scholarly journals Continuous Production of Galacto-Oligosaccharides by an Enzyme Membrane Reactor Utilizing Free Enzymes

Membranes ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 203
Author(s):  
Teng Cao ◽  
Melinda Pázmándi ◽  
Ildikó Galambos ◽  
Zoltán Kovács
Keyword(s):  
Enzyme Preparation ◽  
Continuous Production ◽  
Extended Period ◽  
Degree Of Polymerization ◽  
Enzyme Inactivation ◽  
Membrane Reactors ◽  
Feed Concentration ◽  
Total Carbohydrate ◽  
Significant Deterioration ◽  
Recirculation Flow

Galacto-oligosaccharides (GOS) are prebiotic compounds widely used for their health-promoting effects. Conventionally, GOS is produced by the enzymatic conversion of lactose in stirred tank reactors (STR). The high operational costs associated with enzyme inactivation and removal might be reduced by the application of enzyme membrane reactors (EMR). In this study, we aimed to assess the potential of continuous GOS production by EMR using soluble Biolacta N5, a Bacillus circulans-derived commercial enzyme preparation. The steady-state performance of the EMR equipped with an ultrafiltration module was investigated as function of residence time (1.1–2.8 h) and enzyme load (17–190 U·g−1) under fixed operational settings of temperature (50 °C), pH (6.0), lactose feed concentration (300 g·kg−1), and recirculation flow-rate (0.18 m3·h−1). Results indicate that the yield of oligosaccharides with higher degree of polymerization (DP3-6) in STR (approx. 38% on total carbohydrate basis) exceeds that measured in EMR (ranging from 24% to 33%). However, a stable catalytic performance without a significant deterioration in product quality was observed when operating the EMR for an extended period of time (>120 h). Approx. 1.4 kg of DP3-6 was produced per one gram of crude enzyme preparation over the long-term campaigns, indicating that EMR efficiently recovers enzyme activity.

Commercial cellulases from Trichoderma longibrachiatum enable a large-scale production of chito-oligosaccharides

2016 ◽  
Vol 88 (9) ◽  
pp. 865-872 ◽  
Author(s):  
Gregor Tegl ◽  
Christoph Öhlknecht ◽  
Robert Vielnascher ◽  
Paul Kosma ◽  
Andreas Hofinger-Horvath ◽  
...  
Keyword(s):  
Large Scale ◽  
Enzyme Preparation ◽  
Biological Activities ◽  
Low Cost ◽  
Degree Of Polymerization ◽  
Scale Production ◽  
Product Analysis ◽  
Trichoderma Longibrachiatum ◽  
Large Scale Production ◽  
Enzyme Source

AbstractChito-oligosaccharides (COSs) are a substance class of high interest due to various beneficial bioactive properties. However, detailed mechanistic and application-related investigations are limited due to the poor availability of COSs with defined structural properties. Here, we present the large-scale production of COSs with defined degree of N-acetylation using a commercial cellulase preparation from Trichoderma longibrachiatum. The enzyme preparation was found to exclusively produce COSs lacking of acetyl groups while MS/MS analysis indicated a cellobiohydrolase to be the responsible for hydrolysis with the enzyme preparation. MS and NMR analysis proved the low content of acetyl groups in the COS mix and oligomers with a degree of polymerization (DP) of 2–6 were obtained. The low cost enzyme source was further exploited for large-scale production in a 20 g batch and resulted a COSs yield of 40%. An inexpensive enzyme source for the production of bioactive COSs was successfully implemented and thorough product analysis resulted in well-defined COSs. This strategy could improve the access to this substance class for a more detailed investigation of its various biological activities.

scholarly journals The β-d-xylosidase of Trichoderma reesei is a multifunctional β-d-xylan xylohydrolase

1997 ◽  
Vol 321 (2) ◽  
pp. 375-381 ◽  
Author(s):  
Michael C. HERRMANN ◽  
Maria VRSANSKA ◽  
Milada JURICKOVA ◽  
Jan HIRSCH ◽  
Peter BIELY ◽  
...  
Keyword(s):  
Trichoderma Reesei ◽  
Chain Length ◽  
Enzyme Preparation ◽  
Beech Wood ◽  
Temperature Stability ◽  
Degree Of Polymerization ◽  
Active Enzyme ◽  
Optimal Activity ◽  
High Concentrations ◽  
C 30

An extracellular multifunctional α-d-xylan xylohydrolase, previously described as α-xylosidase, was purified fromTrichoderma reesei RUT C-30 to physical homogeneity. The active enzyme was a 100 (ŷ5) kDa glycosylated monomer that exhibited a pI of 4.7. Its activity was optimal at pH 4 and it was stable between pH 3 and 6. Its temperature-stability was moderate (70% of activity remaining after 60 min at 50 ŶC) and optimal activity was observed at 60 ŶC. It is capable of hydrolysing α-1,4-xylo-oligosaccharides [degree of polymerization (DP) 2Ő7], the apparent Vmax increasing with increasing chain length. The enzyme also attacked debranched beech-wood (Lenzing) xylan and 4-O-methylglucuronoxylan, forming xylose as the only end product. The Km for xylan was 0.7 g/l. For this reason we consider the enzyme to be a α-d-xylan xylohydrolase. The enzyme also exhibits α-l-arabinofuranosidase activity on 4-nitrophenyl α-l-arabinofuranoside, and evidence is presented that this is not caused by an impurity in the enzyme preparation. The α-d-xylan xylohydrolase exhibits glycosyltransferase activity with xylo-oligosaccharides and at high concentrations of 4-nitrophenyl α-d-xylopyranoside (4-Nph-α-Xyl). The enzyme hydrolyses α-1, 4-linkages preferentially to α-1,3-linkages, and α-1,2-linked xylo-oligosaccharides are not hydrolysed at all. The enzyme liberates terminal α-1,4-xylopyranose residues linked to a 2-O-substituted xylopyranose residue, but not that linked to a 3-O-substituted xylopyranose residue. The enzyme does not attack methyl, methyl 1-thio-, benzyl or butyl 1-thio-α-d-xylopyranosides and 4-naphthyl, 2-naphthyl and phenyl α-d-xylopyranosides.

Continuous production of L-tert-leucine in series of two enzyme membrane reactors

1996 ◽  
Vol 14 (6) ◽  
pp. 291-297 ◽  
Author(s):  
U. Kragl ◽  
D. Vasic-Racki ◽  
C. Wandrey
Keyword(s):  
Continuous Production ◽  
Membrane Reactors ◽  
In Series

The influence of pH on the performance of a two-stage anaerobic treatment system: model prediction and validation

1994 ◽  
Vol 30 (8) ◽  
pp. 35-44 ◽  
Author(s):  
M. Romli ◽  
J. Keller ◽  
P. L. Lee ◽  
P. F. Greenfield
Keyword(s):  
Model Prediction ◽  
Anaerobic Treatment ◽  
Dynamic Responses ◽  
Treatment System ◽  
Shock Load ◽  
Feed Concentration ◽  
Two Stage ◽  
Significant Deterioration ◽  
Effluent Quality ◽  
Alkali Addition

The effect of lowering the pH of the acidification reactor on the overall performance of a two-stage anaerobic wastewater treatment system was determined both experimentally and through simulation of a dynamic structured model. The system operated at low pH was then subjected to a short-term step increase in feed concentration. The measured and the predicted dynamic responses of reactor variables to the shock load were evaluated. The result indicated that lowering the pH setpoint from 6.0 to 5.3 led to a reduction in the external alkali addition by 30% without any significant deterioration in the final effluent quality. The model prediction showed good agreement with the experimental results for most reactor variables. The dynamic response of the system to a concentration shock load indicated a decrease in effluent quality during the disturbance, but the system did recover quickly as soon as the shock load terminated. The comparison between the experimental and the simulation results demonstrated the feasibility of the model to be applied for reactor design and operational evaluation purposes.

The purification and properties of (1→4)-β-D-glucan cellobiohydrolase from Sclerotium rolfsii: substrate specificity and mode of action

1984 ◽  
Vol 62 (9) ◽  
pp. 920-926 ◽  
Author(s):  
Rajkumar V. Patil ◽  
Jai C. Sadana
Keyword(s):  
Sodium Dodecyl ◽  
Sclerotium Rolfsii ◽  
Degree Of Polymerization ◽  
Relative Mass ◽  
Cellulolytic Enzyme ◽  
Transferase Activity ◽  
Total Carbohydrate ◽  
Single Polypeptide Chain ◽  
Purification And Properties ◽  
Single Polypeptide

A cellulolytic enzyme which shows high activity towards H3PO4 – swollen cellulose, but no viscosity-lowering activity towards carboxymethylcellulose, has been purified from the culture filtrates of Sclerotium rolfsii. The purified enzyme is homogeneous in disc gel electrophoresis, with and without sodium dodecyl sulfate, and in analytical isoelectric focusing in polyacrylamide gel. The enzyme is a glycoprotein containing 7.0% total carbohydrate and has a relative mass of 41 500 and an isoelectric point of 4.32. The enzyme is composed of a single polypeptide chain and has no cystine or half-cystine residues. It is specific for β-D-(1→4)-linkage. The principal product from each of the substrate was cellobiose (93–96%); glucose was also detected (4–7%). The rate of cellodextrin hydrolysis increased as the degree of polymerization increased. The enzyme has been identified as (1→4)-β-D-glucan cellobiohydrolase. The enzyme does not show transglycosylase or transferase activity.

Application of FRAP and digitized fluorescence microscopy to problems in cell membrane dynamics

1988 ◽  
Vol 46 ◽  
pp. 118-119
Author(s):  
K. Jacobson ◽  
A. Ishihara ◽  
B. Holifield ◽  
F. Zhang
Keyword(s):  
Fluorescence Microscopy ◽  
Cell Biology ◽  
Extended Period ◽  
Dynamic Structure ◽  
Living Cells ◽  
Membrane Dynamics ◽  
Molecular Cell Biology ◽  
Image Averaging ◽  
Single Living Cells ◽  
Single Living

Our laboratory is concerned with understanding the dynamic structure of the plasma membrane with particular reference to the movement of membrane constituents during cell locomotion. In addition to the standard tools of molecular cell biology, we employ both fluorescence recovery after photo- bleaching (FRAP) and digitized fluorescence microscopy (DFM) to investigate individual cells. FRAP allows the measurement of translational mobility of membrane and cytoplasmic molecules in small regions of single, living cells. DFM is really a new form of light microscopy in that the distribution of individual classes of ions, molecules, and macromolecules can be followed in single, living cells. By employing fluorescent antibodies to defined antigens or fluorescent analogs of cellular constituents as well as ultrasensitive, electronic image detectors and video image averaging to improve signal to noise, fluorescent images of living cells can be acquired over an extended period without significant fading and loss of cell viability.

Role of the exosporial membrane in attachment and germination of C. sporogenes

1993 ◽  
Vol 51 ◽  
pp. 38-39
Author(s):  
B.J. Panessa-Warren ◽  
G.T. Tortora ◽  
J.B. Warren
Keyword(s):  
Enzymatic Degradation ◽  
Light Transmission ◽  
Extended Period ◽  
Growth Conditions ◽  
Clostridium Sporogenes ◽  
Radiation Chemical ◽  
Physical Trauma ◽  
Extended Contact ◽  
Cold Pressure

Some bacteria are capable of forming highly resistant spores when environmental conditions are not adequate for growth. Depending on the genus and species of the bacterium, these endospores are resistant in varying degrees to heat, cold, pressure, enzymatic degradation, ionizing radiation, chemical sterilants,physical trauma and organic solvents. The genus Clostridium, responsible for botulism poisoning, tetanus, gas gangrene and diarrhea in man, produces endospores which are highly resistant. Although some sporocides can kill Clostridial spores, the spores require extended contact with a sporocidal agent to achieve spore death. In most clinical situations, this extended period of treatment is not possible nor practical. This investigation examines Clostridium sporogenes endospores by light, transmission and scanning electron microscopy under various dormant and growth conditions, cataloging each stage in the germination and outgrowth process, and analyzing the role played by the exosporial membrane in the attachment and germination of the spore.

Passy-Muir Speaking Valve Use in a Children's Hospital: An Interdisciplinary Approach

2008 ◽  
Vol 18 (2) ◽  
pp. 76-86 ◽  
Author(s):  
Lauren Hofmann ◽  
Joseph Bolton ◽  
Susan Ferry
Keyword(s):  
Tracheostomy Tube ◽  
Pediatric Population ◽  
Interdisciplinary Approach ◽  
Extended Period ◽  
Speech Development ◽  
Tube Placement ◽  
Background Information ◽  
Speaking Valve ◽  
Children's Hospital ◽  
Children’S Hospital

Abstract At The Children's Hospital of Philadelphia (CHOP) we treat many children requiring tracheostomy tube placement. With potential for a tracheostomy tube to be in place for an extended period of time, these children may be at risk for long-term disruption to normal speech development. As such, speaking valves that restore more normal phonation are often key tools in the effort to restore speech and promote more typical language development in this population. However, successful use of speaking valves is frequently more challenging with infant and pediatric patients than with adult patients. The purpose of this article is to review background information related to speaking valves, the indications for one-way valve use, criteria for candidacy, and the benefits of using speaking valves in the pediatric population. This review will emphasize the importance of interdisciplinary collaboration from the perspectives of speech-language pathology and respiratory therapy. Along with the background information, we will present current practices and a case study to illustrate a safe and systematic approach to speaking valve implementation based upon our experiences.

Sign in / Sign up

Export Citation Format

Share Document