Novel In Situ Spectro-Electrochemical Methods for Newer Insights on Enzymatic Reaction Centers

Galacto-oligosaccharides (GOS) are prebiotics that have a beneficial effect on human health by promoting the growth of probiotic bacteria in the gut. GOS are commonly produced from lactose in an enzymatic reaction catalysed by β-galactosidase, named transglycosylation. Lactose is the main constituent of whey permeate (WP), normally wasted output from the cheese industry. Therefore, the main goal of this work was to optimise the synthesis of GOS in WP using β-galatosidase from Aspergillus oryzaea. WP and whey permeate enzymatically treated (WP-GOS) were used as culture media of Lactobacillus plantarum 299v. Lb. plantarum 299v attained the stationary phase in approximately 16 h, reaching 3·6 and 4·1×108 CFU/ml in WP and WP-GOS, respectively. The in situ synthesised GOS were not consumed during growth. No significant differences were observed in the growth kinetics of microorganisms in both media. After fermentation, microorganisms were dehydrated by freeze-drying and spray-drying and stored. The recovery of microorganisms after fermentation, dehydration and storage at 4 °C for at least 120 d was above 108 CFU/g. These studies demonstrated that WP is an appropriate substrate for the synthesis of GOS and the obtained product is also adequate as culture medium of Lb. plantarum 299v. The coexistence of GOS and dehydrated viable probiotic microorganisms, prepared using an effluent as raw material, represents the main achievement of this work, with potential impact in the development of functional foods.

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Analytical Investigation of Fuel Cells by Using In Situ and Ex Situ Diagnostic Methods

Materials Science Forum ◽

10.4028/www.scientific.net/msf.638-642.1125 ◽

2010 ◽

Vol 638-642 ◽

pp. 1125-1130

Author(s):

Günter Schiller ◽

Erich Gülzow ◽

Mathias Schulze ◽

Norbert Wagner ◽

K. Andreas Friedrich

Keyword(s):

Fuel Cells ◽

Current Density ◽

Printed Circuit Boards ◽

Analytical Investigation ◽

Diagnostic Methods ◽

Electrochemical Methods ◽

Measuring System ◽

Ex Situ ◽

German Aerospace

The study of the behaviour of fuel cells by using various in-situ and ex-situ diagnostic methods is a main topic at the German Aerospace Center (DLR). The degradation of cell components of polymer electrolyte fuel cells (PEFC, DMFC) and of solid oxide fuel cells (SOFC) are of special interest. For this purpose physical and electrochemical methods are used individually as well as in combination. In addition to routinely applied electrochemical methods different methods for locally resolved current density measurements by means of segmented cell technology and integrated temperature sensors have been developed. The latest development with segmented bipolar plates based on printed circuit boards (PCB) is used both in single PEFC cells and stacks. Furthermore, a measuring system for segmented SOFC cells has been developed allowing for the spatially resolved characterisation of cells in terms of current density/voltage characteristics, impedance spectroscopy data, operating temperature and gas composition. The paper summarises the capabilities at DLR with respect to the analysis of fuel cells’ behaviour and gives examples of analytical studies to discuss the potentials and limitations of the diagnostic methodology that is applied.

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Novel chitosan derivative soluble at neutral pH and in-situ gellable via peroxidase-catalyzed enzymatic reaction

Journal of Materials Chemistry ◽

10.1039/b812086b ◽

2009 ◽

Vol 19 (2) ◽

pp. 230-235 ◽

Cited By ~ 84

Author(s):

Shinji Sakai ◽

Yusuke Yamada ◽

Takashi Zenke ◽

Koei Kawakami

Keyword(s):

Enzymatic Reaction ◽

Chitosan Derivative ◽

Neutral Ph

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Novel Multifunctional Porous Liquid Composite for Recyclable Sequestration, Storage and In-situ Catalytic Conversion of Carbon Dioxide

10.26434/chemrxiv.12562391.v1 ◽

2020 ◽

Author(s):

Archita Bhattacharjee ◽

Raj Kumar ◽

KAMENDRA SHARMA

Keyword(s):

Carbon Dioxide ◽

Light And Electron Microscopy ◽

Enzymatic Reaction ◽

Catalytic Conversion ◽

Porous Solids ◽

X Ray Diffraction ◽

Hollow Silica ◽

Polymer Surfactant ◽

Silica Nanorods

<div><b>Novel Multifunctional Porous Liquid Composite for Recyclable Sequestration, Storage and In-situ Catalytic Conversion of Carbon Dioxide</b> <br></div><div><br></div><div>Archita Bhattacharjee, Raj Kumar and Prof. K. P. Sharma* Department of Chemistry, IIT Bombay, Powai, India <br></div><div>* E-mail: [email protected] <br></div><div><br></div><div>Keywords: Porous liquid composite, mesoporous liquid, hollow silica nanorods, CO<sub>2</sub> capture, CO<sub>2</sub> catalytic conversion<br></div><div><br></div><div>Abstract: Permanent pores combined with fluidity renders flow processability to porous liquids otherwise not seen in porous solids. Although, sequestration of different gases has recently been shown in porous liquids, there is still adearth of studies for deploying in-situ chemical reactionsto convert adsorbed gases into utility chemicals in this phase. Here, a facile method for the design and development of a new class of solvent-less porous liquid composite which, as shown for the first time, can catalyze the conversion of adsorbed gaseous molecules into industrially relevant product, is shown. The recyclable porous liquid composite comprising polymer-surfactant modified hollow silica nanorods and carbonic anhydrase enzyme not onlysequesters (5.5 ccg<sup>-1</sup> at 273 K and 1 atm) and stores CO<sub>2</sub>,but is also capable of driving an in-situ enzymatic reaction for hydration of CO<sub>2</sub> to HCO<sub>3</sub><sup>-</sup> ion, subsequently converting it CaCO<sub>3</sub> due to reaction with pre-dissolved Ca<sup>2+</sup>. Light and electron microscopy combined with x-ray diffraction reveals the nucleation and growth of calcite and aragonite crystals. Moreover, the liquid-like property of the porous composite material can be harnessed by executing the same reaction via diffusion ofcomplimentary Ca<sup>2+</sup> and HCO<sub>3</sub><sup>-</sup> ions through different compartments separated by an interfacial channel.<br></div><div></div>

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Corrosion behavior of nickel-based 718 alloy determined by in situ electrochemical methods at different partial pressures of H2S in 25 wt% NaCl solution at 150 °C

Rare Metals ◽

10.1007/s12598-019-01303-5 ◽

2019 ◽

Vol 38 (9) ◽

pp. 855-863 ◽

Cited By ~ 2

Author(s):

Yu-Bi Zhang ◽

Xiao-Liang Yang ◽

An Tang

Keyword(s):

Corrosion Behavior ◽

Electrochemical Methods ◽

Nacl Solution ◽

Partial Pressures

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Hollow zeolite microspheres as a nest for enzymes: a new route to hybrid heterogeneous catalysts for chemo-enzymatic cascade reactions

10.26434/chemrxiv.7796648 ◽

2019 ◽

Author(s):

Valentin Smeets ◽

Walid Baaziz ◽

Ovidiu Ersen ◽

Eric M. Gaigneaux ◽

Cédric Boissière ◽

...

Keyword(s):

Heterogeneous Catalysts ◽

Enzymatic Reaction ◽

Building Blocks ◽

Cascade Reactions ◽

Allylic Alcohol ◽

Zeolite Catalysts ◽

Enzyme Loading ◽

Aerosol Process ◽

Enzymatic Systems

<div> <p>Integrating enzymatic and heterogeneous catalysis can pave the way to new and performing cascade chemical processes. In this perspective, the preparation of bifunctional structures combining both an active inorganic catalyst and an enzyme is a key. However, such combinations are not straightforward, for example in the case of zeolite catalysts for which enzyme immobilization would be restricted to the external surface. We overcame this challenge by developing a new kind of hybrid catalysts based on hollow zeolite microspheres. The method leverages on the aerosol-assisted assembly of TS-1 nanocrystals to form hollow zeolite microspheres with tailored hierarchical texture and high epoxidation activity in water. The latter spheres were subsequently loaded with glucose oxidase enzymes which were then cross-linked to secure their entrapment. This controlled design allows to combine all the decisive features of the zeolite with a high enzyme loading. A chemo-enzymatic reaction is demonstrated, where the structured zeolite microsphere is used both as a nest for the enzyme and as an efficient inorganic heterogeneous catalyst. The enzyme ensures the <i>in situ</i> production of H<sub>2</sub>O<sub>2</sub> subsequently utilized by the zeolite for the epoxidation of allylic alcohol. We anticipate our method will open up new perspectives in the field of hybrid catalysis. Starting from various catalytic nano-building blocks, hollow microspheres with open entry ways could be prepared using the aerosol process and could be used as vessels for enzymes or even multi-enzymatic systems, thereby giving access to a multitude of new heterogeneous chemo-biocatalysts. <br></p> </div>

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