Michiel Kleerebezem

Discovering lactic acid bacteria by genomics

This review summarizes a collection of lactic acid bacteria that are now undergoing genomic sequencing and analysis. Summaries are presented on twenty different species, with each overview discussing the organisms fundamental and practical significance, nvironmental habitat, and its role in fermentation, bioprocessing, or probiotics. For those projects where genome sequence data were available by March 2002, summaries include a listing of key statistics and interesting genomic features. These efforts will revolutionize our molecular view of Gram–positive bacteria, as up to 15 genomes from the low GC content lactic acid bacteria are expected to be available in the public domain by the end of 2003. Our collective view of the lactic acid bacteria will be fundamentally changed as we rediscover the relationships and capabilities of these organisms through genomics.

Control of Folate Production in Lactic Acid Bacteria by Using Metabolic Engineering

Folates are essential components in the human diet. They are involved as cofactor in many metabolic reactions, including the biosynthesis of nucleotides, the building blocks of DNA and RNA. Folates are produced in different (green) plants (folium (Latin) = leaf) and by some micro-organisms. Therefore, vegetables and dairy products are the main source of folates for humans. The daily recommended intake for an adult is 200 µg. For pregnant women a double dose is recommended, since folates are known to prevent neural-tube defect in newborns (1). Moreover, folates are reported to protect against some forms of cancer (2). A low folate level in the diet is associated with high homocysteine levels in the blood and, consequently with coronary diseases (3, 4).