scholarly journals A Minimally Invasive Microsensor Specially Designed for Simultaneous Dissolved Oxygen and pH Biofilm Profiling

Sensors ◽  
2019 ◽  
Vol 19 (21) ◽  
pp. 4747 ◽  
Author(s):  
Xavier Guimerà ◽  
Ana Moya ◽  
Antonio David Dorado ◽  
Xavi Illa ◽  
Rosa Villa ◽  
...  
Keyword(s):  
Minimally Invasive ◽  
Dissolved Oxygen ◽  
Ph Monitoring ◽  
Ph Sensing ◽  
Wide Ph Range ◽  
Ph Range ◽  
Biofilm Structure ◽  
Parallel Arrays ◽  
Ph Electrodes

A novel sensing device for simultaneous dissolved oxygen (DO) and pH monitoring specially designed for biofilm profiling is presented in this work. This device enabled the recording of instantaneous DO and pH dynamic profiles within biofilms, improving the tools available for the study and the characterization of biological systems. The microsensor consisted of two parallel arrays of microelectrodes. Microelectrodes used for DO sensing were bare gold electrodes, while microelectrodes used for pH sensing were platinum-based electrodes modified using electrodeposited iridium oxide. The device was fabricated with a polyimide (Kapton®) film of 127 µm as a substrate for minimizing the damage caused on the biofilm structure during its insertion. The electrodes were covered with a Nafion® layer to increase sensor stability and repeatability and to avoid electrode surface fouling. DO microelectrodes showed a linear response in the range 0–8 mg L−1, a detection limit of 0.05 mg L−1, and a sensitivity of 2.06 nA L mg−1. pH electrodes showed a linear super-Nernstian response (74.2 ± 0.7 mV/pH unit) in a wide pH range (pH 4−9). The multi-analyte sensor array was validated in a flat plate bioreactor where simultaneous and instantaneous pH and DO profiles within a sulfide oxidizing biofilm were recorded. The electrodes spatial resolution, the monitoring sensitivity, and the minimally invasive features exhibited by the proposed microsensor improved biofilm monitoring performance, enabling the quantification of mass transfer resistances and the assessment of biological activity.

scholarly journals Biochemical Characterization of a New β-Agarase from Cellulophaga Algicola

2019 ◽  
Vol 20 (9) ◽  
pp. 2143 ◽  
Author(s):  
Han ◽  
Zhang ◽  
Yang
Keyword(s):  
Structural Model ◽  
Biochemical Characterization ◽  
Maximum Activity ◽  
Optimal Temperature ◽  
Salt Tolerant ◽  
Wide Ph Range ◽  
Specific Activities ◽  
Ph Range ◽  
Layer Chromatography

Cellulophaga algicola DSM 14237, isolated from the Eastern Antarctic coastal zone, was found to be able to hydrolyze several types of polysaccharide materials. In this study, a predicted β-agarase (CaAga1) from C. algicola was heterologously expressed in Escherichia coli. The purified recombinant CaAga1 showed specific activities of 29.39, 20.20, 14.12, and 8.99 U/mg toward agarose, pure agar, and crude agars from Gracilaria lemaneiformis and Porphyra haitanensis, respectively. CaAga1 exhibited an optimal temperature and pH of 40 oC and 7, respectively. CaAga1 was stable over a wide pH range from 4 to 11. The recombinant enzyme showed an unusual thermostability, that is, it was stable at temperature below or equal to 40oC and around 70 oC, but was thermolabile at about 50 oC. With the agarose as the substrate, the Km and Vmax values for CaAga1 were 1.19 mg/mL and 36.21 U/mg, respectively. The reducing reagent (dithiothreitol) enhanced the activity of CaAga1 by more than one fold. In addition, CaAga1 was salt-tolerant given that it retained approximately 70% of the maximum activity in the presence of 2 M NaCl. The thin layer chromatography results indicated that CaAga1 is an endo-type β-agarase and efficiently hydrolyzed agarose into neoagarotetraose (NA4) and neoagarohexaose (NA6). A structural model of CaAga1 in complex with neoagarooctaose (NA8) was built by homology modeling and explained the hydrolysis pattern of CaAga1.

Effect of speciation transformation on the coagulation behavior of Al13 and Al13 aggregates

2009 ◽  
Vol 59 (4) ◽  
pp. 815-822 ◽  
Author(s):  
Xiaohong Wu ◽  
Changqing Ye ◽  
Dongsheng Wang ◽  
Xiaopeng Ge ◽  
Hongxiao Tang
Keyword(s):  
Dominant Species ◽  
Chemical Interaction ◽  
Surface Adsorption ◽  
Surface Precipitation ◽  
Floc Size ◽  
Species Transformation ◽  
Wide Ph Range ◽  
Ph Range

Flocculation of kaolin suspension with aluminium fractal polycations was investigated as a function of aluminium concentration and pH. Aluminium flocculants included Al13 and Al13 aggregates with OH/Al ratio of 2.6 and 2.8, respectively. The flocculation kinetics and floc size distribution were monitored by light scattering. The characterization of flocculants showed that the tridecatmer Al13 and bridged [Al13]n with out-sphere structure were the dominant species for all flocculants in a wide pH range. The coagulation results indicated that the pre and in situ-formed [Al13]n play a key role in removing particles. With the increasing concentration of [Al13]n, coagulation mechanisms were transformed from charge-neutralization, electro-patch coagulation to bridge-aggregation. Moreover, sweep-flocculation was involved at higher dosage besides other three mechanisms when amorphous aluminium oxides formed. Hence, chemical interaction between particles and flocculants evolved from surface adsorption to surface precipitation for aluminium polycations by virtue of species transformation.

scholarly journals Characterization of an Alkaline Alginate Lyase with pH-Stable and Thermo-Tolerance Property

Marine Drugs ◽  
2019 ◽  
Vol 17 (5) ◽  
pp. 308 ◽  
Author(s):  
Yanan Wang ◽  
Xuehong Chen ◽  
Xiaolin Bi ◽  
Yining Ren ◽  
Qi Han ◽  
...  
Keyword(s):  
Marine Bacterium ◽  
Specific Activity ◽  
Alginate Lyase ◽  
Initial Activity ◽  
Alginate Oligosaccharides ◽  
Wide Ph Range ◽  
Encoding Gene ◽  
Ph Range ◽  
Alginate Lyases

Alginate oligosaccharides (AOS) show versatile bioactivities. Although various alginate lyases have been characterized, enzymes with special characteristics are still rare. In this study, a polysaccharide lyase family 7 (PL7) alginate lyase-encoding gene, aly08, was cloned from the marine bacterium Vibrio sp. SY01 and expressed in Escherichia coli. The purified alginate lyase Aly08, with a molecular weight of 35 kDa, showed a specific activity of 841 U/mg at its optimal pH (pH 8.35) and temperature (45 °C). Aly08 showed good pH-stability, as it remained more than 80% of its initial activity in a wide pH range (4.0–10.0). Aly08 was also a thermo-tolerant enzyme that recovered 70.8% of its initial activity following heat shock treatment for 5 min. This study also demonstrated that Aly08 is a polyG-preferred enzyme. Furthermore, Aly08 degraded alginates into disaccharides and trisaccharides in an endo-manner. Its thermo-tolerance and pH-stable properties make Aly08 a good candidate for further applications.

scholarly journals Purification and Characterization of Strong Simultaneous Enzyme Production of Protease and α-Amylase from an Extremophile-Bacillus sp. FW2 and Its Possibility in Food Waste Degradation

Fermentation ◽  
2021 ◽  
Vol 8 (1) ◽  
pp. 12
Author(s):  
Van Hong Thi Pham ◽  
Jaisoo Kim ◽  
Jeahong Shim ◽  
Soonwoong Chang ◽  
Woojin Chung
Keyword(s):  
Food Waste ◽  
Environmental Conditions ◽  
Enzyme Production ◽  
Molecular Weights ◽  
Sds Page ◽  
Metabolic Products ◽  
Wide Ph Range ◽  
Waste Degradation ◽  
Ph Range

Microbial enzymes such as protease and amylase are valuable enzymes with various applications, widely investigated for their applications in degradation of organic waste, biofuel industries, agricultural, pharmaceuticals, chemistry, and biotechnology. In particular, extremophiles play an important role in biorefinery due to their novel metabolic products such as high value catalytic enzymes that are active even under harsh environmental conditions. Due to their potentials and very broad activities, this study isolated, investigated, and characterized the protease- and amylase-producing bacterial strain FW2 that was isolated from food waste. Strain FW2 belongs to the genus Bacillus and was found to be closest to Bacillus amyloliquefaciens DSM 7T with a similarity of 99.86%. This strain was able to degrade organic compounds at temperatures from −6 °C to 75 °C (but weak at 80 °C) under a wide pH range (4.5–12) and high-salinity conditions up to 35% NaCl. Maximum enzyme production was obtained at 1200 ± 23.4 U/mL for protease and 2400 ± 45.8 U/mL for amylase for 4 days at pH 7–7.5, 40–45 °C, and 0–10% NaCl. SDS-PAGE analysis showed that the molecular weights of purified protease were 28 kDa and 44 kDa, corresponding to alkaline protease (AprM) and neutral protease (NprM), respectively, and molecular weight of α-amylase was 55 kDa. Degradation food waste was determined after 15 days, observing a 69% of volume decrease. A potential commercial extremozyme-producing bacteria such as strain FW2 may be a promising contributor to waste degradation under extreme environmental conditions.

scholarly journals Localization and partial characterization of thermostable glucoamylase produced by newly isolated Thermomyces lanuginosus TO3 in submerged fermentation

2008 ◽  
Vol 51 (4) ◽  
pp. 657-665 ◽  
Author(s):  
Aline Zorzetto Lopes Gonçalves ◽  
Ana Flávia Azevedo Carvalho ◽  
Roberto da Silva ◽  
Eleni Gomes
Keyword(s):  
Submerged Fermentation ◽  
Sole Carbon Source ◽  
Soluble Starch ◽  
Maximum Activity ◽  
Thermomyces Lanuginosus ◽  
Fermentation Time ◽  
Enzyme Productivity ◽  
Wide Ph Range ◽  
Ph Range

Thermophilic Thermomyces lanuginosus strain TO3 was isolated from compost pile samples and was used for its ability to produce considerable glucoamylase activity when growing in liquid medium at 45ºC with starch as the sole carbon source. Enzyme productivity was high in submerged fermentation (SmF) with maximum activity of 13 U/mL after 168 h of fermentation. Higher quantities of glucose were released when the substrate for enzyme was soluble starch than maltose or maltooligosaccharides were used. The distribution of glucoamylase between the extracellular and cell-associated fractions varied according to fermentation time. Glucoamylase produced from T. lanuginosus TO3 had optimum activity at 65 ºC and good thermostability in the absence of substrate, with a half-life of 6 h at 60 ºC. The enzyme was stable over a wide pH range (4.0-10.0).

Poly[1,3(2-ethoxy-4-hydroxy-5-propylphenylene)propylene] copolymer as an ion exchanger

1994 ◽  
Vol 6 (3) ◽  
pp. 201-208 ◽  
Author(s):  
Jayesh R Patel ◽  
Dipan H Sutaria ◽  
Magan N Patel
Keyword(s):  
Metal Ion ◽  
Metal Uptake ◽  
Polyphosphoric Acid ◽  
Average Molecular Weight ◽  
Acid Catalyst ◽  
Wide Ph Range ◽  
Metal Ion Uptake ◽  
Viscosity Study ◽  
Ph Range

The present paper reports the synthesis and characterization of a copolymer, The copolymer sample was synthesized by Friedel-Crafts polycondensation of 2-hydroxy-4 ethoxypropiophenone with 1,3-propane diol in the presence of polyphosphoric acid catalyst. The copolymer was characterized by elemental analysis, IR spectroscopy and viscosity study, and its number-average molecular weight (M) was determined by non-aqueous titration and found to be 2855 g mol- 1. Chelation ion-exchange properties have also been studied, employing a batch-equilibration method. It was employed to study selectivity of metal ion uptake over a wide pH range and in media of various ionic strengths. The overall rate of metal uptake follows the order UOl + > Fe3 + > Cu2 + > Ni2 +.

Preparation and Structural Characterization of Methylmercury(II) Complexes of 5-Aza- and 6-Azauracil Derivatives

1987 ◽  
Vol 42 (12) ◽  
pp. 1556-1562 ◽  
Author(s):  
W. S. Sheldrick ◽  
S. Heeb
Keyword(s):  
Structural Analysis ◽  
Binding Sites ◽  
Ionic Complex ◽  
X Ray ◽  
H Nmr ◽  
Ph Values ◽  
Nmr Data ◽  
Wide Ph Range ◽  
Ph Range

Abstract1:1 Methylmercury(II) complexes of the anti-tumour agent 6-azauracil (6AUH2) and its deriva­tives 6-azathymine (6ATH2). 1-methyl-6-azauracil (6AMUH) and 1-methyl-6-azathymine (6AMTH) have been isolated from aqueous solutions of CH3HgOH and the respective base. N3-Coordination was established by X-ray structural analysis for both [(CH3Hg)6 AUH] (1) (pH 6-8) and [(CH3Hg)6 AMT] (5) (pH 4-12); in addition 1H NMR data are in accordance with an identical binding site in the complexes [(CH3Hg)6AMU] (3) and [(CH3Hg)6 ATH] (4). Using an excess of CH3HgOH. 2:1 complexes with N1, N3-coordination may be prepared for both 6 AUH: and 5 AUH2 in a wide pH range (4-12 and 6-12 respectively). At pH values of 3-4 a 3:1 complex [(CH3Hg)35 AU]NO3 (7), with N1, N3, N5-coordination may be isolated: the binding sites were confirmed by X-ray structural analysis. In no case could an ionic complex with N6- coordination be isolated for a 6-azapyrimidine derivative. The binding preferences of the bases are discussed in the light of MNDO calculations.

scholarly journals Production, Characterization of Tannase fromPenicillium montanenseURM 6286 under SSF Using Agroindustrial Wastes, and Application in the Clarification of Grape Juice (Vitis viniferaL.)

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Juliana Silva de Lima ◽  
Roberta Cruz ◽  
Julyanna Cordoville Fonseca ◽  
Erika Valente de Medeiros ◽  
Marília de Holanda Cavalcanti Maciel ◽  
...  
Keyword(s):  
Tannic Acid ◽  
Enzyme Production ◽  
Grape Juice ◽  
Tannin Content ◽  
Crude Enzyme Extract ◽  
Agroindustrial Waste ◽  
Wide Ph Range ◽  
Ph Range ◽  
Agroindustrial Wastes

Tannase is an enzyme that hydrolyzes esters and lateral bonds of tannins, such as tannic acid, releasing glucose and gallic acid and stands out in the clarification of wines and juices. Fungi of the generaAspergillusandPenicilliumare excellent producers of this enzyme. The search for fungi that produce high levels of tannase as well as new substrates for the enzyme production by the SSF is required. The objectives of this study were to evaluate the production of tannase byAspergillusandPenicilliumspecies through SSF using leaves and agroindustrial waste barbados cherry and mangaba fruit as substrate, select the best producer, optimize production, characterize the crude enzyme extract, and apply it the clarification of grape juice. Selecting the best producer was performed by planning Placket-Burman and RSM.P. montanenseshowed highest activity with 41.64 U/mL after 72 h of fermentation residue using barbados cherry, with 3.5% tannic acid and 70% moisture. The enzyme showed the highest activity at pH 9.0 and 50°C. The tannase ofP. montanensewas stable over a wide pH range and temperature and, when applied to grape juice, showed higher efficiency by reducing 46% of the tannin content after incubation 120 m.

scholarly journals Production and characterization of cyclodextrin glycosyltransferase from Bacillus.sp isolated from Cuban Soil.

2014 ◽  
Author(s):  
Héctor Luis. Ramirez Pérez
Keyword(s):  
Kinetic Parameters ◽  
Initial Rate ◽  
Cyclodextrin Glycosyltransferase ◽  
Product Concentration ◽  
Wide Ph Range ◽  
Significant Yield ◽  
Influence Of Substrate ◽  
Ph Range ◽  
Cyclodextrin Production

A cyclodextrin glycosyltransferase (CGTase) from an alkaliphilic Bacillus.sp strain, isolated from Cuba soil, was purified with Sephadex G-50 with a yield of 66.5 %. The CGTase was stable over a very wide pH range, 6.0 –10, at 25°C and was most active at pH 7.5. The enzyme exhibited an optimum temperature of 60°C and was stable to 50°C for at least 8 h. The T50 value – defined as the temperature at which 50% of the initial activity was retained– was 63 °C in this enzyme . The influence of substrate or product concentration on the initial rate of CD production was studied and the kinetic parameters were determined. The analysis of kinetic parameters Km and Vmax was obtained by the action of CGTase on the starch of corn with respect to β-CD and the values were 4.1 g/L and 5,2 μM β-CD/min ml respectively.. The purified CGTase from Bacillus.sp could be used for an efficient cyclodextrin production which significant yield of γ-cyclodextrins.

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