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PHOTOCHEMICAL BIOSENSORS
No full textPhotochemical biosensors have been developed for immunoassay: (1)
Luminescent immunosensor, and (2) Electrochemical luminescent (ECL)
immunosensor. A luminescent immunosensor is based on enzyme-linked immunoassay
in which such a luminescence catalyzing enzyme as peroxidase
is used as label. An ECL immunosensor utilizes the inhibition of ECL
by antigen-antibody reaction
OPTICAL SENSORS FOR FERMENTATION PROCESSES
No full textIn spite of the great effort of chemical engineers today the on-line measurement
in fermentation processes is still limited to physical and chemical quantities.
The most important biological parameters, such as biomass, substrate,
product or metabolites are still not accessible to on-line measurements.
As a company strongly involved in the development and production of measurement
equipment for bioprocesses, Ingold Messtechnik AG started a few years
ago a research program directed to the development of on-line sensors for biological
parameters. For the following reasons an approach using the optical
measurement technology has been considered as the most promising one:
- The optical measurement technology has at least for laboratory use already
reached a very high and sophisticated standard. The future developments
of optical components such as semiconductor detectors or fiber optics will
certainly increase the versatility of this technique.
- There are many compounds of biological origin which can be directly measured
by optical methods (e.g. absorption, fluorescence attenuated total
reflection).
- The combination of optical methods with chemical mediator substances would
allow to measure also physical or chemical parameters such as pH or oxygen
concentration. The use of enzymes and/or fluorescence labelled antibodies
would allow to make this technique highly versatile
GLUCOSE SENSOR: Precision and Method Comparison; Data from 14 Laboratories
No full textThe glucose biosensor consists of the bicoloured test strip Haemoglucoquant
20-800 as a specific receptor and the RefloluxNII as a transducer unit.
Glucose oxidase and peroxidase are immobilized in the layers of the test strip
togehter with a selected chromogen to make possible reflectance measurements
at 950 nm
IMMOBILISIERTE SYSTEME FUR DIE HERSTELLUNG VON MILCHSÄURE
No full textPrinciples of cell immobilization and extractive bioconversion were introduced into the classical
process of lactic acid fermentation. Lactobacillus bulgaricus was used in a column reactor filled
with porous rings of sintered glass as carrier material. In continuous operation a volumetric
productivity of 8.7 g/I-h was obtained. Similar trials with Lactobacillus delbrickii adhering to
porous keramicsled to a productivity of up to 17 g/Ih. A flocculent Lactobacillus Species, newly
isolated from nature, was applied in a continuous upflow-tower reactor without any carrier
material. L(+)-lactic acid resulted from glucose and lactose with a productivity of 6.0 g/I-h and a
dilution rate of 2.0 hl. To eliminate product inhibition, basic data of an extractive bioconversion
of sugar to lactic acid were evaluated and a concept of continuous lactic acid production
including immobilized cells and extraction is presented
PROZESSLINIE ZUR HERSTELLUNG VON STARTERKULTUREN IN DER GBF
No full textStarter cultures are implemented in wide variety of applications such
as, e.g. in the pharmacy sector (intestinal flora). The main area of
applications does however lie in the sector of food preservation and
improvement.
The list of food stuffs produced with the aid of microorganisms is
long, extending from bakery, milk and raw meat products, alcoholic
drinks and sauerkraut production right through to east Asian soja and
rice products. These fermented food products have since time immemorial
played a significant role in human food consumption.
The desired characteristics of fermented food stuffs were previously
ranked as follows
- long storage life without refrigeration
- hygienic safety
- improved nutritional value
- preparation for immediate consumption
- flavour and aroma improvement
Today the characteristic pleasurable aspect of these food stuffs has a
high rank:
The various raw material qualities, fermentation technologies and
microbial performances are crucial for the formation of unique flavour
and aroma sensations, which, despite progressive standardization of
Production methods, can still be considered manifold. This also helps
explain the significant importance of fermented foods on the world
market despite the partial availability of other highly developed
preservation and processing methods
KONTINUIERLICHE SAUERTEIGFERMENTATION MIT EINER 2-STUFIGEN PILOTANLAGE
No full textThe mode of sour-dough fermentation is of great importance for the economics of bread
production in both small and industrial bakeries. Onestage fermentation processes,
which can be adapted to fit ideally the production coditions present in a small bakeries,
have been developed in recent years. A similar process suitable for the industrial
scale production of bread has not, as yet, been found because certain microbiological
principles, baking requirements and also the special production conditions
specific to bread-making in Germany all stand in the way of a simple solution. It
should be pointed out that industrial production requires daily within a limited period
large quantities of different types of sour-dough for baking a wide range of
breads. For this reason, the practice up till now, in all German factories, has been
to produce sour-dough in batches. A better solution to the problem is envisaged in a
continuous sour-dough fermentation process. For this purpose a pilot fermenter have
been built. The pilot fermenter is designed on the same principles as those of an
industrial plant. It consists of a fermentation tube and tank. The dough which comes
out of the first stage is led to a kneader in which it can be blended with various
ground products to obtain doughs of varied composition. In the second stage, these
doughs are then allowed to ripen to the required degree. Details of initial results
obtained are outlined. During the continuous operation of both stages of the pilot
plant, a sour-dough was produced with characteristics corresponding to those of sourdough
produced with a similar industrial plant. Thus the results of the trial operation
have established a standard procedure against which to compare all future fermentation
tests
TRINKWASSER-DENITRIFIKATION DURCH ALGINAT-FIXIERTE MIKROORGANISMEN IM PILOTMASSSTAB
No full textIn den vergangenen Jahren kam es durch die intensive Düngung von Agrarflächen zu einem stetigen Anstieg des Nitrates im Grundwasser. Zahlreiche Trinkwasserbrunnen mußten nach Überschreitung des zulässigen EGGrenzwertes stillgelegt werden oder können nur noch nach Verschneidung
mit unbelastetem Wasser genutzt werden.
Daher wurden in der Bundesrepublik Deutschland bereits beträchtliche
Anstrengungen unternommen, um wirtschaftliche Denitrifikationsverfahren zur Sanierung der Trinkwassergewinnung zu entwickeln.
Einige Hersteller erproben z. Zt. ihr jeweiliges Verfahren in Zusammenarbeit mit verschiedenen Wasserversorgern.
Schwerpunktmäßig konzentrierten sich diese Aktivitäten bei biologischen
Prozessen auf die Denitrifizierung unter Zuschlag von Wasserstoff,
Essigsäure oder Ethanol.
In Zusammenarbeit mit dem Institut für technische Chemie der TU Braunschweig und der GBF Braunschweig ist es gelungen, ein neuartiges biologisches Verfahren zu entwickeln. Die im Labormaßstab gewonnenen Erkenntnisse lassen erwarten, daß es durch den Einsatz polymerfixierter
Mikroorganismen in Wirbelbettreaktoren gelingt, den Anforderungen der
Praxis hinsichtlich Denitrifikationsleistung und hygienischer Unbedenklichkeit gerecht zu werden
BIOTECHNOLOGISCHE METHODEN IN DER JAPANISCHEN LEBENSMITTEL-INDUSTRIE
No full textStatistical data about food intake in Japan and the Japanese food industry exhibit
significant differences as compared to Western countries. The introduction of biotechnological
methods into the food-related industry in Japan is mediated mainly by the Ministry of Agriculture, Forestry and Fisheries (MAFF) and by "research associations" which are composed of
up to 50 companies. At present, such research associations are centered around the developmentof bioreactors and protein engineering techniques as applied to the food industry
LEBENSMITTELTECHNOLOGISCHE FORSCHUNGSAKTIVITÄTEN IM EG-BEREICH
No full textBisher gibt es im EG-Bereich kein eigenständiges Forschungsgebiet Lebensmitteltechnologie. Lebensmittelwissenschaftliche und -technologische Fragen konnten in verschiedenen
anderen Programmen, die bisher durchgeführt worden sind,
mitberücksichtigt werden, jedoch meist eher als Randgebiet.
Dies ist etwas erstaunlich, denn für den Zeitraum von 1987
bis 1991 sind für Forschungsaktivitäten ingesamt etwa
5,4 Milliarden Ecu vorgesehen, und Fragen im Zusammenhang
mit der Ernährung spielen bekanntlich eine nicht unerhebliche
Rolle.
Auf die Möglichkeiten in der Vergangenheit und die diesbezüglichen Einzelheiten sol] hier nicht weiter eingegangen werden,
vielmehr sollen 3 Komplexe beschrieben werden, die derzeit
noch laufende Projekte und zukünftige mögliche Forschungsprogramme etwas beschreiben. Es handelt sich um ein sogenanntes COST-Projekt, das unmittelbar lebensmitteltechnologischen
Fragen gewidmet ist und gegenwärtig noch läuft, weiterhin
um das vorgesehene FLAIR-Programm, das ebenfalls zentral
lebensmitteltechnologische Fragen zum Inhalt haben soll, und
schließlich das ECLAIR-Programm, das eher die biotechnologischen Möglichkeiten und deren Anwendung im landwirtschaftlichen Rahmen beinhaltet. Bei der Darstellung dieser Möglichkeiten soll insbesondere der wissenschaftliche Inhalt dargestellt werden, die administrativen Hintergründe können nur
angedeutet werden, da sie im allgemeinen auch recht kompliziert sind
THERMODYNAMIC AND KINETIC ASPECTS OF THE FOLDING AND SELFASSEMBLY OF PROTEINS
No full textThe acquisition of the spatial structure of proteins may be described as a
hierarchical condensation reaction. Starting from next-neighbor interac tions (involved in secondary structure formation), the native tertiary and
quaternary structure are generated by the merging and docking of domains
and subunits. The overall kinetics of the folding and assembly of multi subunit oligomeric proteins consist of consecutive unimolecular and bimo lecular steps which may be distinguished by concentration-dependent recon stitution experiments.
In order to reach the native state, both folding and association must be
tuned such that the formation of the correct subunit recognition sites
precedes association. Beyond a limiting concentration, "wrong aggregation”
(in vitro) or precipitation of "inclusion bodies" (in overexpressing
strains of bacteria) are found to outrun proper structure formation. Other
variables determining the yield and rate of in vitro reconstitution are the
temperature, pH, ionic strength and specific ligands. Apart from the physi co-chemical parameters, folding in vivo may be affected by codon usage,
amino-acid pools and genome organization