Thermal Biosensors in Biotechnology - Advances in Biochemical Engineering Biotechnology - page 43

Fig.4. Purification of arginase via FPLC and ET analysis
AMP-sepharose suspension to the LDH solution. Both examples, arginase and
lactate dehydrogenase monitoring,might be attractive in industrial scale purifi-
cation of enzymes.
Due to their limited stability,the use of immobilized enzymes might be pro-
blematic for monitoring enzyme production (e.g.,urease for arginase monitor-
ing).Optical methods which do not need immobilized biocompounds should be
more profitable in long-term procedures. Nevertheless, special dyes or sub-
strates with varying optical characteristics after an enzymatic conversion must
have at one's disposal.
On-line-monitoring of enzyme production during industrial fermentation
processes are problematic because sampling probes are still not adequate for
long-term use. In particular, clogging falsifies the real enzyme activity. More-
over, a lot of enzymes are produced intracellularly and complicate a simple
monitoring procedure. Therefore, this kind of monitoring is still under devel-
opment.
3.4
Process Monitoring
The ET has been employed in several biotechnological processes. This section
focuses on selected experiments shown in Table 5.
Mattiasson et al. (1983) used the ET for monitoring and control of a cultiva-
tion of immobilized Saccharomyces cerevisiae . Here, sucrose and ethanol were
monitored on-line,and the data were used for computer-controlled sucrose feed.