Make cheese without bacteria, and you'll wind up with bland curds, like those in packaged cottage cheese. To get the powerful zing of Roquefort or the nutty warmth of Gouda, you have to add the right starter organism to help ferment the milk. In fact, each of the endless varieties of cheese owes its distinctive taste to the bacteria it contains. The most common starter is Lactococcus lactis, and researchers from Gnoscope and the Institut National de la Recherche Agronomique have now sequenced its complete genome. Their report appears in the April issue of Genome Research.
This genome is the first from a large family of lactic acid bacteria to be mapped in full. Other related organisms include yogurt starters and pathogens such as Streptococcus pneumoniae. The genome includes 2.4 million nucleotides and encodes 2,310 genes. The scientists found that 363 of those genes were specific for lactococciand surprisingly, some genes indicate that the bacteria may very well be capable of performing aerobic respiration. This research is bound to get better with age, as cheesemakers use the new information to improve on the texture, taste and preservation of their products.