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Microbial biosensors generally
offer an attractive alternative to the existing methods of water analysis. One
particular advantage of those systems is the ability to measure direct effects
on living cells, e.g., their respiratory activity and its alteration caused by
environmental pollutants. It is true that microbial sensors, often do not
provide the optimum solution for the determination of individual analytes when
compared to established physico-chemical analysis methods. However, these
biosensing devices are predestined for the summary determination of
environmentally relevant compounds and their complex effects, respectively. For
this reason, microbial sensors allow an integral evaluation of the degree of
environmental pollution including the interaction of various compounds.
Moreover, in some cases specific metabolic pathways in microorganisms are used,
resulting in the development of microbial sensors for the more selective
analysis for those compounds or pollutants, which cannot be measured by simple
enzyme reactions, e.g., the determination of aromatic compounds and heavy
metals.
Pharmacom has great interest of
developing microbiological biosensors on respiratory basis for the measurement
of the following environmentally relevant compounds: inorganic N-compounds,
heavy metals, organic xenobiotics and the estimation of sum parameters or
so-called complex parameters such as BOD, ADOC, N-BOD, and the inhibition of
nitrification
We intend to prototype a microbial system for the point-of-care and diagnostics
market. The microbial biosensor consists of a transducer in conjunction with
immobilized viable or non-viable microbial cells. Non-viable cells obtained
after permeabilization or whole cells containing periplasmic enzymes have mostly
been used as an economical substitute for enzymes. Viable cells make use of the
respiratory and metabolic functions of the cell, the analyte to be monitored
being either a substrate or an inhibitor of these processes.
Bioluminescence-based microbial biosensors can also be developed using
genetically engineered microorganisms constructed by fusing the lux gene with an
inducible gene promoter for toxicity and bioavailability testing. |