticles. While substantial advances have been made in MONPs-based enzymatic biosensors, their applications to real samples still lie ahead because issues such as reproducibility and sensor stability have to be solved. (author)

Optimization of enzymatic clarification of green asparagus juice using response surface methodology.

Science.gov (United States)

Chen, Xuehong; Xu, Feng; Qin, Weidong; Ma, Lihua; Zheng, Yonghua

2012-06-01

Enzymatic clarification conditions for green asparagus juice were optimized by using response surface methodology (RSM). The asparagus juice was treated with pectinase at different temperatures (35 °C-45 °C), pH values (4.00-5.00), and enzyme concentrations (0.6-1.8 v/v%). The effects of enzymatic treatment on juice clarity and 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical-scavenging capacity were investigated by employing a 3-factor central composite design coupled with RSM. According to response surface analysis, the optimal enzymatic treatment condition was pectinase concentration of 1.45%, incubation temperature of 40.56 °C and pH of 4.43. The clarity, juice yield, and soluble solid contents in asparagus juice were significantly increased by enzymatic treatment at the optimal conditions. DPPH radical-scavenging capacity was maintained at the level close to that of raw asparagus juice. These results indicated that enzymatic treatment could be a useful technique for producing green asparagus juice with high clarity and high-antioxidant activity. Treatment with 1.45% pectinase at 40.56 ° C, pH 4.43, significantly increased the clarity and yield of asparagus juice. In addition, enzymatic treatment maintained antioxidant activity. Thus, enzymatic treatment has the potential for industrial asparagus juice clarification. © 2012 Institute of Food Technologists®

Similar potential ATP-P production and enzymatic activities in the microplankton community off Concepción (Chile) under oxic and suboxic conditions

Science.gov (United States)

González, Rodrigo R.; Gutiérrez, Marcelo H.; Quiñones, Renato A.

2007-11-01

The effects of the oxygen minimum zone on the metabolism of the heterotrophic microplankton community (0.22-100 μm) in the Humboldt Current System, as well as the factors controlling its biomass production, remain unknown. Here we compare the effect of four sources of dissolved organic carbon (glucose, oxaloacetate, glycine, leucine) on microbial biomass production (such as ATP-P) and the potential enzymatic activities involved in catabolic pathways under oxic and suboxic conditions. Our results show significant differences ( p oxygen minimum zone has the same or greater potential growth than the community inhabiting more oxygenated strata of the water column and that malate dehydrogenase is the activity that best represents the metabolic potential of the community.

Production of MAG via enzymatic glycerolysis

Science.gov (United States)

Jamlus, Norul Naziraa Ahmad; Derawi, Darfizzi; Salimon, Jumat

2015-09-01

Enzymatic glycerolysis of a medium chain methyl ester, methyl laurate was performed using lipase Candida antarctica (Novozyme 435) for 6 hours at 55°C. The percentage of components mixture of product were determined by using gas chromatography technique. The enzymatic reaction was successfully produced monolaurin (45.9 %), dilaurin (47.1 %) and trilaurin (7.0 %) respectively. Thin layer chromatography (TLC) plate also showed a good separation of component spots. Fourier transformation infra-red (FTIR) spectrum showed the presence of ester carbonyl at wavenumber 1739.99 cm-1 and hydrogen bonded O-H at 3512.03 cm-1. The product is potentially to be used as emulsifier and additive in food industry, pharmaceutical, as well as antibacterial.

Lignosulfonate and elevated pH can enhance enzymatic saccharification of lignocelluloses

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Wang ZJ

2013-01-01

Full Text Available Abstract Background Nonspecific (nonproductive binding (adsorption of cellulase by lignin has been identified as a key barrier to reduce cellulase loading for economical sugar and biofuel production from lignocellulosic biomass. Sulfite Pretreatment to Overcome Recalcitrance of Lignocelluloses (SPORL is a relatively new process, but demonstrated robust performance for sugar and biofuel production from woody biomass especially softwoods in terms of yields and energy efficiencies. This study demonstrated the role of lignin sulfonation in enhancing enzymatic saccharification of lignocelluloses – lignosulfonate from SPORL can improve enzymatic hydrolysis of lignocelluloses, contrary to the conventional belief that lignin inhibits enzymatic hydrolysis due to nonspecific binding of cellulase. Results The study found that lignosulfonate from SPORL pretreatment and from a commercial source inhibits enzymatic hydrolysis of pure cellulosic substrates at low concentrations due to nonspecific binding of cellulase. Surprisingly, the reduction in enzymatic saccharification efficiency of a lignocellulosic substrate was fully recovered as the concentrations of these two lignosulfonates increased. We hypothesize that lignosulfonate serves as a surfactant to enhance enzymatic hydrolysis at higher concentrations and that this enhancement offsets its inhibitive effect from nonspecific binding of cellulase, when lignosulfonate is applied to lignocellulosic solid substrates. Lignosulfonate can block nonspecific binding of cellulase by bound lignin on the solid substrates, in the same manner as a nonionic surfactant, to significantly enhance enzymatic saccharification. This enhancement is linearly proportional to the amount of lignosulfonate applied which is very important to practical applications. For a SPORL-pretreated lodgepole pine solid, 90% cellulose saccharification was achieved at cellulase loading of 13 FPU/g glucan with the application of its

Radiation degradation and the subsequent enzymatic hydrolysis of waste paper

International Nuclear Information System (INIS)

Kamakura, M.; Kaetsu, I.

1982-01-01

Various studies have been carried out to find methods for the pretreatment of waste cellulosic materials to make them more susceptible to enzymatic hydrolysis. In the work reported here, the effects of preirradiating waste papers on subsequent enzymatic hydrolysis have been studied

Effects of six selected antibiotics on plant growth and soil microbial and enzymatic activities

International Nuclear Information System (INIS)

Liu Feng; Ying Guangguo; Tao Ran; Zhao Jianliang; Yang Jifeng; Zhao Lanfeng

2009-01-01

The potential impact of six antibiotics (chlortetracycline, tetracycline and tylosin; sulfamethoxazole, sulfamethazine and trimethoprim) on plant growth and soil quality was studied by using seed germination test on filter paper and plant growth test in soil, soil respiration and phosphatase activity tests. The phytotoxic effects varied between the antibiotics and between plant species (sweet oat, rice and cucumber). Rice was most sensitive to sulfamethoxazole with the EC10 value of 0.1 mg/L. The antibiotics tested inhibited soil phosphatase activity during the 22 days' incubation. Significant effects on soil respiration were found for the two sulfonamides (sulfamethoxazole and sulfamethazine) and trimethoprim, whereas little effects were observed for the two tetracyclines and tylosin. The effective concentrations (EC10 values) for soil respiration in the first 2 days were 7 mg/kg for sulfamethoxazole, 13 mg/kg for sulfamethazine and 20 mg/kg for trimethoprim. Antibiotic residues in manure and soils may affect soil microbial and enzyme activities. - Terrestrial ecotoxicological effects of antibiotics are related to their sorption and degradation behavior in soil.

Effects of six selected antibiotics on plant growth and soil microbial and enzymatic activities

Energy Technology Data Exchange (ETDEWEB)

Liu Feng [State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, 511 Kehua Street, Tianhe District, Guangzhou 510640 (China); Ying Guangguo, E-mail: guangguo.ying@gmail.co [State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, 511 Kehua Street, Tianhe District, Guangzhou 510640 (China); Tao Ran; Zhao Jianliang; Yang Jifeng [State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, 511 Kehua Street, Tianhe District, Guangzhou 510640 (China); Zhao Lanfeng [College of Resource and Environmental Science, South China Agricultural University, Guangzhou 510642 (China)

2009-05-15

The potential impact of six antibiotics (chlortetracycline, tetracycline and tylosin; sulfamethoxazole, sulfamethazine and trimethoprim) on plant growth and soil quality was studied by using seed germination test on filter paper and plant growth test in soil, soil respiration and phosphatase activity tests. The phytotoxic effects varied between the antibiotics and between plant species (sweet oat, rice and cucumber). Rice was most sensitive to sulfamethoxazole with the EC10 value of 0.1 mg/L. The antibiotics tested inhibited soil phosphatase activity during the 22 days' incubation. Significant effects on soil respiration were found for the two sulfonamides (sulfamethoxazole and sulfamethazine) and trimethoprim, whereas little effects were observed for the two tetracyclines and tylosin. The effective concentrations (EC10 values) for soil respiration in the first 2 days were 7 mg/kg for sulfamethoxazole, 13 mg/kg for sulfamethazine and 20 mg/kg for trimethoprim. Antibiotic residues in manure and soils may affect soil microbial and enzyme activities. - Terrestrial ecotoxicological effects of antibiotics are related to their sorption and degradation behavior in soil.

Application of enzymatic methods for chia (Salvia hispanica L oil extraction

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Norma Ciau-Solís

2016-07-01

Full Text Available Aim. The aim was to evaluate the use of different enzymatic treatments on the oil extraction yield from Chia (Salvia hispanica L. seeds Methods. Enzymatic extraction was performed by treating of whole and degummed chia flours with different conditions of enzyme concentration, pH and temperature. Commercial enzymes were employed: Viscozyme LTM (endo-1,3 (4-betaglucanase derived from Aspergillus aculeatus, with 100 FBG g (Beta Glucanase-unit Fungal and Neutrase0.8LTM, neutral protease with 0.8 AU-NH/g of activity, derived from Bacillus amyloliquefaciens. Results. All treatments of enzymatic oil extraction were different (P <0.05 and the maximum oil yield obtained was 9.35%. Conclusion. Oil extraction using enzymatic methods is not a viable for chia seed

Synthetic microbial ecology and the dynamic interplay between microbial genotypes.

Science.gov (United States)

Dolinšek, Jan; Goldschmidt, Felix; Johnson, David R

2016-11-01

Assemblages of microbial genotypes growing together can display surprisingly complex and unexpected dynamics and result in community-level functions and behaviors that are not readily expected from analyzing each genotype in isolation. This complexity has, at least in part, inspired a discipline of synthetic microbial ecology. Synthetic microbial ecology focuses on designing, building and analyzing the dynamic behavior of ‘ecological circuits’ (i.e. a set of interacting microbial genotypes) and understanding how community-level properties emerge as a consequence of those interactions. In this review, we discuss typical objectives of synthetic microbial ecology and the main advantages and rationales of using synthetic microbial assemblages. We then summarize recent findings of current synthetic microbial ecology investigations. In particular, we focus on the causes and consequences of the interplay between different microbial genotypes and illustrate how simple interactions can create complex dynamics and promote unexpected community-level properties. We finally propose that distinguishing between active and passive interactions and accounting for the pervasiveness of competition can improve existing frameworks for designing and predicting the dynamics of microbial assemblages.

Soil Rhizosphere Microbial Communities and Enzyme Activities under Organic Farming in Alabama

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Zachary Senwo

2011-07-01

Full Text Available Evaluation of the soil rhizosphere has been limited by the lack of robust assessments that can explore the vast complex structure and diversity of soil microbial communities. Our objective was to combine fatty acid methyl ester (FAME and pyrosequencing techniques to evaluate soil microbial community structure and diversity. In addition, we evaluated biogeochemical functionality of the microbial communities via enzymatic activities of nutrient cycling. Samples were taken from a silt loam at 0–10 and 10–20 cm in an organic farm under lettuce (Lactuca sativa, potato (Solanum tuberosum, onion (Allium cepa L, broccoli (Brassica oleracea var. botrytis and Tall fescue pasture grass (Festuca arundinacea. Several FAMEs (a15:0, i15:0, i15:1, i16:0, a17:0, i17:0, 10Me17:0, cy17:0, 16:1ω5c and 18:1ω9c varied among the crop rhizospheres. FAME profiles of the soil microbial community under pasture showed a higher fungal:bacterial ratio compared to the soil under lettuce, potato, onion, and broccoli. Soil under potato showed higher sum of fungal FAME indicators compared to broccoli, onion and lettuce. Microbial biomass C and enzyme activities associated with pasture and potato were higher than the other rhizospheres. The lowest soil microbial biomass C and enzyme activities were found under onion. Pyrosequencing revealed significant differences regarding the maximum operational taxonomic units (OTU at 3% dissimilarity level (roughly corresponding to the bacterial species level at 0–10 cm (581.7–770.0 compared to 10–20 cm (563.3–727.7 soil depths. The lowest OTUs detected at 0–10 cm were under broccoli (581.7; whereas the lowest OTUs found at 10–20 cm were under potato (563.3. The predominant phyla (85% in this soil at both depths were Bacteroidetes (i.e., Flavobacteria, Sphingobacteria, and Proteobacteria. Flavobacteriaceae and Xanthomonadaceae were predominant under broccoli. Rhizobiaceae, Hyphomicrobiaceae, and Acidobacteriaceae were more

Contrasting effects of untreated textile wastewater onto the soil available nitrogen-phosphorus and enzymatic activities in aridisol.

Science.gov (United States)

Arif, Muhammad Saleem; Riaz, Muhammad; Shahzad, Sher Muhammad; Yasmeen, Tahira; Buttler, Alexandre; Garcıa-Gil, Juan Carlos; Roohi, Mahnaz; Rasool, Akhtar

2016-02-01

Water shortage and soil qualitative degradation are significant environmental problems in arid and semi-arid regions of the world. The increasing demand for water in agriculture and industry has resulted in the emergence of wastewater use as an alternative in these areas. Textile wastewater is produced in surplus amounts which poses threat to the environment as well as associated flora and fauna. A 60-day incubation study was performed to assess the effects of untreated textile wastewater at 0, 25, 50, 75, and 100% dilution levels on the physico-chemical and some microbial and enzymatic properties of an aridisol soil. The addition of textile wastewater provoked a significant change in soil pH and electrical conductivity and soil dehydrogenase and urease activities compared to the distilled-water treated control soil. Moreover, compared to the control treatment, soil phosphomonoesterase activity was significantly increased from 25 to 75% application rates, but decreased at 100% textile wastewater application rate. Total and available soil N contents increased significantly in response to application of textile wastewater. Despite significant increases in the soil total P contents after the addition of textile wastewater, soil available P content decreased with increasing concentration of wastewater. Changes in soil nutrient contents and related enzymatic activities suggested a dynamic match between substrate availability and soil N and P contents. Aridisols have high fixation and low P availability, application of textile wastewater to such soils should be considered only after careful assessment.

Enzymatic hydrolysis of biomass at high-solids loadings – A review

International Nuclear Information System (INIS)

Modenbach, Alicia A.; Nokes, Sue E.

2013-01-01

Enzymatic hydrolysis is the unit operation in the lignocellulose conversion process that utilizes enzymes to depolymerize lignocellulosic biomass. The saccharide components released are the feedstock for fermentation. When performed at high-solids loadings (≥15% solids, w/w), enzymatic hydrolysis potentially offers many advantages over conversions performed at low- or moderate-solids loadings, including increased sugar and ethanol concentrations and decreased capital and operating costs. The goal of this review is to provide a consolidated source of information on studies using high-solids loadings in enzymatic hydrolysis. Included in this review is a brief discussion of the limitations, such as a lack of available water, difficulty with mixing and handling, insufficient mass and heat transfer, and increased concentration of inhibitors, associated with the use of high solids, as well as descriptions and findings of studies that performed enzymatic hydrolysis at high-solids loadings. Reactors designed and/or equipped for improved handling of high-solids slurries are also discussed. Lastly, this review includes a brief discussion of some of the operations that have successfully scaled-up and implemented high-solids enzymatic hydrolysis at pilot- and demonstration-scale facilities. -- Highlights: •High solids enzymatic hydrolysis needed for conversion process to be cost-effective. •Limitations must be addressed before benefits of high-solid loadings fully realized. •Some success with high-solids loadings at pilot and demonstration scale

Catabolite regulation of enzymatic activities in a white pox pathogen and commensal bacteria during growth on mucus polymers from the coral Acropora palmata.

Science.gov (United States)

Krediet, Cory J; Ritchie, Kim B; Teplitski, Max

2009-11-16

Colonization of host mucus surfaces is one of the first steps in the establishment of coral-associated microbial communities. Coral mucus contains a sulfated glycoprotein (in which oligosaccharide decorations are connected to the polypeptide backbone by a mannose residue) and molecules that result from its degradation. Mucus is utilized as a growth substrate by commensal and pathogenic organisms. Two representative coral commensals, Photobacterium mandapamensis and Halomonas meridiana, differed from a white pox pathogen Serratia marcescens PDL100 in the pattern with which they utilized mucus polymers of Acropora palmata. Incubation with the mucus polymer increased mannopyranosidase activity in S. marcescens, suggestive of its ability to cleave off oligosaccharide side chains. With the exception of glucosidase and N-acetyl galactosaminidase, glycosidases in S. marcescens were subject to catabolite regulation by galactose, glucose, arabinose, mannose and N-acetyl-glucosamine. In commensal P. mandapamensis, at least 10 glycosidases were modestly induced during incubation on coral mucus. Galactose, arabinose, mannose, but not glucose or N-acetyl-glucosamine had a repressive effect on glycosidases in P. mandapamensis. Incubation with the mucus polymers upregulated 3 enzymatic activities in H. meridiana; glucose and galactose appear to be the preferred carbon source in this bacterium. Although all these bacteria were capable of producing the same glycosidases, the differences in the preferred carbon sources and patterns of enzymatic activities induced during growth on the mucus polymer in the presence of these carbon sources suggest that to establish themselves within the coral mucus surface layer commensals and pathogens rely on different enzymatic activities.

Metals other than uranium affected microbial community composition in a historical uranium-mining site.

Science.gov (United States)

Sitte, Jana; Löffler, Sylvia; Burkhardt, Eva-Maria; Goldfarb, Katherine C; Büchel, Georg; Hazen, Terry C; Küsel, Kirsten

2015-12-01

To understand the links between the long-term impact of uranium and other metals on microbial community composition, ground- and surface water-influenced soils varying greatly in uranium and metal concentrations were investigated at the former uranium-mining district in Ronneburg, Germany. A soil-based 16S PhyloChip approach revealed 2358 bacterial and 35 archaeal operational taxonomic units (OTU) within diverse phylogenetic groups with higher OTU numbers than at other uranium-contaminated sites, e.g., at Oak Ridge. Iron- and sulfate-reducing bacteria (FeRB and SRB), which have the potential to attenuate uranium and other metals by the enzymatic and/or abiotic reduction of metal ions, were found at all sites. Although soil concentrations of solid-phase uranium were high, ranging from 5 to 1569 μg·g (dry weight) soil(-1), redundancy analysis (RDA) and forward selection indicated that neither total nor bio-available uranium concentrations contributed significantly to the observed OTU distribution. Instead, microbial community composition appeared to be influenced more by redox potential. Bacterial communities were also influenced by bio-available manganese and total cobalt and cadmium concentrations. Bio-available cadmium impacted FeRB distribution while bio-available manganese and copper as well as solid-phase zinc concentrations in the soil affected SRB composition. Archaeal communities were influenced by the bio-available lead as well as total zinc and cobalt concentrations. These results suggest that (i) microbial richness was not impacted by heavy metals and radionuclides and that (ii) redox potential and secondary metal contaminants had the strongest effect on microbial community composition, as opposed to uranium, the primary source of contamination.

Evaluation of physical structural features on influencing enzymatic hydrolysis efficiency of micronized wood

Science.gov (United States)

Jinxue Jiang; Jinwu Wang; Xiao Zhang; Michael Wolcott

2016-01-01

Enzymatic hydrolysis of lignocellulosic biomass is highly dependent on the changes in structural features after pretreatment. Mechanical milling pretreatment is an effective approach to alter the physical structure of biomass and thus improve enzymatic hydrolysis. This study examined the influence of structural characteristics on the enzymatic hydrolysis of micronized...

Enzymatic saccharification of dilute acid pretreated saline crops for fermentable sugar production

Energy Technology Data Exchange (ETDEWEB)

Zheng, Yi; Zhang, Ruihong [Biological and Agricultural Engineering Department, University of California, Davis One Shields Avenue, Davis, CA 95616 (United States); Pan, Zhongli [Biological and Agricultural Engineering Department, University of California, Davis One Shields Avenue, Davis, CA 95616 (United States); Processed Foods Research Unit, USDA-ARS-WRRC, 800 Buchanan Street, Albany, CA 94710 (United States); Wang, Donghai [Biological and Agricultural Engineering Department, Kansas State University, Manhattan, KS 66506 (United States)

2009-11-15

Four saline crops [athel (Tamarix aphylla L), eucalyptus (Eucalyptus camaldulensis), Jose Tall Wheatgrass (Agropyron elongatum), and Creeping Wild Ryegrass (Leymus triticoides)] that are used in farms for salt uptake from soil and drainage irrigation water have the potential for fuel ethanol production because they don't take a large number of arable lands. Dilute sulfuric acid pretreatment and enzymatic hydrolysis were conducted to select the optimum pretreatment conditions and the best saline crop for further enzymatic hydrolysis research. The optimum dilute acid pretreatment conditions included T = 165 C, t = 8 min, and sulfuric acid concentration 1.4% (w/w). Creeping Wild Ryegrass was decided to be the best saline crop. Solid loading, cellulase and {beta}-glucosidase concentrations had significant effects on the enzymatic hydrolysis of dilute acid pretreated Creeping Wild Ryegrass. Glucose concentration increased by 36 mg/mL and enzymatic digestibility decreased by 20% when the solid loading increased from 4 to 12%. With 8% solid loading, enzymatic digestibility increased by over 30% with the increase of cellulase concentration from 5 to 15 FPU/g-cellulose. Under given cellulase concentration of 15 FPU/g-cellulose, 60% increase of enzymatic digestibility of pretreated Creeping Wild Ryegrass was obtained with the increase of {beta}-glucosidase concentration up to 15 CBU/g-cellulose. With a high solid loading of 10%, fed-batch operation generated 12% and 18% higher enzymatic digestibility and glucose concentration, respectively, than batch process. (author)

Application of extended Kalman filter to identification of enzymatic deactivation.

Science.gov (United States)

Caminal, G; Lafuente, J; López-Santín, J; Poch, M; Solà, C

1987-02-01

A recursive estimation scheme, the Extended Kalman Filter (EKF) technique, was applied to study enzymatic deactivation in the enzymatic hydrolysis of pretreated cellulose using a model previously developed by the authors. When no deactivation model was assumed, the results showed no variation with time for all the model parameters except for the maximum rate of cellobiose-to-glucose conversion (r'(m)).The r'(m) variation occurred in two zones with a grace period. A new model of enzymatic hydrolysis of pretreated cellulose deactivation was proposed and validated showing better behavior than the old deactivation model. This approach allows one to study enzyme deactivation without additional experiments and within operational conditions.

Genome-enabled Modeling of Microbial Biogeochemistry using a Trait-based Approach. Does Increasing Metabolic Complexity Increase Predictive Capabilities?

Science.gov (United States)

King, E.; Karaoz, U.; Molins, S.; Bouskill, N.; Anantharaman, K.; Beller, H. R.; Banfield, J. F.; Steefel, C. I.; Brodie, E.

2015-12-01

The biogeochemical functioning of ecosystems is shaped in part by genomic information stored in the subsurface microbiome. Cultivation-independent approaches allow us to extract this information through reconstruction of thousands of genomes from a microbial community. Analysis of these genomes, in turn, gives an indication of the organisms present and their functional roles. However, metagenomic analyses can currently deliver thousands of different genomes that range in abundance/importance, requiring the identification and assimilation of key physiologies and metabolisms to be represented as traits for successful simulation of subsurface processes. Here we focus on incorporating -omics information into BioCrunch, a genome-informed trait-based model that represents the diversity of microbial functional processes within a reactive transport framework. This approach models the rate of nutrient uptake and the thermodynamics of coupled electron donors and acceptors for a range of microbial metabolisms including heterotrophs and chemolithotrophs. Metabolism of exogenous substrates fuels catabolic and anabolic processes, with the proportion of energy used for cellular maintenance, respiration, biomass development, and enzyme production based upon dynamic intracellular and environmental conditions. This internal resource partitioning represents a trade-off against biomass formation and results in microbial community emergence across a fitness landscape. Biocrunch was used here in simulations that included organisms and metabolic pathways derived from a dataset of ~1200 non-redundant genomes reflecting a microbial community in a floodplain aquifer. Metagenomic data was directly used to parameterize trait values related to growth and to identify trait linkages associated with respiration, fermentation, and key enzymatic functions such as plant polymer degradation. Simulations spanned a range of metabolic complexities and highlight benefits originating from simulations

Microbial activities and dissolved organic matter dynamics in oil-contaminated surface seawater from the Deepwater Horizon oil spill site.

Science.gov (United States)

Ziervogel, Kai; McKay, Luke; Rhodes, Benjamin; Osburn, Christopher L; Dickson-Brown, Jennifer; Arnosti, Carol; Teske, Andreas

2012-01-01

The Deepwater Horizon oil spill triggered a complex cascade of microbial responses that reshaped the dynamics of heterotrophic carbon degradation and the turnover of dissolved organic carbon (DOC) in oil contaminated waters. Our results from 21-day laboratory incubations in rotating glass bottles (roller bottles) demonstrate that microbial dynamics and carbon flux in oil-contaminated surface water sampled near the spill site two weeks after the onset of the blowout were greatly affected by activities of microbes associated with macroscopic oil aggregates. Roller bottles with oil-amended water showed rapid formation of oil aggregates that were similar in size and appearance compared to oil aggregates observed in surface waters near the spill site. Oil aggregates that formed in roller bottles were densely colonized by heterotrophic bacteria, exhibiting high rates of enzymatic activity (lipase hydrolysis) indicative of oil degradation. Ambient waters surrounding aggregates also showed enhanced microbial activities not directly associated with primary oil-degradation (β-glucosidase; peptidase), as well as a twofold increase in DOC. Concurrent changes in fluorescence properties of colored dissolved organic matter (CDOM) suggest an increase in oil-derived, aromatic hydrocarbons in the DOC pool. Thus our data indicate that oil aggregates mediate, by two distinct mechanisms, the transfer of hydrocarbons to the deep sea: a microbially-derived flux of oil-derived DOC from sinking oil aggregates into the ambient water column, and rapid sedimentation of the oil aggregates themselves, serving as vehicles for oily particulate matter as well as oil aggregate-associated microbial communities.

Microbial activities and dissolved organic matter dynamics in oil-contaminated surface seawater from the Deepwater Horizon oil spill site.

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Kai Ziervogel

Full Text Available The Deepwater Horizon oil spill triggered a complex cascade of microbial responses that reshaped the dynamics of heterotrophic carbon degradation and the turnover of dissolved organic carbon (DOC in oil contaminated waters. Our results from 21-day laboratory incubations in rotating glass bottles (roller bottles demonstrate that microbial dynamics and carbon flux in oil-contaminated surface water sampled near the spill site two weeks after the onset of the blowout were greatly affected by activities of microbes associated with macroscopic oil aggregates. Roller bottles with oil-amended water showed rapid formation of oil aggregates that were similar in size and appearance compared to oil aggregates observed in surface waters near the spill site. Oil aggregates that formed in roller bottles were densely colonized by heterotrophic bacteria, exhibiting high rates of enzymatic activity (lipase hydrolysis indicative of oil degradation. Ambient waters surrounding aggregates also showed enhanced microbial activities not directly associated with primary oil-degradation (β-glucosidase; peptidase, as well as a twofold increase in DOC. Concurrent changes in fluorescence properties of colored dissolved organic matter (CDOM suggest an increase in oil-derived, aromatic hydrocarbons in the DOC pool. Thus our data indicate that oil aggregates mediate, by two distinct mechanisms, the transfer of hydrocarbons to the deep sea: a microbially-derived flux of oil-derived DOC from sinking oil aggregates into the ambient water column, and rapid sedimentation of the oil aggregates themselves, serving as vehicles for oily particulate matter as well as oil aggregate-associated microbial communities.

pH catalyzed pretreatment of corn bran for enhanced enzymatic arabinoxylan degradation

DEFF Research Database (Denmark)

Agger, Jane; Johansen, Katja Salomon; Meyer, Anne S.

2011-01-01

Corn bran is mainly made up of the pericarp of corn kernels and is a byproduct stream resulting from the wet milling step in corn starch processing. Through statistic modeling this study examined the optimization of pretreatment of corn bran for enzymatic hydrolysis. A low pH pretreatment (pH 2......, 150°C, 65min) boosted the enzymatic release of xylose and glucose and maximized biomass solubilization. With more acidic pretreatment followed by enzymatic hydrolysis the total xylose release was maximized (at pH 1.3) reaching ∼50% by weight of the original amount present in destarched corn bran......, but the enzyme catalyzed xylose release was maximal after pretreatment at approx. pH 2. The total glucose release peaked after pretreatment of approx. pH 1.5 with an enzymatic release of approx. 68% by weight of the original amounts present in destarched corn bran. For arabinose the enzymatic release...

Enhancement of enzymatic saccharification of Eucalyptus globulus: steam explosion versus steam treatment.

Science.gov (United States)

Martin-Sampedro, Raquel; Revilla, Esteban; Villar, Juan C; Eugenio, Maria E

2014-09-01

Steam explosion and steam pre-treatment have proved capable of enhancing enzymatic saccharification of lignocellulosic materials. However, until now, these methods had not been compared under the same operational conditions and using the same raw material. Both pre-treatments lead to increased yields in the saccharification of Eucalyptus globulus; but results have been better with steam pre-treatments, despite the more accessible surface of exploded samples. The reason for this finding could be enzymatic inhibition: steam explosion causes a more extensive extraction of hemicelluloses and releases a greater amount of degradation products which can inhibit enzymatic action. Enzymatic inhibition is also dependent on the amount and chemical structure of lignin, which was also a contributing factor to the lower enzymatic yields obtained with the most severe pre-treatment. Thus, the highest yields (46.7% glucose and 73.4% xylose yields) were obtained after two cycle of steam treatment, of 5 and 3 min, at 183°C. Copyright © 2014 Elsevier Ltd. All rights reserved.

Enzymatic Synthesis of Biobased Polyesters and Polyamides

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Yi Jiang

2016-06-01

Full Text Available Nowadays, “green” is a hot topic almost everywhere, from retailers to universities to industries; and achieving a green status has become a universal aim. However, polymers are commonly considered not to be “green”, being associated with massive energy consumption and severe pollution problems (for example, the “Plastic Soup” as a public stereotype. To achieve green polymers, three elements should be entailed: (1 green raw materials, catalysts and solvents; (2 eco-friendly synthesis processes; and (3 sustainable polymers with a low carbon footprint, for example, (biodegradable polymers or polymers which can be recycled or disposed with a gentle environmental impact. By utilizing biobased monomers in enzymatic polymerizations, many advantageous green aspects can be fulfilled. For example, biobased monomers and enzyme catalysts are renewable materials that are derived from biomass feedstocks; enzymatic polymerizations are clean and energy saving processes; and no toxic residuals contaminate the final products. Therefore, synthesis of renewable polymers via enzymatic polymerizations of biobased monomers provides an opportunity for achieving green polymers and a future sustainable polymer industry, which will eventually play an essential role for realizing and maintaining a biobased and sustainable society.

Metal nanostructures for non-enzymatic glucose sensing

International Nuclear Information System (INIS)

Tee, Si Yin; Teng, Choon Peng; Ye, Enyi

2017-01-01

This review covers the recent development of metal nanostructures in electrochemical non-enzymatic glucose sensing. It highlights a variety of nanostructured materials including noble metals, other transition metals, bimetallic systems, and their hybrid with carbon-based nanomaterials. Particularly, attention is devoted to numerous approaches that have been implemented for improving the sensors performance by tailoring size, shape, composition, effective surface area, adsorption capability and electron-transfer properties. The correlation of the metal nanostructures to the glucose sensing performance is addressed with respect to the linear concentration range, sensitivity and detection limit. In overall, this review provides important clues from the recent scientific achievements of glucose sensor nanomaterials which will be essentially useful in designing better and more effective electrocatalysts for future electrochemical sensing industry. - Highlights: • Overview of recent development of metal nanostructures in electrochemical non-enzymatic glucose sensing. • Special attention is focussed on noble metals, other transition metals, bimetallic systems, and their hybrid with carbon-based nanomaterials. • Merits and limitations of various metal nanostructures in electrochemical non-enzymatic glucose sensing. • Strategies to improve the glucose sensing performance of metal nanostructures as electrocatalysts.

A Low-Cost Wheat Bran Medium for Biodegradation of the Benzidine-Based Carcinogenic Dye Trypan Blue Using a Microbial Consortium

Directory of Open Access Journals (Sweden)

Harshad Lade

2015-03-01

Full Text Available Environmental release of benzidine-based dyes is a matter of health concern. Here, a microbial consortium was enriched from textile dye contaminated soils and investigated for biodegradation of the carcinogenic benzidine-based dye Trypan Blue using wheat bran (WB as growth medium. The PCR-DGGE analysis of enriched microbial consortium revealed the presence of 15 different bacteria. Decolorization studies suggested that the microbial consortium has high metabolic activity towards Trypan Blue as complete removal of 50 mg∙L−1 dye was observed within 24 h at 30 ± 0.2 °C and pH 7. Significant reduction in TOC (64% and COD (88% of dye decolorized broths confirmed mineralization. Induction in azoreductase (500%, NADH-DCIP reductase (264% and laccase (275% proved enzymatic decolorization of dye. HPLC analysis of dye decolorized products showed the formation of six metabolites while the FTIR spectrum indicated removal of diazo bonds at 1612.30 and 1581.34 cm−1. The proposed dye degradation pathway based on GC-MS and enzyme analysis suggested the formation of two low molecular weight intermediates. Phytotoxicity and acute toxicity studies revealed the less toxic nature of the dye degradation products. These results provide experimental evidence for the utilization of agricultural waste as a novel low-cost growth medium for biodegradation of benzidine-based dyes, and suggested the potential of the microbial consortium in detoxification.

Automatic single- and multi-label enzymatic function prediction by machine learning

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Shervine Amidi

2017-03-01

Full Text Available The number of protein structures in the PDB database has been increasing more than 15-fold since 1999. The creation of computational models predicting enzymatic function is of major importance since such models provide the means to better understand the behavior of newly discovered enzymes when catalyzing chemical reactions. Until now, single-label classification has been widely performed for predicting enzymatic function limiting the application to enzymes performing unique reactions and introducing errors when multi-functional enzymes are examined. Indeed, some enzymes may be performing different reactions and can hence be directly associated with multiple enzymatic functions. In the present work, we propose a multi-label enzymatic function classification scheme that combines structural and amino acid sequence information. We investigate two fusion approaches (in the feature level and decision level and assess the methodology for general enzymatic function prediction indicated by the first digit of the enzyme commission (EC code (six main classes on 40,034 enzymes from the PDB database. The proposed single-label and multi-label models predict correctly the actual functional activities in 97.8% and 95.5% (based on Hamming-loss of the cases, respectively. Also the multi-label model predicts all possible enzymatic reactions in 85.4% of the multi-labeled enzymes when the number of reactions is unknown. Code and datasets are available at https://figshare.com/s/a63e0bafa9b71fc7cbd7.

Application of bioinformatics tools and databases in microbial dehalogenation research (a review).

Science.gov (United States)

Satpathy, R; Konkimalla, V B; Ratha, J

2015-01-01

Microbial dehalogenation is a biochemical process in which the halogenated substances are catalyzed enzymatically in to their non-halogenated form. The microorganisms have a wide range of organohalogen degradation ability both explicit and non-specific in nature. Most of these halogenated organic compounds being pollutants need to be remediated; therefore, the current approaches are to explore the potential of microbes at a molecular level for effective biodegradation of these substances. Several microorganisms with dehalogenation activity have been identified and characterized. In this aspect, the bioinformatics plays a key role to gain deeper knowledge in this field of dehalogenation. To facilitate the data mining, many tools have been developed to annotate these data from databases. Therefore, with the discovery of a microorganism one can predict a gene/protein, sequence analysis, can perform structural modelling, metabolic pathway analysis, biodegradation study and so on. This review highlights various methods of bioinformatics approach that describes the application of various databases and specific tools in the microbial dehalogenation fields with special focus on dehalogenase enzymes. Attempts have also been made to decipher some recent applications of in silico modeling methods that comprise of gene finding, protein modelling, Quantitative Structure Biodegradibility Relationship (QSBR) study and reconstruction of metabolic pathways employed in dehalogenation research area.

Microbial ecology-based engineering of Microbial Electrochemical Technologies.

Science.gov (United States)

Koch, Christin; Korth, Benjamin; Harnisch, Falk

2018-01-01

Microbial ecology is devoted to the understanding of dynamics, activity and interaction of microorganisms in natural and technical ecosystems. Bioelectrochemical systems represent important technical ecosystems, where microbial ecology is of highest importance for their function. However, whereas aspects of, for example, materials and reactor engineering are commonly perceived as highly relevant, the study and engineering of microbial ecology are significantly underrepresented in bioelectrochemical systems. This shortfall may be assigned to a deficit on knowledge and power of these methods as well as the prerequisites for their thorough application. This article discusses not only the importance of microbial ecology for microbial electrochemical technologies but also shows which information can be derived for a knowledge-driven engineering. Instead of providing a comprehensive list of techniques from which it is hard to judge the applicability and value of information for a respective one, this review illustrates the suitability of selected techniques on a case study. Thereby, best practice for different research questions is provided and a set of key questions for experimental design, data acquisition and analysis is suggested. © 2017 The Authors. Microbial Biotechnology published by John Wiley & Sons Ltd and Society for Applied Microbiology.

Microbial bebop: creating music from complex dynamics in microbial ecology.

Science.gov (United States)

Larsen, Peter; Gilbert, Jack

2013-01-01

In order for society to make effective policy decisions on complex and far-reaching subjects, such as appropriate responses to global climate change, scientists must effectively communicate complex results to the non-scientifically specialized public. However, there are few ways however to transform highly complicated scientific data into formats that are engaging to the general community. Taking inspiration from patterns observed in nature and from some of the principles of jazz bebop improvisation, we have generated Microbial Bebop, a method by which microbial environmental data are transformed into music. Microbial Bebop uses meter, pitch, duration, and harmony to highlight the relationships between multiple data types in complex biological datasets. We use a comprehensive microbial ecology, time course dataset collected at the L4 marine monitoring station in the Western English Channel as an example of microbial ecological data that can be transformed into music. Four compositions were generated (www.bio.anl.gov/MicrobialBebop.htm.) from L4 Station data using Microbial Bebop. Each composition, though deriving from the same dataset, is created to highlight different relationships between environmental conditions and microbial community structure. The approach presented here can be applied to a wide variety of complex biological datasets.

Enzymatic cell disruption of microalgae biomass in biorefinery processes.

Science.gov (United States)

Demuez, Marie; Mahdy, Ahmed; Tomás-Pejó, Elia; González-Fernández, Cristina; Ballesteros, Mercedes

2015-10-01

When employing biotechnological processes for the procurement of biofuels and bio-products from microalgae, one of the most critical steps affecting economy and yields is the "cell disruption" stage. Currently, enzymatic cell disruption has delivered effective and cost competitive results when compared to mechanical and chemical cell disruption methods. However, the introduction of enzymes implies additional associated cost within the overall process. In order to reduce this cost, autolysis of microalgae is proposed as alternative enzymatic cell disruption method. This review aims to provide the state of the art of enzymatic cell disruption treatments employed in biorefinery processes and highlights the use of endopeptidases. During the enzymatic processes of microalgae life cycle, some lytic enzymes involved in cell division and programmed cell death have been proven useful in performing cell lysis. In this context, the role of endopeptidases is emphasized. Mirroring these natural events, an alternative cell disruption approach is proposed and described with the potential to induce the autolysis process using intrinsic cell enzymes. Integrating induced autolysis within biofuel production processes offers a promising approach to reduce overall global costs and energetic input associated with those of current cell disruption methods. A number of options for further inquiry are also discussed. © 2015 Wiley Periodicals, Inc.

Optimization of Substrate Feeding for Enzymatic Biodiesel Production

DEFF Research Database (Denmark)

Price, Jason Anthony; Huusom, Jakob Kjøbsted; Nordblad, Mathias

2013-01-01

to be effective in mitigating the effects of substrate inhibition. Using enzymatic biodiesel production as a case study, the volumetric productivity of the reactor is increased while minimizing inactivation of the enzyme due to the alcohol. This is done by using a simple optimization routine where the substrate...... (both the vegetable oil and alcohol) feed rate/concentration is manipulated simultaneously. The results of the simulation were tested in the laboratory and are sufficiently positive to suggest the implementation of a feeding strategy for large scale enzymatic biodiesel production...

Moving towards a Competitive Fully Enzymatic Biodiesel Process

Directory of Open Access Journals (Sweden)

Silvia Cesarini

2015-06-01

Full Text Available Enzymatic biodiesel synthesis can solve several problems posed by the alkaline-catalyzed transesterification but it has the drawback of being too expensive to be considered competitive. Costs can be reduced by lipase improvement, use of unrefined oils, evaluation of soluble/immobilized lipase preparations, and by combination of phospholipases with a soluble lipase for biodiesel production in a single step. As shown here, convenient natural tools have been developed that allow synthesis of high quality FAMEs (EN14214 from unrefined oils in a completely enzymatic single-step process, making it fully competitive.

Whey-derived valuable products obtained by microbial fermentation.

Science.gov (United States)

Pescuma, Micaela; de Valdez, Graciela Font; Mozzi, Fernanda

2015-08-01

Whey, the main by-product of the cheese industry, is considered as an important pollutant due to its high chemical and biological oxygen demand. Whey, often considered as waste, has high nutritional value and can be used to obtain value-added products, although some of them need expensive enzymatic synthesis. An economical alternative to transform whey into valuable products is through bacterial or yeast fermentations and by accumulation during algae growth. Fermentative processes can be applied either to produce individual compounds or to formulate new foods and beverages. In the first case, a considerable amount of research has been directed to obtain biofuels able to replace those derived from petrol. In addition, the possibility of replacing petrol-derived plastics by biodegradable polymers synthesized during bacterial fermentation of whey has been sought. Further, the ability of different organisms to produce metabolites commonly used in the food and pharmaceutical industries (i.e., lactic acid, lactobionic acid, polysaccharides, etc.) using whey as growth substrate has been studied. On the other hand, new low-cost functional whey-based foods and beverages leveraging the high nutritional quality of whey have been formulated, highlighting the health-promoting effects of fermented whey-derived products. This review aims to gather the multiple uses of whey as sustainable raw material for the production of individual compounds, foods, and beverages by microbial fermentation. This is the first work to give an overview on the microbial transformation of whey as raw material into a large repertoire of industrially relevant foods and products.

Preparation and Enzymatic Degradation of Porous Crosslinked Polylactides of Biomass Origin

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Yuya Kido

2014-06-01

Full Text Available To understand the enzymatic degradation behavior of crosslinked polylactide (PLA, the preparation and enzymatic degradation of both thermoplastic (linear and crosslinked PLAs that have pore structures with different dimensions were carried out. The porous structures of the linear PLA samples were of micro and nanoporous nature, and prepared by batch foaming with supercritical CO2 and compared with the porous structures of crosslinked PLA (Lait-X created by the salt leaching method. The surface and cross-sectional morphologies of the porous structures were investigated by using scanning electron microscopy. The morphological analysis of porous Lait-X showed a rapid loss of physical features within 120 h of exposure to proteinase-K enzymatic degradation at 37 °C. Due to the higher affinity for water, enhanced enzymatic activity as compared to the linear PLA porous structures in the micro and nanoporous range was observed.

Enzymatic, antimicrobial and toxicity studies of the aqueous extract of Ananas comosus (pineapple) crown leaf.

Science.gov (United States)

Dutta, Sangita; Bhattacharyya, Debasish

2013-11-25

Various parts of the plant pineapple (Ananas comosus) are used in traditional medicine worldwide for treatment of a number of diseases and disorders. In folk medicine, pineapple leaf extract was used as an antimicrobial, vermicide, purgative, emmenagoogue, abortifacient, anti-oedema and anti-inflammatory agent. Compared to the fruit and stem extracts of pineapple, information about its leaf extract is limited. The potential of pineapple crown leaf extract as an ethno-medicine has been evaluated in terms of its enzymatic activities related to wound healing, antimicrobial property and toxicity. Major protein components of the extract were revealed by 2-D gel electrophoresis followed by MS/MS analysis. Zymography, DQ-gelatin assay were performed to demonstrate proteolytic, fibrinolytic, gelatinase and collagenase activities. DNase and RNase activities were revealed from agarose gel electrophoresis. Antimicrobial activity was evaluated spectrophotometrically from growth inhibition. Sprague-Dawley rat model was used to measure acute and sub-acute toxicity of the extract by analyzing blood markers. The extract contains several proteins that were clustered under native condition. Proteomic studies indicated presence of fruit bromelain as major protein constituent of the extract. It showed nonspecific protease activity, gelatinolytic, collagenase, fibrinolytic, acid and alkaline phosphatase, peroxidase, DNase and RNase activities along with considerable anti-microbial property. The leaf extract did not induce any toxicity in rats after oral administration of acute and sub-acute doses. Pineapple leaf extract is nontoxic, contains enzymes related to damage tissue repairing, wound healing and possibly prevents secondary infections from microbial organisms. © 2013 Elsevier Ireland Ltd. All rights reserved.

Divergence of dominant factors in soil microbial communities and functions in forest ecosystems along a climatic gradient

Science.gov (United States)

Xu, Zhiwei; Yu, Guirui; Zhang, Xinyu; He, Nianpeng; Wang, Qiufeng; Wang, Shengzhong; Xu, Xiaofeng; Wang, Ruili; Zhao, Ning

2018-03-01

Soil microorganisms play an important role in regulating nutrient cycling in terrestrial ecosystems. Most of the studies conducted thus far have been confined to a single forest biome or have focused on one or two controlling factors, and few have dealt with the integrated effects of climate, vegetation, and soil substrate availability on soil microbial communities and functions among different forests. In this study, we used phospholipid-derived fatty acid (PLFA) analysis to investigate soil microbial community structure and extracellular enzymatic activities to evaluate the functional potential of soil microbes of different types of forests in three different climatic zones along the north-south transect in eastern China (NSTEC). Both climate and forest type had significant effects on soil enzyme activities and microbial communities with considerable interactive effects. Except for soil acid phosphatase (AP), the other three enzyme activities were much higher in the warm temperate zone than in the temperate and the subtropical climate zones. The soil total PLFAs and bacteria were much higher in the temperate zone than in the warm temperate and the subtropical zones. The soil β-glucosidase (BG) and N-acetylglucosaminidase (NAG) activities were highest in the coniferous forest. Except for the soil fungi and fungi-bacteria (F/B), the different groups of microbial PLFAs were much higher in the conifer broad-leaved mixed forests than in the coniferous forests and the broad-leaved forests. In general, soil enzyme activities and microbial PLFAs were higher in primary forests than in secondary forests in temperate and warm temperate regions. In the subtropical region, soil enzyme activities were lower in the primary forests than in the secondary forests and microbial PLFAs did not differ significantly between primary and secondary forests. Different compositions of the tree species may cause variations in soil microbial communities and enzyme activities. Our results

Acacia Changes Microbial Indicators and Increases C and N in Soil Organic Fractions in Intercropped Eucalyptus Plantations

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Arthur P. A. Pereira

2018-04-01

Full Text Available Intercropping forest plantations of Eucalyptus with nitrogen-fixing trees can increase soil N inputs and stimulate soil organic matter (OM cycling. However, microbial indicators and their correlation in specific fractions of soil OM are unclear in the tropical sandy soils. Here, we examined the microbial indicators associated with C and N in the soil resulting from pure and intercropped Eucalyptus grandis and Acacia mangium plantations. We hypothesized that introduction of A. mangium in a Eucalyptus plantation promotes changes in microbial indicators and increases C and N concentrations on labile fractions of the soil OM, when compared to pure eucalyptus plantations. We determined the microbial and enzymatic activity, and the potential for C degradation by the soil microbial community. Additionally, we evaluated soil OM fractions and litter parameters. Soil (0–20 cm and litter samples were collected at 27 and 39 months after planting from the following treatments: pure E. grandis (E and A. mangium (A plantations, pure E. grandis plantations with N fertilizer (E+N and an E. grandis, and A. mangium intercropped plantations (E+A. The results showed that intercropped plantations (E+A increase 3, 45, and 70% microbial biomass C as compared to A, E+N, and E, at 27 months after planting. The metabolic quotient (qCO2 showed a tendency toward stressful values in pure E. grandis plantations and a strong correlation with dehydrogenase activity. A and E+A treatments also exhibited the highest organic fractions (OF and C and N contents. A canonical redundancy analysis revealed positive correlations between microbial indicators of soil and litter attributes, and a strong effect of C and N variables in differentiating A and E+A from E and E+N treatments. The results suggested that a significant role of A. mangium enhance the dynamics of soil microbial indicators which help in the accumulation of C and N in soil OF in intercropped E. grandis plantations. Our

Acacia Changes Microbial Indicators and Increases C and N in Soil Organic Fractions in Intercropped Eucalyptus Plantations

Science.gov (United States)

Pereira, Arthur P. A.; Zagatto, Maurício R. G.; Brandani, Carolina B.; Mescolotti, Denise de Lourdes; Cotta, Simone R.; Gonçalves, José L. M.; Cardoso, Elke J. B. N.

2018-01-01

Intercropping forest plantations of Eucalyptus with nitrogen-fixing trees can increase soil N inputs and stimulate soil organic matter (OM) cycling. However, microbial indicators and their correlation in specific fractions of soil OM are unclear in the tropical sandy soils. Here, we examined the microbial indicators associated with C and N in the soil resulting from pure and intercropped Eucalyptus grandis and Acacia mangium plantations. We hypothesized that introduction of A. mangium in a Eucalyptus plantation promotes changes in microbial indicators and increases C and N concentrations on labile fractions of the soil OM, when compared to pure eucalyptus plantations. We determined the microbial and enzymatic activity, and the potential for C degradation by the soil microbial community. Additionally, we evaluated soil OM fractions and litter parameters. Soil (0–20 cm) and litter samples were collected at 27 and 39 months after planting from the following treatments: pure E. grandis (E) and A. mangium (A) plantations, pure E. grandis plantations with N fertilizer (E+N) and an E. grandis, and A. mangium intercropped plantations (E+A). The results showed that intercropped plantations (E+A) increase 3, 45, and 70% microbial biomass C as compared to A, E+N, and E, at 27 months after planting. The metabolic quotient (qCO2) showed a tendency toward stressful values in pure E. grandis plantations and a strong correlation with dehydrogenase activity. A and E+A treatments also exhibited the highest organic fractions (OF) and C and N contents. A canonical redundancy analysis revealed positive correlations between microbial indicators of soil and litter attributes, and a strong effect of C and N variables in differentiating A and E+A from E and E+N treatments. The results suggested that a significant role of A. mangium enhance the dynamics of soil microbial indicators which help in the accumulation of C and N in soil OF in intercropped E. grandis plantations. Our results are

Acacia Changes Microbial Indicators and Increases C and N in Soil Organic Fractions in Intercropped Eucalyptus Plantations.

Science.gov (United States)

Pereira, Arthur P A; Zagatto, Maurício R G; Brandani, Carolina B; Mescolotti, Denise de Lourdes; Cotta, Simone R; Gonçalves, José L M; Cardoso, Elke J B N

2018-01-01

Intercropping forest plantations of Eucalyptus with nitrogen-fixing trees can increase soil N inputs and stimulate soil organic matter (OM) cycling. However, microbial indicators and their correlation in specific fractions of soil OM are unclear in the tropical sandy soils. Here, we examined the microbial indicators associated with C and N in the soil resulting from pure and intercropped Eucalyptus grandis and Acacia mangium plantations. We hypothesized that introduction of A. mangium in a Eucalyptus plantation promotes changes in microbial indicators and increases C and N concentrations on labile fractions of the soil OM, when compared to pure eucalyptus plantations. We determined the microbial and enzymatic activity, and the potential for C degradation by the soil microbial community. Additionally, we evaluated soil OM fractions and litter parameters. Soil (0-20 cm) and litter samples were collected at 27 and 39 months after planting from the following treatments: pure E. grandis (E) and A. mangium (A) plantations, pure E. grandis plantations with N fertilizer (E+N) and an E. grandis , and A. mangium intercropped plantations (E+A). The results showed that intercropped plantations (E+A) increase 3, 45, and 70% microbial biomass C as compared to A, E+N, and E, at 27 months after planting. The metabolic quotient ( q CO 2 ) showed a tendency toward stressful values in pure E. grandis plantations and a strong correlation with dehydrogenase activity. A and E+A treatments also exhibited the highest organic fractions (OF) and C and N contents. A canonical redundancy analysis revealed positive correlations between microbial indicators of soil and litter attributes, and a strong effect of C and N variables in differentiating A and E+A from E and E+N treatments. The results suggested that a significant role of A. mangium enhance the dynamics of soil microbial indicators which help in the accumulation of C and N in soil OF in intercropped E. grandis plantations. Our results

Preparation and characterization of electrically conducting polypyrrole Sn(IV phosphate cation-exchanger and its application as Mn(II ion selective membrane electrode

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A.A. Khan

2011-10-01

Full Text Available Polypyrrole Sn(IV phosphate, an organic–inorganic composite cation-exchanger was synthesized via sol-gel mixing of an organic polymer, polypyrrole, into the matrices of the inorganic precipitate of Sn(IV phosphate. The physico-chemical properties of the material were determined using Atomic Absorption Spectrometry (AAS, CHN elemental analysis (inductively coupled plasma mass spectrometry, ICP-MS, UV–VIS spectrophotometry, FTIR (Fourier Transform Infra-Red, SEM (Scanning Electron Microscopy, TGA–DTA (Thermogravimetric Analysis–Differential Thermal Analysis, and XRD (X-ray diffraction. Ion-exchange behavior was observed to characterize the material. On the basis of distribution studies, the material was found to be highly selective for toxic heavy metal ion Mn2+. Due to its selective nature, the material was used as an electroactive component for the construction of an ion-selective membrane electrode. The proposed electrode shows fairly good discrimination of mercury ion over several other inorganic ions. The analytical utility of this electrode was established by employing it as an indicator electrode in electrometric titrations for Mn(II in water.

Enzymatic degradation of polycaprolactone–gelatin blend

International Nuclear Information System (INIS)

Banerjee, Aditi; Chatterjee, Kaushik; Madras, Giridhar

2015-01-01

Blends of polycaprolactone (PCL), a synthetic polymer and gelatin, natural polymer offer a optimal combination of strength, water wettability and cytocompatibility for use as a resorbable biomaterial. The enzymatic degradation of PCL, gelatin and PCL–gelatin blended films was studied in the presence of lipase (Novozym 435, immobilized) and lysozyme. Novozym 435 degraded the PCL films whereas lysozyme degraded the gelatin. Though Novozym 435 and lysozyme individually could degrade PCL–gelatin blended films, the combination of these enzymes showed the highest degradation of these blended films. Moreover, the enzymatic degradation was much faster when fresh enzymes were added at regular intervals. The changes in physico-chemical properties of polymer films due to degradation were studied by scanning electron microscopy, Fourier transform infrared spectroscopy and differential scanning calorimetry. These results have important implications for designing resorbable biomedical implants. (paper)

Microbial bebop: creating music from complex dynamics in microbial ecology.

Directory of Open Access Journals (Sweden)

Peter Larsen

Full Text Available In order for society to make effective policy decisions on complex and far-reaching subjects, such as appropriate responses to global climate change, scientists must effectively communicate complex results to the non-scientifically specialized public. However, there are few ways however to transform highly complicated scientific data into formats that are engaging to the general community. Taking inspiration from patterns observed in nature and from some of the principles of jazz bebop improvisation, we have generated Microbial Bebop, a method by which microbial environmental data are transformed into music. Microbial Bebop uses meter, pitch, duration, and harmony to highlight the relationships between multiple data types in complex biological datasets. We use a comprehensive microbial ecology, time course dataset collected at the L4 marine monitoring station in the Western English Channel as an example of microbial ecological data that can be transformed into music. Four compositions were generated (www.bio.anl.gov/MicrobialBebop.htm. from L4 Station data using Microbial Bebop. Each composition, though deriving from the same dataset, is created to highlight different relationships between environmental conditions and microbial community structure. The approach presented here can be applied to a wide variety of complex biological datasets.

Study of manganese binding to the ferroxidase centre of human H-type ferritin.

Science.gov (United States)

Ardini, Matteo; Howes, Barry D; Fiorillo, Annarita; Falvo, Elisabetta; Sottini, Silvia; Rovai, Donella; Lantieri, Marco; Ilari, Andrea; Gatteschi, Dante; Spina, Gabriele; Chiancone, Emilia; Stefanini, Simonetta; Fittipaldi, Maria

2018-05-01

Ferritins are ubiquitous and conserved proteins endowed with enzymatic ferroxidase activity, that oxidize Fe(II) ions at the dimetal ferroxidase centre to form a mineralized Fe(III) oxide core deposited within the apo-protein shell. Herein, the in vitro formation of a heterodimetal cofactor constituted by Fe and Mn ions has been investigated in human H ferritin (hHFt). Namely, Mn and Fe binding at the hHFt ferroxidase centre and its effects on Fe(II) oxidation have been investigated by UV-Vis ferroxidation kinetics, fluorimetric titrations, multifrequency EPR, and preliminary Mössbauer spectroscopy. Our results show that in hHFt, both Fe(II) and Mn(II) bind the ferroxidase centre forming a Fe-Mn cofactor. Moreover, molecular oxygen seems to favour Mn(II) binding and increases the ferroxidation activity of the Mn-loaded protein. The data suggest that Mn influences the Fe binding and the efficiency of the ferroxidation reaction. The higher efficiency of the Mn-Fe heterometallic centre may have a physiological relevance in specific cell types (i.e. glia cells), where the concentration of Mn is the same order of magnitude as iron. Copyright © 2018 Elsevier Inc. All rights reserved.

Testing the applicability of rapid on-site enzymatic activity detection for surface water monitoring

Science.gov (United States)

Stadler, Philipp; Vogl, Wolfgang; Juri, Koschelnik; Markus, Epp; Maximilian, Lackner; Markus, Oismüller; Monika, Kumpan; Peter, Strauss; Regina, Sommer; Gabriela, Ryzinska-Paier; Farnleitner Andreas, H.; Matthias, Zessner

2015-04-01

On-site detection of enzymatic activities has been suggested as a rapid surrogate for microbiological pollution monitoring of water resources (e.g. using glucuronidases, galactosidases, esterases). Due to the possible short measuring intervals enzymatic methods have high potential as near-real time water quality monitoring tools. This presentation describes results from a long termed field test. For twelve months, two ColiMinder devices (Vienna Water Monitoring, Austria) for on-site determination of enzymatic activity were tested for stream water monitoring at the experimental catchment HOAL (Hydrological Open Air Laboratory, Center for Water Resource Systems, Vienna University of Technology). The devices were overall able to follow and reflect the diverse hydrological and microbiological conditions of the monitored stream during the test period. Continuous data in high temporal resolution captured the course of enzymatic activity in stream water during diverse rainfall events. The method also proofed sensitive enough to determine diurnal fluctuations of enzymatic activity in stream water during dry periods. The method was able to capture a seasonal trend of enzymatic activity in stream water that matches the results gained from Colilert18 analysis for E. coli and coliform bacteria of monthly grab samples. Furthermore the comparison of ColiMinder data with measurements gained at the same test site with devices using the same method but having different construction design (BACTcontrol, microLAN) showed consistent measuring results. Comparative analysis showed significant differences between measured enzymatic activity (modified fishman units and pmol/min/100ml) and cultivation based analyses (most probable number, colony forming unit). Methods of enzymatic activity measures are capable to detect ideally the enzymatic activity caused by all active target bacteria members, including VBNC (viable but nonculturable) while cultivation based methods cannot detect VBNC

Radiation pretreatments of cellulose materials for the enhancement of enzymatic hydrolysis

International Nuclear Information System (INIS)

Ardica, S.; Calderaro, E.; Cappadona, C.

1985-01-01

The effect of γ-ray pre-irradiation of cellulose materials such as wood chips, paper, grain straw, hay and kapok on glucose production on enzymatic hydrolysis by cellulase has been investigated. These materials have been irradiated in air, water and acetate buffer solution over the dose range 10 3 to 4 x 10 6 Gy. In the relatively low dose range, up to about 5 x 10 5 Gy, the glucose yields after enzymatic hydrolysis are practically insensitive to radiation. At higher dose levels, up to 1.7 to 2 x 10 6 Gy, the pre-irradiation becomes very effective on enzymatic cellulose conversion. It has been found that the radiation-induced degradation of cellulose into low molecular weight polysaccharides is dependent on the nature and chemical composition of the cellulose materials and on the radiation environmental conditions. Further increases of dose causes radiation-induced structural modifications in polysaccharides previously produced, which can lead to a decrease in glucose production by enzymatic hydrolysis. (author)

Recent Advances in Enzymatic Fuel Cells: Experiments and Modeling

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Ivan Ivanov

2010-04-01

Full Text Available Enzymatic fuel cells convert the chemical energy of biofuels into electrical energy. Unlike traditional fuel cell types, which are mainly based on metal catalysts, the enzymatic fuel cells employ enzymes as catalysts. This fuel cell type can be used as an implantable power source for a variety of medical devices used in modern medicine to administer drugs, treat ailments and monitor bodily functions. Some advantages in comparison to conventional fuel cells include a simple fuel cell design and lower cost of the main fuel cell components, however they suffer from severe kinetic limitations mainly due to inefficiency in electron transfer between the enzyme and the electrode surface. In this review article, the major research activities concerned with the enzymatic fuel cells (anode and cathode development, system design, modeling by highlighting the current problems (low cell voltage, low current density, stability will be presented.

Resistant starch but not enzymatic treated waxy maize delays development of diabetes in Zucker Diabetic Fatty rats

DEFF Research Database (Denmark)

Hedemann, Mette Skou; Hermansen, Kjeld; Pedersen, Sven

2017-01-01

excretion during week 8 in rats fed the GLU and EMS diets than that of rats fed S and RS showed that they were diabetic. Urinary nontargeted metabolomics revealed that the diabetic state of rats fed S, GLU, and EMS diets influenced microbial metabolism, as well as amino acid, lipid, and vitamin metabolism......Background: The incidence of type 2 diabetes (T2D) is increasing worldwide, and nutritional management of circulating glucose may be a strategic tool in the prevention of T2D. Objective: We studied whether enzymatically modified waxy maize with an increased degree of branching delayed the onset...... glucose concentrations in feed-deprived rats, none of the groups developed diabetes. However, in week 9, plasma glucose after feed deprivation was significantly lower in rats fed the S and RS diets (13.5 mmol/L) than in rats fed the GLU and EMS diets (17.0–18.9 mmol/L), and rats fed RS had lower HbA1c (4...

Tandem and sequential multi-enzymatic syntheses

NARCIS (Netherlands)

Kim, B.G.; Ahn, J.H.; Sello, G.; Di Gennaro, P.; van Herk, T.; Hartog, A.F.; Wever, R.; Oroz-Guinea, I.; Sánchez-Moreno, I.; García-Junceda, E.; Wu, B.; Szymanski, W.; Feringa, B.L.; Janssen, D.B.; Villo, L.; Kreen, M.; Kudryashova, M.; Metsala, A.; Tamp, S.; Lille, ü.; Pehk, T.; Parve, O.; McClean, K.; Eddowes, P.; Whittall, J.; Sutton, P.W.

2012-01-01

This chapter contains sections titled: Production of Isorhamnetin 3-O-Glucoside in Escherichia coli Using Engineered Glycosyltransferase Multienzymatic Preparation of (−)-3-(Oxiran-2-yl)Benzoic Acid Enzymatic Synthesis of Carbohydrates from Dihydroxyacetone and Aldehydes by a One Pot Enzyme Cascade

Real-time ESI-MS of enzymatic conversion: impact of organic solvents and multiplexing.

Science.gov (United States)

Scheerle, Romy K; Grassmann, Johanna; Letzel, Thomas

2012-01-01

Different enzymatic assays were characterized systematically by real-time electrospray ionization mass spectrometry (ESI-MS) in the presence of organic solvents as well as in multiplex approaches and in a combination of both. Typically, biological enzymatic reactions are studied in aqueous solutions, since most enzymes show their full activity solely in aqueous solutions. However, in recent years, the use of organic solvents in combination with enzymatic reactions has gained increasing interest due to biotechnological advantages in chemical synthesis, development of online coupled setups screening for enzyme regulatory compounds, advantages regarding mass spectrometric detection and others. In the current study, the influence of several common organic solvents (methanol, ethanol, isopropanol, acetone, acetonitrile) on enzymatic activity (hen egg white lysozyme, chitinase, α-chymotrypsin, elastase from human neutrophils and porcine pancreas, acetylcholinesterase) was tested. Moreover, multiplexing is a promising approach enabling fast and cost-efficient screening methods, e.g. for determination of inhibitors in complex mixtures or in the field of biomedical research. Although in multiplexed setups the enzymatic activity may be affected by the presence of other substrates and/or enzymes, the expected advantages possibly will predominate. To investigate those effects, we measured multiple enzymatic assays simultaneously. For all conducted measurements, the conversion rate of the substrate(s) was calculated, which reflects the enzymatic activity. The results provide an overview about the susceptibility of the selected enzymes towards diverse factors and a reference point for many applications in analytical chemistry and biotechnology.

Enzymatic pH control for biomimetic depostion of calcium phosphate coatings

NARCIS (Netherlands)

Nijhuis, A.W.G.; Nejadnik, M.R.; Nudelman, F.; Walboomers, X.F.; Riet, te J.; Habibovic, P.; Birgani, Z.T.; Li, Y.B.; Bomans, P.H.H.; Jansen, J.A.; Sommerdijk, N.A.J.M.; Leeuwenburgh, S.C.G.

2014-01-01

The current study examines the enzymatic decomposition of urea into carbon dioxide and ammonia as a means to increase the pH during biomimetic deposition of calcium phospate (CaP) onto implant surfaces. The kinetics of the enzymatically induced pH increase were studied by monitoring pH, calcium

Enzymatic pH control for biomimetic deposition of calcium phosphate coatings

NARCIS (Netherlands)

Nijhuis, A.W.G.; Nejadnik, M.R.; Nudelman, F.; Walboomers, X.F.; Riet, J. te; Habibovic, P.; Tahmasebi Birgani, Z.; Li, Y.; Bomans, P.H.; Jansen, J.A.; Sommerdijk, N.A.; Leeuwenburgh, S.C.G.

2014-01-01

The current study examines the enzymatic decomposition of urea into carbon dioxide and ammonia as a means to increase the pH during biomimetic deposition of calcium phosphate (CaP) onto implant surfaces. The kinetics of the enzymatically induced pH increase were studied by monitoring pH, calcium

Therapeutic effectiveness of a new enzymatic bleaching dentifrice.

Science.gov (United States)

Forner, Leopaldo; Amengual, José; Liena, Carmen; Riutord, Pere

2012-01-01

Research into bleaching focuses on new products in order to minimize undesirable effects. This study evaluated the bleaching effectiveness of a new enzymatic-activated dentifrice. A total of 20 volunteers were bleached with a dentifrice containing 5% lactoperoxidase and 3% carbamide peroxide applied three times a day for two minutes over 21 days. Color was recorded before and after the treatment using a spectrophotometer. CIELAB differences were calculated before and after treatment using the paired t test (P whitening teeth. Enzymatic dental bleaching is able to increase the efficiency of low concentration peroxides, reducing the potential risk of peroxides on oral tissues.

Multi-Scale Computational Enzymology: Enhancing Our Understanding of Enzymatic Catalysis

Science.gov (United States)

Gherib, Rami; Dokainish, Hisham M.; Gauld, James W.

2014-01-01

Elucidating the origin of enzymatic catalysis stands as one the great challenges of contemporary biochemistry and biophysics. The recent emergence of computational enzymology has enhanced our atomistic-level description of biocatalysis as well the kinetic and thermodynamic properties of their mechanisms. There exists a diversity of computational methods allowing the investigation of specific enzymatic properties. Small or large density functional theory models allow the comparison of a plethora of mechanistic reactive species and divergent catalytic pathways. Molecular docking can model different substrate conformations embedded within enzyme active sites and determine those with optimal binding affinities. Molecular dynamics simulations provide insights into the dynamics and roles of active site components as well as the interactions between substrate and enzymes. Hybrid quantum mechanical/molecular mechanical (QM/MM) can model reactions in active sites while considering steric and electrostatic contributions provided by the surrounding environment. Using previous studies done within our group, on OvoA, EgtB, ThrRS, LuxS and MsrA enzymatic systems, we will review how these methods can be used either independently or cooperatively to get insights into enzymatic catalysis. PMID:24384841

Multi-Scale Computational Enzymology: Enhancing Our Understanding of Enzymatic Catalysis

Directory of Open Access Journals (Sweden)

Rami Gherib

2013-12-01

Full Text Available Elucidating the origin of enzymatic catalysis stands as one the great challenges of contemporary biochemistry and biophysics. The recent emergence of computational enzymology has enhanced our atomistic-level description of biocatalysis as well the kinetic and thermodynamic properties of their mechanisms. There exists a diversity of computational methods allowing the investigation of specific enzymatic properties. Small or large density functional theory models allow the comparison of a plethora of mechanistic reactive species and divergent catalytic pathways. Molecular docking can model different substrate conformations embedded within enzyme active sites and determine those with optimal binding affinities. Molecular dynamics simulations provide insights into the dynamics and roles of active site components as well as the interactions between substrate and enzymes. Hybrid quantum mechanical/molecular mechanical (QM/MM can model reactions in active sites while considering steric and electrostatic contributions provided by the surrounding environment. Using previous studies done within our group, on OvoA, EgtB, ThrRS, LuxS and MsrA enzymatic systems, we will review how these methods can be used either independently or cooperatively to get insights into enzymatic catalysis.

ETHANOL ORGANOSOLV PRETREATMENT OF BAMBOO FOR EFFICIENT ENZYMATIC SACCHARIFICATION

Directory of Open Access Journals (Sweden)

Zhiqiang Li,

2012-06-01

Full Text Available Bamboo is a potential lignocellulosic biomass for the production of bioethanol because of its high cellulose and hemicelluloses content. In this research, ethanol organosolv pretreatment with dilute sulfuric acid as the catalyst was studied in order to enhance enzymatic saccharification of moso bamboo. The addition of 2% (w/w bamboo dilute sulfuric acid in 75% ethanol had a particularly strong effect on fractionation of bamboo. It yielded a solids fraction containing 83.4% cellulose in the treated substrate. The cellulose conversion to glucose yield reached 77.1 to 83.4% after enzymatic hydrolysis of the solids fraction for 48 h at an enzyme loading of 15 FPU cellulase/g cellulose and 30 IU β-glucosidase/g cellulose. The enzymatic hydrolysis rate was significantly accelerated as the ethanol organosolv pretreatment time increased, reaching the highest enzymatic glucose yield of 83.4% after 48 h at 50 °C. The concentrations of fermentation inhibitors such as HMF (5-hydroxy-2-methyl furfural and furfural were 0.96 g/L and 4.38 g/L in the spent liquor after the ethanol organosolv pretreatment, which were slightly lower than the concentrations quantified during H2SO4-water treatment. Spent liquor was diluted with water, and more than 87.2% of lignin in raw bamboo was recovered as ethanol organosolv lignin through the filtration process.

Production of xylooligosaccharide from wheat bran by microwave assisted enzymatic hydrolysis.

Science.gov (United States)

Wang, Tseng-Hsing; Lu, Shin

2013-06-01

The effective production of xylooligosaccharides (XOS) from wheat bran was investigated. Wheat bran contains rich hemicellulose which can be hydrolyzed by enzyme; the XOS were obtained by microwave assisted enzymatic hydrolysis. To improve the productivity of XOS, repeated microwave assisted enzymatic hydrolysis and activated carbon adsorption method was chosen to eliminate macromolecules in the XOS. On the basis of experimental data, an industrial XOS production process consisting of pretreatment, repeated microwave assisted enzymatic treatment and purification was designed. Using the designed process, 3.2g dry of purified XOS was produced from 50 g dry wheat bran powder. Copyright © 2012 Elsevier Ltd. All rights reserved.

Enzymatic pH Control for Biomimetic Deposition of Calcium Phosphate Coatings

NARCIS (Netherlands)

Nijhuis, A.W.; Reza Nejadnik, M.; Nudelman, F.; Walboomers, X.F.; te Riet, J.; Habibovic, Pamela; Tahmasebi Birgani, Zeinab; Yubao, L.; Bomans, P.H.H.; Jansen, J.A.; Sommerdijk, N.A.J.M.; Leeuwenburgh, S.C.G.

2014-01-01

The current study has focused on enzymatic decomposition of urea into carbon dioxide and ammonia as a means to increase the pH during biomimetic deposition of Calcium Phospate (CaP) onto implant surfaces. The kinetics of the enzymatically induced pH increase were studied by monitoring pH, calcium

Microbial community structure elucidates performance of Glyceria maxima plant microbial fuel cell

NARCIS (Netherlands)

Timmers, R.A.; Rothballer, M.; Strik, D.P.B.T.B.; Engel, M.; Schulz, M.; Hartmann, A.; Hamelers, H.V.M.; Buisman, C.J.N.

2012-01-01

The plant microbial fuel cell (PMFC) is a technology in which living plant roots provide electron donor, via rhizodeposition, to a mixed microbial community to generate electricity in a microbial fuel cell. Analysis and localisation of the microbial community is necessary for gaining insight into

Enzymatic added extraction and clarification of fruit juices-A review.

Science.gov (United States)

Sharma, Harsh P; Patel, Hiral; Sugandha

2017-04-13

Enzymatic treatment for juice extraction is most commonly used now a days. The enzymatic process is claimed to offer a number of advantages over mechanical-thermal comminution of several fruit pulps. Enzymes are an integral component of modern fruit juice manufacturing and are highly suitable for optimizing processes. Their main purposes are: increase extraction of juice from raw material, increase processing efficiency (pressing, solid settling or removal), and generate a final product that is clear and visually attractive. Juice extraction can be done by using various mechanical processes, which may be achieved through diffusion extraction, decanter centrifuge, screw type juice extractor, fruit pulper and by different types of presses. Enzymatic treatment prior to mechanical extraction significantly improves juice recovery compared to any other extraction process. Enzymatic hydrolysis of the cell walls increases the extraction yield, reducing sugars, soluble dry matter content and galacturonic acid content and titrable acidity of the products. Enzymatic degradation of the biomaterial depends upon the type of enzyme, incubation time, incubation temperature, enzyme concentration, agitation, pH and use of different enzyme combinations. We can conclude from the technical literature that use of the enzymes i.e. cellulases, pectinases, amylases and combination of these enzymes can give better juice yield with superior quality of the fruit juice. Pectinase enzyme can give maximum juice yield i.e. 92.4% at 360 minutes incubation time, 37°C incubation temperature and 5 mg/100 g of enzyme concentration. Whereas the combination of two enzymes i.e. pectin methyl esterase (PME) and polygalacturonase (PG) at 120 minutes of incubation time, 50°C of incubation temperature and 0.05 mg/100 gm of enzymatic concentration can give the maximum yield of 96.8% for plum fruits. This paper discusses the use of enzymes in fruit juice production focusing on the juice recovery

Isoprene Production on Enzymatic Hydrolysate of Peanut Hull Using Different Pretreatment Methods

Directory of Open Access Journals (Sweden)

Sumeng Wang

2016-01-01

Full Text Available The present study is about the use of peanut hull for isoprene production. In this study, two pretreatment methods, hydrogen peroxide-acetic acid (HPAC and popping, were employed prior to enzymatic hydrolysis, which could destroy the lignocellulosic structure and accordingly improve the efficiency of enzymatic hydrolysis. It is proven that the isoprene production on enzymatic hydrolysate with HPAC pretreatment is about 1.9-fold higher than that of popping pretreatment. Moreover, through High Performance Liquid Chromatography (HPLC analysis, the amount and category of inhibitors such as formic acid, acetic acid, and HMF were assayed and were varied in different enzymatic hydrolysates, which may be the reason leading to a decrease in isoprene production during fermentation. To further increase the isoprene yield, the enzymatic hydrolysate of HPAC was detoxified by activated carbon. As a result, using the detoxified enzymatic hydrolysate as the carbon source, the engineered strain YJM21 could accumulate 297.5 mg/L isoprene, which accounted for about 90% of isoprene production by YJM21 fermented on pure glucose (338.6 mg/L. This work is thought to be the first attempt on isoprene production by E. coli using peanut hull as the feedstock. More importantly, it also shows the prospect of peanut hull to be considered as an alternative feedstock for bio-based chemicals or biofuels production due to its easy access and high polysaccharide content.

Biocolloids with ordered urease multilayer shells as enzymatic reactors.

Science.gov (United States)

Lvov, Y; Caruso, F

2001-09-01

The preparation of biocolloids with organized enzyme-containing multilayer shells for exploitation as colloidal enzymatic nanoreactors is described. Urease multilayers were assembled onto submicrometer-sized polystyrene spheres by the sequential adsorption of urease and polyelectrolyte, in a predetermined order, utilizing electrostatic interactions for layer growth. The catalytic activity of the biocolloids increased proportionally with the number of urease layers deposited on the particles, demonstrating that biocolloid particles with tailored enzymatic activities can be produced. It was further found that precoating the latex spheres with nanoparticles (40-nm silica or 12-nm magnetite) enhanced both the stability (with respect to adsorption) and enzymatic activity of the urease multilayers. The presence of the magnetite nanoparticle coating also provided a magnetic function that allowed the biocolloids to be easily and rapidly separated with a permanent magnet. The fabrication of such colloids opens new avenues for the application of bioparticles and represents a promising route for the creation of complex catalytic particles.

High volumetric power density, non-enzymatic, glucose fuel cells.

Science.gov (United States)

Oncescu, Vlad; Erickson, David

2013-01-01

The development of new implantable medical devices has been limited in the past by slow advances in lithium battery technology. Non-enzymatic glucose fuel cells are promising replacement candidates for lithium batteries because of good long-term stability and adequate power density. The devices developed to date however use an "oxygen depletion design" whereby the electrodes are stacked on top of each other leading to low volumetric power density and complicated fabrication protocols. Here we have developed a novel single-layer fuel cell with good performance (2 μW cm⁻²) and stability that can be integrated directly as a coating layer on large implantable devices, or stacked to obtain a high volumetric power density (over 16 μW cm⁻³). This represents the first demonstration of a low volume non-enzymatic fuel cell stack with high power density, greatly increasing the range of applications for non-enzymatic glucose fuel cells.

Multiple enzymatic profiles of Vibrio parahaemolyticus strains isolated from oysters

Directory of Open Access Journals (Sweden)

Renata Albuquerque Costa

Full Text Available The enzymatic characterization of vibrios has been used as a virulence indicator of sanitary interest. The objective of this study was to determine the enzymatic profile of Vibrio parahaemolyticus strains (n = 70 isolated from Crassostrea rhizophorae oysters. The strains were examined for the presence of gelatinase (GEL, caseinase (CAS, elastase (ELAS, phospholipase (PHOS, lipase (LIP, amilase (AML and DNase. All enzymes, except elastase, were detected in more than 60% of the strains. The most recurrent enzymatic profiles were AML + DNase + PHOS + GEL + LIP (n = 16; 22.9% and AML + CAS + DNase + PHOS + GEL + LIP (n = 21; 30%. Considering the fact that exoenzyme production by vibrios is closely related to virulence, one must be aware of the bacteriological risk posed to human health by the consumption of raw or undercooked oysters.

Integration of antimicrobial pectin-based edible coating and active modified atmosphere packaging to preserve the quality and microbial safety of fresh-cut persimmon (Diospyros kaki Thunb. cv. Rojo Brillante).

Science.gov (United States)

Sanchís, Elena; Ghidelli, Christian; Sheth, Chirag C; Mateos, Milagros; Palou, Lluís; Pérez-Gago, María B

2017-01-01

The greatest hurdle to the commercial marketing of fresh-cut fruits is related to their higher susceptibility to enzymatic browning, tissue softening, and microbial growth. The aim of this study was to test the efficacy of a pectin-based edible coating and low oxygen modified atmosphere packaging (MAP) to control enzymatic browning and reduce microbial growth of fresh-cut 'Rojo Brillante' persimmon. The survival of Escherichia coli, Salmonella enteritidis and Listeria monocytogenes artificially inoculated on fresh-cut fruit was also assessed. The pectin coating was amended with 500 IU mL -1 nisin (NI) as antimicrobial agent and 10 g kg -1 citric acid and 10 g kg -1 calcium chloride as anti-browning and firming agents, respectively. Persimmon slices were dipped in the coating or in water (control) and packed under 5 kPa O 2 (MAP) or in ambient atmosphere for up to 9 days at 5 °C. Microbial growth, package gas composition, colour, firmness, polyphenol oxidase activity, visual quality and overall sensory flavour of persimmon slices were measured during storage. Coating application combined with active MAP significantly reduced the CO 2 emission and O 2 consumption in the package. The coating was effective in reducing browning and also inhibited the growth of mesophilic aerobic bacteria. Coating also reduced the populations of E. coli, S. enteritidis and L. monocytogenes. The combination of the pectin-based edible coating and active MAP proved to be the most effective treatment to maintain the sensory and microbiological quality of persimmon slices for more than 9 days of storage. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

Comparison of fermentation of diets of variable composition and microbial populations in the rumen of sheep and Rusitec fermenters. I. Digestibility, fermentation parameters, and microbial growth.

Science.gov (United States)

Martínez, M E; Ranilla, M J; Tejido, M L; Ramos, S; Carro, M D

2010-08-01

Four ruminally and duodenally cannulated sheep and 8 Rusitec fermenters were used to determine the effects of forage to concentrate (F:C) ratio and type of forage in the diet on ruminal fermentation and microbial protein synthesis. The purpose of the study was to assess how closely fermenters can mimic the dietary differences found in vivo. The 4 experimental diets contained F:C ratios of 70:30 or 30:70 with either alfalfa hay or grass hay as the forage. Microbial growth was determined in both systems using (15)N as a microbial marker. Rusitec fermenters detected differences between diets similar to those observed in sheep by changing F:C ratio on pH; neutral detergent fiber digestibility; total volatile fatty acid concentrations; molar proportions of acetate, propionate, butyrate, isovalerate, and caproate; and amylase activity. In contrast, Rusitec fermenters did not reproduce the dietary differences found in sheep for NH(3)-N and lactate concentrations, dry matter (DM) digestibility, proportions of isobutyrate and valerate, carboxymethylcellulase and xylanase activities, and microbial growth and its efficiency. Regarding the effect of the type of forage in the diet, Rusitec fermenters detected differences between diets similar to those found in sheep for most determined parameters, with the exception of pH, DM digestibility, butyrate proportion, and carboxymethylcellulase activity. Minimum pH and maximal volatile fatty acid concentrations were reached at 2h and at 6 to 8h postfeeding in sheep and fermenters, respectively, indicating that feed fermentation was slower in fermenters compared with that in sheep. There were differences between systems in the magnitude of most determined parameters. In general, fermenters showed lower lactate concentrations, neutral detergent fiber digestibility, acetate:propionate ratios, and enzymatic activities. On the contrary, fermenters showed greater NH(3)-N concentrations, DM digestibility, and proportions of propionate

Enzymatic activity of the cellulolytic complex produced by Trichoderma reesei. Enzymatic hydrolysis of cellulose; Actividad enzimatica del complejo celulolitico producido por Trichoderma reesei. Hidrolisis enzimatica de la celulosa

Energy Technology Data Exchange (ETDEWEB)

Alfonsel, M; Negro, M J; Saez, R; Martin, C

1986-07-01

The enzymatic activity characterization of the cellulolytic complex obtained from Trichoderma reesei QM 9414 and the influence of the enzymatic hydrolysis conditions on the hydrolysis yield are studied. Pure cellulose and native or alkali pretreated biomass Onopordum nervosum have been used as substrates. The values of pH, temperature, substrate concentration and enzyme-substrate ratio for the optimum activity of that complex, evaluated as glucose and reducing sugars production, have been selected. Previous studies on enzymatic hydrolysis of 0. nervosum have shown a remarkable effect of the alkaline pretreatments on the final hydrolysis yield. (Author) 10 refs.

Enzymatic assay for methotrexate in erythrocytes

DEFF Research Database (Denmark)

Schrøder, H; Heinsvig, E M

1985-01-01

Methotrexate (MTX) accumulates in erythrocytes in MTX-treated patients. We present a modified enzymatic assay measuring MTX concentrations between 10 and 60 nmol/l in erythrocytes, adapted for a centrifugal analyser (Cobas Bio). About 40 patient's samples could be analysed within 1 h. The detection...

Summary of the co-ordinated research project on development, standardization and validation of nuclear based technologies for estimating microbial protein supply in ruminant livestock for improving productivity

International Nuclear Information System (INIS)

Jayasuriya, M.C.N.

1999-01-01

A major constraint to animal production in developing countries is poor nutrition due to inadequate or fluctuating nutrient supply. This results in low rates of reproduction and production as well as increased susceptibility to disease and mortality. Microbial cells formed as a result of rumen degradation of carbohydrates under anaerobic conditions are a major source of protein for ruminants. They provide the majority of the amino acids that the host animal requires for tissue maintenance, growth and production. In roughage-fed ruminants, micro-organisms are virtually the only source of protein. Therefore, a knowledge of the microbial contribution to the nutrition of the host animal is essential to developing feed supplementation strategies for improving ruminant production. While this factor has been recognized for many years, it has been extremely difficult to determine the microbial protein contribution to ruminant nutrition. The methods generally used for determining microbial protein production depend on the use of natural microbial markers such as RNA (ribonucleic acid) and DAPA (diamino-pimelic acid) or of isotopes 35 S, 15 N or 32 P. However, these methods involve surgical intervention such as post-rumen cannulation and complex procedures that require accurate and quantitative information on both digesta and microbial marker flow. A calorimetric technique using enzymatic procedures was developed for measuring purine derivatives (PD) in urine under a Technical Contract. With knowledge of the amount of PD excreted in the urine, the microbial protein supply to the host animal can be estimated. The principle of the method is that nucleic acids leaving the rumen are essentially of microbial origin. The nucleic acids are extensively digested in the small intestine and the resulting purines are absorbed

Bioethanol Production By Utilizing Cassava Peels Waste Through Enzymatic And Microbiological Hydrolysis

Science.gov (United States)

Witantri, R. G.; Purwoko, T.; Sunarto; Mahajoeno, E.

2017-07-01

Cassava peels waste contains, cellulose which is quite high at 43.626%, this is a potential candidate as a raw for bioethanol production. The purpose of this study was to determine the performance of the enzymatic hydrolysis, microbiological (Effective microbe) and fermentation in cassava peel waste is known from the results of quantitative measurement of multiple ethanol parameters (DNS Test, pH, ethanol concentration). This research was carried out in stages, the first stage is hydrolysis with completely randomized design with single factor variation of the catalyst, consisting of three levels ie cellulase enzymes, multienzyme and effective microbial EM4. The second stage is fermentation with factorial randomized block design, consisting of three groups of variations of catalyst, and has two factors: variations of fermipan levels 1, 2, 3% and the duration of fermentation, 2,4,6 days. The parameters in the test is a reducing sugar, pH and concentration of ethanol. The results showed that variation of hydrolysis treatment, fermentation time, and fermipan levels has real effect on the fermentation process. On average the highest ethanol content obtained from the treatment with multienzyme addition, with the addition of 2% fermipan levels and on the 2nd day of fermentation that is equal to 3.76%.

Quantifying enzymatic lysis: estimating the combined effects of chemistry, physiology and physics

International Nuclear Information System (INIS)

Mitchell, Gabriel J; Weitz, Joshua S; Nelson, Daniel C

2010-01-01

The number of microbial pathogens resistant to antibiotics continues to increase even as the rate of discovery and approval of new antibiotic therapeutics steadily decreases. Many researchers have begun to investigate the therapeutic potential of naturally occurring lytic enzymes as an alternative to traditional antibiotics. However, direct characterization of lytic enzymes using techniques based on synthetic substrates is often difficult because lytic enzymes bind to the complex superstructure of intact cell walls. Here we present a new standard for the analysis of lytic enzymes based on turbidity assays which allow us to probe the dynamics of lysis without preparing a synthetic substrate. The challenge in the analysis of these assays is to infer the microscopic details of lysis from macroscopic turbidity data. We propose a model of enzymatic lysis that integrates the chemistry responsible for bond cleavage with the physical mechanisms leading to cell wall failure. We then present a solution to an inverse problem in which we estimate reaction rate constants and the heterogeneous susceptibility to lysis among target cells. We validate our model given simulated and experimental turbidity assays. The ability to estimate reaction rate constants for lytic enzymes will facilitate their biochemical characterization and development as antimicrobial therapeutics

Quantifying enzymatic lysis: estimating the combined effects of chemistry, physiology and physics.

Science.gov (United States)

Mitchell, Gabriel J; Nelson, Daniel C; Weitz, Joshua S

2010-10-04

The number of microbial pathogens resistant to antibiotics continues to increase even as the rate of discovery and approval of new antibiotic therapeutics steadily decreases. Many researchers have begun to investigate the therapeutic potential of naturally occurring lytic enzymes as an alternative to traditional antibiotics. However, direct characterization of lytic enzymes using techniques based on synthetic substrates is often difficult because lytic enzymes bind to the complex superstructure of intact cell walls. Here we present a new standard for the analysis of lytic enzymes based on turbidity assays which allow us to probe the dynamics of lysis without preparing a synthetic substrate. The challenge in the analysis of these assays is to infer the microscopic details of lysis from macroscopic turbidity data. We propose a model of enzymatic lysis that integrates the chemistry responsible for bond cleavage with the physical mechanisms leading to cell wall failure. We then present a solution to an inverse problem in which we estimate reaction rate constants and the heterogeneous susceptibility to lysis among target cells. We validate our model given simulated and experimental turbidity assays. The ability to estimate reaction rate constants for lytic enzymes will facilitate their biochemical characterization and development as antimicrobial therapeutics.

Detection of extracellular enzymatic activity in microorganisms ...

African Journals Online (AJOL)

Detection of extracellular enzymatic activity in microorganisms isolated from waste vegetable oil contaminated soil using plate methodologies. Eugenia G. Ortiz Lechuga, Isela Quintero Zapata, Katiushka Arévalo Niño ...

Detection of extracellular enzymatic activity in microorganisms ...

African Journals Online (AJOL)

sunny t

2015-09-18

Sep 18, 2015 ... microorganisms with all three enzymatic activities, thereby establishing these techniques as ... supplemented at 1% with vegetable oils, including olive (OLI) ..... cepacia lipase for biodiesel fuel production from soybean oil.

Fecal microbial determinants of fecal and systemic estrogens and estrogen metabolites: a cross-sectional study.

Science.gov (United States)

Flores, Roberto; Shi, Jianxin; Fuhrman, Barbara; Xu, Xia; Veenstra, Timothy D; Gail, Mitchell H; Gajer, Pawel; Ravel, Jacques; Goedert, James J

2012-12-21

High systemic estrogen levels contribute to breast cancer risk for postmenopausal women, whereas low levels contribute to osteoporosis risk. Except for obesity, determinants of non-ovarian systemic estrogen levels are undefined. We sought to identify members and functions of the intestinal microbial community associated with estrogen levels via enterohepatic recirculation. Fifty-one epidemiologists at the National Institutes of Health, including 25 men, 7 postmenopausal women, and 19 premenopausal women, provided urine and aliquots of feces, using methods proven to yield accurate and reproducible results. Estradiol, estrone, 13 estrogen metabolites (EM), and their sum (total estrogens) were quantified in urine and feces by liquid chromatography/tandem mass spectrometry. In feces, β-glucuronidase and β-glucosidase activities were determined by realtime kinetics, and microbiome diversity and taxonomy were estimated by pyrosequencing 16S rRNA amplicons. Pearson correlations were computed for each loge estrogen level, loge enzymatic activity level, and microbiome alpha diversity estimate. For the 55 taxa with mean relative abundance of at least 0.1%, ordinal levels were created [zero, low (below median of detected sequences), high] and compared to loge estrogens, β-glucuronidase and β-glucosidase enzymatic activity levels by linear regression. Significance was based on two-sided tests with α=0.05. In men and postmenopausal women, levels of total urinary estrogens (as well as most individual EM) were very strongly and directly associated with all measures of fecal microbiome richness and alpha diversity (R≥0.50, P≤0.003). These non-ovarian systemic estrogens also were strongly and significantly associated with fecal Clostridia taxa, including non-Clostridiales and three genera in the Ruminococcaceae family (R=0.57-0.70, P=0.03-0.002). Estrone, but not other EM, in urine correlated significantly with functional activity of fecal β-glucuronidase (R=0.36, P=0

Microbial Rechargeable Battery

NARCIS (Netherlands)

Molenaar, Sam D.; Mol, Annemerel R.; Sleutels, Tom H.J.A.; Heijne, Ter Annemiek; Buisman, Cees J.N.

2016-01-01

Bioelectrochemical systems hold potential for both conversion of electricity into chemicals through microbial electrosynthesis (MES) and the provision of electrical power by oxidation of organics using microbial fuel cells (MFCs). This study provides a proof of concept for a microbial

Multi-Scale Computational Enzymology: Enhancing Our Understanding of Enzymatic Catalysis

OpenAIRE

Rami Gherib; Hisham M. Dokainish; James W. Gauld

2013-01-01

Elucidating the origin of enzymatic catalysis stands as one the great challenges of contemporary biochemistry and biophysics. The recent emergence of computational enzymology has enhanced our atomistic-level description of biocatalysis as well the kinetic and thermodynamic properties of their mechanisms. There exists a diversity of computational methods allowing the investigation of specific enzymatic properties. Small or large density functional theory models allow the comparison of a pleth...

Precision Synthesis of Functional Polysaccharide Materials by Phosphorylase-Catalyzed Enzymatic Reactions

Directory of Open Access Journals (Sweden)

Jun-ichi Kadokawa

2016-04-01

Full Text Available In this review article, the precise synthesis of functional polysaccharide materials using phosphorylase-catalyzed enzymatic reactions is presented. This particular enzymatic approach has been identified as a powerful tool in preparing well-defined polysaccharide materials. Phosphorylase is an enzyme that has been employed in the synthesis of pure amylose with a precisely controlled structure. Similarly, using a phosphorylase-catalyzed enzymatic polymerization, the chemoenzymatic synthesis of amylose-grafted heteropolysaccharides containing different main-chain polysaccharide structures (e.g., chitin/chitosan, cellulose, alginate, xanthan gum, and carboxymethyl cellulose was achieved. Amylose-based block, star, and branched polymeric materials have also been prepared using this enzymatic polymerization. Since phosphorylase shows a loose specificity for the recognition of substrates, different sugar residues have been introduced to the non-reducing ends of maltooligosaccharides by phosphorylase-catalyzed glycosylations using analog substrates such as α-d-glucuronic acid and α-d-glucosamine 1-phosphates. By means of such reactions, an amphoteric glycogen and its corresponding hydrogel were successfully prepared. Thermostable phosphorylase was able to tolerate a greater variance in the substrate structures with respect to recognition than potato phosphorylase, and as a result, the enzymatic polymerization of α-d-glucosamine 1-phosphate to produce a chitosan stereoisomer was carried out using this enzyme catalyst, which was then subsequently converted to the chitin stereoisomer by N-acetylation. Amylose supramolecular inclusion complexes with polymeric guests were obtained when the phosphorylase-catalyzed enzymatic polymerization was conducted in the presence of the guest polymers. Since the structure of this polymeric system is similar to the way that a plant vine twines around a rod, this polymerization system has been named �

B-Vitamin Competition: Intracellular and Dissolved B-Vitamins Provide Insight into Marine Microbial Community Dynamics

Science.gov (United States)

Suffridge, C.; Gomez-Consarnau, L.; Qu, P.; Tenenbaum, N.; Fu, F.; Hutchins, D. A.; Sanudo-Wilhelmy, S. A.

2016-02-01

The availability of B-vitamins has the ability to directly affect the dynamics of the marine microbial community. Here we show, for the first time, the connection between dissolved and intracellular B-vitamins in a marine environmental community. Two incubation experiments were conducted at a long-term study site (SPOT) in the San Pedro Basin off the coast of Los Angeles, CA. Experiments were conducted in oligotrophic, preupwelling conditions. Due to the 2015 El Niño event, the seasonal upwelling at SPOT did not occur, creating unusually nutrient depleted conditions. Vitamins B1, B7, and B12 were added in addition to macronutrients at concentrations similar to typical SPOT upwelling conditions. Intracellular and dissolved B-vitamin analyses were conducted to determine shifts in cellular B-vitamin requirements as a function of growth rate. We observed a significant bacterioplankton and phytoplankton growth responses with the addition of B-vitamins in a manner that appears to match the enzymatic requirements for these compounds (e.g. B1>B7>B12). Intracellular B-vitamin analysis of T0 samples support this observation, as all four forms of B12 were not detectable within cells, yet multiple forms of B1 and B7 were detected at or near levels previously reported. Treatments with B12 and macronutrients were observed to have the greatest growth rates. This finding, in addition to the apparent lack of intracellular B12 in the initial community, appears to indicate that the initial microbial community was limited by B12. The addition of each vitamin caused a distinct shift in the blooming microbial community. Our results demonstrate that B-vitamins strongly influence not only the growth rate, but also the species composition and species succession of the microbial community as a whole. Large-scale changes to upwelling regimes are predicted in the future ocean; our results indicate that B-vitamins will have a substantial role in controlling microbial community dynamics under

Understanding the effects of lignosulfonate on enzymatic saccharification of pure cellulose

Science.gov (United States)

Hongming Lou; Haifeng Zhou; Xiuli Li; Mengxia Wang; J.Y. Zhu; Xueqing Qiu

2014-01-01

The effects of lignosulfonate (LS) on enzymatic saccharification of pure cellulose were studied. Four fractions of LS with different molecular weight (MW) prepared by ultrafiltration of a commercial LS were applied at different loadings to enzymatic hydrolysis of Whatman paper under different pH. Using LS fractions with low MW and high degree of sulfonation can enhance...

Rapid and sensitive enzymatic-radiochemical assay for the determination of triglycerides

International Nuclear Information System (INIS)

Khoo, J.C.; Miller, E.; Goldberg, D.I.

1987-01-01

An enzymatic-radiochemical method suitable for the determination of triglyceride levels of cells in culture is described. The method is based on the enzymatic hydrolysis of triglycerides to free fatty acids which then complex with 63 Ni. The method is rapid, accurate, and inexpensive. The procedure extends the sensitivity of triglyceride measurement to as low as 0.25 nanomoles

Electrochemical, Chemical and Enzymatic Oxidations of Phenothiazines

NARCIS (Netherlands)

Blankert, B.; Hayen, H.; van Leeuwen, S.M.; Karst, U.; Bodoki, E.; Lotrean, S.; Sandulescu, R.; Mora Diaz, N.; Dominguez, O.; Arcos, J.; Kauffmann, J.-M.

2005-01-01

The oxidation of several phenothiazine drugs (phenothiazine, promethazine hydrochloride, promazine hydrochloride, trimeprazine hydrochloride and ethopropazine hydrochloride) has been carried out in aqueous acidic media by electrochemical, chemical and enzymatic methods. The chemical oxidation was

Microbial biosensors

International Nuclear Information System (INIS)

Le Yu; Chen, Wilfred; Mulchandani, Ashok

2006-01-01

A microbial biosensor is an analytical device that couples microorganisms with a transducer to enable rapid, accurate and sensitive detection of target analytes in fields as diverse as medicine, environmental monitoring, defense, food processing and safety. The earlier microbial biosensors used the respiratory and metabolic functions of the microorganisms to detect a substance that is either a substrate or an inhibitor of these processes. Recently, genetically engineered microorganisms based on fusing of the lux, gfp or lacZ gene reporters to an inducible gene promoter have been widely applied to assay toxicity and bioavailability. This paper reviews the recent trends in the development and application of microbial biosensors. Current advances and prospective future direction in developing microbial biosensor have also been discussed

Childhood microbial keratitis

Directory of Open Access Journals (Sweden)

Abdullah G Al Otaibi

2012-01-01

Conclusion: Children with suspected microbial keratitis require comprehensive evaluation and management. Early recognition, identifying the predisposing factors and etiological microbial organisms, and instituting appropriate treatment measures have a crucial role in outcome. Ocular trauma was the leading cause of childhood microbial keratitis in our study.

Enzymatic saccharification of brown seaweed for production of fermentable sugars.

Science.gov (United States)

Sharma, Sandeep; Horn, Svein Jarle

2016-08-01

This study shows that high drying temperatures negatively affect the enzymatic saccharification yield of the brown seaweed Saccharina latissima. The optimal drying temperature of the seaweed in terms of enzymatic sugar release was found to be 30°C. The enzymatic saccharification process was optimized by investigating factors such as kinetics of sugar release, enzyme dose, solid loading and different blend ratios of cellulases and an alginate lyase. It was found that the seaweed biomass could be efficiently hydrolysed to fermentable sugars using a commercial cellulase cocktail. The inclusion of a mono-component alginate lyase was shown to improve the performance of the enzyme blend, in particular at high solid loadings. At 25% dry matter loading a combined glucose and mannitol concentration of 74g/L was achieved. Copyright © 2016 Elsevier Ltd. All rights reserved.

ENZYMATIC AND NON-ENZYMATIC ANTIOXIDANT DEFENSE WITH ALZHEIMER DISEASE1

Directory of Open Access Journals (Sweden)

A. Vaisi-Raygani

2007-07-01

Full Text Available The etiopathogenesis of Alzheimer's disease (AD is still unclear.  However, long-term oxidative stress is believed to be one of the major contributing factors in progression of neuronal degeneration and decline of cognitive function in AD. In order to assess the presence of oxidative stress in AD, we examined the enzymatic activities of the erythrocyte Cu-Zn superoxide dismutase (Cu-Zn SOD, glutathione peroxidase (GSH-Px, catalase (CAT, and plasma level of total antioxidant status (TAS in AD and control groups (age and sex-matched. The results showed that the Cu-Zn SOD activity was significantly higher and the level of GSH-Px and TAS activities were significantly lower in AD subjects than that in the control group (2111 ± 324 U/grHb, 43.7 ± 11.6 U/grHb, and 1.17 ± 0.23 mmol/l compared with 1371 ± 211 U/grHb; t= -2.17, P = 0.036, 56.3 ± 9.5 U/grHb; t=3.8, P = 0.014, and 1.54±0.2 mmol/l; t=11.18, P < 0.001, respectively.  While, the erythrocyte CAT activity was lower in AD subjects compared to the control group, the difference was not statistically significant (t = 1.3, P = 0.15. These findings support the idea that the oxidative stress plays an important role in the pathogenesis underlying AD neurodegeneration. In addition, the enzymatic activity of the erythrocyte Cu-Zn SOD and GSH-Px and the plasma level of TAS can be used as a measure of the oxidative stress and a marker for pathological changes in the brain of patients with AD. 

A Networks Approach to Modeling Enzymatic Reactions.

Science.gov (United States)

Imhof, P

2016-01-01

Modeling enzymatic reactions is a demanding task due to the complexity of the system, the many degrees of freedom involved and the complex, chemical, and conformational transitions associated with the reaction. Consequently, enzymatic reactions are not determined by precisely one reaction pathway. Hence, it is beneficial to obtain a comprehensive picture of possible reaction paths and competing mechanisms. By combining individually generated intermediate states and chemical transition steps a network of such pathways can be constructed. Transition networks are a discretized representation of a potential energy landscape consisting of a multitude of reaction pathways connecting the end states of the reaction. The graph structure of the network allows an easy identification of the energetically most favorable pathways as well as a number of alternative routes. © 2016 Elsevier Inc. All rights reserved.

Microbial quality of soil from the Pampa biome in response to different grazing pressures

Directory of Open Access Journals (Sweden)

Rafael S. Vargas

2015-06-01

Full Text Available The aim of this study was to evaluate the impact of different grazing pressures on the activity and diversity of soil bacteria. We performed a long-term experiment in Eldorado do Sul, southern Brazil, that assessed three levels of grazing pressure: high pressure (HP, with 4% herbage allowance (HA, moderate pressure (MP, with 12% HA, and low pressure (LP, with 16% HA. Two reference areas were also assessed, one of never-grazed native vegetation (NG and another of regenerated vegetation after two years of grazing (RG. Soil samples were evaluated for microbial biomass and enzymatic (β-glucosidase, arylsulfatase and urease activities. The structure of the bacterial community and the population of diazotrophic bacteria were evaluated by RFLP of the 16S rRNA and nifH genes, respectively. The diversity of diazotrophic bacteria was assessed by partial sequencing of the 16S rDNA gene. The presence of grazing animals increased soil microbial biomass in MP and HP. The structures of the bacterial community and the populations of diazotrophic bacteria were altered by the different grazing managements, with a greater diversity of diazotrophic bacteria in the LP treatment. Based on the characteristics evaluated, the MP treatment was the most appropriate for animal production and conservation of the Pampa biome.

Enzymatic detection of formalin-fixed museum specimens for DNA analysis and enzymatic maceration of formalin-fixed specimens

DEFF Research Database (Denmark)

Sørensen, Margrethe; Redsted Rasmussen, Arne; Simonsen, Kim Pilkjær

2016-01-01

% ethanol. The method was subsequently tested on wild-living preserved specimens and an archived specimen. The protease enzyme used was SavinaseH 16 L, Type EX from Novozymes A/S. The enzymatic screening test demands only simple laboratory equipment. The method is useful for natural history collections...

Starch facilitates enzymatic wheat gluten hydrolysis

NARCIS (Netherlands)

Hardt, N.A.; Boom, R.M.; Goot, van der A.J.

2015-01-01

Wheat gluten can be hydrolyzed by either using (vital) wheat gluten or directly from wheat flour. This study investigates the influence of the presence of starch, the main component of wheat, on enzymatic wheat gluten hydrolysis. Wheat gluten present in wheat flour (WFG) and vital wheat gluten (VWG)

Characterization of microbial metabolism of Syrah grape products in an in vitro colon model using targeted and non-targeted analytical approaches.

Science.gov (United States)

Aura, Anna-Marja; Mattila, Ismo; Hyötyläinen, Tuulia; Gopalacharyulu, Peddinti; Cheynier, Veronique; Souquet, Jean-Marc; Bes, Magali; Le Bourvellec, Carine; Guyot, Sylvain; Orešič, Matej

2013-03-01

Syrah red grapes are used in the production of tannin-rich red wines. Tannins are high molecular weight molecules, proanthocyanidins (PAs), and poorly absorbed in the upper intestine. In this study, gut microbial metabolism of Syrah grape phenolic compounds was investigated. Syrah grape pericarp was subjected to an enzymatic in vitro digestion model, and red wine and grape skin PA fraction were prepared. Microbial conversion was screened using an in vitro colon model with faecal microbiota, by measurement of short-chain fatty acids by gas chromatography (GC) and microbial phenolic metabolites using GC with mass detection (GC-MS). Red wine metabolites were further profiled using two-dimensional GC mass spectrometry (GCxGC-TOFMS). In addition, the effect of PA structure and dose on conversion efficiency was investigated by GC-MS. Red wine exhibited a higher degree of C1-C3 phenolic acid formation than PA fraction or grape pericarp powders. Hydroxyphenyl valeric acid (flavanols and PAs as precursors) and 3,5-dimethoxy-4-hydroxybenzoic acid (anthocyanin as a precursor) were identified from the red wine metabolite profile. In the absence of native grape pericarp or red wine matrix, the isolated PAs were found to be effective in the dose-dependent inhibition of microbial conversions and short-chain fatty acid formation. Metabolite profiling was complementary to targeted analysis. The identified metabolites had biological relevance, because the structures of the metabolites resembled fragments of their grape phenolic precursors or were in agreement with literature data.

Cost analysis of enzymatic biodiesel production in small-scaled packed-bed reactors

NARCIS (Netherlands)

Budzaki, S.; Miljic, G.; Sundaram, S.; Tisma, M.; Hessel, V.

2017-01-01

A cost analysis of enzymatic biodiesel production in small-scaled packed-bed reactors using refined sunflower oil is performed in this work. A few enzymatic micro-flow reactors have so far reached a performance close to gram-scale, which might be sufficient for the pharmaceutical industry. This

Characterization of Volatile Flavor Compounds in Chinese Rice Wine Fermented from Enzymatic Extruded Rice.

Science.gov (United States)

Xu, Enbo; Long, Jie; Wu, Zhengzong; Li, Hongyan; Wang, Fang; Xu, Xueming; Jin, Zhengyu; Jiao, Aiquan

2015-07-01

Enzymatic extrusion, instead of traditional steam cooking, to treat rice is an efficient and alternative pretreatment for Chinese rice wine fermentation. In order to determine the formation of volatiles in enzymatic extrusion-processed rice wine (EE), and to confirm its characteristic flavor compounds, headspace solid-phase micro-extraction followed by GC-MS was used. A total of 66 volatile compounds were identified in EE. During fermentation, most volatiles generated from enzymatic extruded rice had the similar trends with those from steam-cooked rice, but the differences in the concentration of volatiles indicated a changed balance of flavors release caused by enzymatic extrusion. Besides, the concentrations and sorts of volatiles in EEs fermented from different rice particle sizes, were not dramatically different. By principal component analysis, EE could be distinctly separated from other traditional Chinese rice wines according to its characteristic volatiles, namely, 2-heptanol, 1-octen-3-ol, ethyl 4-hydroxybenzoate, methylpentyl 2-propenoate, γ-hexalactone, and 4-vinylguaiacol. Enzymatic extrusion liquefaction has been a popular thermal treatment for cereals, and gradually being applied in fermentation and liquor-making industry all over the world. The characterization of volatile flavor compounds in Chinese rice wine processed by enzymatic extrusion liquefaction pretreatment, might be made use not only for a better understanding of this new-type rice wine, but for the further utilization of enzymatic extrusion in other wine or alcohol production as well. © 2015 Institute of Food Technologists®

Bioethanol production: Pretreatment and enzymatic hydrolysis of softwood

Energy Technology Data Exchange (ETDEWEB)

Tengborg, Charlotte

2000-05-01

The enzymatic hydrolysis process can be used to produce bioethanol from softwood, which are the dominating raw material in the Northern hemisphere. This thesis deals with the development of the process focusing on the pretreatment and the enzymatic hydrolysis stages. The influence of pretreatment conditions on sugar yield, and the effect of inhibitors on the ethanol yield, were investigated for spruce and pine. The maximum yields of hemicellulose sugars and glucose were obtained under different pretreatment conditions. This indicates that two-stage pretreatment may be preferable. The added catalysts, H{sub 2}SO{sub 4} and SO{sub 2}, resulted in similar total sugar yields about 40 g/100 g dry raw material. However, the fermentability of SO{sub 2}-impregnated material was better. This pretreatment resulted in the formation of inhibitors to the subsequent process steps, e.g. sugar and lignin degradation products. The glucose yield in the enzymatic hydrolysis stage was affected by various parameters such as enzyme loading, temperature, pH, residence time, substrate concentration, and agitation. To decrease the amount of fresh water used and thereby waste water produced, the sugar-rich prehydrolysate from the pretreatment step was included in the enzymatic hydrolysis of the solid fraction, resulting in a reduction in the cellulose conversion of up to 36%. Different prehydrolysate detoxification methods, such as treatment with Ca(OH){sub 2}, laccase, and fermentation using yeast, were investigated. The latter was shown to be very efficient. The amount of fresh water used can be further reduced by recycling various process streams. This was simulated experimentally in a bench-scale process. A reduction in fresh water demand of 50% was obtained without any further negative effects on either hydrolysis or fermentation.

Substrate specificity and copper loading of the manganese-oxidizing multicopper oxidase Mnx from Bacillus sp. PL-12.

Science.gov (United States)

Butterfield, Cristina N; Tebo, Bradley M

2017-02-22

Manganese(ii) oxidation in the environment is thought to be driven by bacteria because enzymatic catalysis is many orders of magnitude faster than the abiotic processes. The heterologously purified Mn oxidase (Mnx) from marine Bacillus sp. PL-12 is made up of the multicopper oxidase (MCO) MnxG and two small Cu and heme-binding proteins of unknown function, MnxE and MnxF. Mnx binds Cu and oxidizes both Mn(ii) and Mn(iii), generating Mn(iv) oxide minerals that resemble those found on the Bacillus spore surface. Spectroscopic techniques have illuminated details about the metallo-cofactors of Mnx, but very little is known about their requirement for catalytic activity, and even less is known about the substrate specificity of Mnx. Here we quantify the canonical MCO Cu and persistent peripheral Cu bound to Mnx, and test Mnx oxidizing ability toward different substrates at varying pH. Mn(ii) appears to be the best substrate in terms of k cat , but its oxidation does not follow Michaelis-Menten kinetics, instead showing a sigmoidal cooperative behavior. Mnx also oxidizes Fe(ii) substrate, but in a Michaelis-Menten manner and with a decreased activity, as well as organic substrates. The reduced metals are more rapidly consumed than the larger organic substrates, suggesting the hypothesis that the Mnx substrate site is small and tuned for metal oxidation. Of biological relevance is the result that Mnx has the highest catalytic efficiency for Mn(ii) at the pH of sea water, especially when the protein is loaded with greater than the requisite four MCO copper atoms, suggesting that the protein has evolved specifically for Mn oxidation.

Production of a generic microbial feedstock for lignocellulose biorefineries through sequential bioprocessing.

Science.gov (United States)

Chang, Chen-Wei; Webb, Colin

2017-03-01

Lignocellulosic materials, mostly from agricultural and forestry residues, provide a potential renewable resource for sustainable biorefineries. Reducing sugars can be produced only after a pre-treatment stage, which normally involves chemicals but can be biological. In this case, two steps are usually necessary: solid-state cultivation of fungi for deconstruction, followed by enzymatic hydrolysis using cellulolytic enzymes. In this research, the utilisation of solid-state bioprocessing using the fungus Trichoderma longibrachiatum was implemented as a simultaneous microbial pretreatment and in-situ enzyme production method for fungal autolysis and further enzyme hydrolysis of fermented solids. Suspending the fermented solids in water at 50°C led to the highest hydrolysis yields of 226mg/g reducing sugar and 7.7mg/g free amino nitrogen (FAN). The resultant feedstock was shown to be suitable for the production of various products including ethanol. Copyright © 2016 Elsevier Ltd. All rights reserved.

Microstructural study of pre-treated and enzymatic hydrolyzed bamboo

Directory of Open Access Journals (Sweden)

Funsho O. KOLAWOLE

2016-07-01

Full Text Available Bamboo was used as biomass feedstock which was pre-treated using dilute acid hydrolysis followed by enzymatic hydrolysis. The bamboo was mechanical ground to particle sizes 212–500µm, followed by pre-treatment with dilute sulfuric acid at a concentration of 0.5 and 1.0 (%v/v at temperatures of 25, 110, 120, 150 and 200°C with time intervals of 2 and 4 hours. Pre-hydrolyzate was later analyzed for reducing sugar using UV-Vis spectrophotometry. Under the above conditions, a maximum glucose yield of 153.1 mg/g was obtained at 200°C and acid concentrations of 1% for 4 hours. Water insoluble solids obtained were subsequently hydrolyzed with Celluclast (Trichoderma reesi and β-glucosidase (Novozyme 188 for 72 hours. Optical Microscope and ESEM images of bamboo samples were obtained at various stages of pre-treatment and enzymatic hydrolysis. Result reveals a breakdown in the ligno-cellulosic structure of the bamboo during exposure to dilute acid and enzymatic hydrolysis.

ASSOCIATION BETWEEN ENZYMATIC AND NON-ENZYMATIC ANTIOXIDANT DEFENSE WITH ALZHEIMER DISEASE

Directory of Open Access Journals (Sweden)

A. Vaisi-Raygani

2008-04-01

Full Text Available The etiopathogenesis of dementia in Alzheimer's disease (AD is still unclear. However, long-term oxidative stress is believed to be one of the major contributing factors in progression of neuronal degeneration and decline of cognitive function in AD. In order to assess the presence of oxidative stress in AD, we examined the enzymatic activities of the erythrocyte Cu-Zn superoxide dismutase (Cu-Zn SOD, glutathione peroxidase (GSH-Px, catalase (CAT, and plasma level of total antioxidant status (TAS in AD and control groups (age and sex-matched. The results showed that the Cu-Zn SOD activity was significantly higher and the level of GSH-Px and TAS activities were significantly lower in AD subjects than that in the control group (2111±324 U/grHb, 43.7±11.6 U/grHb, and 1.17 ±0.23 mmol/L compared with 1371±211 U/gHb; t= -2.17, p=0.036, 56.3±9.5 U/gHb; t=3.8, p=0.014, and 1.54±0.2 mmol/L; t=11.18, P<0.001, respectively. While, the erythrocyte CAT activity was lower in AD subjects compared to the control group, the difference was not statistically significant (t=1.3, P=0.15. These findings support the idea that the oxidative stress plays an important role in the pathogenesis underlying AD neurodegeneration. In addition, the enzymatic activity of the erythrocyte Cu-Zn SOD and GSH-Px and the plasma level of TAS can be used as a measure of the oxidative stress and a marker for pathological changes in the brain of patients with AD.

Characterization of bacterial functional groups and microbial activity in microcosms with glyphosate application

Science.gov (United States)

Moyano, Sofia; Bonetto, Mariana; Baigorria, Tomas; Pegoraro, Vanesa; Ortiz, Jimena; Faggioli, Valeria; Conde, Belen; Cazorla, Cristian; Boccolini, Monica

2017-04-01

Glyphosate is a worldwide used herbicide as c. 90% of transgenic crops are tolerant to it. Microbial degradation of glyphosate molecule in soil is considered the most important process that determines its persistence in the environment. However, the impact of this herbicide on target groups of soil biota remains poorly understood. Our objective was to characterize the abundance of bacterial groups and global microbial activity, under controlled conditions with application of increasing doses of glyphosate. A bioassay was carried out in microcosms using an agricultural soil (Typic Argiudoll) with registered history of glyphosate application from National Institute of Agricultural Technology (INTA, EEA Marcos Juarez, Argentina). Glyphosate of commercial formulation (74.7%) was used and the following treatments were evaluated: Soil without glyphosate (control), and Soil with doses equivalent to 1.12 and 11.2 kg ai ha-1. Microbiological parameters were estimated at 3, 7, 14 and 21 days after herbicide application by counting heterotrophic, cellulolytic, nitrogen fixing (N), and nitrifying bacteria; and fluorescein diacetate hydrolysis (FDA), microbial respiration (MR) and microbial biomass (C-BM). The N cycle related bacteria showed greater sensitivity to glyphosate with significant increases in abundance. On the other hand the C cycle parameters were strongly conditioned by the time elapsed since the application of the herbicide, as did the MR. The FDA declined with the highest dose, while the C-BM was not affected. Therefore, we conclude that in the studied experimental conditions glyphosate stimulated bacterial growth (i.e. target abundances) representing a source of N, C and nutrients. On the other hand, enzymatic activity (FDA) decreased when glyphosate was applied in the highest dose, whereas, it had no effect on the MR nor C-BM, which could be attributable to the organic matter content of the soil. However, future research in field conditions is necessary, for

Enzymatic studies on phosphorus availability from phosphate compounds by microbial activities using nuclear techniques

International Nuclear Information System (INIS)

Abou Seer, A.M.M.

2002-01-01

the present study aimed to evaluate to evaluate the of phosphate solubilizing bacteria (PSB) and vesicular arbuscular mycorrhizae(VAM) as microbiological mean to convert the sparingly soluble P into available from utilized by plant through excretion of acid and alkaline phosphatase. rock phosphate as natural and a cheap source of P- fertilizer was applied in the present study. To trace the effect of microbial activity and phosphatase enzymes on phosphate availability from its compounds , set of experiments were conducted either in the lab. or green house. The obtained results could be summarized as following:- 1- phosphate solubilizing bacteria(PSB) w isolated from samples of fertile soil, 16 colonies showed positive reaction were chosen .2- bacteria , which exhibited high phosphate clearing zone (PCZ) selected to detect their efficiencies for dissolving rock phospate and select the effective one (most potent) on the basis of highest production of phosphatase and phosphorus solubilization.3- identification of the most potent (pseudomonas aeruginosa) 4- effective environmental and nutritional factors on phosphatase production by pseudomonas aeruginosa were discussed.green-house experiment: inoculation of wheat (triticum aestivum cv.sakha 8) with either PSB and /or VAM with or without rock-P fertilization was under taken. dual inoculation with psb (pseudomonas aeruginosa) and VAM improved the dry matter yield and N and P uptake by wheat as compared to other treatments. application of psb as well as VAM increased the availability of rock phosphate to be utilized by wheat

Structural changes in lignin during organosolv pretreatment of Liriodendron tulipifera and the effect on enzymatic hydrolysis

International Nuclear Information System (INIS)

Koo, Bon-Wook; Min, Byeong-Cheol; Gwak, Ki-Seob; Lee, Soo-Min; Choi, Joon-Weon; Yeo, Hwanmyeong; Choi, In-Gyu

2012-01-01

Although organosolv pretreatment removed substantial amounts of lignin and xylan, the yield of glucan which is a major sugar source for fermentation to ethanol is more than 90% in most conditions of the organosolv pretreatment. Relative lignin contents of all pretreated biomass were more than 200 g kg −1 , however enzymatic conversions were increased dramatically comparing to untreated biomass. Therefore the correlation between lignin and enzymatic hydrolysis could not be explained just by lignin content, and other changes resulting from lignin removal affected enzymatic hydrolysis. Results on enzymatic conversion and sugar recovery suggested that the critical temperature improving enzymatic hydrolysis significantly was between 120 °C and 130 °C. Microscopic analysis using Field emission scanning electron microscopy (FE-SEM) showed that structural lignin changes happened through organosolv pretreatment. Lignins were isolated from lignin carbohydrate complex (LCC) at the initial stage and then migrated to the surface of biomass. The isolated and migrated lignins were finally redistributed onto surface. These structural changes formed droplets on surface and increased pore volume in pretreated biomass. The increase in pore volume also increased available surface area and enzyme adsorption at initial stage, and thus enzymatic conversion increased significantly through organosolv pretreatment. It was verified that the droplets were mainly composed of lignin and the lignin droplets inhibited enzymatic hydrolysis through adsorption with cellulase. -- Highlights: ► Just lignin contents cannot explain a correlation with enzymatic hydrolysis. ► Several changes resulted from lignin removal must affect enzymatic hydrolysis. ► Droplets are formed by structural changes in lignin during organosolv pretreatment. ► Formation of the lignin droplet increases the pore volume in biomass. ► The increase in pore volume enhances the enzymatic hydrolysis.

Enzymatic reduction of U(VI) in groundwaters

International Nuclear Information System (INIS)

Addelouas, A.; Gong, W.; Lutze, W.; Nuttall, E.; Fritz, B.; Crovisier, J.L.

1999-01-01

The use of enzymatic reduction of U(VI) in remediation of groundwater contaminated with U(VI) is receiving considerable attention. Certain strains of bacteria can combine the oxidation of an organic compound to the reduction of U(VI) to U(IV), which precipitates as uraninite. In the present study, we tested the reduction of U(VI) in groundwaters with various origins and compositions. In all groundwaters u(VI) was reduced by sulfate reducing bacteria that had been activated by ethanol and tri-metaphosphate. The reduction rate of U(VI) depends on sulfate concentration in water and the abundance of bacteria in the system. This work shows that bacteria capable of U(VI) reduction are ubiquitous in nature, and suggests the possibility of a large application of the enzymatic reduction of U(VI) for in situ clean up of groundwaters contaminated with uranium. (authors)

Investigation of bi-enzymatic reactor based on hybrid monolith with nanoparticles embedded and its proteolytic characteristics.

Science.gov (United States)

Shangguan, Lulu; Zhang, Lingyi; Xiong, Zhichao; Ren, Jun; Zhang, Runsheng; Gao, Fangyuan; Zhang, Weibing

2015-04-03

The bottom-up strategy of proteomic profiling study based on mass spectrometer (MS) has drawn high attention. However, conventional solution-based digestion could not satisfy the demands of highly efficient and complete high throughput proteolysis of complex samples. We proposed a novel bi-enzymatic reactor by immobilizing two different enzymes (trypsin/chymotrypsin) onto a mixed support of hybrid organic-inorganic monolith with SBA-15 nanoparticles embedded. Typsin and chymotrypsin were crossly immobilized onto the mixed support by covalent bonding onto the monolith with glutaraldehyde as bridge reagent and chelation via copper ion onto the nanoparticles, respectively. Compared with single enzymatic reactors, the bi-enzymatic reactor improved the overall functional analysis of membrane proteins of rat liver by doubling the number of identified peptides (from 1184/1010 with trypsin/chymotrypsin enzymatic reactors to 2891 with bi-enzymatic reactor), which led to more proteins identified with deep coverage (from 452/336 to 620); the efficiency of the bi-enzymatic reactor is also better than that of solution-based tandem digestion, greatly shorting the digestion time from 24h to 50s. Moreover, more transmembrane proteins were identified by bi-enzymatic reactor (106) compared with solution-based tandem digestion (95) with the same two enzymes and enzymatic reactors with single enzyme immobilized (75 with trypsin and 66 with chymotrypsin). The proteolytic characteristics of the bi-enzymatic reactors were evaluated by applying them to digestion of rat liver proteins. The reactors showed good digestion capability for proteins with different hydrophobicity and molecular weight. Copyright © 2015 Elsevier B.V. All rights reserved.

Adhesion improvement of lignocellulosic products by enzymatic pre-treatment.

Science.gov (United States)

Widsten, Petri; Kandelbauer, Andreas

2008-01-01

Enzymatic bonding methods, based on laccase or peroxidase enzymes, for lignocellulosic products such as medium-density fiberboard and particleboard are discussed with reference to the increasing costs of presently used petroleum-based adhesives and the health concerns associated with formaldehyde emissions from current composite products. One approach is to improve the self-bonding properties of the particles by oxidation of their surface lignin before they are fabricated into boards. Another method involves using enzymatically pre-treated lignins as adhesives for boards and laminates. The application of this technology to achieve wet strength characteristics in paper is also reviewed.

Evaluation of wet oxidation pretreatment for enzymatic hydrolysis of softwood

DEFF Research Database (Denmark)

Palonen, H.; Thomsen, A.B.; Tenkanen, M.

2004-01-01

The wet oxidation pretreatment (water, oxygen, elevated temperature, and pressure) of softwood (Picea abies) was investigated for enhancing enzymatic hydrolysis. The pretreatment was preliminarily optimized. Six different combinations of reaction time, temperature, and pH were applied......, and the compositions of solid and liquid fractions were analyzed. The solid fraction after wet oxidation contained 58-64% cellulose, 2-16% hemicellulose, and 24-30% lignin. The pretreatment series gave information about the roles of lignin and hemicellulose in the enzymatic hydrolysis. The temperature...

Microbial community structure elucidates performance of Glyceria maxima plant microbial fuel cell

OpenAIRE

Timmers, R.A.; Rothballer, M.; Strik, D.P.B.T.B.; Engel, M.; Schulz, M.; Hartmann, A.; Hamelers, H.V.M.; Buisman, C.J.N.

2012-01-01

The plant microbial fuel cell (PMFC) is a technology in which living plant roots provide electron donor, via rhizodeposition, to a mixed microbial community to generate electricity in a microbial fuel cell. Analysis and localisation of the microbial community is necessary for gaining insight into the competition for electron donor in a PMFC. This paper characterises the anode-rhizosphere bacterial community of a Glyceria maxima (reed mannagrass) PMFC. Electrochemically active bacteria (EAB) w...

Microbial community structure elucidates performance of Glyceria maxima plant microbial fuel cell

OpenAIRE

Timmers, Ruud A.; Rothballer, Michael; Strik, David P. B. T. B.; Engel, Marion; Schulz, Stephan; Schloter, Michael; Hartmann, Anton; Hamelers, Bert; Buisman, Cees

2012-01-01

The plant microbial fuel cell (PMFC) is a technology in which living plant roots provide electron donor, via rhizodeposition, to a mixed microbial community to generate electricity in a microbial fuel cell. Analysis and localisation of the microbial community is necessary for gaining insight into the competition for electron donor in a PMFC. This paper characterises the anode–rhizosphere bacterial community of a Glyceria maxima (reed mannagrass) PMFC. Electrochemically active bacteria (EAB) w...

Starch: chemistry, microstructure, processing and enzymatic degradation

Science.gov (United States)

Starch is recognized as one of the most abundant and important commodities containing value added attributes for a vast number of industrial applications. Its chemistry, structure, property and susceptibility to various chemical, physical and enzymatic modifications offer a high technological value ...

Enzymatic production of polysaccharides from gum tragacanth

DEFF Research Database (Denmark)

2014-01-01

Plant polysaccharides, relating to the field of natural probiotic components, can comprise structures similar to human milk oligosaccharides. A method for enzymatic hydrolysis of gum tragacanth from the bush-like legumes of the genus Astragalus, using a combination of pectin hydrolases...

Nonfeed application of rendered animal proteins for microbial production of eicosapentaenoic acid by the fungus Pythium irregulare.

Science.gov (United States)

Liang, Yi; Garcia, Rafael A; Piazza, George J; Wen, Zhiyou

2011-11-23

Rendered animal proteins are well suited for animal nutrition applications, but the market is maturing, and there is a need to develop new uses for these products. The objective of this study is to explore the possibility of using animal proteins as a nutrient source for microbial production of omega-3 polyunsaturated fatty acids by the microalga Schizochytrium limacinum and the fungus Pythium irregulare. To be absorbed by the microorganisms, the proteins needed to be hydrolyzed into small peptides and free amino acids. The utility of the protein hydrolysates for microorganisms depended on the hydrolysis method used and the type of microorganism. The enzymatic hydrolysates supported better cell growth performance than the alkali hydrolysates did. P. irregulare displayed better overall growth performance on the experimental hydrolysates compared to S. limacinum. When P. irregulare was grown in medium containing 10 g/L enzymatic hydrolysate derived from meat and bone meal or feather meal, the performance of cell growth, lipid synthesis, and omega-3 fatty acid production was comparable to the that of culture using commercial yeast extract. The fungal biomass derived from the animal proteins had 26-29% lipid, 32-34% protein, 34-39% carbohydrate, and industrial microorganisms which can produce omega-3 fatty acids for making omega-3-fortified foods or feeds.

Sequence homolog-based molecular engineering for shifting the enzymatic pH optimum

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Fuqiang Ma

2016-09-01

Full Text Available Cell-free synthetic biology system organizes multiple enzymes (parts from different sources to implement unnatural catalytic functions. Highly adaption between the catalytic parts is crucial for building up efficient artificial biosynthetic systems. Protein engineering is a powerful technology to tailor various enzymatic properties including catalytic efficiency, substrate specificity, temperature adaptation and even achieve new catalytic functions. However, altering enzymatic pH optimum still remains a challenging task. In this study, we proposed a novel sequence homolog-based protein engineering strategy for shifting the enzymatic pH optimum based on statistical analyses of sequence-function relationship data of enzyme family. By two statistical procedures, artificial neural networks (ANNs and least absolute shrinkage and selection operator (Lasso, five amino acids in GH11 xylanase family were identified to be related to the evolution of enzymatic pH optimum. Site-directed mutagenesis of a thermophilic xylanase from Caldicellulosiruptor bescii revealed that four out of five mutations could alter the enzymatic pH optima toward acidic condition without compromising the catalytic activity and thermostability. Combination of the positive mutants resulted in the best mutant M31 that decreased its pH optimum for 1.5 units and showed increased catalytic activity at pH < 5.0 compared to the wild-type enzyme. Structure analysis revealed that all the mutations are distant from the active center, which may be difficult to be identified by conventional rational design strategy. Interestingly, the four mutation sites are clustered at a certain region of the enzyme, suggesting a potential “hot zone” for regulating the pH optima of xylanases. This study provides an efficient method of modulating enzymatic pH optima based on statistical sequence analyses, which can facilitate the design and optimization of suitable catalytic parts for the construction

Origin, enzymatic response and fate of dissolved organic matter during flood and non-flood conditions in a river-floodplain system of the Danube (Austria).

Science.gov (United States)

Sieczko, Anna; Peduzzi, Peter

2014-01-01

Spectroscopic techniques and extracellular enzyme activity measurements were combined with assessments of bacterial secondary production (BSP) to elucidate flood-pulse-linked differences in carbon (C) sources and related microbial processes in a river-floodplain system near Vienna (Austria). Surface connection with the main channel significantly influenced the quantity and quality of dissolved organic matter (DOM) in floodplain backwaters. The highest values of dissolved organic carbon (DOC) and chromophoric DOM (CDOM) were observed during the peak of the flood, when DOC increased from 1.36 to 4.37 mg l -1 and CDOM from 2.94 to 14.32 m -1 . The flood introduced DOC which consisted of more allochthonously-derived, aromatic compounds. Bacterial enzymatic activity, as a proxy to track the response to changes in DOM, indicated elevated utilization of imported allochthonous material. Based on the enzyme measurements, new parameters were calculated: metabolic effort and enzymatic indices (EEA 1 and EEA 2). During connection, bacterial glucosidase and protease activity were dominant, whereas during disconnected phases a switch to lignin degradation (phenol oxidase) occurred. The enzymatic activity analysis revealed that flooding mobilized reactive DOM, which then supported bacterial metabolism. No significant differences in overall BSP between the two phases were detected, indicating that heterogeneous sources of C sufficiently support BSP. The study demonstrates that floods are important for delivering DOM, which, despite its allochthonous origin, is reactive and can be effectively utilized by aquatic bacteria in this river-floodplain systems. The presence of active floodplains, characterized by hydrological connectivity with the main channel, creates the opportunity to process allochthonous DOC. This has potential consequences for carbon flux, enhancing C sequestration and mineralization processes in this river-floodplain system.

Economical synthesis of silver nanoparticles using leaf extract of Acalypha hispida and its application in the detection of Mn(II ions

Directory of Open Access Journals (Sweden)

R. Sithara

2017-11-01

Full Text Available This study was focused on the synthesis of silver nanoparticles using Acalypha hispida leaf extract and the characterization of the particles using UV–Vis spectroscopy, XRD, FT-IR, and TEM. The results showed the formation of silver nanoparticles, crystalline in nature, with an average size of 20–50 nm. The leaf extract components were analyzed with GC–MS and exhibited a high content of Phytol (40.52%, n-Hexadecanoic acid (9.67%, 1,2,3-Benzenetriol (7.04%, α-d-Mannofuranoside methyl (6.22%, and d-Allose (4.45%. The optimization and statistical investigation of reaction parameters were studied and maximum yield with suitable properties of silver nanoparticles was obtained at leaf extract volume (0.5 mL, the concentration of silver nitrate (1.75 mM, and reaction temperature (50 °C. The method of detecting Mn2+ ions using the colloidal silver nanoparticles was discussed. The minimum and maximum detection limit were found to be 50 and 200 µM of Mn(II ions, respectively. Thus, the obtained results encourage the use of economical synthesis of silver nanoparticles in the development of nanosensors to detect the pollutants present in industrial effluents.

BIOTRANSFORMATION AND REMOVAL OF SULFUR FROM DIBENZOTHIOPHENE USING IMPROVED BIOCATALYTIC METHODS

OpenAIRE

LAROTTA, C. E; MORA, A. L; MADERO, A; MOGOLLÓN, L. I

1998-01-01

Three methods for the removal of sulfurfrom dibenzothiophene were evaluated using biocatalytic processes. The methods were a microbial, an enzymatic and a combined one that involves a previous enzymatic oxidation followed by microbial degradation. The byconversion was evaluated over the molecular dibenzothiophene model, obtaining higher byconversion percentages through the combined method. The microorganisms used in this study correspond to several Colombian indigenous strains isolated by dir...

Perspectives for the industrial enzymatic production of glycosides.

Science.gov (United States)

de Roode, B Mattheus; Franssen, Maurice C R; van der Padt, Albert; Boom, Remko M

2003-01-01

Glycosides are of commercial interest for industry in general and specifically for the pharmaceutical and food industry. Currently chemical preparation of glycosides will not meet EC food regulations, and therefore chemical preparation of glycosides is not applicable in the food industry. Thus, enzyme-catalyzed reactions are a good alternative. However, until now the low yields obtained by enzymatic methods prevent the production of glycosides on a commercial scale. Therefore, high yields should be established by a combination of optimum reaction conditions and continuous removal of the product. Unfortunately, a bioreactor for the commercial scale production of glycosides is not available. The aim of this article is to discuss the literature with respect to enzymatic production of glycosides and the design of an industrially viable bioreactor system.

From Fed-batch to Continuous Enzymatic Biodiesel Production

DEFF Research Database (Denmark)

Price, Jason Anthony; Nordblad, Mathias; Woodley, John M.

2015-01-01

In this this paper, we use mechanistic modelling to guide the development of acontinuous enzymatic process that is performed as a fed-batch operation. In this workwe use the enzymatic biodiesel process as a case study. A mechanistic model developedin our previous work was used to determine...... measured components (triglycerides, diglycerides, monoglycerides, free fatty acid and fatty acid methyl esters(biodiesel)) much better than using fed-batch data alone given the smaller residuals. We also observe a reduction in the correlation between the parameters.The model was then used to predict that 5...... reactors are required (with a combined residence time of 30 hours) to reach a final biodiesel concentration within 2 % of the95.6 mass % achieved in a fed-batch operation, for 24 hours....

Improving biogas production from microalgae by enzymatic pretreatment.

Science.gov (United States)

Passos, Fabiana; Hom-Diaz, Andrea; Blanquez, Paqui; Vicent, Teresa; Ferrer, Ivet

2016-01-01

In this study, enzymatic pretreatment of microalgal biomass was investigated under different conditions and evaluated using biochemical methane potential (BMP) tests. Cellulase, glucohydrolase and an enzyme mix composed of cellulase, glucohydrolase and xylanase were selected based on the microalgae cell wall composition (cellulose, hemicellulose, pectin and glycoprotein). All of them increased organic matter solubilisation, obtaining high values already after 6h of pretreatment with an enzyme dose of 1% for cellulase and the enzyme mix. BMP tests with pretreated microalgae showed a methane yield increase of 8 and 15% for cellulase and the enzyme mix, respectively. Prospective research should evaluate enzymatic pretreatments in continuous anaerobic reactors so as to estimate the energy balance and economic cost of the process. Copyright © 2015 Elsevier Ltd. All rights reserved.

Variations in Enzymatic Activities of Shoots and Roots as an Indicator for Irradiated Seeds

International Nuclear Information System (INIS)

Abdelbbaary, N.A.; Elagamay, M.R.

2005-01-01

Germinated seedlings from oil seeds (sesame and sunflower) and legumes (Trigonella, Haricot, broad bean and cow pea) were irradiated with gamma rays at doses of 0, 0.2, 0.4, 0.8 and 1 kGy and the data were collected from shoots and roots. Enzymatic activities appeared to be correlated with gamma irradiation dose. The enzymatic activities of irradiated seeds understudy were significantly higher than controls. The peroxidase activities were nearly similar in both roots and shoots, while acid phosphatase activities in roots were higher than in shoots. Also protein contents were higher in roots. The peroxidase and acid phosphatase specific activities in roots were similar. Shoots peroxidase enzymatic activity increased with increased gamma doses. The seedling under study showed two different levels of peroxidase activity, higher as sesame, Trigonella and Sunflower, and lower such as all other legumes understudy. Similar tendency have been also noticed in roots-enzymatic activity, positive correlation between gamma doses treatment and peroxidase enzymatic activity, again two groups higher activity cow pea, broad bean, bean and Trigonella lower such as sesame, such as sesame, sunflower and haircut

Enzymatic conversion of lignocellulose into fermentable sugars

DEFF Research Database (Denmark)

Jørgensen, Henning; Kristensen, Jan Bach; Felby, Claus

2007-01-01

and hemicelluloses but these are not readily accessible to enzymatic hydrolysis and require a pretreatment, which causes an extensive modification of the lignocellulosic structure. A number of pretreatment technologies are under development and being tested in pilot scale. Hydrolysis of lignocellulose carbohydrates...

Evaluation of soluble fraction and enzymatic residual fraction of dilute dry acid, ethylenediamine, and steam explosion pretreated corn stover on the enzymatic hydrolysis of cellulose.

Science.gov (United States)

Qin, Lei; Liu, Li; Li, Wen-Chao; Zhu, Jia-Qing; Li, Bing-Zhi; Yuan, Ying-Jin

2016-06-01

This study is aimed to examine the inhibition of soluble fraction (SF) and enzymatic residual fraction (ERF) in dry dilute acid (DDA), ethylenediamine (EDA) and steam explosion (SE) pretreated corn stover (CS) on the enzymatic digestibility of cellulose. SF of DDA, EDA and SE pretreated CS has high xylose, soluble lignin and xylo-oligomer content, respectively. SF of EDA pretreated CS leads to the highest inhibition, followed by SE and DDA pretreated CS. Inhibition of ERF of DDA and SE pretreated CS is higher than that of EDA pretreated CS. The inhibition degree (A0/A) of SF is 1.76 and 1.21 times to that of ERF for EDA and SE pretreated CS, respectively. The inhibition degree of ERF is 1.05 times to that of SF in DDA pretreated CS. The quantitative analysis shows that SF of EDA pretreated CS, SF and ERF of SE pretreated CS cause significant inhibition during enzymatic hydrolysis. Copyright © 2016 Elsevier Ltd. All rights reserved.

Endophytic fungi and soil microbial community characteristics over different years of phytoremediation in a copper tailings dam of Shanxi, China.

Science.gov (United States)

Tong, Jia; Miaowen, Cao; Juhui, Jing; Jinxian, Liu; Baofeng, Chai

2017-01-01

We conducted a survey of native grass species infected by endophytic fungi in a copper tailings dam over progressive years of phytoremediation. We investigated how endophytic fungi, soil microbial community structure and soil physiochemical properties and enzymatic activity varied in responses to heavy metal pollution over different stages of phytoremediation. endophyte infection frequency increased with years of phytoremediation. Rates of endophyte infection varied among different natural grass species in each sub-dam. Soil carbon content and soil enzymatic activity gradually increased through the years of phytoremediation. endophyte infection rates of Bothriochloa ischaemum and Festuca rubra were positively related to levels of cadmium (Cd) pollution levels, and fungal endophytes associated with Imperata cylindrical and Elymus dahuricus developed tolerance to lead (Pb). The structure and relative abundance of bacterial communities varied little over years of phytoremediation, but there was a pronounced variation in soil fungi types. Leotiomycetes were the dominant class of resident fungi during the initial phytoremediation period, but Pezizomycetes gradually became dominant as the phytoremediation period progressed. Fungal endophytes in native grasses as well as soil fungi and soil bacteria play different ecological roles during phytoremediation processes. Copyright © 2016 Elsevier B.V. All rights reserved.

Proceedings of the 8. International Symposium on Microbial Ecology : microbial biosystems : new frontiers

International Nuclear Information System (INIS)

Bell, C.R.; Brylinsky, M.; Johnson-Green, P.

2000-01-01

A wide range of disciplines were presented at this conference which reflected the importance of microbial ecology and provided an understanding of the factors that determine the growth and activities of microorganisms. The conference attracted 1444 delegates from 54 countries. The research emerging from the rapidly expanding frontier of microbial ecosystems was presented in 62 oral presentation and 817 poster presentations. The two volumes of these proceedings presented a total of 27 areas in microbial ecology, some of which included terrestrial biosystems, aquatic, estuarine, surface and subsurface microbial ecology. Other topics included bioremediation, microbial ecology in industry and microbial ecology of oil fields. Some of the papers highlighted the research that is underway to determine the feasibility of using microorganisms for enhanced oil recovery (EOR). Research has shown that microbial EOR can increase production at lower costs than conventional oil recovery. The use of bacteria has also proven to be a feasible treatment method in the biodegradation of hydrocarbons associated with oil spills. refs., tabs., figs

A singular enzymatic megacomplex from Bacillus subtilis.

Science.gov (United States)

Straight, Paul D; Fischbach, Michael A; Walsh, Christopher T; Rudner, David Z; Kolter, Roberto

2007-01-02

Nonribosomal peptide synthetases (NRPS), polyketide synthases (PKS), and hybrid NRPS/PKS are of particular interest, because they produce numerous therapeutic agents, have great potential for engineering novel compounds, and are the largest enzymes known. The predicted masses of known enzymatic assembly lines can reach almost 5 megadaltons, dwarfing even the ribosome (approximately 2.6 megadaltons). Despite their uniqueness and importance, little is known about the organization of these enzymes within the native producer cells. Here we report that an 80-kb gene cluster, which occupies approximately 2% of the Bacillus subtilis genome, encodes the subunits of approximately 2.5 megadalton active hybrid NRPS/PKS. Many copies of the NRPS/PKS assemble into a single organelle-like membrane-associated complex of tens to hundreds of megadaltons. Such an enzymatic megacomplex is unprecedented in bacterial subcellular organization and has important implications for engineering novel NRPS/PKSs.

[Characterization and microbial community shifts of rice strawdegrading microbial consortia].

Science.gov (United States)

Wang, Chunfang; Ma, Shichun; Huang, Yan; Liu, Laiyan; Fan, Hui; Deng, Yu

2016-12-04

To study the relationship between microbial community and degradation rate of rice straw, we compared and analyzed cellulose-decomposing ability, microbial community structures and shifts of microbial consortia F1 and F2. We determined exoglucanase activity by 3, 5-dinitrosalicylic acid colorimetry. We determined content of cellulose, hemicellulose and lignin in rice straw by Van Soest method, and calculated degradation rates of rice straw by the weight changes before and after a 10-day incubation. We analyzed and compared the microbial communities and functional microbiology shifts by clone libraries, Miseq analysis and real time-PCR based on the 16S rRNA gene and cel48 genes. Total degradation rate, cellulose, and hemicellulose degradation rate of microbial consortia F1 were significantly higher than that of F2. The variation trend of exoglucanase activity in both microbial consortia F1 and F2 was consistent with that of cel48 gene copies. Microbial diversity of F1 was complex with aerobic bacteria as dominant species, whereas that of F2 was simple with a high proportion of anaerobic cellulose decomposing bacteria in the later stage of incubation. In the first 4 days, unclassified Bacillales and Bacillus were dominant in both F1 and F2. The dominant species and abundance became different after 4-day incubation, Bacteroidetes and Firmicutes were dominant phyla of F1 and F2, respectively. Although Petrimonas and Pusillimonas were common dominant species in F1 and F2, abundance of Petrimonas in F2 (38.30%) was significantly higher than that in F1 (9.47%), and the abundance of Clostridiales OPB54 in F2 increased to 14.85% after 8-day incubation. The abundance of cel48 gene related with cellulose degradation rate and exoglucanase activity, and cel48 gene has the potential as a molecular marker to monitor the process of cellulose degradation. Microbial community structure has a remarkable impact on the degradation efficiency of straw cellulose, and Petrimonas

Xylanase supplementation on enzymatic saccharification of dilute acid pretreated poplars at different severities

Science.gov (United States)

Chao Zhang; Xinshu Zhuang; Zhao Jiang Wang; Fred Matt; Franz St. John; J.Y. Zhu

2013-01-01

Three pairs of solid substrates from dilute acid pretreatment of two poplar wood samples were enzymatically hydrolyzed by cellulase preparations supplemented with xylanase. Supplementation of xylanase improved cellulose saccharification perhaps due to improved cellulose accessibility by xylan hydrolysis. Total xylan removal directly affected enzymatic cellulose...

Enzymatic Hydrolysis of Alkaline Pretreated Coconut Coir

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Akbarningrum Fatmawati

2013-06-01

Full Text Available The purpose of this research is to study the effect of concentration and temperature on the cellulose and lignin content, and the reducing sugars produced in the enzymatic hydrolysis of coconut coir. In this research, the coconut coir is pretreated using 3%, 7%, and 11% NaOH solution at 60oC, 80oC, and 100oC. The pretreated coir were assayed by measuring the amount of cellulose and lignin and then hydrolysed using Celluclast and Novozyme 188 under various temperature (30oC, 40oC, 50oC and pH (3, 4, 5. The hydrolysis results were assayed for the reducing sugar content. The results showed that the alkaline delignification was effective to reduce lignin and to increase the cellulose content of the coir. The best delignification condition was observed at 11% NaOH solution and 100oC which removed 14,53% of lignin and increased the cellulose content up to 50,23%. The best condition of the enzymatic hydrolysis was obtained at 50oC and pH 4 which produced 7,57 gr/L reducing sugar. © 2013 BCREC UNDIP. All rights reservedReceived: 2nd October 2012; Revised: 31st January 2013; Accepted: 6th February 2013[How to Cite: Fatmawati, A., Agustriyanto, R., Liasari, Y. (2013. Enzymatic Hydrolysis of Alkaline Pre-treated Coconut Coir. Bulletin of Chemical Reaction Engineering & Catalysis, 8 (1: 34-39 (doi:10.9767/bcrec.8.1.4048.34-39[Permalink/DOI: http://dx.doi.org/10.9767/bcrec.8.1.4048.34-39] | View in  |

Inhibition of peptide aggregation by means of enzymatic phosphorylation

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Kristin Folmert

2016-11-01

Full Text Available As is the case in numerous natural processes, enzymatic phosphorylation can be used in the laboratory to influence the conformational populations of proteins. In nature, this information is used for signal transduction or energy transfer, but has also been shown to play an important role in many diseases like tauopathies or diabetes. With the goal of determining the effect of phosphorylation on amyloid fibril formation, we designed a model peptide which combines structural characteristics of α-helical coiled-coils and β-sheets in one sequence. This peptide undergoes a conformational transition from soluble structures into insoluble amyloid fibrils over time and under physiological conditions and contains a recognition motif for PKA (cAMP-dependent protein kinase that enables enzymatic phosphorylation. We have analyzed the pathway of amyloid formation and the influence of enzymatic phosphorylation on the different states along the conformational transition from random-coil to β-sheet-rich oligomers to protofilaments and on to insoluble amyloid fibrils, and we found a remarkable directing effect from β-sheet-rich structures to unfolded structures in the initial growth phase, in which small oligomers and protofilaments prevail if the peptide is phosphorylated.

Pretreatment of corn stover using wet oxidation to enhance enzymatic digestibility.

Science.gov (United States)

Varga, Eniko; Schmidt, Anette S; Réczey, Kati; Thomsen, Anne Belinda

2003-01-01

Corn stover is an abundant, promising raw material for fuel ethanol production. Although it has a high cellulose content, without pretreatment it resists enzymatic hydrolysis, like most lignocellulosic materials. Wet oxidation (water, oxygen, mild alkali or acid, elevated temperature and pressure) was investigated to enhance the enzymatic digestibility of corn stover. Six different combinations of reaction temperature, time, and pH were applied. The best conditions (60 g/L of corn stover, 195 degrees C, 15 min, 12 bar O2, 2 g/L of Na2CO3) increased the enzymatic conversion of corn stover four times, compared to untreated material. Under these conditions 60% of hemicellulose and 30% of lignin were solubilized, whereas 90% of cellulose remained in the solid fraction. After 24-h hydrolysis at 50 degrees C using 25 filter paper units (FPU)/g of drymatter (DM) biomass, the achieved conversion of cellulose to glucose was about 85%. Decreasing the hydrolysis temperature to 40 degrees C increased hydrolysis time from 24 to 72 h. Decreasing the enzyme loading to 5 FPU/g of DM biomass slightly decreased the enzymatic conversion from 83.4 to 71%. Thus, enzyme loading can be reduced without significantly affecting the efficiency of hydrolysis, an important economical aspect.

The variations of enzymatic activity of pepsin preparation by γ-irradiation

International Nuclear Information System (INIS)

Kimura, Syojiro; Taimatsu, Meiko; Kanbashi, Toshitaka; Okamoto, Shinichi; Ohnishi, Tokuhiro.

1993-01-01

Effect of γ-irradiation on the enzymatic activity of raw pepsin and some saccharated pepsin preparations were studied in the dose range from 0 to 300 kGy. As a result, the apparent reduction rate of saccharated pepsin preparations is less than of raw pepsin. K values of raw and saccharated pepsins were 0.014 and 0.0040-0.0061, and G values of raw and saccharated pepsins were 3.98 and 1.13-1.73, respectively. The lower K and G values of saccharated pepsin than those of raw pepsin seem to be due to radiolytic products of lactose in the preparations as an excipient. Retention rates of enzymatic activity of irradiated preparations at the dose of 25 kGy, which is a complete sterilization dose of pharmaceutical materials, were estimated to be 83% for raw pepsin, and 86% and 93% for saccharated pepsin preparations. At the dose of 10 kGy suggested for food irradiation the retention rates were more than 93% for all pepsins. Therefore, this method is applicable considering the stability of the enzymatic activity after irradiation in the proper range of dose. However, it is necessary to consider the fact that radiolytic products of lactose affect the measurement of enzymatic activity. (author)

Kinetic study of enzymatic hydrolysis of acid-pretreated coconut coir

Science.gov (United States)

Fatmawati, Akbarningrum; Agustriyanto, Rudy

2015-12-01

Biomass waste utilization for biofuel production such as bioethanol, has become more prominent currently. Coconut coir is one of lignocellulosic food wastes, which is abundant in Indonesia. Bioethanol production from such materials consists of more than one step. Pretreatment and enzymatic hydrolysis is crucial steps to produce sugar which can then be fermented into bioethanol. In this research, ground coconut coir was pretreated using dilute sulfuric acid at 121°C. This pretreatment had increased the cellulose content and decreased the lignin content of coconut coir. The pretreated coconut coir was hydrolyzed using a mix of two commercial cellulase enzymes at pH of 4.8 and temperature of 50°C. The enzymatic hydrolysis was conducted at several initial coconut coir slurry concentrations (0.1-2 g/100 mL) and reaction times (2-72 hours). The reducing sugar concentration profiles had been produced and can be used to obtain reaction rates. The highest reducing sugar concentration obtained was 1,152.567 mg/L, which was produced at initial slurry concentration of 2 g/100 mL and 72 hours reaction time. In this paper, the reducing sugar concentrations were empirically modeled as a function of reaction time using power equations. Michaelis-Menten kinetic model for enzymatic hydrolysis reaction is adopted. The kinetic parameters of that model for sulfuric acid-pretreated coconut coir enzymatic hydrolysis had been obtained which are Vm of 3.587×104 mg/L.h, and KM of 130.6 mg/L.

Novel investigation of enzymatic biodiesel reaction by isothermal calorimetry

DEFF Research Database (Denmark)

Søtoft, Lene Fjerbaek; Westh, Peter; Christensen, Knud V.

2010-01-01

Isothermal calorimetry (ITC) was used to investigate solvent-free enzymatic biodiesel production. The transesterification of rapeseed oil with methanol and ethanol was catalyzed by immobilized lipase Novozym 435 at 40 °C. The aim of the study was to determine reaction enthalpy for the enzymatic...... transesterification and to elucidate the mass transfer and energetic processes taking place. Based on the measured enthalpy and composition change in the system, the heat of reaction at 40 °C for the two systems was determined as −9.8 ± 0.9 kJ/mole biodiesel formed from rapeseed oil and methanol, and −9.3 ± 0.7 k...

Enhanced enzymatic cellulose degradation by cellobiohydrolases via product removal

DEFF Research Database (Denmark)

Ahmadi Gavlighi, Hassan; Meyer, Anne S.; Mikkelsen, Jørn Dalgaard

2013-01-01

Product inhibition by cellobiose decreases the rate of enzymatic cellulose degradation. The optimal reaction conditions for two Emericella (Aspergillus) nidulans-derived cellobiohydrolases I and II produced in Pichia pastoris were identified as CBHI: 52 °C, pH 4.5–6.5, and CBHII: 46 °C, pH 4.......8. The optimum in a mixture of the two was 50 °C, pH 4.9. An almost fourfold increase in enzymatic hydrolysis yield was achieved with intermittent product removal of cellobiose with membrane filtration (2 kDa cut-off): The conversion of cotton cellulose after 72 h was ~19 % by weight, whereas the conversion...

Lignin-based polyoxyethylene ether enhanced enzymatic hydrolysis of lignocelluloses by dispersing cellulase aggregates.

Science.gov (United States)

Lin, Xuliang; Qiu, Xueqing; Yuan, Long; Li, Zihao; Lou, Hongming; Zhou, Mingsong; Yang, Dongjie

2015-06-01

Water-soluble lignin-based polyoxyethylene ether (EHL-PEG), prepared from enzymatic hydrolysis lignin (EHL) and polyethylene glycol (PEG1000), was used to improve enzymatic hydrolysis efficiency of corn stover. The glucose yield of corn stover at 72h was increased from 16.7% to 70.1% by EHL-PEG, while increase in yield with PEG4600 alone was 52.3%. With the increase of lignin content, EHL-PEG improved enzymatic hydrolysis of microcrystalline cellulose more obvious than PEG4600. EHL-PEG could reduce at least 88% of the adsorption of cellulase on the lignin film measured by quartz crystal microbalance with dissipation monitoring (QCM-D), while reduction with PEG4600 was 43%. Cellulase aggregated at 1220nm in acetate buffer analyzed by dynamic light scattering. EHL-PEG dispersed cellulase aggregates and formed smaller aggregates with cellulase, thereby, reduced significantly nonproductive adsorption of cellulase on lignin and enhanced enzymatic hydrolysis of lignocelluloses. Copyright © 2015 Elsevier Ltd. All rights reserved.

Effect of restricted motion in high temperature on enzymatic activity of the pancreas

Science.gov (United States)

Abdusattarov, A.; Smirnova, G. I.

1980-01-01

Effects of 30 day hypodynamia coupled with high temperature (35-36 C) on enzymatic activity of the pancreas of male adult rats were studied. The test animals were divided into four groups. Group one served as controls (freedom of movement and a temperature of 25-26 C, considered optimal). The remaining animals were divided into three additional groups: Group two freedom of movement but high temperature (35-36 C); group three hypodynamia but an optimal temperature; group four hypodynamia and 35-36 C. Considerable change in the enzymatic activity in the pancreas of the four groups is observed in three experimental groups (two, three, and four) as compared to the control (group one). The results indicate that adaption of the organism to the thermal factor and restricted movement is accompanied by a change in the enzymatic spectrum of the pancreas. With the combined effect of these two stresses under conditions of the adaption of the organism especially sharp shifts occur in the enzymatic activity.

Antimicrobial and enzymatic activity of anemophilous fungi of a public university in Brazil

Directory of Open Access Journals (Sweden)

LAUREANA V. SOBRAL

2017-10-01

Full Text Available ABSTRACT To the fungal microbiota the UFPE and biotechnological potential enzymatic and antimicrobial production. Air conditioned environments were sampled using a passive sedimentation technique, the air I ratio and the presence of aflatoxigenic strains evaluated for ANVISA. Icelles were to determine the enzymatic activity of lipase, amylase and protease metabolic liquids to determine antimicrobial activity. Diversity was observed in all CAV environments, CFU/m3 ranged from 14 to 290 and I/E ratio from 0.1 to 1.5. The of the fungal genera were: Aspergillus (50%, Penicillium (21%, Talaromyces (14%, Curvularia and Paecilomyces (7% each. Aspergillus sydowii (Bainier & Sartory Thom & Church presented enzymatic activity and the Talaromyces purpureogenus Samson, Yilmaz, Houbraken, Spierenb., Seifert, Peterson, Varga & Frisvad presented antibacterial activity against all bacteria that all environments present fungal species biodiversity no toxigenic or pathogenic fungi were found, according to ANVISA legislation for conditioned environments and airborne filamentous fungi present potential for enzymatic and antimicrobial activity.

Influence of enzymatic hydrolysis on the allergenic reactivity of processed cashew and pistachio.

Science.gov (United States)

Cuadrado, Carmen; Cheng, Hsiaopo; Sanchiz, Africa; Ballesteros, Isabel; Easson, Michael; Grimm, Casey C; Dieguez, M Carmen; Linacero, Rosario; Burbano, Carmen; Maleki, Soheila J

2018-02-15

Cashew and pistachio allergies are considered a serious health problem. Previous studies have shown that thermal processing, pressurization and enzymatic hydrolysis may reduce the allergenic properties of food by changing the protein structure. This study assesses the allergenic properties of cashew and pistachio after thermal treatment (boiling and autoclaving), with or without pressure (autoclaving), and multiple enzymatic treatments under sonication, by SDS-PAGE, western blot and ELISA, with serum IgE of allergic individuals, and mass spectroscopy. Autoclaving and enzymatic hydrolysis under sonication separately induced a measurable reduction in the IgE binding properties of pastes made from treated cashew and pistachio nuts. These treatments were more effective with pistachio allergens. However, heat combined with enzymatic digestion was necessary to markedly lower IgE binding to cashew allergens. The findings identify highly effective simultaneous processing conditions to reduce or even abolish the allergenic potency of cashew and pistachio. Copyright © 2017 Elsevier Ltd. All rights reserved.

Radiolytic and enzymatic dimerization of tyrosyl residues in insulin, ribonuclease, papain and collagen

Energy Technology Data Exchange (ETDEWEB)

Boguta, G; Dancewicz, A M [Institute of Nuclear Research, Warsaw (Poland)

1983-03-01

Insulin ribonuclease, papain and collagen solutions saturated with nitrogen, N/sub 2/O or air were irradiated with doses of 10 to 640 Gy of gamma rays. Protein solutions were also oxidized enzymatically in a system of horse-radish peroxidase: hydrogen peroxide. Column chromatography (Sephadex G-75 or Sephacryl S-200) of treated protein solutions revealed that they contain protein molecular aggregates. Nitrogen saturation of solution before irradiation was most favourable for radiation-induced aggregation of proteins. Fluorescence analysis of protein solutions resulted in detection of dityrosyl structures in irradiated as well as in enzymatically oxidized proteins. Concentration of dityrosine in proteins studied was determined fluorimetrically in their hydrolysates separated on BioGel P-2 column. In irradiated proteins, dityrosine was present almost exclusively in their aggregated forms. In proteins oxidized enzymatically, dityrosine was also present in fractions containing apparently unchanged protein. Mechanisms which could account for differences in the yield of dityrosine formation in radiolysis and in enzymatic oxidation of proteins are suggested.

Radiolytic and enzymatic dimerization of tyrosyl residues in insulin, ribonuclease, papain and collagen

International Nuclear Information System (INIS)

Boguta, G.; Dancewicz, A.M.

1983-01-01

Insulin ribonuclease, papain and collagen solutions saturated with nitrogen, N 2 O or air were irradiated with doses of 10 to 640 Gy of gamma rays. Protein solutions were also oxidized enzymatically in a system of horse-radish peroxidase: hydrogen peroxide. Column chromatography (Sephadex G-75 or Sephacryl S-200) of treated protein solutions revealed that they contain protein molecular aggregates. Nitrogen saturation of solution before irradiation was most favourable for radiation-induced aggregation of proteins. Fluorescence analysis of protein solutions resulted in detection of dityrosyl structures in irradiated as well as in enzymatically oxidized proteins. Concentration of dityrosine in proteins studied was determined fluorimetrically in their hydrolysates separated on BioGel P-2 column. In irradiated proteins, dityrosine was present almost exclusively in their aggregated forms. In proteins oxidized enzymatically, dityrosine was also present in fractions containing apparently unchanged protein. Mechanisms which could account for differences in the yield of dityrosine formation in radiolysis and in enzymatic oxidation of proteins are suggested. (author)

Microbial conversion technologies

Energy Technology Data Exchange (ETDEWEB)

Lau, P. [National Research Council of Canada, Ottawa, ON (Canada). Bioconversion and Sustainable Development

2006-07-01

Microbes are a biomass and an valuable resource. This presentation discussed microbial conversion technologies along with background information on microbial cells, their characteristics and microbial diversity. Untapped opportunities for microbial conversion were identified. Metagenomic and genome mining approaches were also discussed, as they can provide access to uncultivated or unculturable microorganisms in communal populations and are an unlimited resource for biocatalysts, novel genes and metabolites. Genome mining was seen as an economical approach. The presentation also emphasized that the development of microbial biorefineries would require significant insights into the relevant microorganisms and that biocatalysts were the ultimate in sustainability. In addition, the presentation discussed the natural fibres initiative for biochemicals and biomaterials. Anticipated outputs were identified and work in progress of a new enzyme-retting cocktail to provide diversity and/or consistency in fibre characteristics for various applications were also presented. It was concluded that it is necessary to leverage understanding of biological processes to produce bioproducts in a clean and sustainable manner. tabs., figs.

Chelating agents improve enzymatic solubilization of pectinaceous co-processing streams

DEFF Research Database (Denmark)

Ravn, Helle Christine; Meyer, Anne S.

2014-01-01

of different levels of ethylene-diaminetetraacetic acid (EDTA), citric acid, oxalic acid, and phosphate was assessed in relation to enzymatic solubilization of isopropanol precipitatable oligo- and polysaccharides from sugar beet pulp, citrus peel, and two types of potato pulp. The two types of potato pulp...... solubilization yields. The effect of the chelating agents correlated to their dissociation constants (pKa values) and calcium binding constants and citric acid and EDTA exerted highest effects. Maximum polysaccharide yield was obtained for FiberBind 400 where the enzymatic treatment in presence of citric acid...

Synthesis, Characterization, and Biological Activity of Mn(II, Fe(II, Co(II, Ni(II, Cu(II, Zn(II, and Cd(II Complexes of N-Thiophenoyl-N′-Phenylthiocarbohydrazide

Directory of Open Access Journals (Sweden)

M. Yadav

2013-01-01

Full Text Available Mn(II, Fe(II, Co(II, Ni(II, Cu(II, Zn(II, and Cd(II complex of N-thiophenoyl -N′-phenylthiocarbohydrazide (H2 TPTH have been synthesized and characterized by elemental analysis, magnetic susceptibility measurements, infrared, NMR, electronic, and ESR spectral studies. The complexes were found to have compositions [Mn(H TPTH2], [Co(TPTH (H2O2], [Ni(TPTH (H2O2], [Cu(TPTH], [Zn(H TPTH], [Cd(H TPTH2], and [Fe(H TPTH2(EtOH]. The magnetic and electronic spectral studies suggest square planar geometry for [Cu(TPTH], tetrahedral geometry for [Zn(TPTH] and [Cd(H TPTH2], and octahedral geometry for rest of the complexes. The infrared spectral studies of the 1 : 1 deprotonated complexes suggest bonding through enolic oxygen, thiolato sulfur, and both the hydrazinic nitrogens. Thus, H2TPTH acts as a binegative tetradentate ligand. H2 TPTH and its metal complexes have been screened against several bacteria and fungi.

Solid-phase extraction of Mn(II), Co(II), Ni(II), Cu(II), Cd(II) and Pb(II) ions from environmental samples by flame atomic absorption spectrometry (FAAS)

Energy Technology Data Exchange (ETDEWEB)

Duran, Celal [Department of Chemistry, Faculty of Art and Science, Karadeniz Technical University, 61080 Trabzon (Turkey); Gundogdu, Ali [Department of Chemistry, Faculty of Art and Science, Karadeniz Technical University, 61080 Trabzon (Turkey); Bulut, Volkan Numan [Department of Chemistry, Giresun Faculty of Art and Science, Karadeniz Technical University, 28049 Giresun (Turkey); Soylak, Mustafa [Department of Chemistry, Faculty of Art and Science, Erciyes University, 38039 Kayseri (Turkey)]. E-mail: soylak@erciyes.edu.tr; Elci, Latif [Department of Chemistry, Faculty of Art and Science, Pamukkale University, 20020 Denizli (Turkey); Sentuerk, Hasan Basri [Department of Chemistry, Faculty of Art and Science, Karadeniz Technical University, 61080 Trabzon (Turkey); Tuefekci, Mehmet [Department of Chemistry, Faculty of Art and Science, Karadeniz Technical University, 61080 Trabzon (Turkey)

2007-07-19

A new method using a column packed with Amberlite XAD-2010 resin as a solid-phase extractant has been developed for the multi-element preconcentration of Mn(II), Co(II), Ni(II), Cu(II), Cd(II), and Pb(II) ions based on their complex formation with the sodium diethyldithiocarbamate (Na-DDTC) prior to flame atomic absorption spectrometric (FAAS) determinations. Metal complexes sorbed on the resin were eluted by 1 mol L{sup -1} HNO{sub 3} in acetone. Effects of the analytical conditions over the preconcentration yields of the metal ions, such as pH, quantity of Na-DDTC, eluent type, sample volume and flow rate, foreign ions etc. have been investigated. The limits of detection (LOD) of the analytes were found in the range 0.08-0.26 {mu}g L{sup -1}. The method was validated by analyzing three certified reference materials. The method has been applied for the determination of trace elements in some environmental samples.

Influence of enzymatic maceration on the microstructure and microhardness of compact bone

International Nuclear Information System (INIS)

Yin Ling; Venkatesan, Sudharshan; Kalyanasundaram, Shankar; Qin Qinghua

2010-01-01

The cleaning of fresh bones to remove their soft tissues while maintaining their structural integrity is a basic and essential part of bone studies. The primary issue is how the cleaning process influences bone microstructures and mechanical properties. We cleaned fresh lamb femurs using enzymatic maceration in comparison with water maceration at room temperature. The microstructures of these compact bones were examined using scanning electron microscopy (SEM) and their porosities were quantified using image processing software. The bone microhardness was measured using a Vickers indentation tester for studying the mechanical properties. The results show that enzymatic maceration of compact bone resulted in a significant microhardness reduction in comparison with water maceration. However, enzymatic maceration did not cause any significant change of porosity in bone structures.

Influence of enzymatic maceration on the microstructure and microhardness of compact bone

Energy Technology Data Exchange (ETDEWEB)

Yin Ling [School of Engineering and Physical Sciences, James Cook University, Townsville, QLD 4811 (Australia); Venkatesan, Sudharshan; Kalyanasundaram, Shankar; Qin Qinghua, E-mail: ling.yin@jcu.edu.a [Department of Engineering, Australian National University, Canberra, ACT 0200 (Australia)

2010-02-15

The cleaning of fresh bones to remove their soft tissues while maintaining their structural integrity is a basic and essential part of bone studies. The primary issue is how the cleaning process influences bone microstructures and mechanical properties. We cleaned fresh lamb femurs using enzymatic maceration in comparison with water maceration at room temperature. The microstructures of these compact bones were examined using scanning electron microscopy (SEM) and their porosities were quantified using image processing software. The bone microhardness was measured using a Vickers indentation tester for studying the mechanical properties. The results show that enzymatic maceration of compact bone resulted in a significant microhardness reduction in comparison with water maceration. However, enzymatic maceration did not cause any significant change of porosity in bone structures.

Rapid microbial respiration of oil from the Deepwater Horizon spill in offshore surface waters of the Gulf of Mexico

International Nuclear Information System (INIS)

Edwards, Bethanie R; Reddy, Christopher M; Carmichael, Catherine A; Longnecker, Krista; Van Mooy, Benjamin A S; Camilli, Richard

2011-01-01

The Deepwater Horizon oil spill was one of the largest oil spills in history, and the fate of this oil within the Gulf of Mexico ecosystem remains to be fully understood. The goal of this study-conducted in mid-June of 2010, approximately two months after the oil spill began-was to understand the key role that microbes would play in the degradation of the oil in the offshore oligotrophic surface waters near the Deepwater Horizon site. As the utilization of organic carbon by bacteria in the surface waters of the Gulf had been previously shown to be phosphorus limited, we hypothesized that bacteria would be unable to rapidly utilize the oil released from the Macondo well. Although phosphate was scarce throughout the sampling region and microbes exhibited enzymatic signs of phosphate stress within the oil slick, microbial respiration within the slick was enhanced by approximately a factor of five. An incubation experiment to determine hydrocarbon degradation rates confirmed that a large fraction of this enhanced respiration was supported by hydrocarbon degradation. Extrapolating our observations to the entire area of the slick suggests that microbes had the potential to degrade a large fraction of the oil as it arrived at the surface from the well. These observations decidedly refuted our hypothesis. However, a concomitant increase in microbial abundance or biomass was not observed in the slick, suggesting that microbial growth was nutrient limited; incubations amended with nutrients showed rapid increases in cell number and biomass, which supported this conclusion. Our study shows that the dynamic microbial community of the Gulf of Mexico supported remarkable rates of oil respiration, despite a dearth of dissolved nutrients.

Kinetic study of batch and fed-batch enzymatic saccharification of pretreated substrate and subsequent fermentation to ethanol

Directory of Open Access Journals (Sweden)

Gupta Rishi

2012-03-01

Full Text Available Abstract Background Enzymatic hydrolysis, the rate limiting step in the process development for biofuel, is always hampered by its low sugar concentration. High solid enzymatic saccharification could solve this problem but has several other drawbacks such as low rate of reaction. In the present study we have attempted to enhance the concentration of sugars in enzymatic hydrolysate of delignified Prosopis juliflora, using a fed-batch enzymatic hydrolysis approach. Results The enzymatic hydrolysis was carried out at elevated solid loading up to 20% (w/v and a comparison kinetics of batch and fed-batch enzymatic hydrolysis was carried out using kinetic regimes. Under batch mode, the actual sugar concentration values at 20% initial substrate consistency were found deviated from the predicted values and the maximum sugar concentration obtained was 80.78 g/L. Fed-batch strategy was implemented to enhance the final sugar concentration to 127 g/L. The batch and fed-batch enzymatic hydrolysates were fermented with Saccharomyces cerevisiae and ethanol production of 34.78 g/L and 52.83 g/L, respectively, were achieved. Furthermore, model simulations showed that higher insoluble solids in the feed resulted in both smaller reactor volume and shorter residence time. Conclusion Fed-batch enzymatic hydrolysis is an efficient procedure for enhancing the sugar concentration in the hydrolysate. Restricting the process to suitable kinetic regimes could result in higher conversion rates.

Kinetic study of batch and fed-batch enzymatic saccharification of pretreated substrate and subsequent fermentation to ethanol

Science.gov (United States)

2012-01-01

Background Enzymatic hydrolysis, the rate limiting step in the process development for biofuel, is always hampered by its low sugar concentration. High solid enzymatic saccharification could solve this problem but has several other drawbacks such as low rate of reaction. In the present study we have attempted to enhance the concentration of sugars in enzymatic hydrolysate of delignified Prosopis juliflora, using a fed-batch enzymatic hydrolysis approach. Results The enzymatic hydrolysis was carried out at elevated solid loading up to 20% (w/v) and a comparison kinetics of batch and fed-batch enzymatic hydrolysis was carried out using kinetic regimes. Under batch mode, the actual sugar concentration values at 20% initial substrate consistency were found deviated from the predicted values and the maximum sugar concentration obtained was 80.78 g/L. Fed-batch strategy was implemented to enhance the final sugar concentration to 127 g/L. The batch and fed-batch enzymatic hydrolysates were fermented with Saccharomyces cerevisiae and ethanol production of 34.78 g/L and 52.83 g/L, respectively, were achieved. Furthermore, model simulations showed that higher insoluble solids in the feed resulted in both smaller reactor volume and shorter residence time. Conclusion Fed-batch enzymatic hydrolysis is an efficient procedure for enhancing the sugar concentration in the hydrolysate. Restricting the process to suitable kinetic regimes could result in higher conversion rates. PMID:22433563

Structural Characterization and Enzymatic Modification of Soybean Polysaccharides

DEFF Research Database (Denmark)

Pierce, Brian; Wichmann, Jesper

% galacturonic acid, 8% xylose, 3% rhamnose, and 3% fucose. Currently, the majority of this material is disposed of as waste, increasing production costs. Opportunities exist for the develop-ment of novel functional ingredients from this abundant and underutilized ma-terial; however, efforts in this area......The work in this thesis explores the structure of soybean polysaccharides, and examines approaches for the chemical and enzymatic degradation and solu-bilization of this material. Soybean polysaccharides are produced in large quantities globally as a by-product of various soy production processes...... are currently limited by the material’s insol-ubility. A central hypothesis of this work was that by obtaining a more complete understanding of the structure of this material, chemical and enzymatic ap-proaches could be developed to modify the polysaccharides, creating soluble polysaccharide fractions...

Microbial redox processes in deep subsurface environments and the potential application of (perchlorate in oil reservoirs

Directory of Open Access Journals (Sweden)

Martin G Liebensteiner

2014-09-01

Full Text Available The ability of microorganisms to thrive under oxygen-free conditions in subsurface environments relies on the enzymatic reduction of oxidized elements, such as sulfate, ferric iron or CO2, coupled to the oxidation of inorganic or organic compounds. A broad phylogenetic and functional diversity of microorganisms from subsurface environments has been described using isolation-based and advanced molecular ecological techniques. The physiological groups reviewed here comprise iron-, manganese- and nitrate-reducing microorganisms. In the context of recent findings also the potential of chlorate and perchlorate [jointly termed (perchlorate] reduction in oil reservoirs will be discussed. Special attention is given to elevated temperatures that are predominant in the deep subsurface. Microbial reduction of (perchlorate is a thermodynamically favorable redox process, also at high temperature. However, knowledge about (perchlorate reduction at elevated temperatures is still scarce and restricted to members of the Firmicutes and the archaeon Archaeoglobus fulgidus. By analyzing the diversity and phylogenetic distribution of functional genes in (metagenome databases and combining this knowledge with extrapolations to earlier-made physiological observations we speculate on the potential of (perchlorate reduction in the subsurface and more precisely oil fields. In addition, the application of (perchlorate for bioremediation, souring control and microbial enhanced oil recovery are addressed.

Production of a carob enzymatic extract: potential use as a biofertilizer.

Science.gov (United States)

Parrado, J; Bautista, J; Romero, E J; García-Martínez, A M; Friaza, V; Tejada, M

2008-05-01

In this paper, we describe a biological process that converts carob germ (CG), a proteinic vegetable by-product, into a water-soluble enzymatic hydrolyzate extract (CGHE). The chemical and physical properties are also described. The conversion is done using a proteolytic enzyme mixture. The main component of CGHE extracted by the enzymatic process is protein (68%), in the form of peptides and free amino acids, having a high content of glutamine and arginine, and a minor component of phytohormones, which are also extracted and solubilized from the CG. We have also compared its potential fertilizer/biostimulant capacity on growth, flowering, and fruiting of tomato plants (Licopericon pimpinellifolium cv. Momotaro) with that of an animal enzymatic protein hydrolyzate. CGHE had a significantly beneficial impact, most notably regarding the greater plant height, number of flowers per plant, and number of fruits per plant. This could be due primarily to its phytohormonal action.

Operation variables in transesterification of vegetable oil: an enzymatic catalysis review

Directory of Open Access Journals (Sweden)

Andrés Felipe Rojas González

2010-01-01

Full Text Available This paper presents the results of a literature review regarding how operating conditions influence vegetable oil enzymatic transesterification yield. The following parameters were studied: temperature and time reaction, alcohol: oil molar ratio, alcohol type, biocatalyst type and concentration, solvent, mixed intensity, reagent purity and free fatty acid and moisture concentration. Yields greater than 90% can be achieved in the enzymatic catalyst of vegetable oil using 35-50°C temperatures, long time reactions (7- 90h and a 3:1alcohol: vegetable oil molar ratio; however, such values would intrinsically depend on the type of lipase and oil u- sed. It was also found that free fatty acid and moisture concentration were parameters which did not require rigorous control due to high enzyme specificity. Lipases immobilised from Pseudomona cepacia bacteria and Rhizopus orizae fungi were most used in vegetable oil enzymatic transesterification.

Dynamic Simulation, Sensitivity and Uncertainty Analysis of a Demonstration Scale Lignocellulosic Enzymatic Hydrolysis Process

DEFF Research Database (Denmark)

Prunescu, Remus Mihail; Sin, Gürkan

2014-01-01

This study presents the uncertainty and sensitivity analysis of a lignocellulosic enzymatic hydrolysis model considering both model and feed parameters as sources of uncertainty. The dynamic model is parametrized for accommodating various types of biomass, and different enzymatic complexes...

Microbial Inoculants and Their Impact on Soil Microbial Communities: A Review

Directory of Open Access Journals (Sweden)

Darine Trabelsi

2013-01-01

Full Text Available The knowledge of the survival of inoculated fungal and bacterial strains in field and the effects of their release on the indigenous microbial communities has been of great interest since the practical use of selected natural or genetically modified microorganisms has been developed. Soil inoculation or seed bacterization may lead to changes in the structure of the indigenous microbial communities, which is important with regard to the safety of introduction of microbes into the environment. Many reports indicate that application of microbial inoculants can influence, at least temporarily, the resident microbial communities. However, the major concern remains regarding how the impact on taxonomic groups can be related to effects on functional capabilities of the soil microbial communities. These changes could be the result of direct effects resulting from trophic competitions and antagonistic/synergic interactions with the resident microbial populations, or indirect effects mediated by enhanced root growth and exudation. Combination of inoculants will not necessarily produce an additive or synergic effect, but rather a competitive process. The extent of the inoculation impact on the subsequent crops in relation to the buffering capacity of the plant-soil-biota is still not well documented and should be the focus of future research.

Colloid-based multiplexed method for screening plant biomass-degrading glycoside hydrolase activities in microbial communities

Energy Technology Data Exchange (ETDEWEB)

Reindl, W.; Deng, K.; Gladden, J.M.; Cheng, G.; Wong, A.; Singer, S.W.; Singh, S.; Lee, J.-C.; Yao, J.-S.; Hazen, T.C.; Singh, A.K; Simmons, B.A.; Adams, P.D.; Northen, T.R.

2011-05-01

The enzymatic hydrolysis of long-chain polysaccharides is a crucial step in the conversion of biomass to lignocellulosic biofuels. The identification and characterization of optimal glycoside hydrolases is dependent on enzyme activity assays, however existing methods are limited in terms of compatibility with a broad range of reaction conditions, sample complexity, and especially multiplexity. The method we present is a multiplexed approach based on Nanostructure-Initiator Mass Spectrometry (NIMS) that allowed studying several glycolytic activities in parallel under diverse assay conditions. Although the substrate analogs carried a highly hydrophobic perfluorinated tag, assays could be performed in aqueous solutions due colloid formation of the substrate molecules. We first validated our method by analyzing known {beta}-glucosidase and {beta}-xylosidase activities in single and parallel assay setups, followed by the identification and characterization of yet unknown glycoside hydrolase activities in microbial communities.

Combined subcritical water and enzymatic hydrolysis for reducing sugar production from coconut husk

Science.gov (United States)

Muharja, Maktum; Junianti, Fitri; Nurtono, Tantular; Widjaja, Arief

2017-05-01

Coconut husk wastes are abundantly available in Indonesia. It has a potential to be used into alternative renewable energy sources such as hydrogen using enzymatic hydrolysis followed by a fermentation process. Unfortunately, enzymatic hydrolysis is hampered by the complex structure of lignocellulose, so the cellulose component is hard to degrade. In this study, Combined Subcritical Water (SCW) and enzymatic hydrolysis are applied to enhance fermentable, thereby reducing production of sugar from coconut husk. There were two steps in this study, the first step was coconut husk pretreated by SCW in batch reactor at 80 bar and 150-200°C for 60 minutes reaction time. Secondly, solid fraction from the results of SCW was hydrolyzed using the mixture of pure cellulose and xylanase enzymes. Analysis was conducted on untreated and SCW-treated by gravimetric assay, liquid fraction after SCW and solid fraction after enzymatic hydrolysis using DNS assay. The maximum yield of reducing sugar (including xylose, arabinose glucose, galactose, mannose) was 1.254 gr per 6 gr raw material, representing 53.95% of total sugar in coconut husk biomass which was obtained at 150°C 80 bar for 60 minutes reaction time of SCW-treated and 6 hour of enzymatic hydrolysis using mixture of pure cellulose and xylanase enzymes (18.6 U /gram of coconut husk).

Molecular microbial ecology manual

NARCIS (Netherlands)

Kowalchuk, G.A.; Bruijn, de F.J.; Head, I.M.; Akkermans, A.D.L.

2004-01-01

The field of microbial ecology has been revolutionized in the past two decades by the introduction of molecular methods into the toolbox of the microbial ecologist. This molecular arsenal has helped to unveil the enormity of microbial diversity across the breadth of the earth's ecosystems, and has

Role of supramolecular cellulose structures in enzymatic hydrolysis of plant cell walls

DEFF Research Database (Denmark)

Thygesen, Lisbeth Garbrecht; Hidayat, Budi Juliman; Johansen, Katja Salomon

2011-01-01

The study of biomass deconstruction by enzymatic hydrolysis has hitherto not focussed on the importance of supramolecular structures of cellulose. In lignocellulose fibres, regions with a different organisation of the microfibrils are present. These regions are called dislocations or slip planes ...... the initial part of enzymatic hydrolysis of cellulose. The implications of this phenomenon have not yet been recognized or explored within cellulosic biofuels....

Microbial electrosynthetic cells

Energy Technology Data Exchange (ETDEWEB)

May, Harold D.; Marshall, Christopher W.; Labelle, Edward V.

2018-01-30

Methods are provided for microbial electrosynthesis of H.sub.2 and organic compounds such as methane and acetate. Method of producing mature electrosynthetic microbial populations by continuous culture is also provided. Microbial populations produced in accordance with the embodiments as shown to efficiently synthesize H.sub.2, methane and acetate in the presence of CO.sub.2 and a voltage potential. The production of biodegradable and renewable plastics from electricity and carbon dioxide is also disclosed.

Rapid near infrared spectroscopy for prediction of enzymatic hydrolysis of corn bran after various pretreatments

DEFF Research Database (Denmark)

Baum, Andreas; Wittrup Agger, Jane; Meyer, Anne S.

2012-01-01

Efficient generation of a fermentable hydrolysate is a primary requirement in the utilization of fibrous plant biomass as feedstocks in bioethanol processes. The first biomass conversion step usually involves a hydrothermal pretreatment before enzymatic hydrolysis. The purpose of the pretreatment...... step is to increase the responsivity of the substrate to enzymatic attack and the type of pretreatment affects the enzymatic conversion efficiency. Destarched corn bran is a fibrous, heteroxylan-rich side-stream from the starch industry which may be used as a feedstock for bioethanol production...... release of different levels of arabinose, xylose and glucose from all the differently pretreated destarched corn bran samples. The present study also demonstrates a generic, non-destructive solution to determine the enzymatic monosaccharide release from polymers in biomass side-streams, thereby...

Enzymatic hydrolysis and fermentation of agricultural residues to ethanol

Energy Technology Data Exchange (ETDEWEB)

Mes-Hartree, M.; Hogan, C.M.; Saddler, J.N.

1984-01-01

A combined enzymatic hydrolysis and fermentation process was used to convert steam-treated wheat and barley straw to ethanol. Maximum conversion efficiencies were obtained when the substrates were steamed for 90 s. These substrates could yield over 0.4 g ethanol/g cellulose following a combined enzymatic hydrolysis and fermentation process procedure using culture filtrates derived from Trichoderma harzianum E58. When culture filtrates from Trichoderma reesei C30 and T. reesei QM9414 were used, the ethanol yields obtained were 0.32 and 0.12 g ethanol/g cellulose utilized, respectively. The lower ethanol yields obtained with these strains were attributed to the lower amounts of ..beta..-glucosidase detected in the T. reesei culture filtrates.

Enzymatic digestibility and ethanol fermentability of AFEX-treated starch-rich lignocellulosics such as corn silage and whole corn plant

Directory of Open Access Journals (Sweden)

Thelen Kurt D

2010-06-01

Full Text Available Abstract Background Corn grain is an important renewable source for bioethanol production in the USA. Corn ethanol is currently produced by steam liquefaction of starch-rich grains followed by enzymatic saccharification and fermentation. Corn stover (the non-grain parts of the plant is a potential feedstock to produce cellulosic ethanol in second-generation biorefineries. At present, corn grain is harvested by removing the grain from the living plant while leaving the stover behind on the field. Alternatively, whole corn plants can be harvested to cohydrolyze both starch and cellulose after a suitable thermochemical pretreatment to produce fermentable monomeric sugars. In this study, we used physiologically immature corn silage (CS and matured whole corn plants (WCP as feedstocks to produce ethanol using ammonia fiber expansion (AFEX pretreatment followed by enzymatic hydrolysis (at low enzyme loadings and cofermentation (for both glucose and xylose using a cellulase-amylase-based cocktail and a recombinant Saccharomyces cerevisiae 424A (LNH-ST strain, respectively. The effect on hydrolysis yields of AFEX pretreatment conditions and a starch/cellulose-degrading enzyme addition sequence for both substrates was also studied. Results AFEX-pretreated starch-rich substrates (for example, corn grain, soluble starch had a 1.5-3-fold higher enzymatic hydrolysis yield compared with the untreated substrates. Sequential addition of cellulases after hydrolysis of starch within WCP resulted in 15-20% higher hydrolysis yield compared with simultaneous addition of hydrolytic enzymes. AFEX-pretreated CS gave 70% glucan conversion after 72 h of hydrolysis for 6% glucan loading (at 8 mg total enzyme loading per gram glucan. Microbial inoculation of CS before ensilation yielded a 10-15% lower glucose hydrolysis yield for the pretreated substrate, due to loss in starch content. Ethanol fermentation of AFEX-treated (at 6% w/w glucan loading CS hydrolyzate (resulting

Enzymatic digestibility and ethanol fermentability of AFEX-treated starch-rich lignocellulosics such as corn silage and whole corn plant

Science.gov (United States)

2010-01-01

Background Corn grain is an important renewable source for bioethanol production in the USA. Corn ethanol is currently produced by steam liquefaction of starch-rich grains followed by enzymatic saccharification and fermentation. Corn stover (the non-grain parts of the plant) is a potential feedstock to produce cellulosic ethanol in second-generation biorefineries. At present, corn grain is harvested by removing the grain from the living plant while leaving the stover behind on the field. Alternatively, whole corn plants can be harvested to cohydrolyze both starch and cellulose after a suitable thermochemical pretreatment to produce fermentable monomeric sugars. In this study, we used physiologically immature corn silage (CS) and matured whole corn plants (WCP) as feedstocks to produce ethanol using ammonia fiber expansion (AFEX) pretreatment followed by enzymatic hydrolysis (at low enzyme loadings) and cofermentation (for both glucose and xylose) using a cellulase-amylase-based cocktail and a recombinant Saccharomyces cerevisiae 424A (LNH-ST) strain, respectively. The effect on hydrolysis yields of AFEX pretreatment conditions and a starch/cellulose-degrading enzyme addition sequence for both substrates was also studied. Results AFEX-pretreated starch-rich substrates (for example, corn grain, soluble starch) had a 1.5-3-fold higher enzymatic hydrolysis yield compared with the untreated substrates. Sequential addition of cellulases after hydrolysis of starch within WCP resulted in 15-20% higher hydrolysis yield compared with simultaneous addition of hydrolytic enzymes. AFEX-pretreated CS gave 70% glucan conversion after 72 h of hydrolysis for 6% glucan loading (at 8 mg total enzyme loading per gram glucan). Microbial inoculation of CS before ensilation yielded a 10-15% lower glucose hydrolysis yield for the pretreated substrate, due to loss in starch content. Ethanol fermentation of AFEX-treated (at 6% w/w glucan loading) CS hydrolyzate (resulting in 28 g/L ethanol

Enzymatic transesterification of used frying oils

Energy Technology Data Exchange (ETDEWEB)

Kovacs, S.; Hancsok, J. (Univ. of Pannonia, Veszprem (HU)), Email: hancsokj@almos.uni-pannon.hu

2009-07-01

The research of converting used frying oils to less harmful products with much higher value was forced by environmental, human biological and economical reasons. One possible pathway of the transformation is the enzymatic transesterification. Through the research work used frying oils (UFO) and sunflower oils (SO) from different origins were first properly pre-treated. Then the previously mentioned feeds and different mixtures of them were transesterified in the presence of Novozym 435 enzyme catalyst under different process conditions. Characteristics of the produced methyl esters were evaluated according to the requirements of EN 14214:2009 standard. We determined that the transesterification of used frying oils is not expediential in the presence of enzyme catalyst because the significant decreasing of catalyst activity. We have found proper UFO and SO mixtures and combination of process conditions (pressure: atmospheric, temperature: 54 +-1 deg C; methanol to triglyceride molar ratio: 4:1; reaction time: 16 hours) resulting in high (>90 %) yield of monoesters. We clearly established that the best results through the enzymatic transesterification were obtained with the improved sunflower oils containing the highest amount (>88 %) of oleic acid and the used frying oils originated from this source. (orig.)

Microbial Energy Conversion

Energy Technology Data Exchange (ETDEWEB)

Buckley, Merry [American Society for Microbiology (ASM), Washington, DC (United States); Wall, Judy D. [Univ. of Missouri, Columbia, MO (United States)

2006-10-01

The American Academy of Microbiology convened a colloquium March 10-12, 2006, in San Francisco, California, to discuss the production of energy fuels by microbial conversions. The status of research into various microbial energy technologies, the advantages and disadvantages of each of these approaches, research needs in the field, and education and training issues were examined, with the goal of identifying routes for producing biofuels that would both decrease the need for fossil fuels and reduce greenhouse gas emissions. Currently, the choices for providing energy are limited. Policy makers and the research community must begin to pursue a broader array of potential energy technologies. A diverse energy portfolio that includes an assortment of microbial energy choices will allow communities and consumers to select the best energy solution for their own particular needs. Funding agencies and governments alike need to prepare for future energy needs by investing both in the microbial energy technologies that work today and in the untested technologies that will serve the world’s needs tomorrow. More mature bioprocesses, such as ethanol production from starchy materials and methane from waste digestors, will find applications in the short term. However, innovative techniques for liquid fuel or biohydrogen production are among the longer term possibilities that should also be vigorously explored, starting now. Microorganisms can help meet human energy needs in any of a number of ways. In their most obvious role in energy conversion, microorganisms can generate fuels, including ethanol, hydrogen, methane, lipids, and butanol, which can be burned to produce energy. Alternatively, bacteria can be put to use in microbial fuel cells, where they carry out the direct conversion of biomass into electricity. Microorganisms may also be used some day to make oil and natural gas technologies more efficient by sequestering carbon or by assisting in the recovery of oil and

The transcriptional response of microbial communities in thawing Alaskan permafrost soils

Science.gov (United States)

Coolen, Marco J. L.; Orsi, William D.

2015-01-01

Thawing of permafrost soils is expected to stimulate microbial decomposition and respiration of sequestered carbon. This could, in turn, increase atmospheric concentrations of greenhouse gasses, such as carbon dioxide and methane, and create a positive feedback to climate warming. Recent metagenomic studies suggest that permafrost has a large metabolic potential for carbon processing, including pathways for fermentation and methanogenesis. Here, we performed a pilot study using ultrahigh throughput Illumina HiSeq sequencing of reverse transcribed messenger RNA to obtain a detailed overview of active metabolic pathways and responsible organisms in up to 70 cm deep permafrost soils at a moist acidic tundra location in Arctic Alaska. The transcriptional response of the permafrost microbial community was compared before and after 11 days of thaw. In general, the transcriptional profile under frozen conditions suggests a dominance of stress responses, survival strategies, and maintenance processes, whereas upon thaw a rapid enzymatic response to decomposing soil organic matter (SOM) was observed. Bacteroidetes, Firmicutes, ascomycete fungi, and methanogens were responsible for largest transcriptional response upon thaw. Transcripts indicative of heterotrophic methanogenic pathways utilizing acetate, methanol, and methylamine were found predominantly in the permafrost table after thaw. Furthermore, transcripts involved in acetogenesis were expressed exclusively after thaw suggesting that acetogenic bacteria are a potential source of acetate for acetoclastic methanogenesis in freshly thawed permafrost. Metatranscriptomics is shown here to be a useful approach for inferring the activity of permafrost microbes that has potential to improve our understanding of permafrost SOM bioavailability and biogeochemical mechanisms contributing to greenhouse gas emissions as a result of permafrost thaw. PMID:25852660

The transcriptional response of microbial communities in thawing Alaskan permafrost soils

Directory of Open Access Journals (Sweden)

M J L Coolen

2015-03-01

Full Text Available Thawing of permafrost soils is expected to stimulate microbial decomposition and respiration of sequestered carbon. This could, in turn, increase atmospheric concentrations of greenhouse gases, such as carbon dioxide and methane, and create a positive feedback to climate warming. Recent metagenomic studies suggest that permafrost has a large metabolic potential for carbon processing, including pathways for fermentation and methanogenesis. Here, we performed a pilot study using ultrahigh throughput Illumina HiSeq sequencing of reverse transcribed messenger RNA to obtain a detailed overview of active metabolic pathways and responsible organisms in up to 70 cm deep permafrost soils at a moist acidic tundra location in Arctic Alaska. The transcriptional response of the permafrost microbial community was compared before and after eleven days of thaw. In general, the transcriptional profile under frozen conditions suggests a dominance of stress responses, survival strategies, and maintenance processes, whereas upon thaw a rapid enzymatic response to decomposing soil organic matter (SOM was observed. Bacteroidetes, Firmicutes, ascomycete fungi, and methanogens were responsible for largest transcriptional response upon thaw. Transcripts indicative of heterotrophic methanogenic pathways utilizing acetate, methanol, and methylamine were found predominantly in the permafrost table after thaw. Furthermore, transcripts involved in acetogenesis were expressed exclusively after thaw suggesting that acetogenic bacteria are a potential source of acetate for acetoclastic methanogenesis in freshly thawed permafrost. Metatranscriptomics is shown here to be a useful approach for inferring the activity of permafrost microbes that has potential to improve our understanding of permafrost SOM bioavailability and biogeochemical mechanisms contributing to greenhouse gas emissions as a result of permafrost thaw.

Microbial bioinformatics 2020.

Science.gov (United States)

Pallen, Mark J

2016-09-01

Microbial bioinformatics in 2020 will remain a vibrant, creative discipline, adding value to the ever-growing flood of new sequence data, while embracing novel technologies and fresh approaches. Databases and search strategies will struggle to cope and manual curation will not be sustainable during the scale-up to the million-microbial-genome era. Microbial taxonomy will have to adapt to a situation in which most microorganisms are discovered and characterised through the analysis of sequences. Genome sequencing will become a routine approach in clinical and research laboratories, with fresh demands for interpretable user-friendly outputs. The "internet of things" will penetrate healthcare systems, so that even a piece of hospital plumbing might have its own IP address that can be integrated with pathogen genome sequences. Microbiome mania will continue, but the tide will turn from molecular barcoding towards metagenomics. Crowd-sourced analyses will collide with cloud computing, but eternal vigilance will be the price of preventing the misinterpretation and overselling of microbial sequence data. Output from hand-held sequencers will be analysed on mobile devices. Open-source training materials will address the need for the development of a skilled labour force. As we boldly go into the third decade of the twenty-first century, microbial sequence space will remain the final frontier! © 2016 The Author. Microbial Biotechnology published by John Wiley & Sons Ltd and Society for Applied Microbiology.

Primary productivity as a control over soil microbial diversity along environmental gradients in a polar desert ecosystem

Directory of Open Access Journals (Sweden)

Kevin M. Geyer

2017-07-01

Full Text Available Primary production is the fundamental source of energy to foodwebs and ecosystems, and is thus an important constraint on soil communities. This coupling is particularly evident in polar terrestrial ecosystems where biological diversity and activity is tightly constrained by edaphic gradients of productivity (e.g., soil moisture, organic carbon availability and geochemical severity (e.g., pH, electrical conductivity. In the McMurdo Dry Valleys of Antarctica, environmental gradients determine numerous properties of soil communities and yet relatively few estimates of gross or net primary productivity (GPP, NPP exist for this region. Here we describe a survey utilizing pulse amplitude modulation (PAM fluorometry to estimate rates of GPP across a broad environmental gradient along with belowground microbial diversity and decomposition. PAM estimates of GPP ranged from an average of 0.27 μmol O2/m2/s in the most arid soils to an average of 6.97 μmol O2/m2/s in the most productive soils, the latter equivalent to 217 g C/m2/y in annual NPP assuming a 60 day growing season. A diversity index of four carbon-acquiring enzyme activities also increased with soil productivity, suggesting that the diversity of organic substrates in mesic environments may be an additional driver of microbial diversity. Overall, soil productivity was a stronger predictor of microbial diversity and enzymatic activity than any estimate of geochemical severity. These results highlight the fundamental role of environmental gradients to control community diversity and the dynamics of ecosystem-scale carbon pools in arid systems.

Enzymatic Hydrolysis of Oleuropein from Olea europea (Olive Leaf Extract and Antioxidant Activities

Directory of Open Access Journals (Sweden)

Jiao-Jiao Yuan

2015-02-01

Full Text Available Oleuropein (OE, the main polyphenol in olive leaf extract, is likely to decompose into hydroxytyrosol (HT and elenolic acid under the action of light, acid, base, high temperature. In the enzymatic process, the content of OE in olive leaf extract and enzyme are key factors that affect the yield of HT. A selective enzyme was screened from among 10 enzymes with a high OE degradation rate. A single factor (pH, temperature, time, enzyme quantity optimization process and a Box-Behnken design were studied for the enzymatic hydrolysis of 81.04% OE olive leaf extract. Additionally, enzymatic hydrolysis results with different substrates (38.6% and 81.04% OE were compared and the DPPH antioxidant properties were also evaluated. The result showed that the performance of hydrolysis treatments was best using hemicellulase as a bio-catalyst, and the high purity of OE in olive extract was beneficial to biotransform OE into HT. The optimal enzymatic conditions for achieving a maximal yield of HT content obtained by the regression were as follows: pH 5, temperature 55 °C and enzyme quantity 55 mg. The experimental result was 11.31% ± 0.15%, and the degradation rate of OE was 98.54%. From the present investigation of the antioxidant activity determined by the DPPH method, the phenol content and radical scavenging effect were both decreased after enzymatic hydrolysis by hemicellulase. However, a high antioxidant activity of the ethyl acetate extract enzymatic hydrolysate (IC50 = 41.82 μg/mL was demonstated. The results presented in this work suggested that hemicellulase has promising and attractive properties for industrial production of HT, and indicated that HT might be a valuable biological component for use in pharmaceutical products and functional foods.

Coated tube for immunochemical and enzymatic assays

International Nuclear Information System (INIS)

Brown, J.L.; Lin, W.H.-T.; Woods, J.W.

1979-01-01

Containers such as test tubes suitable for use in solid phase immunochemical, enzymatical and particularly radioimmunoassay procedures are described. The lower part of the tube is a polymer, coated with an inert protein to which a biologically active substance eg an antibody to triiodothyronine, thyroxine or digoxin, is attached. (U.K.)

[Response surface method optimize of nano-silica solid dispersion technology assistant enzymatic hydrolysis preparation genistein].

Science.gov (United States)

Jin, Xin; Zhang, Zhen-Hai; Zhu, Jing; Sun, E; Yu, Dan-Hong; Chen, Xiao-Yun; Liu, Qi-Yuan; Ning, Qing; Jia, Xiao-Bin

2012-04-01

This article reports that nano-silica solid dispersion technology was used to raise genistein efficiency through increasing the enzymatic hydrolysis rate. Firstly, genistin-nano-silica solid dispersion was prepared by solvent method. And differential scanning calorimetry (DSC) and transmission electron microscopy (TEM) were used to verify the formation of solid dispersion, then enzymatic hydrolysis of solid dispersion was done by snailase to get genistein. With the conversion of genistein as criteria, single factor experiments were used to study the different factors affecting enzymatic hydrolysis of genistin and its solid dispersion. And then, response surface method was used to optimize of nano-silica solid dispersion technology assistant enzymatic hydrolysis. The optimum condition to get genistein through enzymatic hydrolysis of genistin-nano-silica solid dispersion was pH 7.1, temperature 52.2 degrees C, enzyme concentration 5.0 mg x mL(-1) and reaction time 7 h. Under this condition, the conversion of genistein was (93.47 +/- 2.40)%. Comparing with that without forming the genistin-nano-silica solid dispersion, the conversion increased 2.62 fold. At the same time, the product of hydrolysis was purified to get pure genistein. The method of enzymatic hydrolysis of genistin-nano-silica solid dispersion by snailase to obtain genistein is simple, efficiency and suitable for the modern scale production.

Bio-based alkyds by direct enzymatic bulk polymerization

DEFF Research Database (Denmark)

Nguyen, Hiep Dinh

to a corresponding classical reference. In a further development of the system, it has been found possible to use the esters of pentaerythritol and stearic acid in combination with the penta-aze derivative for the preparation of pseudo alkyds containing only pentaerythritol as polyol with high degree of branching....... Bio-based alkyds prepared from a combination of glycerol, and tall oil fatty acids, and azelaic acid by enzymatic polymerization show improved hydrophobicity and lower glass transition temperatures compared to an alkyd prepared from the same raw materials by a classical boiling method. The enzymatic...... of pentaerythritol derivatized with azelaic acid (or penta-aze) was examined and tested for the production of more branched alkyd systems. A photostability test validated the concept, and the method also resulted in alkyds with improved hydrophobicity and lower glass transition temperatures compared...

Process Evaluation Tools for Enzymatic Cascades Welcome Message

DEFF Research Database (Denmark)

Abu, Rohana

improvement and implementation. Hence, the goal of this thesis is to evaluate the process concepts in enzymatic cascades in a systematic manner, using tools such as thermodynamic and kinetic analysis. Three relevant case studies have been used to exemplify the approach. In the first case study, thermodynamic......Biocatalysis is attracting significant attention from both academic and industrial scientists due to the excellent capability of enzyme to catalyse selective reactions. Recently, much interest has been shown in the application of enzymatic cascades as a useful tool in organic synthesis......, the kinetics can be controlled in a highly efficient way to achieve a sufficiently favourable conversion to a given target product. This is exemplified in the second case study, in the kinetic modelling of the formation of 2-ketoglutarate from glucoronate, the second case study. This cascade consists of 4...

Enzymatic Hydrolysis of Pretreated Fibre Pressed Oil Palm Frond by using Sacchariseb C6

Science.gov (United States)

Hashim, F. S.; Yussof, H. W.; Zahari, M. A. K. M.; Rahman, R. A.; Illias, R. M.

2017-06-01

Enzymatic hydrolysis becomes a prominent technology for conversion of cellulosic biomass to its glucose monomers that requires an action of cellulolytic enzymes in a sequential and synergistic manner. In this study, the effect of agitation speed, glucan loading, enzyme loading, temperature and reaction time on the production of glucose from fibre pressed oil palm frond (FPOPF) during enzymatic hydrolysis was screened by a half factorial design 25-1 using Response Surface Methodology (RSM). The FPOPF sample was first delignified by alkaline pretreatment at 4.42 (w/v) sodium hydroxide for an hour prior to enzymatic hydrolysis using commercial cellulase enzyme, Sacchariseb C6. The effect of enzymatic hydrolysis on the structural of FPOPF has been evaluated by Scanning Electron Microscopy (SEM) analysis. Characterization of raw FPOPF comprised of 4.5 extractives, 40.7 glucan, 26.1 xylan, 26.2 lignin and 1.8 ash, whereas for pretreated FPOPF gave 0.3 extractives, 61.4 glucan, 20.4 xylan, 13.3 lignin and 1.3 ash. From this study, it was found that the best enzymatic hydrolysis condition yielded 33.01 ± 0.73 g/L of glucose when performed at 200 rpm of agitation speed, 60 FPU/mL of enzyme loading, 4 (w/w) of glucan loading, temperature at 55 □ and 72 hours of reaction time. The model obtained was significant with p-value enzymatic hydrolysis from pretreated FPOPF produce high amount of glucose that enhances it potential for industrial application. This glucose can be further used to produce high-value products.

Pretreatment of corn stover using wet oxidation to enhance enzymatic digestibility

DEFF Research Database (Denmark)

Varga, E.; Schmidt, A.S.; Reczey, K.

2003-01-01

was about 85%. Decreasing the hydrolysis temperature to 40degreesC increased hydrolysis time from 24 to 72 h. Decreasing the enzyme loading to 5 FPU/g of DM biomass slightly decreased the enzymatic conversion from 83.4 to 71%. Thus, enzyme loading can be reduced without significantly affecting......) was investigated to enhance the enzymatic digestibility of corn stover. Six different combinations of reaction temperature, time, and pH were applied. The best conditions (60 g/L of corn stover, 195degreesC, 15 min, 12 bar O-2, 2 g/L of Na2CO) increased the enzymatic conversion of corn stover four times, compared...... to untreated material. Under these conditions 60% of hemicellulose and 30% of lignin were solubilized, whereas 90% of cellulose remained in the solid fraction. After 24-h hydrolysis at 50degreesC using 25 filter paper units (FPU)/g of drymatter (DM) biomass, the achieved conversion of cellulose to glucose...

Development of a Multi-Point Quantitation Method to Simultaneously Measure Enzymatic and Structural Components of the Clostridium thermocellum Cellulosome Protein Complex

Energy Technology Data Exchange (ETDEWEB)

Dykstra, Andrew B [ORNL; St. Brice, Lois [Dartmouth College; Rodriguez, Jr., Miguel [ORNL; Raman, Babu [ORNL; Izquierdo, Javier [ORNL; Cook, Kelsey [ORNL; Lynd, Lee R [ORNL; Hettich, Robert {Bob} L [ORNL

2014-01-01

Clostridium thermocellum has emerged as a leading bioenergy-relevant microbe due to its ability to solubilize cellulose into carbohydrates, mediated by multi-component membrane-attached complexes termed cellulosomes. To probe microbial cellulose utilization rates, it is desirable to be able to measure the concentrations of saccharolytic enzymes and estimate the total amount of cellulosome present on a mass basis. Current cellulase determination methodologies involve labor-intensive purification procedures and only allow for indirect determination of abundance. We have developed a method using multiple reaction monitoring (MRM-MS) to simultaneously quantitate both enzymatic and structural components of the cellulosome protein complex in samples ranging in complexity from purified cellulosomes to whole cell lysates, as an alternative to a previously-developed enzyme-linked immunosorbent assay (ELISA) method of cellulosome quantitation. The precision of the cellulosome mass concentration in technical replicates is better than 5% relative standard deviation for all samples, indicating high precision for determination of the mass concentration of cellulosome components.

Thermal, spectral, magnetic and biological studies of thiosemicarbazones complexes with metal ions: Cu(II), Co(II), Ni(II), Fe(III), Zn(II), Mn(II) and UO2(VI)

International Nuclear Information System (INIS)

Mashaly, M.M.; Seleem, H.S.; El-Behairy, M.A.; Habib, H.A.

2004-01-01

Thiosemicarbazones ligands, isatin-3-thiosemicarbazone(HIT) and N-acetylisatin-3-thiosemicarbazone (HAIT), which have tridentate ONN coordinating sites were prepared. The complexes of both ligands with Cu(II), Co(II), Ni(II), Fe(III), Zn(II), Mn(II) and UO 2 (VI) ions were isolated. The ligands and their metal complexes were characterized by elemental analysis, IR, UV-Vis and mass spectra, also by conductance, magnetic moment and TG-DSC measurements. All the transition metal complexes have octahedral configurations, except Cu-complexes which have planar geometry and the UO 2 (VI) complexes which have coordination number 8 and may acquire the distorted dodecahedral geometry. Thermal studies explored the possibility of obtaining new complexes. Inversion from octahedral to square-planar configuration occurred upon heating the parent Ni-HIAT complex to form the corresponding pyrolytic product. The antifungal activity against the tested organisms showed that some metal complexes enhanced the activity with respect to the parent ligands. (author)

[Methods for enzymatic determination of triglycerides in liver homogenates].

Science.gov (United States)

Höhn, H; Gartzke, J; Burck, D

1987-10-01

An enzymatic method is described for the determination of triacylglycerols in liver homogenate. In contrast to usual methods, higher reliability and selectivity are achieved by omitting the extraction step.

11 Soil Microbial Biomass

African Journals Online (AJOL)

186–198. Insam H. (1990). Are the soil microbial biomass and basal respiration governed by the climatic regime? Soil. Biol. Biochem. 22: 525–532. Insam H. D. and Domsch K. H. (1989). Influence of microclimate on soil microbial biomass. Soil Biol. Biochem. 21: 211–21. Jenkinson D. S. (1988). Determination of microbial.

MBGD update 2013: the microbial genome database for exploring the diversity of microbial world.

Science.gov (United States)

Uchiyama, Ikuo; Mihara, Motohiro; Nishide, Hiroyo; Chiba, Hirokazu

2013-01-01

The microbial genome database for comparative analysis (MBGD, available at http://mbgd.genome.ad.jp/) is a platform for microbial genome comparison based on orthology analysis. As its unique feature, MBGD allows users to conduct orthology analysis among any specified set of organisms; this flexibility allows MBGD to adapt to a variety of microbial genomic study. Reflecting the huge diversity of microbial world, the number of microbial genome projects now becomes several thousands. To efficiently explore the diversity of the entire microbial genomic data, MBGD now provides summary pages for pre-calculated ortholog tables among various taxonomic groups. For some closely related taxa, MBGD also provides the conserved synteny information (core genome alignment) pre-calculated using the CoreAligner program. In addition, efficient incremental updating procedure can create extended ortholog table by adding additional genomes to the default ortholog table generated from the representative set of genomes. Combining with the functionalities of the dynamic orthology calculation of any specified set of organisms, MBGD is an efficient and flexible tool for exploring the microbial genome diversity.

Microbial ecology of terrestrial Antarctica: Are microbial systems at risk from human activities?

Energy Technology Data Exchange (ETDEWEB)

White, G.J.

1996-08-01

Many of the ecological systems found in continental Antarctica are comprised entirely of microbial species. Concerns have arisen that these microbial systems might be at risk either directly through the actions of humans or indirectly through increased competition from introduced species. Although protection of native biota is covered by the Protocol on Environmental Protection to the Antarctic Treaty, strict measures for preventing the introduction on non-native species or for protecting microbial habitats may be impractical. This report summarizes the research conducted to date on microbial ecosystems in continental Antarctica and discusses the need for protecting these ecosystems. The focus is on communities inhabiting soil and rock surfaces in non-coastal areas of continental Antarctica. Although current polices regarding waste management and other operations in Antarctic research stations serve to reduce the introduction on non- native microbial species, importation cannot be eliminated entirely. Increased awareness of microbial habitats by field personnel and protection of certain unique habitats from physical destruction by humans may be necessary. At present, small-scale impacts from human activities are occurring in certain areas both in terms of introduced species and destruction of habitat. On a large scale, however, it is questionable whether the introduction of non-native microbial species to terrestrial Antarctica merits concern.

New eutectic ionic liquids for lipase activation and enzymatic preparation of biodiesel†

Science.gov (United States)

Zhao, Hua; Baker, Gary A.; Holmes, Shaletha

2012-01-01

The enzymatic preparation of biodiesel has been hampered by the lack of suitable solvents with desirable properties such as high lipase compatibility, low cost, low viscosity, high biodegradability, and ease of product separation. Recent interest in using ionic liquids (ILs) as advanced reaction media has led to fast reaction rates and high yields in the enzymatic synthesis of biodiesel. However, conventional (i.e., cation–anion paired) ILs based on imidazolium and other quaternary ammonium salts remain too expensive for wide application at industrial scales. In this study, we report on newly-synthesized eutectic ILs derived from choline acetate or choline chloride coupled with biocompatible hydrogen-bond donors, such as glycerol. These eutectic solvents have favorable properties including low viscosity, high biodegradability, and excellent compatibility with Novozym® 435, a commercial immobilized Candida antarctica lipase B. Furthermore, in a model biodiesel synthesis system, we demonstrate high reaction rates for the enzymatic transesterification of Miglyol® oil 812 with methanol, catalyzed by Novozym® 435 in choline acetate/glycerol (1 : 1.5 molar ratio). The high conversion (97%) of the triglyceride obtained within 3 h, under optimal conditions, suggests that these novel eutectic solvents warrant further exploration as potential media in the enzymatic production of biodiesel. PMID:21283901

Continuous enzymatic hydrolysis of lignocellulosic biomass with simultaneous detoxification and enzyme recovery.

Science.gov (United States)

Gurram, Raghu N; Menkhaus, Todd J

2014-07-01

Recovering hydrolysis enzymes and/or alternative enzyme addition strategies are two potential mechanisms for reducing the cost during the biochemical conversion of lignocellulosic materials into renewable biofuels and biochemicals. Here, we show that enzymatic hydrolysis of acid-pretreated pine wood with continuous and/or fed-batch enzyme addition improved sugar conversion efficiencies by over sixfold. In addition, specific activity of the hydrolysis enzymes (cellulases, hemicellulases, etc.) increased as a result of continuously washing the residual solids with removal of glucose (avoiding the end product inhibition) and other enzymatic inhibitory compounds (e.g., furfural, hydroxymethyl furfural, organic acids, and phenolics). As part of the continuous hydrolysis, anion exchange resin was tested for its dual application of simultaneous enzyme recovery and removal of potential enzymatic and fermentation inhibitors. Amberlite IRA-96 showed favorable adsorption profiles of inhibitors, especially furfural, hydroxymethyl furfural, and acetic acid with low affinity toward sugars. Affinity of hydrolysis enzymes to adsorb onto the resin allowed for up to 92 % of the enzymatic activity to be recovered using a relatively low-molar NaCl wash solution. Integration of an ion exchange column with enzyme recovery into the proposed fed-batch hydrolysis process can improve the overall biorefinery efficiency and can greatly reduce the production costs of lignocellulosic biorenewable products.

Numerical prediction of kinetic model for enzymatic hydrolysis of cellulose using DAE-QMOM approach

Science.gov (United States)

Jamil, N. M.; Wang, Q.

2016-06-01

Bioethanol production from lignocellulosic biomass consists of three fundamental processes; pre-treatment, enzymatic hydrolysis, and fermentation. In enzymatic hydrolysis phase, the enzymes break the cellulose chains into sugar in the form of cellobiose or glucose. A currently proposed kinetic model for enzymatic hydrolysis of cellulose that uses population balance equation (PBE) mechanism was studied. The complexity of the model due to integrodifferential equations makes it difficult to find the analytical solution. Therefore, we solved the full model of PBE numerically by using DAE-QMOM approach. The computation was carried out using MATLAB software. The numerical results were compared to the asymptotic solution developed in the author's previous paper and the results of Griggs et al. Besides confirming the findings were consistent with those references, some significant characteristics were also captured. The PBE model for enzymatic hydrolysis process can be solved using DAE-QMOM method. Also, an improved understanding of the physical insights of the model was achieved.

Enzymatic browning control in cut apples (Red delicious through a system of active packaging

Directory of Open Access Journals (Sweden)

Felipe Jadán Piedra

2017-03-01

Full Text Available Enzymatic browning is one of the most relevant mechanisms of deterioration that take place in fresh-cut fruit and vegetables, as a consequence of the activity of the polyphenol oxidase enzyme on the phenolic compounds release after cellular lysis . This work is focused on the reduction of these enzymatic activity by an active packaging technology, which make use of a material that incorporates antioxidant active agents. Thus, films of ethylene-vynil alcohol copolymer (EVOH containing a typical food antioxidant, such as ascorbic acid and a polyphenol oxidase-inhibiting agent, the 4-hexylresorcinol have been developed and used to wrap apple slices. The evolution of color, the enzymatic activity and the kinetic of agents release to food simulants were monitored. The results showed an improvement of apple slice color stability and a reduction of the enzymatic activity. The film with 10 % of agents in 3/1 ratio (4-hexylresorcinol/ascorbic acid provided the best results.

Microbial transglutaminase and its application in the food industry. A review.

Science.gov (United States)

Kieliszek, Marek; Misiewicz, Anna

2014-05-01

The extremely high costs of manufacturing transglutaminase from animal origin (EC 2.3.2.13) have prompted scientists to search for new sources of this enzyme. Interdisciplinary efforts have been aimed at producing enzymes synthesised by microorganisms which may have a wider scope of use. Transglutaminase is an enzyme that catalyses the formation of isopeptide bonds between proteins. Its cross-linking property is widely used in various processes: to manufacture cheese and other dairy products, in meat processing, to produce edible films and to manufacture bakery products. Transglutaminase has considerable potential to improve the firmness, viscosity, elasticity and water-binding capacity of food products. In 1989, microbial transglutaminase was isolated from Streptoverticillium sp. Its characterisation indicated that this isoform could be extremely useful as a biotechnological tool in the food industry. Currently, enzymatic preparations are used in almost all industrial branches because of their wide variety and low costs associated with their biotechnical production processes. This paper presents an overview of the literature addressing the characteristics and applications of transglutaminase.

Effect of enzymatic depolymerization on physicochemical and rheological properties of guar gum.

Science.gov (United States)

Mudgil, Deepak; Barak, Sheweta; Khatkar, B S

2012-09-01

Depolymerization of guar gum using enzymatic hydrolysis was performed to obtain depolymerized guar gum having functional application as soluble dietary fiber. Enzymatic hydrolysis of guar gum significantly affected the physicochemical and rheological characteristics of guar gum. The depolymerized guar gum showed a significant increase in crystallinity index from 3.86% to 13.2% and flow behavior index from 0.31 to 1.7 as compared to native guar gum. Remarkable decrease in intrinsic viscosity and consistency index was also observed from 9 to 0.28 and 4.04 to 0.07, respectively. Results revealed that enzymatic hydrolysis of guar gum resulted in a polysaccharide with low degree of polymerization, viscosity and consistency which could make it useful for incorporation in food products as dietary fiber without affecting the rheology, consistency and texture of the products. Copyright © 2012 Elsevier Ltd. All rights reserved.

Enzymatic Dissolution of Biocomposite Solids Consisting of Phosphopeptides to Form Supramolecular Hydrogels

KAUST Repository

Shi, Junfeng; Yuan, Dan; Haburcak, Richard; Zhang, Qiang; Zhao, Chao; Zhang, Xixiang; Xu, Bing

2015-01-01

Enzyme-catalyzed dephosphorylation is essential for biomineralization and bone metabolism. Here we report the exploration of using enzymatic reaction to transform biocomposites of phosphopeptides and calcium (or strontium) ions to supramolecular hydrogels as a mimic of enzymatic dissolution of biominerals. 31P NMR shows that strong affinity between the phosphopeptides and alkaline metal ions (e.g., Ca2+ or Sr2+) induces the formation of biocomposites as precipitates. Electron microscopy reveals that the enzymatic reaction regulates the morphological transition from particles to nanofibers. Rheology confirms the formation of a rigid hydrogel. As the first example of enzyme-instructed dissolution of a solid to form supramolecular nanofibers/hydrogels, this work provides an approach to generate soft materials with desired properties, expands the application of supramolecular hydrogelators, and offers insights to control the demineralization of calcified soft tissues.

Enzymatic Dissolution of Biocomposite Solids Consisting of Phosphopeptides to Form Supramolecular Hydrogels

KAUST Repository

Shi, Junfeng

2015-10-14

Enzyme-catalyzed dephosphorylation is essential for biomineralization and bone metabolism. Here we report the exploration of using enzymatic reaction to transform biocomposites of phosphopeptides and calcium (or strontium) ions to supramolecular hydrogels as a mimic of enzymatic dissolution of biominerals. 31P NMR shows that strong affinity between the phosphopeptides and alkaline metal ions (e.g., Ca2+ or Sr2+) induces the formation of biocomposites as precipitates. Electron microscopy reveals that the enzymatic reaction regulates the morphological transition from particles to nanofibers. Rheology confirms the formation of a rigid hydrogel. As the first example of enzyme-instructed dissolution of a solid to form supramolecular nanofibers/hydrogels, this work provides an approach to generate soft materials with desired properties, expands the application of supramolecular hydrogelators, and offers insights to control the demineralization of calcified soft tissues.

Enzymatic network for production of ether amines from alcohols

DEFF Research Database (Denmark)

Palacio, Cyntia M.; Crismaru, Ciprian G.; Bartsch, Sebastian

2016-01-01

We constructed an enzymatic network composed of three different enzymes for the synthesis of valuable ether amines. The enzymatic reactions are interconnected to catalyze the oxidation and subsequent transamination of the substrate and to provide cofactor recycling. This allows production...... of the desired ether amines from the corresponding ether alcohols with inorganic ammonium as the only additional substrate. To examine conversion, individual and overall reaction equilibria were established. Using these data, it was found that the experimentally observed conversions of up to 60% observed...... for reactions containing 10mM alcohol and up to 280mM ammonia corresponded well to predicted conversions. The results indicate that efficient amination can be driven by high concentrations of ammonia and may require improving enzyme robustness for scale-up....

Microbial functional diversity and enzymatic activity of soil degraded by sulphur mining reclaimed with various waste

Science.gov (United States)

Joniec, Jolanta; Frąc, Magdalena

2017-10-01

The aim of the study was to evaluate microbial functional diversity based on community level physiological profiling and β-glucosidase activity changes in soil degraded by sulphur mining and subjected to reclamation with various waste. The experiment was set up in the area of the former `Jeziórko' Sulphur Mine (Poland), on a soilless substrate with a particle size distribution of slightly loamy sand. The experimental variants included the application of post-flotation lime, sewage sludge and mineral wool. The analyses of soil samples included the assessment of the following microbiological indices: β-glucosidase activity and functional diversity average well color development and richness). The results indicate that sewage sludge did not exert a significant impact on the functional diversity of microorganisms present in the reclaimed soil. In turn, the application of other types of waste contributed to a significant increase in the parameters of total metabolic activity and functional diversity of the reclaimed soil. However, the temporal analysis of the metabolic profile of soil microorganisms demonstrated that a single application of waste did not yield a durable, stable metabolic profile in the reclaimed soil. Still, there was an increase in β-glucosidase activity, especially in objects treated with sewage sludge.

Enzymatic activity measured by microcalorimetry in soil amended with organic residues

Directory of Open Access Journals (Sweden)

Karina Cenciani

2011-08-01

Full Text Available Enzymatic activity is an important property for soil quality evaluation. Two sequences of experiments were carried out in order to evaluate the enzymatic activity in a soil (Rhodic Eutrudox amended with cattle manure, earthworm casts, or sewage sludges from the municipalities of Barueri and Franca. The activity of commercial enzymes was measured by microcalorimetry in the same soil samples after sterilization. In the first experiment, the enzyme activities of cellulase, protease, and urease were determined in the soil samples during a three month period. In the second sequence of experiments, the thermal effect of the commercial enzymes cellulase, protease, and urease on sterilized soil samples under the same tretaments was monitored for a period of 46 days. The experimental design was randomized and arranged as factorial scheme in five treatments x seven samplings with five replications. The treatment effects were statistically evaluated by one-way analysis of variance. Tukey´s test was used to compare means at p < 0.05. The presence of different sources of organic residues increased the enzymatic activity in the sampling period. Cattle manure induced the highest enzymatic activity, followed by municipal sewage sludge, whereas earthworm casts induced the lowest activity, but differed from control treatment. The thermal effect on the enzyme activity of commercial cellulase, protease, and urease showed a variety of time peaks. These values probably oscillated due to soil physical-chemical factors affecting the enzyme activity on the residues.

Enzymatic formulation capable of degrading scrapie prion under mild digestion conditions.

Directory of Open Access Journals (Sweden)

Emeka A Okoroma

Full Text Available The prion agent is notoriously resistant to common proteases and conventional sterilisation procedures. The current methods known to destroy prion infectivity such as incineration, alkaline and thermal hydrolysis are harsh, destructive, environmentally polluting and potentially hazardous, thus limit their applications for decontamination of delicate medical and laboratory devices, remediation of prion contaminated environment and for processing animal by-products including specified risk materials and carcases. Therefore, an environmentally friendly, non-destructive enzymatic degradation approach is highly desirable. A feather-degrading Bacillus licheniformis N22 keratinase has been isolated which degraded scrapie prion to undetectable level of PrP(Sc signals as determined by Western Blot analysis. Prion infectivity was verified by ex vivo cell-based assay. An enzymatic formulation combining N22 keratinase and biosurfactant derived from Pseudomonas aeruginosa degraded PrP(Sc at 65 °C in 10 min to undetectable level -. A time-course degradation analysis carried out at 50 °C over 2 h revealed the progressive attenuation of PrP(Sc intensity. Test of residual infectivity by standard cell culture assay confirmed that the enzymatic formulation reduced PrP(Sc infectivity to undetectable levels as compared to cells challenged with untreated standard scrapie sheep prion (SSBP/1 (p-value = 0.008 at 95% confidence interval. This novel enzymatic formulation has significant potential application for prion decontamination in various environmentally friendly systems under mild treatment conditions.

The properties of main oxidases associated with enzymatic ...

African Journals Online (AJOL)

Lenovo User

2012-07-03

Jul 3, 2012 ... 1College of Food Science and Engineering, Shandong Agricultural University, Taian, Shandong, 271018,. People's Republic of China. 2The Central Hospital of Taian, Taian, Shandong ... pear vinegar, preserved pear and canned pear. However, enzymatic browning during processing impairs sensory.

Enzymatic hydrolysis of lactose of whey permeate

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Karina Nascimento de Almeida

2015-09-01

Full Text Available The whey permeate is the residual of the concentration process of the whey proteins by ultrafiltration method. It contains important nutrients such as lactose, minerals and some proteins and lipids. It is without an ending industrial waste that causes serious damage to the environment. For its full use the lactose must be hydrolyzed to enable its consumption by intolerant people. The enzymatic hydrolysis by lactase (β-galactosidase of Kluyveromyces lactis yeast is a safe method that does not compromise the integrity of other nutrients, enabling further use of the permeate as a raw material. This study aimed to perform tests of enzymatic hydrolysis of lactose in whey permeate formulations in a concentration of 0.2%, 0.7% and 1% at 30, 60 and 90 minutes with pH 6.3 medium and 37 °C. The reactions were monitored by high performance liquid chromatography which showed that the enzyme concentration of 0.7% at time 30 minutes formulations became safe for consumption by lactose intolerant people, according to minimum levels established by law.

Enzymatic U(VI) reduction by Desulfosporosinus species

International Nuclear Information System (INIS)

Suzuki, Y.; Kelly, S.D.; Kemner, K.M.; Banfield, J.F.

2004-01-01

Here we tested U(VI) reduction by a Desulfosporosinus species (sp.) isolate and type strain (DSM 765) in cell suspensions (pH 7) containing 1 mM U(VI) and lactate, under an atmosphere containing N 2 -CO 2 -H 2 (90: 5: 5). Although neither Desulfosporosinus species (spp.) reduced U(VI) in cell suspensions with 0.25% Na-bicarbonate or 0.85% NaCl, U(VI) was reduced in these solutions by a control strain, desulfovibrio desulfuricans (ATCC 642). However, both Desulfosporosinus strains reduced U(VI) in cell suspensions depleted in bicarbonate and NaCl. No U(VI) reduction was observed without lactate and H 2 electron donors or with heat-killed cells, indicating enzymatic U(VI) reduction. Uranium(VI) reduction by both strains was inhibited when 1 mM CuCl 2 was added to the cell suspensions. Because the Desulfosporosinus DSM 765 does not contain cytochrome c 3 used by Desulfovibrio spp. to reduce U(VI), Desulfosporosinus species reduce uranium via a different enzymatic pathway. (orig.)

The effects of xylitol and sorbitol on lysozyme- and peroxidase-related enzymatic and candidacidal activities.

Science.gov (United States)

Kim, Bum-Soo; Chang, Ji-Youn; Kim, Yoon-Young; Kho, Hong-Seop

2015-07-01

To investigate whether xylitol and sorbitol affect enzymatic and candidacidal activities of lysozyme, the peroxidase system, and the glucose oxidase-mediated peroxidase system. Xylitol and sorbitol were added to hen egg-white lysozyme, bovine lactoperoxidase, glucose oxidase-mediated peroxidase, and whole saliva in solution and on hydroxyapatite surfaces. The enzymatic activities of lysozyme, peroxidase, and glucose oxidase-mediated peroxidase were determined by the turbidimetric method, the NbsSCN assay, and production of oxidized o-dianisidine, respectively. Candidacidal activities were determined by comparing colony forming units using Candida albicans ATCC strains 10231, 11006, and 18804. While xylitol and sorbitol did not affect the enzymatic activity of hen egg-white lysozyme both in solution and on hydroxyapatite surfaces, they did inhibit the enzymatic activity of salivary lysozyme significantly in solution, but not on the surfaces. Xylitol and sorbitol enhanced the enzymatic activities of both bovine lactoperoxidase and salivary peroxidase significantly in a dose-dependent manner in solution, but not on the surfaces. Sorbitol, but not xylitol, inhibited the enzymatic activity of glucose oxidase-mediated peroxidase significantly. Both xylitol and sorbitol did not affect candidacidal activities of hen egg-white lysozyme, the bovine lactoperoxidase system, or the glucose oxidase-mediated bovine lactoperoxidase system. Xylitol and sorbitol inhibited salivary lysozyme activity, but enhanced both bovine lactoperoxidase and salivary peroxidase activities significantly in solution. Xylitol and sorbitol did not augment lysozyme- and peroxidase-related candidacidal activities. Copyright © 2015 Elsevier Ltd. All rights reserved.

Microbial biodiversity, quality and shelf life of microfiltered and pasteurized extended shelf life (ESL) milk from Germany, Austria and Switzerland.

Science.gov (United States)

Schmidt, Verena S J; Kaufmann, Veronika; Kulozik, Ulrich; Scherer, Siegfried; Wenning, Mareike

2012-03-01

Information on factors limiting the shelf life of extended shelf life (ESL) milk produced by microfiltration and subsequent pasteurization is very limited. In this study, three different batches of ESL milk were analyzed at different stages of the production process and during storage at 4 °C, 8 °C and 10 °C in order to evaluate the changes in bacterial cell counts, microbial diversity and enzymatic quality. Additionally, detailed biodiversity analyses of 250 retail ESL milk packages produced by five manufacturers in Germany, Austria and Switzerland were performed at the end of shelf life. It was observed that microfiltration decreased the microbial loads by 5-6 log₁₀ units to lower than 1 CFU/mL. However, bacterial counts at the end of shelf life were extremely variable and ranged between ESL treatment, causing stochastic variations of initial species distributions in individual packages. This would result in the development of significantly different bacterial populations during cold storage, including the occasional development of high numbers of pathogenic species such as B. cereus or Acinetobacter. Copyright © 2011 Elsevier B.V. All rights reserved.

Scale-up and integration of alkaline hydrogen peroxide pretreatment, enzymatic hydrolysis, and ethanolic fermentation.

Science.gov (United States)

Banerjee, Goutami; Car, Suzana; Liu, Tongjun; Williams, Daniel L; Meza, Sarynna López; Walton, Jonathan D; Hodge, David B

2012-04-01

Alkaline hydrogen peroxide (AHP) has several attractive features as a pretreatment in the lignocellulosic biomass-to-ethanol pipeline. Here, the feasibility of scaling-up the AHP process and integrating it with enzymatic hydrolysis and fermentation was studied. Corn stover (1 kg) was subjected to AHP pretreatment, hydrolyzed enzymatically, and the resulting sugars fermented to ethanol. The AHP pretreatment was performed at 0.125 g H(2) O(2) /g biomass, 22°C, and atmospheric pressure for 48 h with periodic pH readjustment. The enzymatic hydrolysis was performed in the same reactor following pH neutralization of the biomass slurry and without washing. After 48 h, glucose and xylose yields were 75% and 71% of the theoretical maximum. Sterility was maintained during pretreatment and enzymatic hydrolysis without the use of antibiotics. During fermentation using a glucose- and xylose-utilizing strain of Saccharomyces cerevisiae, all of the Glc and 67% of the Xyl were consumed in 120 h. The final ethanol titer was 13.7 g/L. Treatment of the enzymatic hydrolysate with activated carbon prior to fermentation had little effect on Glc fermentation but markedly improved utilization of Xyl, presumably due to the removal of soluble aromatic inhibitors. The results indicate that AHP is readily scalable and can be integrated with enzyme hydrolysis and fermentation. Compared to other leading pretreatments for lignocellulosic biomass, AHP has potential advantages with regard to capital costs, process simplicity, feedstock handling, and compatibility with enzymatic deconstruction and fermentation. Biotechnol. Bioeng. 2012; 109:922-931. © 2011 Wiley Periodicals, Inc. Copyright © 2011 Wiley Periodicals, Inc.

Aqueous two-phase systems for extractive enzymatic hydrolysis of biomass

DEFF Research Database (Denmark)

Bussamra, Bianca Consorti; Azzoni, Sindelia Freitas; Mussatto, Solange I.

and enzymes, phase diagrams and volumetric ratios. The results of this project will make possible to design a process that enables high sugar concentration during the hydrolysis reaction, overcoming one of the biggest drawbacks regarding the production of second-generation ethanol: the enzymatic inhibition...... optimal aqueous two-phase systems for the separation of sugars and enzymes, which allow the development of an improved second-generation ethanol process.......Sugars derived from lignocellulosic materials are the main carbon sources in bio-based processes aiming to produce renewable fuels and chemicals. One of the major drawbacks during enzymatic hydrolysis of lignocellulosic materials to obtainsugars is the inhibition of enzymes by reaction products...

In-Vitro Enzymatic Degradation of γ-irradiated Porous Chitosan Scaffold: Crystallinity and degree of deacetylation

International Nuclear Information System (INIS)

Ismail Zainol; Azreena Mastor; Suhaida Md Ghani; Ahmad Fuad Yahya; Hazizan Md Akil

2009-01-01

Full text: Enzymatic degradation behavior of porous chitosan membrane was carried out in vitro by using enzymatic hydrolysis of chitosan in lysozyme solution. Chitosan was first modified by reducing its molecular weight by gamma (γ) radiation in the solid state. The chitosan powder was irradiated with gamma Co 60 source with various doses of 10, 25, 50 and 100 kGy. The molecular weight of irradiated chitosan was measured using visco metric method. The modified chitosan was transform into a porous membrane by lyophilization method. Degree of deacetylation (DD) and crystallinity of samples were measured using FTIR and XRD respectively on both gamma irradiated and enzymatic degradation samples. The results suggested that the irradiated chitosan become less crystalline without changes in DD. The enzymatic degradation of chitosan however shows an increment in DD and crystallinity. (author)

Impact of lignins isolated from pretreated lignocelluloses on enzymatic cellulose saccharification

DEFF Research Database (Denmark)

Barsberg, Søren Talbro; Selig, Michael Joseph; Felby, Claus

2013-01-01

and cellulose-lignin systems. Consequently, the presence of the lignins had minimal effect, if any, on enzymatic cellulose conversion. Furthermore, this result, coupled with significant calcium levels in the isolated lignins, supports previous work suggesting lignin-calcium complexes reduce enzyme......Lignins were enzymatically isolated from corn stover and wheat straw samples and subjected to hydrothermal or wet oxidation pretreatments for enzyme adsorption experimentations. Lignin contents of the isolates ranged from 26 to 71 % (w/w); cellulose ranged from 3 to 22 % (w/w); xylan from 0.7 to 6...

Impact of enzymatic digestion on bacterial community composition in CF airway samples

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Kayla M. Williamson

2017-05-01

Full Text Available Background Previous studies have demonstrated the importance of DNA extraction methods for molecular detection of Staphylococcus, an important bacterial group in cystic fibrosis (CF. We sought to evaluate the effect of enzymatic digestion (EnzD prior to DNA extraction on bacterial communities identified in sputum and oropharyngeal swab (OP samples from patients with CF. Methods DNA from 81 samples (39 sputum and 42 OP collected from 63 patients with CF was extracted in duplicate with and without EnzD. Bacterial communities were determined by rRNA gene sequencing, and measures of alpha and beta diversity were calculated. Principal Coordinate Analysis (PCoA was used to assess differences at the community level and Wilcoxon Signed Rank tests were used to compare relative abundance (RA of individual genera for paired samples with and without EnzD. Results Shannon Diversity Index (alpha-diversity decreased in sputum and OP samples with the use of EnzD. Larger shifts in community composition were observed for OP samples (beta-diversity, measured by Morisita-Horn, whereas less change in communities was observed for sputum samples. The use of EnzD with OP swabs resulted in significant increase in RA for the genera Gemella (p < 0.01, Streptococcus (p < 0.01, and Rothia (p < 0.01. Staphylococcus (p < 0.01 was the only genus with a significant increase in RA from sputum, whereas the following genera decreased in RA with EnzD: Veillonella (p < 0.01, Granulicatella (p < 0.01, Prevotella (p < 0.01, and Gemella (p = 0.02. In OP samples, higher RA of Gram-positive taxa was associated with larger changes in microbial community composition. Discussion We show that the application of EnzD to CF airway samples, particularly OP swabs, results in differences in microbial communities detected by sequencing. Use of EnzD can result in large changes in bacterial community composition, and is particularly useful for detection of Staphylococcus in CF OP

Enzymatically crosslinked silk-hyaluronic acid hydrogels.

Science.gov (United States)

Raia, Nicole R; Partlow, Benjamin P; McGill, Meghan; Kimmerling, Erica Palma; Ghezzi, Chiara E; Kaplan, David L

2017-07-01

In this study, silk fibroin and hyaluronic acid (HA) were enzymatically crosslinked to form biocompatible composite hydrogels with tunable mechanical properties similar to that of native tissues. The formation of di-tyrosine crosslinks between silk fibroin proteins via horseradish peroxidase has resulted in a highly elastic hydrogel but exhibits time-dependent stiffening related to silk self-assembly and crystallization. Utilizing the same method of crosslinking, tyramine-substituted HA forms hydrophilic and bioactive hydrogels that tend to have limited mechanics and degrade rapidly. To address the limitations of these singular component scaffolds, HA was covalently crosslinked with silk, forming a composite hydrogel that exhibited both mechanical integrity and hydrophilicity. The composite hydrogels were assessed using unconfined compression and infrared spectroscopy to reveal of the physical properties over time in relation to polymer concentration. In addition, the hydrogels were characterized by enzymatic degradation and for cytotoxicity. Results showed that increasing HA concentration, decreased gelation time, increased degradation rate, and reduced changes that were observed over time in mechanics, water retention, and crystallization. These hydrogel composites provide a biologically relevant system with controllable temporal stiffening and elasticity, thus offering enhanced tunable scaffolds for short or long term applications in tissue engineering. Copyright © 2017 Elsevier Ltd. All rights reserved.

Effect of Maize Biomass Composition on the Optimization of Dilute-Acid Pretreatments and Enzymatic Saccharification

NARCIS (Netherlands)

Torres Salvador, A.F.; Weijde, van der R.T.; Dolstra, O.; Visser, R.G.F.; Trindade, L.M.

2013-01-01

At the core of cellulosic ethanol research are innovations leading to reductions in the chemical and energetic stringency of thermochemical pretreatments and enzymatic saccharification. In this study, key compositional features of maize cell walls influencing the enzymatic conversion of biomass into

Influence of enzymatic reactions on the electrochemical behavior of EN X2CrNiMo17-11-2 (AISI 316L) stainless steel in bio-corrosion: role of interfacial processes on the modification of the passive layer; Influence des reactions enzymatiques sur le comportement electrochimique de l'acier inoxydable ENX2CrNiMo17-11-2 (AISI 316L) en biocorrosion: role des processus interfaciaux sur la modification du film passif

Energy Technology Data Exchange (ETDEWEB)

Landoulsi, J

2008-01-15

The outstanding corrosion behavior of stainless steels (SS) results from the presence of thin oxide layer (some nanometers). In non sterile aqueous media, stainless steels may exhibit a non stable behavior resulting from interactions between microbial species and passive film. In fact, microorganisms can be deeply involved in the corrosion processes usually reported as Microbial Influenced Corrosion (MIC). They can induce the initiation or the acceleration of this phenomenon and they do so when organized in bio-films. From the electrochemical point of view, stainless steels showed an increase of the free corrosion potential (Ecorr) attributed to the bio-film settlement. The Eco' ennoblement was broadly reported in seawater and seems to be confirmed in fresh water according to recent findings. A considerable progress in the comprehension of MIC processes was related to the role of extracellular species, essentially enzymes. Many enzymatic reactions occurring in bio-films consist on using oxygen as electron acceptor to generate hydrogen peroxide and related species. The aim of this work is to understand the mechanisms involved in the electrochemical behavior of stainless steel according to an enzymatic approach in medium simulating fresh water. To this end, glucose oxidase was chosen to globalize aerobic activities of bio-films. Electrochemical measurements in situ and surface analysis allow the comprehension of the role and the nature of interfacial processes. Surface characterization was performed with the help of a new quantitative utilization of XPS analysis and AFM. Results show a significant evolution in term of morphology (surface organization), (ii) chemical composition (passive layer, adsorbed organic species) and (iii) chemical reaction (oxidation, dissolution, effect of enzyme). Finally, a new enzymatic system is proposed to mimic specific physicochemical conditions at the SS / bio-film interface, in particular enzymatic generation of oxidant species

Efficient sugar release by acetic acid ethanol-based organosolv pretreatment and enzymatic saccharification.

Science.gov (United States)

Zhang, Hongdan; Wu, Shubin

2014-12-03

Acetic acid ethanol-based organosolv pretreatment of sugar cane bagasse was performed to enhance enzymatic hydrolysis. The effect of different parameters (including temperature, reaction time, solvent concentration, and acid catalyst dose) on pretreatment prehydrolyzate and subsequent enzymatic digestibility was determined. During the pretreatment process, 11.83 g of xylose based on 100 g of raw material could be obtained. After the ethanol-based pretreatment, the enzymatic hydrolysis was enhanced and the highest glucose yield of 40.99 g based on 100 g of raw material could be obtained, representing 93.8% of glucose in sugar cane bagasse. The maximum total sugar yields occurred at 190 °C, 45 min, 60:40 ethanol/water, and 5% dosage of acetic acid, reaching 58.36 g (including 17.69 g of xylose and 40.67 g of glucose) based on 100 g of raw material, representing 85.4% of total sugars in raw material. Furthermore, characterization of the pretreated sugar cane bagasse using X-ray diffraction and scanning electron microscopy analyses were also developed. The results suggested that ethanol-based organosolv pretreatment could enhance enzymatic digestibilities because of the delignification and removal of xylan.

Microbial decomposition of keratin in nature-a new hypothesis of industrial relevance.

Science.gov (United States)

Lange, Lene; Huang, Yuhong; Busk, Peter Kamp

2016-03-01

Discovery of keratin-degrading enzymes from fungi and bacteria has primarily focused on finding one protease with efficient keratinase activity. Recently, an investigation was conducted of all keratinases secreted from a fungus known to grow on keratinaceous materials, such as feather, horn, and hooves. The study demonstrated that a minimum of three keratinases is needed to break down keratin, an endo-acting, an exo-acting, and an oligopeptide-acting keratinase. Further, several studies have documented that disruption of sulfur bridges of the keratin structure acts synergistically with the keratinases to loosen the molecular structure, thus giving the enzymes access to their substrate, the protein structure. With such complexity, it is relevant to compare microbial keratin decomposition with the microbial decomposition of well-studied polymers such as cellulose and chitin. Interestingly, it was recently shown that the specialized enzymes, lytic polysaccharide monoxygenases (LPMOs), shown to be important for breaking the recalcitrance of cellulose and chitin, are also found in keratin-degrading fungi. A holistic view of the complex molecular self-assembling structure of keratin and knowledge about enzymatic and boosting factors needed for keratin breakdown have been used to formulate a hypothesis for mode of action of the LPMOs in keratin decomposition and for a model for degradation of keratin in nature. Testing such hypotheses and models still needs to be done. Even now, the hypothesis can serve as an inspiration for designing industrial processes for keratin decomposition for conversion of unexploited waste streams, chicken feather, and pig bristles into bioaccessible animal feed.

Unraveling the mechanism responsible for the contrasting tolerance of Synechocystis and Synechococcus to Cr(VI): Enzymatic and non-enzymatic antioxidants

Energy Technology Data Exchange (ETDEWEB)

Gupta, Alka [Molecular Biology Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400085 (India); Ballal, Anand, E-mail: aballal@barc.gov.in [Molecular Biology Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400085 (India); Homi Bhabha National Institute, Training School Complex, Anushakti Nagar, Mumbai 40085 (India)

2015-07-15

Highlights: • Cr(VI) accumulation generates higher ROS in Synechocystis than in Synechococcus. • Synechococcus exhibits better photosynthetic activity in response to Cr(VI). • Synechococcus has higher enzymatic/non-enzymatic antioxidants than Synechocystis. • Synechococcus shows better tolerance to other oxidative stresses than Synechocystis. • Differential detoxification of ROS is responsible for the contrasting tolerance to Cr(VI) - Abstract: Two unicellular cyanobacteria, Synechocystis and Synechococcus, showed contrasting tolerance to Cr(VI); with Synechococcus being 12-fold more tolerant than Synechocystis to potassium dichromate. The mechanism responsible for this differential sensitivity to Cr(VI) was explored in this study. Total content of photosynthetic pigments as well as photosynthetic activity decreased at lower concentration of Cr(VI) in Synechocystis as compared to Synechococcus. Experiments with {sup 51}Cr showed Cr to accumulate intracellularly in both the cyanobacteria. At lower concentrations, Cr(VI) caused excessive ROS generation in Synechocystis as compared to that observed in Synechococcus. Intrinsic levels of enzymatic antioxidants, i.e., superoxide dismutase, catalase and 2-Cys-peroxiredoxin were considerably higher in Synechococcus than Synechocystis. Content of total thiols (both protein as well as non-protein) and reduced glutathione (GSH) was also higher in Synechococcus as compared to Synechocystis. This correlated well with higher content of carbonylated proteins observed in Synechocystis than Synechococcus. Additionally, in contrast to Synechocystis, Synechococcus exhibited better tolerance to other oxidative stresses like high intensity light and H{sub 2}O{sub 2}. The data indicate that the disparity in the ability to detoxify ROS could be the primary mechanism responsible for the differential tolerance of these cyanobacteria to Cr(VI)

Pretreatments and enzymatic hydrolysis of sugarcane bagasse aiming at the enhancement of the yield of glucose and xylose

Directory of Open Access Journals (Sweden)

A. de A. Guilherme

Full Text Available ABSTRACT This work studied the enzymatic hydrolysis of sugarcane bagasse aiming at the production of glucose and xylose. The bagasse was subjected to two different pretreatments: combined acid and alkalinepretreatment and hydrogen peroxidepretreatment. The enzymatic hydrolysis was optimized and a kinetic study was carried out in a stirred tank reactor (STR in batch mode. Optimal conditions were obtained by subjecting the bagasse to the hydrogen peroxide pretreatment followed by enzymatic hydrolysis. The addition of xylanases to the enzymatic mixture improved the production of fermentable sugars by 48%.

Laboratory scale production of glucose syrup by the enzymatic ...

African Journals Online (AJOL)

Jen

Laboratory scale production of glucose syrup by the enzymatic ... The industrial processing of starch to glucose, maltose and dextrin involves gelatinization, ... due to non-availability of appropriate technology and industry to harness these into.

Biotechnological Aspects of Microbial Extracellular Electron Transfer

Science.gov (United States)

Kato, Souichiro

2015-01-01

Extracellular electron transfer (EET) is a type of microbial respiration that enables electron transfer between microbial cells and extracellular solid materials, including naturally-occurring metal compounds and artificial electrodes. Microorganisms harboring EET abilities have received considerable attention for their various biotechnological applications, in addition to their contribution to global energy and material cycles. In this review, current knowledge on microbial EET and its application to diverse biotechnologies, including the bioremediation of toxic metals, recovery of useful metals, biocorrosion, and microbial electrochemical systems (microbial fuel cells and microbial electrosynthesis), were introduced. Two potential biotechnologies based on microbial EET, namely the electrochemical control of microbial metabolism and electrochemical stimulation of microbial symbiotic reactions (electric syntrophy), were also discussed. PMID:26004795

Effects of lipids on enzymatic hydrolysis and physical properties of starch.

Science.gov (United States)

Ai, Yongfeng; Hasjim, Jovin; Jane, Jay-lin

2013-01-30

This study aimed to understand effects of lipids, including corn oil (CO), soy lecithin (SL), palmitic acid (PA), stearic acid (SA), oleic acid (OA), and linoleic acid (LA), on the enzymatic hydrolysis and physical properties of normal corn (NCS), tapioca (TPS), waxy corn (WCS), and high-amylose corn (HA7) starch, and to elucidate mechanisms of interactions between the starches and lipids. After cooking with the lipids (10%, w/w, dsb), NCS, TPS, and HA7 showed significant decreases in enzymatic hydrolysis, and their DSC thermograms displayed amylose-lipid-complex dissociation peaks except with the CO. (13)C NMR spectra of amylodextrin with CO showed downfield changes in the chemical shifts of carbons 1 and 4 of the anhydroglucose unit, indicating helical complex formation. Generally, free fatty acids (FFAs) reduced, but SL increased the peak viscosities of starches. FFAs and SL decreased, but CO increased the gel strength of NCS. These lipids displayed little impacts on the enzymatic hydrolysis and physical properties of WCS because it lacked amylose. Copyright © 2012 Elsevier Ltd. All rights reserved.

Mussel-inspired co-deposition to enhance bisphenol A removal in a bifacial enzymatic membrane reactor

DEFF Research Database (Denmark)

Cao, Xiaotong; Luo, Jianquan; Woodley, John M.

2018-01-01

were used as the matrix to further exploit the potential of the biocatalytic membranes. such prepared biocatalytic membranes were enzymatically active on both sides, making it possible to construct a bifacial enzymatic membrane reactor (EMR) for highly efficient micro-pollutants removal (taking...

A theoretical reassessment of microbial maintenance and implications for microbial ecology modeling.

Science.gov (United States)

Wang, Gangsheng; Post, Wilfred M

2012-09-01

We attempted to reconcile three microbial maintenance models (Herbert, Pirt, and Compromise) through a theoretical reassessment. We provided a rigorous proof that the true growth yield coefficient (Y(G)) is the ratio of the specific maintenance rate (a in Herbert) to the maintenance coefficient (m in Pirt). Other findings from this study include: (1) the Compromise model is identical to the Herbert for computing microbial growth and substrate consumption, but it expresses the dependence of maintenance on both microbial biomass and substrate; (2) the maximum specific growth rate in the Herbert (μ(max,H)) is higher than those in the other two models (μ(max,P) and μ(max,C)), and the difference is the physiological maintenance factor (m(q) = a); and (3) the overall maintenance coefficient (m(T)) is more sensitive to m(q) than to the specific growth rate (μ(G)) and Y(G). Our critical reassessment of microbial maintenance provides a new approach for quantifying some important components in soil microbial ecology models. © This article is a US government work and is in the public domain in the USA.

The Microbial DNA Index System (MiDIS): A tool for microbial pathogen source identification

Energy Technology Data Exchange (ETDEWEB)

Velsko, S. P. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

2010-08-09

The microbial DNA Index System (MiDIS) is a concept for a microbial forensic database and investigative decision support system that can be used to help investigators identify the sources of microbial agents that have been used in a criminal or terrorist incident. The heart of the proposed system is a rigorous method for calculating source probabilities by using certain fundamental sampling distributions associated with the propagation and mutation of microbes on disease transmission networks. This formalism has a close relationship to mitochondrial and Y-chromosomal human DNA forensics, and the proposed decision support system is somewhat analogous to the CODIS and SWGDAM mtDNA databases. The MiDIS concept does not involve the use of opportunistic collections of microbial isolates and phylogenetic tree building as a basis for inference. A staged approach can be used to build MiDIS as an enduring capability, beginning with a pilot demonstration program that must meet user expectations for performance and validation before evolving into a continuing effort. Because MiDIS requires input from a a broad array of expertise including outbreak surveillance, field microbial isolate collection, microbial genome sequencing, disease transmission networks, and laboratory mutation rate studies, it will be necessary to assemble a national multi-laboratory team to develop such a system. The MiDIS effort would lend direction and focus to the national microbial genetics research program for microbial forensics, and would provide an appropriate forensic framework for interfacing to future national and international disease surveillance efforts.

Screening of microbial lipases and evalutaion of their potential to produce glycerides with high gamma linolenic acid concentration

Directory of Open Access Journals (Sweden)

Patricia B.L. Fregolente

2009-12-01

Full Text Available Gamma-linolenic acid (GLA, 18:3, cis- 6,9,12-octadecatrienoic acid, an important compound in n-6 eicosanoid family biosynthesis, occurs in the lipids of a few plant and microbial sources. This study focused on the screening of microbial strains with suitable lipase activity for enrichment of GLA by selective hydrolysis of the borage oil (21.6 % of GLA/total fatty acids. Firstly, 352 microrganisms were tested for their lipolytic capacity using screening techniques on agar plates containing borage oil, strains were then selected and screened for their activity (U/mg using both submerged fermentation (SmF and solid state fermentation (SSF. The rate of hydrolysis and the selective preference of these hydrolytic enzymes towards fatty acids, with a special focus on enrichment of GLA were studied and compared with those obtained by two commercially-available lipases. Only one of the lipases tested during this study displayed selectivity, discriminating the GLA during the hydrolysis reaction. Using the enzymatic extract from Geotrichum candidum as a biocatalyst of the reaction, it was possible to obtain a percentage of 41.7% of GLA in acylglycerols fraction when the borage oil was treated in a fixed-bed reactor for 24 hours at 30ºC.

Metabolic and phylogenetic analysis of microbial communities during phytoremediation of soil contaminated with weathered hydrocarbons and heavy metals.

Science.gov (United States)

Palmroth, Marja R T; Koskinen, Perttu E P; Kaksonen, Anna H; Münster, Uwe; Pichtel, John; Puhakka, Jaakko A

2007-12-01

In the current study, the microbial ecology of weathered hydrocarbon and heavy metal contaminated soil undergoing phytoremediation was studied. The relationship of functional diversity, measured as carbon source utilisation in Biolog plates and extracellular enzymatic activities, and genetic diversity of bacteria was evaluated. Denaturing gradient gel electrophoresis was used for community analyses at the species level. Bulk soil and rhizosphere soil from pine and poplar plantations were analysed separately to determine if the plant rhizosphere impacted hydrocarbon degradation. Prevailing microbial communities in the field site were both genetically and metabolically diverse. Furthermore, both tree rhizosphere and fertilisation affected the compositions of these communities and increased activities of extracellular aminopeptidases. In addition, the abundance of alkane hydroxylase and naphthalene dioxygenase genes in the communities was low, but the prevalence of these genes was increased by the addition of bioavailable hydrocarbons. Tree rhizosphere communities had greater hydrocarbon degradation potential than those of bulk soil. Hydrocarbon utilising communities were dominated generally by the species Ralstonia eutropha and bacteria belonging to the genus Burkholderia. Despite the presence of viable hydrocarbon-degrading microbiota, decomposition of hydrocarbons from weathered hydrocarbon contaminated soil over four years, regardless of the presence of vegetation, was low in unfertilised soil. Compost addition enhanced the removal of hydrocarbons.

Effects of Elevated Carbon Dioxide and Salinity on the Microbial Diversity in Lithifying Microbial Mats

Directory of Open Access Journals (Sweden)

Steven R. Ahrendt

2014-03-01

Full Text Available Atmospheric levels of carbon dioxide (CO2 are rising at an accelerated rate resulting in changes in the pH and carbonate chemistry of the world’s oceans. However, there is uncertainty regarding the impact these changing environmental conditions have on carbonate-depositing microbial communities. Here, we examine the effects of elevated CO2, three times that of current atmospheric levels, on the microbial diversity associated with lithifying microbial mats. Lithifying microbial mats are complex ecosystems that facilitate the trapping and binding of sediments, and/or the precipitation of calcium carbonate into organosedimentary structures known as microbialites. To examine the impact of rising CO2 and resulting shifts in pH on lithifying microbial mats, we constructed growth chambers that could continually manipulate and monitor the mat environment. The microbial diversity of the various treatments was compared using 16S rRNA gene pyrosequencing. The results indicated that elevated CO2 levels during the six month exposure did not profoundly alter the microbial diversity, community structure, or carbonate precipitation in the microbial mats; however some key taxa, such as the sulfate-reducing bacteria Deltasulfobacterales, were enriched. These results suggest that some carbonate depositing ecosystems, such as the microbialites, may be more resilient to anthropogenic-induced environmental change than previously thought.

Enzymatic Saccharification and Ethanol Fermentation of Reed Pretreated with Liquid Hot Water

Directory of Open Access Journals (Sweden)

Jie Lu

2012-01-01

Full Text Available Reed is a widespread-growing, inexpensive, and readily available lignocellulosic material source in northeast China. The objective of this study is to evaluate the liquid hot water (LHW pretreatment efficiency of reed based on the enzymatic digestibility and ethanol fermentability of water-insoluble solids (WISs from reed after the LHW pretreatment. Several variables in the LHW pretreatment and enzymatic hydrolysis process were optimized. The conversion of glucan to glucose and glucose concentrations are considered as response variables in different conditions. The optimum conditions for the LHW pretreatment of reed area temperature of 180°C for 20min and a solid-to-liquid ratio of 1 : 10. These optimum conditions for the LHW pretreatment of reed resulted in a cellulose conversion rate of 82.59% in the subsequent enzymatic hydrolysis at 50°C for 72 h with a cellulase loading of 30 filter paper unit per gram of oven-dried WIS. Increasing the pretreatment temperature resulted in a higher enzymatic digestibility of the WIS from reed. Separate hydrolysis and fermentation of WIS showed that the conversion of glucan to ethanol reached 99.5% of the theoretical yield. The LHW pretreatment of reed is a suitable method to acquire a high recovery of fermentable sugars and high ethanol conversion yield.

MICROBIAL FUEL CELL

DEFF Research Database (Denmark)

2008-01-01

A novel microbial fuel cell construction for the generation of electrical energy. The microbial fuel cell comprises: (i) an anode electrode, (ii) a cathode chamber, said cathode chamber comprising an in let through which an influent enters the cathode chamber, an outlet through which an effluent...

Improving enzymatic hydrolysis of industrial hemp (Cannabis sativa L.) by electron beam irradiation

International Nuclear Information System (INIS)

Shin, Soo-Jeong; Sung, Yong Joo

2008-01-01

The electron beam irradiation was applied as a pretreatment of the enzymatic hydrolysis of hemp biomass with doses of 150, 300 and 450 kGy. The higher irradiation dose resulted in the more extraction with hot-water extraction or 1% sodium hydroxide solution extraction. The higher solubility of the treated sample was originated from the chains scission during irradiation, which was indirectly demonstrated by the increase of carbonyl groups as shown in diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) spectra. The changes in the micro-structure of hemp resulted in the better response to enzymatic hydrolysis with commercial cellulases (Celluclast 1.5L and Novozym 342). The improvement in enzymatic hydrolysis by the irradiation was more evident in the hydrolysis of the xylan than in that of the cellulose

Improving enzymatic hydrolysis of industrial hemp ( Cannabis sativa L.) by electron beam irradiation

Science.gov (United States)

Shin, Soo-Jeong; Sung, Yong Joo

2008-09-01

The electron beam irradiation was applied as a pretreatment of the enzymatic hydrolysis of hemp biomass with doses of 150, 300 and 450 kGy. The higher irradiation dose resulted in the more extraction with hot-water extraction or 1% sodium hydroxide solution extraction. The higher solubility of the treated sample was originated from the chains scission during irradiation, which was indirectly demonstrated by the increase of carbonyl groups as shown in diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) spectra. The changes in the micro-structure of hemp resulted in the better response to enzymatic hydrolysis with commercial cellulases (Celluclast 1.5L and Novozym 342). The improvement in enzymatic hydrolysis by the irradiation was more evident in the hydrolysis of the xylan than in that of the cellulose.

Improving enzymatic hydrolysis of industrial hemp (Cannabis sativa L.) by electron beam irradiation

Energy Technology Data Exchange (ETDEWEB)

Shin, Soo-Jeong [Chungbuk National University, Cheongju, Chungbuk 361-763 (Korea, Republic of); Sung, Yong Joo [KT and G Central Research Institute, 302 Shinseong-Dong, Yuseong-Gu, Daejeon 305-805 (Korea, Republic of)], E-mail: yosung17@yahoo.co.kr

2008-09-15

The electron beam irradiation was applied as a pretreatment of the enzymatic hydrolysis of hemp biomass with doses of 150, 300 and 450 kGy. The higher irradiation dose resulted in the more extraction with hot-water extraction or 1% sodium hydroxide solution extraction. The higher solubility of the treated sample was originated from the chains scission during irradiation, which was indirectly demonstrated by the increase of carbonyl groups as shown in diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) spectra. The changes in the micro-structure of hemp resulted in the better response to enzymatic hydrolysis with commercial cellulases (Celluclast 1.5L and Novozym 342). The improvement in enzymatic hydrolysis by the irradiation was more evident in the hydrolysis of the xylan than in that of the cellulose.

PARTIAL CHARACTERIZATION OF ENZYMATIC ACTIVITIES PRODUCED BY A WILD STRAIN OF A. NIGER

Directory of Open Access Journals (Sweden)

María Martos

2012-12-01

Full Text Available Aspergillus niger, isolated from decay citrus peels in the province of Misiones, was able to produce pectinases by submerged fermentation. The enzymatic extract exhibited polygalacturonase, pectinesterase and lyase activities. Others enzymes capable of degrading cell wall polymers were also detected in the enzymatic extract such as cellulases and xylanases. Polygalacturonase was an endo-polygalacturonase. The enzyme exhibited a maximal activity at pH range between 4.5 to 5.0, was stable in the pH range from 2.5 to 5.5 and remained unchanged when was incubated at temperatures lower than 50 ºC. The fungi produced three PG isoenzymes. The enzymatic extract was able to clarify apple juice. The results observed make the pectinolytic enzymes produced by A. niger appropriate for future application in fruit juice processing industries.

Molecular ecology of microbial mats

NARCIS (Netherlands)

Bolhuis, H.; Cretoiu, M.S.; Stal, L.J.

2014-01-01

Phototrophic microbial mats are ideal model systems for ecological and evolutionary analysis of highly diverse microbial communities. Microbial mats are small-scale, nearly closed, and self-sustaining benthic ecosystems that comprise the major element cycles, trophic levels, and food webs. The steep

Properties of the manganese(II) binding site in ternary complexes of Mnter dot ADP and Mnter dot ATP with chloroplast coupling factor 1: Magnetic field dependence of solvent sup 1 H and sup 2 H NMR relaxation rates

Energy Technology Data Exchange (ETDEWEB)

Haddy, A.E.; Frasch, W.D.; Sharp, R.R. (Univ. of Michigan, Ann Arbor (USA))

1989-05-02

The influence of the binding of ADP and ATP on the high-affinity Mn(II) binding site of chloroplast coupling factor 1 (CF{sub 1}) was studied by analysis of field-dependent solvent proton and deuteron spin-lattice relaxation data. In order to characterize metal-nucleotide complexes of CF{sub 1} under conditions similar to those of the NMR experiments, the enzyme was analyzed for bound nucleotides and Mn(II) after incubation with AdN and MnCl{sub 2} and removal of labile ligands by extensive gel filtration chromatography. In the field-dependent NMR experiments, the Mn(II) binding site of CF{sub 1} was studied for three mole ratios of added Mn(II) to CF{sub 1}, 0.5, 1.0, and 1.5, in the presence of an excess of either ADP or ATP. The results were extrapolated to zero Mn(II) concentration to characterize the environment of the first Mn(II) binding site of Cf{sub 1}. In the presence of both adenine nucleotides, pronounced changes in the Mn(II) environment relative to that in Mn(II)-CF{sub 1} were evident; the local relaxation rate maxima were more pronounced and shifted to higher field strengths, and the relaxation rate per bound Mn(II) increased at all field strengths. Analysis of the data revealed that the number of exchangeable water molecules liganded to bound Mn(II) increased from one in the binary Mn(II)-CF{sub 1} complex to three and two in the ternary Mn(II)-ADP-CF{sub 1} and Mn(II)-ATP-CF{sub 1} complexes, respectively; these results suggest that a water ligand to bound Mn(II) in the Mn(II)-ADP-CF{sub 1} complex is replaced by the {gamma}-phosphate of ATP in the Mn(II)-ATP-CF{sub 1} complex. A binding model is presented to account for these observations.

Metal ion effects on enolase activity

International Nuclear Information System (INIS)

Lee, M.E.; Nowak, T.

1986-01-01

Most metal binding studies with yeast enolase suggest that two metals per monomer are required for catalytic activity. The functions of metal I and metal II have not been unequivocally defined. In a series of kinetic experiments where the concentration of MgII is kept constant at subsaturating levels (1mM), the addition of MnII or of ZnII gives a hyperbolic decrease in activity. The final velocity of these mixed metal systems is the same velocity obtained with either only MnII or ZnII respectively. The concentration of MnII (40 μM) or of Zn (2μM) which gives half maximal effect in the presence of (1mM) MgII is approximately the same as the Km' value for MnII (9μM) or ZnII (3μM) respectively. Direct binding of MnII to enolase in the absence and presence of MgII shows that MnII and MgII compete for the same metal site on enolase. In the presence of 2-phosphoglycerate (2-PGA) and MgII, only a single site is occupied by MnII. Results suggest MnII at site I and MgII at site II. PRR and high resolution 1 H and 31 P NMR studies of enzyme-ligand complexes containing MnII and MgII and MnII are consistent with this model. 31 P measurements allow a measure of the equilibrium constant (0.36) for enolase. Saturation transfer measurements yield net rate constants (k/sub f/ = 0.49s -1 ; k/sub r/ = 1.3s -1 ) for the overall reaction. These values are smaller than k/sub cat/ (38s -1 ) measured under analogous conditions. The cation at site I appears to determine catalytic activity

On-chip enzymatic microbiofuel cell-powered integrated circuits.

Science.gov (United States)

Mark, Andrew G; Suraniti, Emmanuel; Roche, Jérôme; Richter, Harald; Kuhn, Alexander; Mano, Nicolas; Fischer, Peer

2017-05-16

A variety of diagnostic and therapeutic medical technologies rely on long term implantation of an electronic device to monitor or regulate a patient's condition. One proposed approach to powering these devices is to use a biofuel cell to convert the chemical energy from blood nutrients into electrical current to supply the electronics. We present here an enzymatic microbiofuel cell whose electrodes are directly integrated into a digital electronic circuit. Glucose oxidizing and oxygen reducing enzymes are immobilized on microelectrodes of an application specific integrated circuit (ASIC) using redox hydrogels to produce an enzymatic biofuel cell, capable of harvesting electrical power from just a single droplet of 5 mM glucose solution. Optimisation of the fuel cell voltage and power to match the requirements of the electronics allow self-powered operation of the on-board digital circuitry. This study represents a step towards implantable self-powered electronic devices that gather their energy from physiological fluids.

Quantitation of Na+, K+-atpase Enzymatic Activity in Tissues of the Mammalian Vestibular System

Science.gov (United States)

Kerr, T. P.

1985-01-01

In order to quantify vestibular Na(+), K(+)-ATPase, a microassay technique was developed which is sufficiently sensitive to measure the enzymatic activity in tissue from a single animal. The assay was used to characterize ATPase in he vestibular apparatus of the Mongolian gerbil. The quantitative procedure employs NPP (5 mM) as synthetic enzyme substrate. The assay relies upon spectrophotometric measurement (410 nm) of nitrophenol (NP) released by enzymatic hydrolysis of the substrate. Product formation in the absence of ouabain reflects both specific (Na(+), K(+)-ATPase) and non-specific (Mg(++)-ATPase) enzymatic activity. By measuring the accumulation of reaction product (NP) at three-minute intervals during the course of incubation, it is found that the overall enzymatic reaction proceeds linearly for at least 45 minutes. It is therefore possible to determine two separate reaction rates from a single set of tissues. Initial results indicate that total activity amounts to 53.3 + or - 11.2 (S.E.M.) nmol/hr/mg dry tissue, of which approximately 20% is ouabain-sensitive.

Cassava Pulp as a Biofuel Feedstock of an Enzymatic Hydrolysis Proces

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Djuma’ali Djuma’ali

2013-03-01

Full Text Available Cassava pulp, a low cost solid byproduct of cassava starch industry, has been proposed as a high potential ethanolic fermentation substrate due to its high residual starch level, low ash content and small particle size of the lignocellulosic fibers. As the economic feasibility depends on complete degradation of the polysaccharides to fermentable glucose, the comparative hydrolytic potential of cassava pulp by six commercial enzymes were studied. Raw cassava pulp (12% w/v, particle size <320 μm hydrolyzed by both commercial pectinolytic (1 and amylolytic (2 enzymes cocktail, yielded 70.06% DE. Hydrothermal treatment of cassava pulp enhanced its susceptibility to enzymatic cleavageas compared to non-hydrothermal treatment raw cassava pulp. Hydrothermal pretreatment has shown that a glucoamylase (3 was the most effective enzyme for hydrolysis process of cassava pulp at temperature 65 °C or 95 °C for 10 min and yielded approximately 86.22% and 90.18% DE, respectively. Enzymatic pretreatment increased cassava pulp vulnerability to cellulase attacks. The optimum conditions for enzymatic pretreatment of 30% (w/v cassava pulp by a potent cellulolytic/ hemicellulolytic enzyme (4 was achieves at 50 °C for 3, meanwhile for liquefaction and saccharification by a thermo-stable α-amylase (5 was achieved at 95 °C for 1 and a glucoamylase (3 at 50 °C for 24 hours, respectively, yielded a reducing sugar level up to 94,1% DE. The high yield of glucose indicates the potential use of enzymatic-hydrothermally treated cassava pulp as a cheap substrate for ethanol production.

Enzymatic Saccharification of Lignocelluloses Should be Conducted at Elevated pH 5.2-6.2

Science.gov (United States)

T.Q. Lan; Hongming Lou; J.Y. Zhu

2013-01-01

This study revealed that cellulose enzymatic saccharification response curves of lignocellulosic substrates were very different from those of pure cellulosic substrates in terms of optimal pH and pH operating window. The maximal enzymatic cellulose saccharification of lignocellulosic substrates occurs at substrate suspension

Pretreatment by radiation and acids of chaff and its effect on enzymatic hydrolysis of cellulose

International Nuclear Information System (INIS)

Kumakura, M.; Kaetsu, I.

1984-01-01

The effect of pretreatment by radiation and acids—sulfuric, hydrochloric and acetic—on the enzymatic hydrolysis of chaff was studied. The combination of radiation and acids accelerates subsequent crushing and enzymatic hydrolysis. The percentage of fine powder below 115 mesh, after the crushing and the glucose yield on subsequent enzymatic hydrolysis, increased with increasing acid concentration, treatment time and irradiation dose. Radiation and hydrochloric acid pretreatment was the most effective in giving a high glucose conversion yield (about 90%). Irradiation dose, acid concentration, treatment temperature and treatment time were 20 Mrad, 0·5%, 70°C, and 5 h, respectively

Enzymatic conversion of all-trans-β-carotene to retinal by a cytosolic enzyme from rabbit and rat intestinal mucosa

International Nuclear Information System (INIS)

Lakshman, M.R.; Mychkovsky, I.; Attlesey, M.

1989-01-01

Enzymatic conversion of all-trans-β-carotene to retinal by a partially purified enzyme from rabbit and rat intestinal mucosa was demonstrated. The enzymatic product was characterized based on the following evidence: (i) the product gave rise to its O-ethyloxime by treatment with O-ethylhydroxylamine with an absorption maximum at 363 nm in ethanol characteristics of authentic retinal O-ethyloxime. High-pressure liquid chromatography (HPLC) of this derivative yielded a sharp peak with a retention time of 7.99 min corresponding to the authentic compound; (ii) the mass spectrum of the O-ethyloxime of the enzymatic product was identical to that of authentic retinal O-ethyloxime; (iii) the specific activity of the enzymatically formed [ 14 C]retinal O-ethyloxime remained constant even after repeated crystallization; (iv) the enzymatic product exhibited an absorption maximum at 370 nm in light petroleum characteristic of authentic retinal. This retinol was enzymatically esterified to retinyl palmitate by rat pancreatic esterase with a retention time of 10 min on HPLC corresponding to authentic retinyl palmitate. Thus, the enzymatic product of β-carotene cleavage by the partially purified intestinal enzyme was unequivocally confirmed to be retinal

Bacterial Production and Enzymatic Activities in Deep-Sea Sediments of the Pacific Ocean: Biogeochemical Implications of Different Temperature Constraints

Science.gov (United States)

Danovaro, R.; Corinaldesi, C.; dell'Anno, A.

2002-12-01

The deep-sea bed, acting as the ultimate sink for organic material derived from the upper oceans primary production, is now assumed to play a key role in biogeochemical cycling of organic matter on global scale. Early diagenesis of organic matter in marine sediments is dependent upon biological processes (largely mediated by bacterial activity) and by molecular diffusion. Organic matter reaching the sea floor by sedimentation is subjected to complex biogeochemical transformations that make organic matter largely unsuitable for direct utilization by benthic heterotrophs. Extracellular enzymatic activities in the sediment is generally recognized as the key step in the degradation and utilization of organic polymers by bacteria and a key role in biopolymeric carbon mobilization is played by aminopeptidase, alkaline phosphatase and glucosidase activities. In the present study we investigated bacterial density, bacterial C production and exo-enzymatic activities (aminopeptidase, glucosidase and phosphatase activity) in deep-sea sediments of the Pacific Ocean in relation with the biochemical composition of sediment organic matter (proteins, carbohydrates and lipids), in order to gather information on organic matter cycling and diagenesis. Benthic viral abundance was also measured to investigate the potential role of viruses on microbial loop functioning. Sediment samples were collected at eight stations (depth ranging from 2070-3100 m) along two transects located at the opposite side (north and south) of ocean seismic ridge Juan Fernandez (along latitudes 33° 20' - 33° 40'), constituted by the submerged vulcanoes, which connects the Chilean coasts to Rapa Nui Island. Since the northern and southern sides of this ridge apparently displayed small but significant differences in deep-sea temperature (related to the general ocean circulation), this sampling strategy allowed also investigating the role of different temperature constraints on bacterial activity and

Microbial biosensors for environmental monitoring

Directory of Open Access Journals (Sweden)

David VOGRINC

2015-12-01

Full Text Available Microbial biosensors are analytical devices capable of sensing substances in the environment due to the specific biological reaction of the microorganism or its parts. Construction of a microbial biosensor requires knowledge of microbial response to the specific analyte. Linking this response with the quantitative data, using a transducer, is the crucial step in the construction of a biosensor. Regarding the transducer type, biosensors are divided into electrochemical, optical biosensors and microbial fuel cells. The use of the proper configuration depends on the selection of the biosensing element. With the use of transgenic E. coli strains, bioluminescence or fluorescence based biosensors were developed. Microbial fuel cells enable the use of the heterogeneous microbial populations, isolated from wastewater. Different microorganisms are used for different pollutants – pesticides, heavy metals, phenolic compounds, organic waste, etc. Biosensing enables measurement of their concentration and their toxic or genotoxic effects on the microbes. Increasing environmental awareness has contributed to the increase of interest for biomonitoring. Although technologies, such as bioinformatics and genetic engineering, allow us to design complex and efficient microbial biosensors for environmental pollutants, the transfer of the laboratory work to the field still remains a problem to solve.

Enzymatic collection test as total gamma irradiation pronostic test in rat, rabbit and man

International Nuclear Information System (INIS)

Breuil, G.; Dinnequin, B.

The purpose of this study is to known, during 30 days, what becomes the animal whose enzymatic co-ordinates are well known. Both 100, 160, 200, 325, 400, 650, 850, 975, 1000, 1300 rads irradiated rabbit serum enzymatic evolution and that of two 1000 rads in toto irradiated leucemic men for a cord graft are studied [fr

Eschar removal by bromelain based enzymatic debridement (Nexobrid®) in burns: An European consensus.

Science.gov (United States)

Hirche, Christoph; Citterio, Antonella; Hoeksema, Henk; Koller, Ján; Lehner, Martina; Martinez, José Ramón; Monstrey, Stan; Murray, Alexandra; Plock, Jan A; Sander, Frank; Schulz, Alexandra; Ziegler, Benjamin; Kneser, Ulrich

2017-12-01

Early debridement and/or eschar removal is regarded as a significant step in the treatment of deep partial and full thickness burns. It aims to control wound bioburden and allows early wound closure by conservative treatment or skin grafting. Preservation of viable dermis accompanied by early wound closure, is regarded as a necessary step to reduce scar related complication, e.g. functional limitations and/or unaesthetic scar formation. Aside from the classical techniques of surgical excision as tangential excision for eschar removal, hydro-surgery, maggot therapy, laser, enzymatic debridement have been described as additional techniques in the burn surgeon's armamentarium. It is widely accepted that early eschar removal within 72h improves the outcome of burn wound treatment by reducing bacterial wound colonization, infection and length of hospital stay. In contrast, the right technique for eschar removal is still a matter of debate. There is increasing evidence that enzymatic debridement is a powerful tool to remove eschar in burn wounds, reducing blood loss, the need for autologous skin grafting and the number of wounds requiring surgical excision. In order to assess the role and clinical advantages of enzymatic debridement by a mixture of proteolytic enzymes enriched in Bromelain (Nexobrid ® ) beyond the scope of the literature and in view of users' experience, a European Consensus Meeting was scheduled. The aim was to provide statements for application, based on the mutual experience of applying enzymatic debridement in more than 500 adult and pediatric patients by the consensus panelists. Issues to be addressed were: indications, pain management and anesthesia, timing of application, technique of application, after-intervention care, skin grafting after enzymatic debridement, blood loss, training strategies and learning curve and areas of future research needs. Sixty-eight (68) consensus statements were provided for the use of enzymatic debridement. The

Enzymatic determination of cadmium, zinc, and lead in plant materials

International Nuclear Information System (INIS)

Muginova, S.V.; Veselova, I.A.; Parova, L.M.; Shekhovtseva, T.N.

2008-01-01

Prospects are outlined for using the following enzymes (native and immobilized on polyurethane foam) in the rapid and highly sensitive determination of cadmium, zinc, and lead ions in plant materials (wild grass, fresh pea, and grape): horseradish peroxidase and alkaline phosphatases isolated from chicken intestine and Greenland seal small intestine. The analytical ranges of the above metals are 1x10 -3 -25; 7x10 -3 -250, and 3x10 -2 -67 mg/kg dry matter, respectively. The enzymatic determination procedures developed are based on the inhibiting effect of metal ions on the catalytic activity of peroxidase in the oxidation of o-dianisidine with hydrogen peroxide and alkaline phosphatases in the hydrolysis of p-nitrophenyl phosphate. The rates of enzymatic reactions were monitored spectrophotometrically or visually. In the analysis of plant extracts, their high acidity was diminished by choosing optimum dilution factors and pH values for test samples and the nature and concentration of a buffer solution. The interference of iron(III) was removed by introducing a 0.1 M tartaric acid solution into the indicator reaction. The accuracy of the results of the enzymatic determination of cadmium, zinc, and lead in plant materials was supported by atomic absorption spectrometry and anodic stripping voltammetry [ru

Functional palm oil-based margarine by enzymatic interesterification

DEFF Research Database (Denmark)

Ibrahim, Nuzul Amri Bin; Xu, Xuebing

Palm stearin, palm kernel and fish oils were blended to a various composition ratios and enzymatically interesterified by Lipozyme TL IM lipase (Thermomyces lanuginosa) using a continuous packed bed reactor. The ratio of the oils ranged from 60-90%, 10-40% and 0-10% respectively. The enzyme was a...

Application of modified multiwalled carbon nanotubes as a sorbent for simultaneous separation and preconcentration trace amounts of Au(III) and Mn(II)

International Nuclear Information System (INIS)

Shamspur, Tayebeh; Mostafavi, Ali

2009-01-01

A solid phase extraction procedure is proposed for simultaneous separation and preconcentration trace amounts of Au(III) and Mn(II) in an aqueous medium by using a column of multiwalled carbon nanotubes modified with the analytical reagent N,N'-bis(2-hydroxybenzylidene)-2,2'(aminophenylthio)ethane. An implementation, it was found that the sorption is quantitative in the pH range 5.0-7.5, whereas quantitative desorption occurs instantaneously with 4.0 mL of 0.1 mol L -1 Na 2 S 2 O 3. Selected elements were also determined by flame atomic absorption spectrometry. Linearity was maintained between 0.2 ng mL -1 to 25 μg mL -1 for gold and 0.08 ng mL -1 to 5 μg mL -1 for manganese in the original solution. Various parameters such as the effect of pH, flow rate, type and amount of eluent, breakthrough volume and interference of a large number of anions and cations on the recovery of the selected ions was studied. Under optimum conditions, the detection limits (3 s, n = 10) for analytes were 0.03 ng mL -1 (gold) and 0.01 ng mL -1 (manganese). The method was successfully applied for separation and determination of gold and manganese ions in water and standard samples.

Effect of elevated manganese on the ultraviolet- and blue light-absorbing compounds of cucumber cotyledons and leaf tissues

International Nuclear Information System (INIS)

Caldwell, C.R.

1998-01-01

The effect of manganese [Mn(II)] on the pigments of cucumber (Cucumis sativus L., cv Poinsett 76) leaf and cotyledon tissues was investigated. Tissue disks (7 mm) were exposed to increasing Mn(II) concentrations from 100 micromolar to 2.5 mM. Acetone (carotenoid-rich fraction) and acidified methanol (flavonoid-rich fraction) extracts were analyzed by high performance liquid chromatography. Although none of the Mn(II)-treated tissues showed visible damage, Mn(II) at concentrations of 250 micromolar and above significantly reduced (60%) the beta-carotene levels of light-incubated leaf tissues. A major Mn(II)-induced, UV-absorbing compound was observed in methanol extracts of cotyledonary tissues exposed to Mn(II) in the dark. In leaf tissues, Mn(II) reduced the levels of certain UV-absorbing compounds under both light conditions. These results demonstrate that excess leaf Mn(II) can rapidly impair isoprenoid metabolism, altering tissue carotenoid composition. Furthermore, Mn(II) may also modify phenylpropanoid metabolism, changing the tissue flavonoid composition. Both situations could sensitize plant tissues to oxidative stresses, particularly enhanced solar UV-B radiation, and may reduce the nutritional quality of leafy vegetables

Improved antimelanogenesis and antioxidant effects of polysaccharide from Cuscuta chinensis Lam seeds after enzymatic hydrolysis.

Science.gov (United States)

Liu, Zi-Jun; Wang, Ya-Lan; Li, Qi-Ling; Yang, Liu

2018-01-01

Cuscuta chinensis polysaccharide (CPS) was extracted using hot water and enzymatically hydrolyzed C. chinensis polysaccharide (ECPS) was produced by the mannase enzymatic hydrolysis process. The purpose of this research was to investigate the antimelanogenic activity of ECPS and CPS in B16F10 melanoma cells. The in vitro antioxidant activity was assessed by their ferric iron reducing power and DPPH free radical scavenging activities. The molecular mass distribution of polysaccharides was determined using SEC-MALLS-RI. CPS was successfully enzymatically degraded using mannase and the weighted average molecular weights of CPS and ECPS were 434.6 kDa and 211.7 kDa. The results of biological activity assays suggested that the enzymatically hydrolyzed polysaccharide had superior antimelanogenic activity and antioxidant effect than the original polysaccharide. ECPS exhibited antimelanogenic activity by down-regulating the expression of tyrosinase, MITF, and TRP-1 without cytotoxic effects in B16F10 melanoma cells. In conclusion, ECPS have the potential to become a skin whitening product.

Pregnancy Exercise Increase Enzymatic Antioxidant In Pregnant Women

Directory of Open Access Journals (Sweden)

Wagey Freddy Wagey

2012-01-01

Full Text Available Objectives: Pregnancy is a vulnerable condition to all kinds of "stress", resulting in changes of physiological and metabolic functions. This research aims to determine effect of exercise during pregnancy in increasing enzymatic antioxidant marked by increase of superoxide dismutase (SOD, gluthation peroxidase (GSHPx, and catalase (CAT levels. Methods: Randomized pre and posttest control group design was employed in this study. A number of 66 pregnant women were recruited in this study and grouped into two groups, i.e 30 of them as control group and the rest as treatment group. Pregnancy exercise was performed to all 36 pregnant women from 20 weeks gestation on treatment group. The exercise was performed in the morning for about 30 minutes, twice a weeks. On the other hand, daily activities was sugested for control group. Student’s t-test was then applied to determine the mean different of treatment and control group with 5 % of significant value. Results: This study reveals that there were significantly higher increase of (superoxide dismutase (SOD, gluthation peroxidase (GSHPx, and catalse (CAT levels of treatment group compare to control group. These enzymatic antioxidant increase among these two group were around 1.36 mg/gHb for SOD; 1.14 IU/gHb for GSHPx; and 0.97 IU/gHb for CAT, (p < 0.05.  Clinical outcomes, such as strengten of pelvic muscle and quality of life of treatment group were significantly better compared to control group (p < 0.05. Conclusions: This means that exercise during pregnancy ages of 20 weeks increase enzymatic antioxidant levels SOD, GSHPx, and CAT higher compare to control group without exercise.  

Pregnancy Exercise Increase Enzymatic Antioxidant In Pregnant Women

Directory of Open Access Journals (Sweden)

Wagey Freddy Wagey

2012-01-01

Full Text Available Objectives: Pregnancy is a vulnerable condition to all kinds of "stress", resulting in changes of physiological and metabolic functions. This research aims to determine effect of exercise during pregnancy in increasing enzymatic antioxidant marked by increase of superoxide dismutase (SOD, gluthation peroxidase (GSHPx, and catalase (CAT levels. Methods: Randomized pre and posttest control group design was employed in this study. A number of 66 pregnant women were recruited in this study and grouped into two groups, i.e 30 of them as control group and the rest as treatment group. Pregnancy exercise was performed to all 36 pregnant women from 20 weeks gestation on treatment group. The exercise was performed in the morning for about 30 minutes, twice a weeks. On the other hand, daily activities was sugested for control group. Student’s t-test was then applied to determine the mean different of treatment and control group with 5 % of significant value. Results: This study reveals that there were significantly higher increase of (superoxide dismutase (SOD, gluthation peroxidase (GSHPx, and catalse (CAT levels of treatment group compare to control group. These enzymatic antioxidant increase among these two group were around 1.36 mg/gHb for SOD; 1.14 IU/gHb for GSHPx; and 0.97 IU/gHb for CAT, (p < 0.05. Clinical outcomes, such as strengten of pelvic muscle and quality of life of treatment group were significantly better compared to control group (p < 0.05. Conclusions: This means that exercise during pregnancy ages of 20 weeks increase enzymatic antioxidant levels SOD, GSHPx, and CAT higher compare to control group without exercise.

Modelling of the enzymatic kinetically controlled synthesis of cephalexin

NARCIS (Netherlands)

Schroën, C.G.P.H.; Fretz, C.B.; Bruin, de V.H.; Berendsen, W.; Moody, H.M.; Roos, E.C.; Roon, van J.L.; Kroon, P.J.; Strubel, M.; Janssen, A.E.M.; Tramper, J.

2002-01-01

In this study the influence of diffusion limitation on enzymatic kinetically controlled cephalexin synthesis from phenylglycine amide and 7-aminodeacetoxycephalosporinic acid (7-ADCA) was investigated systematically. It was found that if diffusion limitation occurred, both the synthesis/hydrolysis

Hydrodynamics of microbial filter feeding

DEFF Research Database (Denmark)

Nielsen, Lasse Tor; Asadzadeh, Seyed Saeed; Dölger, Julia

2017-01-01

Microbial filter feeders are an important group of grazers, significant to the microbial loop, aquatic food webs, and biogeochemical cycling. Our understanding of microbial filter feeding is poor, and, importantly, it is unknown what force microbial filter feeders must generate to process adequate......-feeding choanoflagellate Diaphanoeca grandis using particle tracking, and demonstrate that the current understanding of microbial filter feeding is inconsistent with computational fluid dynamics (CFD) and analytical estimates. Both approaches underestimate observed filtration rates by more than an order of magnitude......; the beating flagellum is simply unable to draw enough water through the fine filter. We find similar discrepancies for other choanoflagellate species, highlighting an apparent paradox. Our observations motivate us to suggest a radically different filtration mechanism that requires a flagellar vane (sheet...

[Effects of litter and root exclusion on soil microbial community composition and function of four plantations in subtropical sandy coastal plain area, China].

Science.gov (United States)

Sang, Chang Peng; Wan, Xiao Hua; Yu, Zai Peng; Wang, Min Huang; Lin, Yu; Huang, Zhi Qun

2017-04-18

We conducted detritus input and removal treatment (DIRT) to examine the effects of shifting above- and belowground carbon (C) inputs on soil microbial biomass, community composition and function in subtropical Pinus elliottii, Eucalyptus urophylla × Eucalyptus grandis, Acacia aulacocarpa and Casuarina equisetifolia coastal sandy plain forests, and the treatments included: root trenching, litter removal and control. Up to September 2015, one year after the experiment began, we collected the 0-10 cm soil samples from each plot. Phospholipid fatty acid (PLFA) analysis was used to characterize the microbial community composition, and micro-hole enzymatic detection technology was utilized to determine the activity of six kinds of soil enzymes. Results showed that changes in microbial biomass induced by the C input manipulations differed among tree species, and mainly affected by litter and root qualily. In E. urophylla × E. grandis stands, root trenching significantly decreased the contents of total PLFAs, Gram-positive bacteria, Gram-negative bacteria, fungi and actinomycetes by 31%, 30%, 32%, 36% and 26%, respectively. Litter removal reduced the contents of Gram-positive bacteria, fungi and actinomycetes by 24%, 27% and 24%, respectively. However, C input manipulations had no significant effect on soil microbial biomassunder other three plantations. According to the effect of C input manipulations on soil microbial community structure, litter and root exclusion decreased fungi abundance and increased actinomycetes abundance. Different treatments under different plantations resulted in various soil enzyme activities. Litter removal significantly decreased the activities of cellobiohydrolase, β-glucosidase, acid phosphatase and N-acetyl-β-d-glucosaminidase of P. elliottii, A. aulacocarpa and C. equisetifolia, root exclusion only decreased and increased the activities of β-glucosidase in P. elliottii and A. aulacocarpa forest soils, respectively. Litter removal also

Visualization of red-ox proteins on the gold surface using enzymatic polypyrrole formation

International Nuclear Information System (INIS)

Ramanaviciene, A.; Kausaite-Minkstimiene, A.; Voronovic, J.; Ramanavicius, A.; Oztekin, Y.; Carac, G.; German, N.

2011-01-01

We describe a new method for the visualization of the activity of red-ox proteins on a gold interface. Glucose oxidase was selected as a model system. Surfaces were modified by adhesion of glucose oxidase on (a) electrochemically cleaned gold; (b) gold films modified with gold nanoparticles, (c) a gold surface modified with self-assembled monolayer, and (d) covalent immobilization of protein on the gold surface modified with a self-assembled monolayer. The simple optical method for the visualization of enzyme on the surfaces is based on the enzymatic formation of polypyrrole. The activity of the enzyme was quantified via enzymatic formation of polypyrrole, which was detected and investigated by quartz microbalance and amperometric techniques. The experimental data suggest that the enzymatic formation of the polymer may serve as a method to indicate the adhesion of active redox enzyme on such surfaces. (author)

Soil organic matter degradation and enzymatic profiles of intertidal and subaqueous soils

Science.gov (United States)

Ferronato, Chiara; Marinari, Sara; Bello, Diana; Vianello, Gilmo; Trasar-Cepeda, Carmen; Vittori Antisari, Livia

2017-04-01

The interest on intertidal and subaqueous soils has recently arisen because of the climate changes forecasts. The preservation of these habitats represents an important challenge for the future of humanity, because these systems represent an important global C sink since soil organic matter (SOM) on intertidal and subaqueous soils undergoes very slow degradation rates due to oxygen limitation. Publications on SOM cycle in saltmarshes are very scarce because of the difficulties involved on those studies i.e. the interaction of many abiotic and biotic factors (e.g., redox changes, water and bio-turbation processes, etc) and stressors (e.g., salinity and anoxia). However, saltmarshes constitute an unique natural system to observe the influence of anoxic conditions on SOM degradation, because the tide fluctuations on the soil surface allow the formation of provisionally or permanently submerged soils. With the aim to investigate the quality of SOM in subaqueous soils, triplicates of subaqueous soils (SASs), intertidal soils (ITSs) and terrestrial soils (TESs) were collected in the saltmarshes of the Baiona Lagoon (Northern Italy) and classified according to their pedogenetic horizons. The SOM quality on each soil horizon was investigated by quantifying SOM, total and water-soluble organic carbon (TOC, WSC) and microbial biomass carbon (MBC). Given the contribution of soil enzymes to the degradation of SOM, some enzymatic assays were also performed. Thereafter, soil classification and humus morpho-functional classification were used to join together similar soil profiles to facilitate the description and discussion of results. Soils were ranked as Aquent or Wassent Entisols, with an A/AC/C pedosequence. SOM, TOC and MBC were statistically higher in A than in AC and C horizons. Among the A horizons, ITSs were those showing the highest values for these parameters (11% TOC, 1.6 mg kg-1 MBC, 0.9 mg kg-1 WSC). These results, combined with the morpho-functional classification

Enzymatic activities of Azotobacter chroococcum and survival in ...

African Journals Online (AJOL)

Enzymatic activities of Azotobacter chroococcum and survival in schloropyrifos amended sterile and non-sterile. M Shukla, V Kumar, RL Thakur, N Narula. Abstract. No Abstract. Cameroon Journal of Experimental Biology Vol. 2 (2) 2006: pp. 88-94. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for ...

Phytase-mediated mineral solubilization from cereals underin vitrogastric conditions

DEFF Research Database (Denmark)

Nielsen, Anne V. F.; Meyer, Anne S.

2016-01-01

that of the microbial phytases. No increases in soluble cadmium, lead or arsenic were observed with microbial phytase-catalyzed phytate dephosphorylation. CONCLUSION Microbial phytase treatment abated phytate chelation hence enhanced the release of iron and zinc from the phytate-rich cereals at the simulated gastric......BACKGROUND Enzymatic dephosphorylation of phytic acid (inositol hexakisphosphate) in cereals may improve mineral bioavailability in humans. This study quantified enzymatic dephosphorylation of phytic acid by measuring inositol tri- to hexakisphosphate (InsP3-6) degradation and iron and zinc release...... cereal phytic acid at similar rates and to similar extents. Microbial phytase-catalysed phytate dephosphorylation was accompanied by increased iron and zinc release from the cereal substrates. For wheat bran at pH 5, the endogenous wheat phytase activity produced mineral release equal to or better than...

Effect of high and low roughage total mixed ration diets on rumen metabolites and enzymatic profiles in crossbred cattle and buffaloes

Directory of Open Access Journals (Sweden)

S. K. Sinha

2017-06-01

Full Text Available Aim: A comparative study was conducted on crossbred cattle and buffaloes to investigate the effect of feeding high and low roughage total mixed ration (TMR diets on rumen metabolites and enzymatic profiles. Materials and Methods: Three rumen-fistulated crossbred cattle and buffalo were randomly assigned as per 3x3 switch over design for 21-days. Three TMR diets consisting of concentrate mixture, wheat straw and green maize fodder in the ratios of (T1 60:20:20, (T2 40:30:30, and (T3 20:40:40, respectively, were fed to the animals ad libitum. Rumen liquor samples were collected at 0, 2, 4, 6, and 8 h post feeding for the estimation of rumen biochemical parameters on 2 consecutive days in each trial. Results: The lactic acid concentration and pH value were comparable in both species and treatments. Feed intake (99.77±2.51 g/kg body weight, ruminal ammonia nitrogen, and total nitrogen were significantly (p0.05 among treatments and significantly (p<0.05 greater in crossbred cattle than buffaloes. Molar proportions of individual VFAs propionate (C3, propionate:butyrate (C3:C4, and (acetate+butyrate:propionate ([C2+C4]:C3 ratio in both crossbred cattle and buffalo were not affected by high or low roughage diet, but percentage of acetate and butyrate varied significantly (p<0.05 among treatment groups. Activities of microbial enzymes were comparable among species and different treatment groups. A total number of rumen protozoa were significantly (p<0.05 higher in crossbred cattle than buffaloes along with significantly (p<0.05 higher population in animal fed with high concentrate diet (T1. Conclusion: Rumen microbial population and fermentation depend on constituents of the treatment diet. However, microbial enzyme activity remains similar among species and different treatments. High concentrate diet increases number of rumen protozoa, and the number is higher in crossbred cattle than buffaloes.

Microbial stratification and microbially catalyzed processes along a hypersaline chemocline

Science.gov (United States)

Hyde, A.; Joye, S. B.; Teske, A.

2017-12-01

Orca Basin is the largest deep hypersaline anoxic basin in the world, covering over 400 km2. Located at the bottom of the Gulf of Mexico, this body of water reaches depths of 200 meters and is 8 times denser (and more saline) than the overlying seawater. The sharp pycnocline prevents any significant vertical mixing and serves as a particle trap for sinking organic matter. These rapid changes in salinity, oxygen, organic matter, and other geochemical parameters present unique conditions for the microbial communities present. We collected samples in 10m intervals throughout the chemocline. After filtering the water, we used high-throughput bacterial and archaeal 16S rRNA gene sequencing to characterize the changing microbial community along the Orca Basin chemocline. The results reveal a dominance of microbial taxa whose biogeochemical function is entirely unknown. We then used metagenomic sequencing and reconstructed genomes for select samples, revealing the potential dominant metabolic processes in the Orca Basin chemocline. Understanding how these unique geochemical conditions shape microbial communities and metabolic capabilities will have implications for the ocean's biogeochemical cycles and the consequences of expanding oxygen minimum zones.

Hydrothermal pretreatment and enzymatic hydrolysis of mixed green and woody lignocellulosics from arid regions

DEFF Research Database (Denmark)

Ashraf, Muhammad Tahir; Thomsen, Mette Hedegaard; Schmidt, Jens Ejbye

2017-01-01

Utilization of multi-specie feedstocks is imperative for application of lignocellulosic biorefineries in arid regions. Different lignocellulosic residues vary in composition and anatomical features. Pretreatment and enzymatic hydrolysis are two processes at the front end of any lignocellulosics...... biorefinery applying biochemical pathway, and have to efficiently deal with the variance in the feedstock composition and properties. However, there is limited knowledge about effect of mixing different lignocellulosics on pretreatment and enzymatic hydrolysis yields. In this study effect of mixing...... on the yields from hydrothermal pretreatment and enzymatic hydrolysis was analyzed by mixing three different lignocellulosic residues — Bermuda grass, Jasmine hedges, and date palm fronds. Results showed that the individual and the mixed lignocellulosics gave same yields when treated under similar conditions...

Microbial electrode sensor for alcohols

Energy Technology Data Exchange (ETDEWEB)

Hikuma, M [Ajinomoto Co., Inc., Kawasaki, Japan; Kubo, T; Yasuda, T; Karube, I; Suzuki, S

1979-10-01

A microbial electrode consisting of immobilized microorganisms, a gas permeable Teflon membrane, and an oxygen electrode was prepared for the continuous determination of methyl and ethyl alcohols. Immobilized Trichosporon brassicae was employed for a microbial electrode sensor for ethyl alcohol. When a sample solution containing ethyl alcohol was injected into a microbial electrode system, the current of the electrode decreased markedly with time until a steady state was reached. The response time was within 10 min by the steady state method and within 6 min by the pulse method. A linear relationship was observed between the current decrease and the concentration of ethyl alcohol below 22.5 mg/liter. The current was reproducible within +- 6% of the relative error when a sample solution containing 16.5 mg/liter ethyl alcohol. The standard deviation was 0.5 mg/liter in 40 experiments. The selectivity of the microbial electrode sensor for ethyl alcohol was satisfactory. The microbial electrode sensor was applied to a fermentation broth of yeasts and satisfactory comparative results were obtained (correlation coefficient 0.98). The current output of the microbial electrode sensor was almost constant for more than three weeks and 2100 assays. A microbial electrode sensor using immobilized bacteria for methyl alcohol was also described.

Global microbialization of coral reefs.

Science.gov (United States)

Haas, Andreas F; Fairoz, Mohamed F M; Kelly, Linda W; Nelson, Craig E; Dinsdale, Elizabeth A; Edwards, Robert A; Giles, Steve; Hatay, Mark; Hisakawa, Nao; Knowles, Ben; Lim, Yan Wei; Maughan, Heather; Pantos, Olga; Roach, Ty N F; Sanchez, Savannah E; Silveira, Cynthia B; Sandin, Stuart; Smith, Jennifer E; Rohwer, Forest

2016-04-25

Microbialization refers to the observed shift in ecosystem trophic structure towards higher microbial biomass and energy use. On coral reefs, the proximal causes of microbialization are overfishing and eutrophication, both of which facilitate enhanced growth of fleshy algae, conferring a competitive advantage over calcifying corals and coralline algae. The proposed mechanism for this competitive advantage is the DDAM positive feedback loop (dissolved organic carbon (DOC), disease, algae, microorganism), where DOC released by ungrazed fleshy algae supports copiotrophic, potentially pathogenic bacterial communities, ultimately harming corals and maintaining algal competitive dominance. Using an unprecedented data set of >400 samples from 60 coral reef sites, we show that the central DDAM predictions are consistent across three ocean basins. Reef algal cover is positively correlated with lower concentrations of DOC and higher microbial abundances. On turf and fleshy macroalgal-rich reefs, higher relative abundances of copiotrophic microbial taxa were identified. These microbial communities shift their metabolic potential for carbohydrate degradation from the more energy efficient Embden-Meyerhof-Parnas pathway on coral-dominated reefs to the less efficient Entner-Doudoroff and pentose phosphate pathways on algal-dominated reefs. This 'yield-to-power' switch by microorganism directly threatens reefs via increased hypoxia and greater CO2 release from the microbial respiration of DOC.

The enzymatic determination of starch in food, feed and raw materials of the starch industry

NARCIS (Netherlands)

Brunt, K.; Sanders, P.; Rozema, T.

1998-01-01

An enzymatic starch determination which can be used for the analysis of starch in a very broad range of different samples is evaluated, ranging from starch in plants, feed and food to industrial applications as starch in starch. The method is based on a complete enzymatic conversion of the starch

Pretreatment and enzymatic hydrolysis of lignocellulosic biomass

Science.gov (United States)

Corredor, Deisy Y.

The performance of soybean hulls and forage sorghum as feedstocks for ethanol production was studied. The main goal of this research was to increase fermentable sugars' yield through high-efficiency pretreatment technology. Soybean hulls are a potential feedstock for production of bio-ethanol due to their high carbohydrate content (≈50%) of nearly 37% cellulose. Soybean hulls could be the ideal feedstock for fuel ethanol production, because they are abundant and require no special harvesting and additional transportation costs as they are already in the plant. Dilute acid and modified steam-explosion were used as pretreatment technologies to increase fermentable sugars yields. Effects of reaction time, temperature, acid concentration and type of acid on hydrolysis of hemicellulose in soybean hulls and total sugar yields were studied. Optimum pretreatment parameters and enzymatic hydrolysis conditions for converting soybean hulls into fermentable sugars were identified. The combination of acid (H2SO4, 2% w/v) and steam (140°C, 30 min) efficiently solubilized the hemicellulose, giving a pentose yield of 96%. Sorghum is a tropical grass grown primarily in semiarid and dry parts of the world, especially in areas too dry for corn. The production of sorghum results in about 30 million tons of byproducts mainly composed of cellulose, hemicellulose, and lignin. Forage sorghum such as brown midrib (BMR) sorghum for ethanol production has generated much interest since this trait is characterized genetically by lower lignin concentrations in the plant compared with conventional types. Three varieties of forage sorghum and one variety of regular sorghum were characterized and evaluated as feedstock for fermentable sugar production. Fourier transform infrared spectroscopy (FTIR), scanning electron microscope (SEM) and X-Ray diffraction were used to determine changes in structure and chemical composition of forage sorghum before and after pretreatment and enzymatic hydrolysis

Optimization of enzymatic hydrolysis of guar gum using response surface methodology.

Science.gov (United States)

Mudgil, Deepak; Barak, Sheweta; Khatkar, B S

2014-08-01

Guar gum is a polysaccharide obtained from guar seed endosperm portion. Enzymatically hydrolyzed guar gum is low in viscosity and has several health benefits as dietary fiber. In this study, response surface methodology was used to determine the optimum conditions for hydrolysis that give minimum viscosity of guar gum. Central composite was employed to investigate the effects of pH (3-7), temperature (20-60 °C), reaction time (1-5 h) and cellulase concentration (0.25-1.25 mg/g) on viscosity during enzymatic hydrolysis of guar (Cyamopsis tetragonolobus) gum. A second order polynomial model was developed for viscosity using regression analysis. Results revealed statistical significance of model as evidenced from high value of coefficient of determination (R(2) = 0.9472) and P < 0.05. Viscosity was primarily affected by cellulase concentration, pH and hydrolysis time. Maximum viscosity reduction was obtained when pH, temperature, hydrolysis time and cellulase concentration were 6, 50 °C, 4 h and 1.00 mg/g, respectively. The study is important in optimizing the enzymatic process for hydrolysis of guar gum as potential source of soluble dietary fiber for human health benefits.

Effect of lignin chemistry on the enzymatic hydrolysis of woody biomass.

Science.gov (United States)

Yu, Zhiying; Gwak, Ki-Seob; Treasure, Trevor; Jameel, Hasan; Chang, Hou-min; Park, Sunkyu

2014-07-01

The impact of lignin-derived inhibition on enzymatic hydrolysis is investigated by using lignins isolated from untreated woods and pretreated wood pulps. A new method, biomass reconstruction, for which isolated lignins are precipitated onto bleached pulps to mimic lignocellulosic biomass, is introduced, for the first time, to decouple the lignin distribution issue from lignin chemistry. Isolated lignins are physically mixed and reconstructed with bleached pulps. Lignins obtained from pretreated woods adsorb two to six times more cellulase than lignins obtained from untreated woods. The higher adsorption of enzymes on lignin correlates with decreased carbohydrate conversion in enzymatic hydrolysis. In addition, the reconstructed softwood substrate has a lower carbohydrate conversion than the reconstructed hardwood substrate. The degree of condensation of lignin increases significantly after pretreatment, especially with softwood lignins. In this study, the degree of condensation of lignin (0.02 to 0.64) and total OH groups in lignin (1.7 to 1.1) have a critical impact on cellulase adsorption (9 to 70%) and enzymatic hydrolysis (83.2 to 58.2%); this may provide insights into the more recalcitrant nature of softwood substrates. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Radiation pretreatments of cellulose materials for the enhancement of enzymatic hydrolysis

International Nuclear Information System (INIS)

Ait Si Mamar, S.; Hadjadj, A.

1990-01-01

The conversion of wheat straw agricultural cellulosic wastes to reducing sugars and glucose has been studied by pretreatments by acid hydrolysis and gamma radiolysis over the dose 0-2 MGy. The pretreatment of cellulosic wastes by gamma radiolysis in the presence of sulfuric acid solution shows that the reducing sugars yield increases with the irradiation dose. The effect of radiation degradation on cellulosic wastes between 0.1 MGy and 2 MGy shows the glucose and reducing sugars yields after enzymatic hydrolysis by cellulase vary with the dose. In the relatively low dose range, up to about 0.5 MGy, the reducing sugars yields vary slightly. For an acid hydrolysis followed by radiation at dose range below 0.5 MGy the reducing sugars yields are practically insensitive to radiation. On the other hand, the pretreatment by radiation in higher dose range from 0.5 to 2 MGy followed by enzymatic hydrolysis is effective for the conversion of cellulosic wastes into glucose. The radiation induced degradation of cellulose into glucose depends on the type of acid hydrolysis and on the enzymatic hydrolysis time by cellulase. Pre-irradiation in air is more effective than in acid solution. (author)

Radiation pretreatments of cellulose materials for the enhancement of enzymatic hydrolysis

Science.gov (United States)

Mamar, S. Ait Si; Hadjadj, A.

The conversion of wheat straw agricultural cellulosic wastes to reduning sugars and glucose has been studied by pretreatments by acid hydrolysis and gamma radiolysis over the dose 0-2 MGy. The pretreatment of cellulosic wastes by gamma radiolysis in the presence of sulfuric acid solution shows that the reducing sugars yield increases with the irradiation dose. The effect of radiation degradation on cellulosic wastes between 0.1 MGy and 2 MGy shows the glucose and reducing sugars yields after enzymatic hydrolysis by cellulase vary with the dose. In the relatively low dose range, up to about 0.5 MGy, the reducing sugars yields vary slightly. For an acid hydrolysis followed by radiation at dose range below 0.5 MGy the reducing sugars yields are practically insensitive to radiation. On the other hand, the pretreatment by radiation in higher dose range from 0.5 to 2 MGy followed by enzymatic hydrolysis is effective for the conversion of cellulosic wastes into glucose. The radiation induced degradation of cellulose into glucose depends on the type of acid hydrolysis and on the enzymatic hydrolysis time by cellulase. Pre-irradiation in air is more effective than in acid solution.

GeoChip-based insights into the microbial functional gene repertoire of marine sponges (high microbial abundance, low microbial abundance) and seawater

KAUST Repository

Bayer, Kristina

2015-01-08

The GeoChip 4.2 gene array was employed to interrogate the microbial functional gene repertoire of sponges and seawater collected from the Red Sea and the Mediterranean. Complementary amplicon sequencing confirmed the microbial community composition characteristic of high microbial abundance (HMA) and low microbial abundance (LMA) sponges. By use of GeoChip, altogether 20 273 probes encoding for 627 functional genes and representing 16 gene categories were identified. Minimum curvilinear embedding analyses revealed a clear separation between the samples. The HMA/LMA dichotomy was stronger than any possible geographic pattern, which is shown here for the first time on the level of functional genes. However, upon inspection of individual genes, very few specific differences were discernible. Differences were related to microbial ammonia oxidation, ammonification, and archaeal autotrophic carbon fixation (higher gene abundance in sponges over seawater) as well as denitrification and radiation-stress-related genes (lower gene abundance in sponges over seawater). Except for few documented specific differences the functional gene repertoire between the different sources appeared largely similar. This study expands previous reports in that functional gene convergence is not only reported between HMA and LMA sponges but also between sponges and seawater.

GeoChip-based insights into the microbial functional gene repertoire of marine sponges (high microbial abundance, low microbial abundance) and seawater

KAUST Repository

Bayer, Kristina; Moitinho-Silva, Lucas; Brü mmer, Franz; Cannistraci, Carlo V.; Ravasi, Timothy; Hentschel, Ute

2015-01-01

The GeoChip 4.2 gene array was employed to interrogate the microbial functional gene repertoire of sponges and seawater collected from the Red Sea and the Mediterranean. Complementary amplicon sequencing confirmed the microbial community composition characteristic of high microbial abundance (HMA) and low microbial abundance (LMA) sponges. By use of GeoChip, altogether 20 273 probes encoding for 627 functional genes and representing 16 gene categories were identified. Minimum curvilinear embedding analyses revealed a clear separation between the samples. The HMA/LMA dichotomy was stronger than any possible geographic pattern, which is shown here for the first time on the level of functional genes. However, upon inspection of individual genes, very few specific differences were discernible. Differences were related to microbial ammonia oxidation, ammonification, and archaeal autotrophic carbon fixation (higher gene abundance in sponges over seawater) as well as denitrification and radiation-stress-related genes (lower gene abundance in sponges over seawater). Except for few documented specific differences the functional gene repertoire between the different sources appeared largely similar. This study expands previous reports in that functional gene convergence is not only reported between HMA and LMA sponges but also between sponges and seawater.

Enzymatic- and temperature-sensitive controlled release of ultrasmall superparamagnetic iron oxides (USPIOs

Directory of Open Access Journals (Sweden)

Ortega Ryan A

2011-02-01

Full Text Available Abstract Background Drug and contrast agent delivery systems that achieve controlled release in the presence of enzymatic activity are becoming increasingly important, as enzymatic activity is a hallmark of a wide array of diseases, including cancer and atherosclerosis. Here, we have synthesized clusters of ultrasmall superparamagnetic iron oxides (USPIOs that sense enzymatic activity for applications in magnetic resonance imaging (MRI. To achieve this goal, we utilize amphiphilic poly(propylene sulfide-bl-poly(ethylene glycol (PPS-b-PEG copolymers, which are known to have excellent properties for smart delivery of drug and siRNA. Results Monodisperse PPS polymers were synthesized by anionic ring opening polymerization of propylene sulfide, and were sequentially reacted with commercially available heterobifunctional PEG reagents and then ssDNA sequences to fashion biofunctional PPS-bl-PEG copolymers. They were then combined with hydrophobic 12 nm USPIO cores in the thin-film hydration method to produce ssDNA-displaying USPIO micelles. Micelle populations displaying complementary ssDNA sequences were mixed to induce crosslinking of the USPIO micelles. By design, these crosslinking sequences contained an EcoRV cleavage site. Treatment of the clusters with EcoRV results in a loss of R2 negative contrast in the system. Further, the USPIO clusters demonstrate temperature sensitivity as evidenced by their reversible dispersion at ~75°C and re-clustering following return to room temperature. Conclusions This work demonstrates proof of concept of an enzymatically-actuatable and thermoresponsive system for dynamic biosensing applications. The platform exhibits controlled release of nanoparticles leading to changes in magnetic relaxation, enabling detection of enzymatic activity. Further, the presented functionalization scheme extends the scope of potential applications for PPS-b-PEG. Combined with previous findings using this polymer platform that

Enzymatic- and temperature-sensitive controlled release of ultrasmall superparamagnetic iron oxides (USPIOs).

Science.gov (United States)

Yu, Shann S; Scherer, Randy L; Ortega, Ryan A; Bell, Charleson S; O'Neil, Conlin P; Hubbell, Jeffrey A; Giorgio, Todd D

2011-02-27

Drug and contrast agent delivery systems that achieve controlled release in the presence of enzymatic activity are becoming increasingly important, as enzymatic activity is a hallmark of a wide array of diseases, including cancer and atherosclerosis. Here, we have synthesized clusters of ultrasmall superparamagnetic iron oxides (USPIOs) that sense enzymatic activity for applications in magnetic resonance imaging (MRI). To achieve this goal, we utilize amphiphilic poly(propylene sulfide)-bl-poly(ethylene glycol) (PPS-b-PEG) copolymers, which are known to have excellent properties for smart delivery of drug and siRNA. Monodisperse PPS polymers were synthesized by anionic ring opening polymerization of propylene sulfide, and were sequentially reacted with commercially available heterobifunctional PEG reagents and then ssDNA sequences to fashion biofunctional PPS-bl-PEG copolymers. They were then combined with hydrophobic 12 nm USPIO cores in the thin-film hydration method to produce ssDNA-displaying USPIO micelles. Micelle populations displaying complementary ssDNA sequences were mixed to induce crosslinking of the USPIO micelles. By design, these crosslinking sequences contained an EcoRV cleavage site. Treatment of the clusters with EcoRV results in a loss of R2 negative contrast in the system. Further, the USPIO clusters demonstrate temperature sensitivity as evidenced by their reversible dispersion at ~75°C and re-clustering following return to room temperature. This work demonstrates proof of concept of an enzymatically-actuatable and thermoresponsive system for dynamic biosensing applications. The platform exhibits controlled release of nanoparticles leading to changes in magnetic relaxation, enabling detection of enzymatic activity. Further, the presented functionalization scheme extends the scope of potential applications for PPS-b-PEG. Combined with previous findings using this polymer platform that demonstrate controlled drug release in oxidative

Nutritional treatment of cancer cachexia in rats. Use of a diet formulated with a crayfish enzymatic extract.

Science.gov (United States)

Cremades, Olga; Parrado, Juan; Jover, María; Collantes de Terán, Laura; Gutiérrez, Juan Francisco; Bautista Palomas, Juan D

2007-09-01

Terminal cancer-associated cachexia, characterized by a marked weight loss, anorexia, asthenia and anemia, is usually associated with a malnutrition status. To investigate whether a diet formulated with a crayfish enzymatic extract, enriched in essential amino acids, omega-3 fatty acids, and astaxanthin, would be effective for the treatment of cancer-associated cachexias, by decreasing mortality and morbidity rates in cachectic rats and/or improving survival. Two types of diet were used: a standard diet and one formulated with crayfish enzymatic extract. Rats were divided into two groups (24 animals per group): one without tumor (T-) and the other with tumor (T+) (AH-130 Yoshida ascites hepatoma). Each group was further divided into two subgroups (12 animals per subgroup). Two subgroups (T-(standard) and T+(standard)) were fed the standard diet and the other two (T-(CFEE) and T+(CFEE)) the crayfish enzymatic extract one for four weeks, after which different tissue and plasma parameters were studied. The implantation of the tumor resulted in a considerable loss of muscle and adipose tissue mass in both groups, but the loss of muscle and fat was lower in the group fed the crayfish enzymatic extract diet. There was also a concomitant increase in the plasma concentration of TNF-alpha, although the increase was smaller in the crayfish enzymatic extract-treated group. This study shows that although the treatment of cachetic rats with the crayfish enzymatic extract diet did not revert the cachexia, it increased survival (57.1% vs. 25.9% in the group treated with crayfish enzymatic extract and standard diets, respectively) and meliorated the cachexia symptoms--anorexia and body mass loss (muscle and adipose tissue).

Microbial characterization of bee pollen from the Vesuvius area collected by using three different traps

Science.gov (United States)

De Prisco, Annachiara; Di Prisco, Gennaro; La Storia, Antonietta; Caprio, Emilio

2017-01-01

Flower pollen is collected by honeybee foragers, adhered on their rear legs and transported into the hives in the form of pellets. Once in the hives, bee pollen is moisturised with nectar and bee mouth secretions and due to enzymatically modifications it becomes the so-called bee-bread, the protein reservoir of young bees. Bee pollen can be artificially removed from bee legs and collected by using specific systems, the bee pollen traps. Bee pollen is commercialized for human consumption as fresh product and after freezing or drying. Although bee pollen is nowadays largely consumed in developed countries, as food or food supplement according to local legislation, little is known on its safety related to microbiological hazards. In this work, we aimed to characterize for the first time the microbiological profile of Italian bee pollen in fresh, frozen and dried form collected along an entire harvesting season. Moreover, monthly microbiological analyses were performed on frozen (storage at -18°C) and dried (storage at room temperature) bee pollen over a 4 months period. Further aim of this work was the evaluation of the possible impact on production level of three different traps used for pollen collection. Our results on microbial contamination of fresh and frozen bee pollen show that a more comprehensive microbiological risk assessment of bee pollen is required. On the other side, dried pollen showed very low microbial contamination and no pathogen survived after the drying process and during storage. PMID:28934240

Algorithms Development in Detection of the Gelatinization Process during Enzymatic ‘Dodol’ Processing

Directory of Open Access Journals (Sweden)

Azman Hamzah

2013-09-01

Full Text Available Computer vision systems have found wide application in foods processing industry to perform quality evaluation. The systems enable to replace human inspectors for the evaluation of a variety of quality attributes. This paper describes the implementation of the Fast Fourier Transform and Kalman filtering algorithms to detect the glutinous rice flour slurry (GRFS gelatinization in an enzymatic „dodol. processing. The onset of the GRFS gelatinization is critical in determining the quality of an enzymatic „dodol.. Combinations of these two algorithms were able to detect the gelatinization of the GRFS. The result shows that the gelatinization of the GRFS was at the time range of 11.75 minutes to 14.75 minutes for 24 batches of processing. This paper will highlight the capability of computer vision using our proposed algorithms in monitoring and controlling of an enzymatic „dodol. processing via image processing technology.

Algorithms Development in Detection of the Gelatinization Process during Enzymatic ‘Dodol’ Processing

Directory of Open Access Journals (Sweden)

Azman Hamzah

2007-11-01

Full Text Available Computer vision systems have found wide application in foods processing industry to perform the quality evaluation. The systems enable to replace human inspectors for the evaluation of a variety of quality attributes. This paper describes the implementation of the Fast Fourier Transform and Kalman filtering algorithms to detect the glutinous rice flour slurry (GRFS gelatinization in an enzymatic ‘dodol’ processing. The onset of the GRFS gelatinization is critical in determining the quality of an enzymatic ‘dodol’. Combinations of these two algorithms were able to detect the gelatinization of the GRFS. The result shows that the gelatinization of the GRFS was at the time range of 11.75 minutes to 15.33 minutes for 20 batches of processing. This paper will highlight the capability of computer vision using our proposed algorithms in monitoring and controlling of an enzymatic ‘dodol’ processing via image processing technology.

Enzymatic saccharification and structural properties of industrial wood sawdust: Recycled ionic liquids pretreatments

International Nuclear Information System (INIS)

Auxenfans, Thomas; Buchoux, Sébastien; Larcher, Dominique; Husson, Gérard; Husson, Eric; Sarazin, Catherine

2014-01-01

Highlights: • 1-Ethyl-3-metylimidazolium acetate is an effective catalyst for pretreatment of hardwood and softwood sawdust. • Regeneration of cellulosic fraction from ionic liquid is discussed. • 1-Ethyl-3-methylimidazolium acetate can be reused at least 7 times without loss of its efficiency. • Removal of extractives and lignin with slight cellulose and xylan losses were observed. • Better cellulase accessibility to cellulose thanks to the expansion of the powder and the creation of a large porous volume. - Abstract: Wood residues constitute a promising challenge for biochemical processing into bioethanol and chemicals with competitive costs. Here, we report the impacts of pretreatments in a hydrophilic ionic liquid ([C2mim][OAc]), onto the physicochemical properties and enzymatic saccharification of softwood (spruce) and hardwood (oak) sawdust. Enzymatic saccharification of IL- pretreated sawdust is significantly increased (up to 7 times) when compared to untreated ones. Methanol, ethanol or water can be used as polar anti-solvent for the recovery of a cellulose rich fraction after dissolution in IL (i.e regeneration step) without any effect on enzymatic saccharification. Chemical, textural and structural modifications possibly induced by the IL pretreatments have been investigated through various means (Infra-red spectroscopy, NMR, X-ray diffraction) in order to correlate the observed modifications in enzymatic saccharification. This mild pretreatment seemed to mainly act in a breakdown of lignocellulosic organization leading to better cellulase accessibility to cellulose thanks to the expansion of the powder and the creation of a large porous volume (5 times more apparent porous volume). Partial removal of lignin and extractives may also contribute to the best enzymatic performances. The recyclability and reuse up to 7 times of [C2mim][OAc] is shown without the need of strictly anhydrous conditions and any alteration of the pretreatment

New microbial resource: microbial diversity, function and dynamics in Chinese liquor starter.

Science.gov (United States)

Huang, Yuhong; Yi, Zhuolin; Jin, Yanling; Zhao, Yonggui; He, Kaize; Liu, Dayu; Zhao, Dong; He, Hui; Luo, Huibo; Zhang, Wenxue; Fang, Yang; Zhao, Hai

2017-11-06

Traditional Chinese liquor (Baijiu) solid state fermentation technology has lasted for several thousand years. The microbial communities that enrich in liquor starter are important for fermentation. However, the microbial communities are still under-characterized. In this study, 454 pyrosequencing technology was applied to comprehensively analyze the microbial diversity, function and dynamics of two most-consumed liquor starters (Jiang- and Nong-flavor) during production. In total, 315 and 83 bacterial genera and 72 and 47 fungal genera were identified in Jiang- and Nong-flavor liquor starter, respectively. The relatively high diversity was observed when the temperature increased to 70 and 62 °C for Jiang- and Nong-flavor liquor starter, respectively. Some thermophilic fungi have already been isolated. Microbial communities that might contribute to ethanol fermentation, saccharification and flavor development were identified and shown to be core communities in correlation-based network analysis. The predictively functional profile of bacterial communities showed significant difference in energy, carbohydrate and amino acid metabolism and the degradation of aromatic compounds between the two kinds of liquor starters. Here we report these liquor starters as a new functionally microbial resource, which can be used for discovering thermophilic and aerobic enzymes and for food and feed preservation.

Steam explosion pretreatment of softwood: the effect of the explosive decompression on enzymatic digestibility.

Science.gov (United States)

Pielhop, Thomas; Amgarten, Janick; von Rohr, Philipp Rudolf; Studer, Michael H

2016-01-01

Steam explosion pretreatment has been examined in many studies for enhancing the enzymatic digestibility of lignocellulosic biomass and is currently the most common pretreatment method in commercial biorefineries. The information available about the effect of the explosive decompression on the biochemical conversion is, however, very limited, and no studies prove that the latter is actually enhanced by the explosion. Hence, it is of great value to discern between the effect of the explosion on the one hand and the steaming on the other hand, to identify their particular influences on enzymatic digestibility. The effect of the explosive decompression in the steam explosion pretreatment of spruce wood chips on their enzymatic cellulose digestibility was studied systematically. The explosion had a high influence on digestibility, improving it by up to 90 % compared to a steam pretreatment without explosion. Two factors were identified to be essentially responsible for the effect of the explosion on enzymatic digestibility: pretreatment severity and pressure difference of the explosion. A higher pretreatment severity can soften up and weaken the lignocellulose structure more, so that the explosion can better break up the biomass and decrease its particle size, which enhances its digestibility. In particular, increasing the pressure difference of the explosion leads to more defibration, a smaller particle size and a better digestibility. Though differences were found in the micro- and nanostructure of exploded and non-exploded biomass, the only influence of the explosion on digestibility was found to be the macroscopic particle size reduction. Steam explosion treatments with a high severity and a high pressure difference of the explosion lead to a comparatively high cellulose digestibility of the-typically very recalcitrant-softwood biomass. This is the first study to show that explosion can enhance the enzymatic digestibility of lignocellulosic biomass. If the

Chemo‐enzymatic epoxidation–process options for improving biocatalytic productivity

DEFF Research Database (Denmark)

Hagström, Anna E. V.; Törnvall, Ulrika; Nordblad, Mathias

2011-01-01

The reactor choice is crucial when designing a process where inactivation of the biocatalyst is a problem. The main bottleneck for the chemo‐enzymatic epoxidation has been found to be enzyme inactivation by the hydrogen peroxide, H2O2, substrate. In the work reported here, the effect of reaction...... parameters on the reaction performance have been investigated and used to establish suitable operating strategies to minimize the inactivation of the enzyme, using rapeseed methyl ester (RME) as a substrate in a solvent‐free system. The use of a controlled fed‐batch reactor for maintaining H2O2 concentration...... at 1.5 M resulted in increased productivity, up to 76 grams of product per gram of biocatalyst with higher retention of enzyme activity. Further investigation included a multistage design that separated the enzymatic reaction and the saturation of the RME substrate with H2O2 into different vessels...

Rational design of functional and tunable oscillating enzymatic networks

Science.gov (United States)

Semenov, Sergey N.; Wong, Albert S. Y.; van der Made, R. Martijn; Postma, Sjoerd G. J.; Groen, Joost; van Roekel, Hendrik W. H.; de Greef, Tom F. A.; Huck, Wilhelm T. S.

2015-02-01

Life is sustained by complex systems operating far from equilibrium and consisting of a multitude of enzymatic reaction networks. The operating principles of biology's regulatory networks are known, but the in vitro assembly of out-of-equilibrium enzymatic reaction networks has proved challenging, limiting the development of synthetic systems showing autonomous behaviour. Here, we present a strategy for the rational design of programmable functional reaction networks that exhibit dynamic behaviour. We demonstrate that a network built around autoactivation and delayed negative feedback of the enzyme trypsin is capable of producing sustained oscillating concentrations of active trypsin for over 65 h. Other functions, such as amplification, analog-to-digital conversion and periodic control over equilibrium systems, are obtained by linking multiple network modules in microfluidic flow reactors. The methodology developed here provides a general framework to construct dissipative, tunable and robust (bio)chemical reaction networks.

Enzymatic epoxidation of biodiesel optimized by response surface ...

African Journals Online (AJOL)

During the enzymatic epoxidation of biodiesel, stearic acid was selected as oxygen carrier. Enzyme screening and the load of stearic acid were investigated. The effects of four main reaction conditions including reaction time, temperature, enzyme load, and mole ratio of H2O2/C=C-bonds on the epoxy oxygen group content ...

Deep subsurface microbial processes

Science.gov (United States)

Lovley, D.R.; Chapelle, F.H.

1995-01-01

Information on the microbiology of the deep subsurface is necessary in order to understand the factors controlling the rate and extent of the microbially catalyzed redox reactions that influence the geophysical properties of these environments. Furthermore, there is an increasing threat that deep aquifers, an important drinking water resource, may be contaminated by man's activities, and there is a need to predict the extent to which microbial activity may remediate such contamination. Metabolically active microorganisms can be recovered from a diversity of deep subsurface environments. The available evidence suggests that these microorganisms are responsible for catalyzing the oxidation of organic matter coupled to a variety of electron acceptors just as microorganisms do in surface sediments, but at much slower rates. The technical difficulties in aseptically sampling deep subsurface sediments and the fact that microbial processes in laboratory incubations of deep subsurface material often do not mimic in situ processes frequently necessitate that microbial activity in the deep subsurface be inferred through nonmicrobiological analyses of ground water. These approaches include measurements of dissolved H2, which can predict the predominant microbially catalyzed redox reactions in aquifers, as well as geochemical and groundwater flow modeling, which can be used to estimate the rates of microbial processes. Microorganisms recovered from the deep subsurface have the potential to affect the fate of toxic organics and inorganic contaminants in groundwater. Microbial activity also greatly influences 1 the chemistry of many pristine groundwaters and contributes to such phenomena as porosity development in carbonate aquifers, accumulation of undesirably high concentrations of dissolved iron, and production of methane and hydrogen sulfide. Although the last decade has seen a dramatic increase in interest in deep subsurface microbiology, in comparison with the study of

The maturing of microbial ecology.

Science.gov (United States)

Schmidt, Thomas M

2006-09-01

A.J. Kluyver and C.B. van Niel introduced many scientists to the exceptional metabolic capacity of microbes and their remarkable ability to adapt to changing environments in The Microbe's Contribution to Biology. Beyond providing an overview of the physiology and adaptability of microbes, the book outlined many of the basic principles for the emerging discipline of microbial ecology. While the study of pure cultures was highlighted, provided a unifying framework for understanding the vast metabolic potential of microbes and their roles in the global cycling of elements, extrapolation from pure cultures to natural environments has often been overshadowed by microbiologists inability to culture many of the microbes seen in natural environments. A combination of genomic approaches is now providing a culture-independent view of the microbial world, revealing a more diverse and dynamic community of microbes than originally anticipated. As methods for determining the diversity of microbial communities become increasingly accessible, a major challenge to microbial ecologists is to link the structure of natural microbial communities with their functions. This article presents several examples from studies of aquatic and terrestrial microbial communities in which culture and culture-independent methods are providing an enhanced appreciation for the microbe's contribution to the evolution and maintenance of life on Earth, and offers some thoughts about the graduate-level educational programs needed to enhance the maturing field of microbial ecology.

A review of metabolic and enzymatic engineering strategies for designing and optimizing performance of microbial cell factories

Directory of Open Access Journals (Sweden)

Amanda K. Fisher

2014-08-01

Full Text Available Microbial cell factories (MCFs are of considerable interest to convert low value renewable substrates to biofuels and high value chemicals. This review highlights the progress of computational models for the rational design of an MCF to produce a target bio-commodity. In particular, the rational design of an MCF involves: (i product selection, (ii de novo biosynthetic pathway identification (i.e., rational, heterologous, or artificial, (iii MCF chassis selection, (iv enzyme engineering of promiscuity to enable the formation of new products, and (v metabolic engineering to ensure optimal use of the pathway by the MCF host. Computational tools such as (i de novo biosynthetic pathway builders, (ii docking, (iii molecular dynamics (MD and steered MD (SMD, and (iv genome-scale metabolic flux modeling all play critical roles in the rational design of an MCF. Genome-scale metabolic flux models are of considerable use to the design process since they can reveal metabolic capabilities of MCF hosts. These can be used for host selection as well as optimizing precursors and cofactors of artificial de novo biosynthetic pathways. In addition, recent advances in genome-scale modeling have enabled the derivation of metabolic engineering strategies, which can be implemented using the genomic tools reviewed here as well.

In-Drift Microbial Communities

Energy Technology Data Exchange (ETDEWEB)

D. Jolley

2000-11-09

As directed by written work direction (CRWMS M and O 1999f), Performance Assessment (PA) developed a model for microbial communities in the engineered barrier system (EBS) as documented here. The purpose of this model is to assist Performance Assessment and its Engineered Barrier Performance Section in modeling the geochemical environment within a potential repository drift for TSPA-SR/LA, thus allowing PA to provide a more detailed and complete near-field geochemical model and to answer the key technical issues (KTI) raised in the NRC Issue Resolution Status Report (IRSR) for the Evolution of the Near Field Environment (NFE) Revision 2 (NRC 1999). This model and its predecessor (the in-drift microbial communities model as documented in Chapter 4 of the TSPA-VA Technical Basis Document, CRWMS M and O 1998a) was developed to respond to the applicable KTIs. Additionally, because of the previous development of the in-drift microbial communities model as documented in Chapter 4 of the TSPA-VA Technical Basis Document (CRWMS M and O 1998a), the M and O was effectively able to resolve a previous KTI concern regarding the effects of microbial processes on seepage and flow (NRC 1998). This document supercedes the in-drift microbial communities model as documented in Chapter 4 of the TSPA-VA Technical Basis Document (CRWMS M and O 1998a). This document provides the conceptual framework of the revised in-drift microbial communities model to be used in subsequent performance assessment (PA) analyses.

In-Drift Microbial Communities

International Nuclear Information System (INIS)

Jolley, D.

2000-01-01

As directed by written work direction (CRWMS M and O 1999f), Performance Assessment (PA) developed a model for microbial communities in the engineered barrier system (EBS) as documented here. The purpose of this model is to assist Performance Assessment and its Engineered Barrier Performance Section in modeling the geochemical environment within a potential repository drift for TSPA-SR/LA, thus allowing PA to provide a more detailed and complete near-field geochemical model and to answer the key technical issues (KTI) raised in the NRC Issue Resolution Status Report (IRSR) for the Evolution of the Near Field Environment (NFE) Revision 2 (NRC 1999). This model and its predecessor (the in-drift microbial communities model as documented in Chapter 4 of the TSPA-VA Technical Basis Document, CRWMS M and O 1998a) was developed to respond to the applicable KTIs. Additionally, because of the previous development of the in-drift microbial communities model as documented in Chapter 4 of the TSPA-VA Technical Basis Document (CRWMS M and O 1998a), the M and O was effectively able to resolve a previous KTI concern regarding the effects of microbial processes on seepage and flow (NRC 1998). This document supercedes the in-drift microbial communities model as documented in Chapter 4 of the TSPA-VA Technical Basis Document (CRWMS M and O 1998a). This document provides the conceptual framework of the revised in-drift microbial communities model to be used in subsequent performance assessment (PA) analyses