Microbial Metabolite Export

Microbial metabolite export is an essential issue in industrial biotechnology. The reason is simple: otherwise, the development of advanced engineered strains might fail. Export belongs to the entire reaction sequence of substrate uptake and conversion to the valuable product finally accumulating in the medium. The relevance of export is probably best studied in the case of amino acid production with Escherichia coli or Corynebacterium glutamicum where specific exporters, when deleted, prevent amino acid production, or when overexpressed, increase amino acid production. However, antibiotic production also relies on exporters as the final step in cellular synthesis of these important metabolites. Another area where the importance of exporters is assessed is the use of whole cells for bioconversions occurring in organic solvents. This review covers these areas, gives a tabular overview on exporters recognized in biotechnology and describes also the varied methodology of exporter identification. Keywords: export; l-cysteine; exporter isolation; l-glutamate; antibiotica; efflux; toxic compounds