Biomedical Engineering Reference
In-Depth Information
(4) many examples of diffi culties with heterologous gene expression
have lead to the implementation of codon optimisation (see for
example Tokuoka et al. 2008), but implementation in expression of
homologous may also be possible.
(5)
deletion of oxaloacetate hydrolase in order to prevent the formation
of oxalic acid (Novozymes; Pedersen et al. 2000).
The near future will bring extensive genome comparisons, microarray
and proteome analyses of production systems and deliver new leads for
targeted modifi cations (as described by Jacobs et al. 2010). Introducing
these leads and combining various mutations—including those induced
via classical mutagenesis and adaptive evolution—in to new production
strains has been facilitated by the availability of so-called Non-homologous
End-joining mutants (reviewed by Meyer 2008) and will offer unlimited
opportunities yet to be invention.
This Systems Biology approach is now also starting to have its impact
on fungal natural product production, wherein traditionally the focus was
more on process improvement in order to increase the product titers. As
such, the combination of strain improvement and fermentation protocols
led to the impressive 50,000-fold improvement in penicillin production.
These surveys include alternatives for submerged fermentations as bubble
columns (König et al. 1982) and the high-tech solid state fermenter, the
PlaFractor, developed by Biocon (Mazumdar-Shaw and Suryanarayan
2003). Also here, the fi rst results of omics technologies have been reported
for
P. chrysogenum
(van den Berg et al. 2008).
The availability of sophisticated expression systems, efficient
production facilities, genome sequences and new technologies as Synthetic
Biology will stimulate further development of fungal enzymes into highly
effi cient biocatalysts for the years to come.
FUNGAL FOOD ENZYMES
The use of enzymes in food production is known for a very long time,
e.g., malt fl our, containing amylase and minor amounts of protease,
in production of bread. During the last decennia these ancient uses of
enzymes have developed into more controlled application of enzymes
in food production processes, using specific and pure enzymes,
secreted during fermentation of bacteria, yeasts and fungi. Here, enzymes,
more specifi cally carbohydrases, lipases and proteases, derived from
fungi with known application benefits in food production will be
discussed.
