Genetic engineering of plants and microbial cells for flavour production

26.7 Conclusion: The introduction of new genes into microorganisms and plants has become more or less a routine. But as long as the regulation mechanisms of biosynthetic pathways are not thoroughly understood, increased levels of desired metabolites will only be achieved randomly by metabolic engineering. Although genome sequencing projects constantly provide a huge number of new genes, their primary functions remain unknown, even when they show high similarity with already characterised structural genes. Detailed biochemical analyses of the recombinant proteins and studies with transgenic lines, where the gene has been downregulated and/or upregulated, are essential. Nevertheless, the few examples presented here already demonstrate that genetic and metabolic engineering has been quite successful for the production of flavours and has great potential.