Propionibacterium freudenreichii subsp. shermanii CIRM-BIA1

All members of the genus Propionibacterium produce propionic acid as a major metabolic end-product; however they are divided into 2 groups, a cutaneous group (which can cause acne) and a dairy group used in cheese production. P.freudenreichii has been long used in Emmental-type cheese ripening, where it drives fermentation of lactate into propionate, acetate and CO(2), resulting in holes. It also plays a role in flavor development of these cheeses. P.freudenreichii are also used in the production of vitamin B12, and strains that overproduce this vitamin have been developed. Additionally as a producer of bifidogenic compounds it stimulates growth of bifidobacteria, which are beneficial to humans. The genome sequence of strain CIRM-BIA1 (other synonyms DSM 4902 / NCIB 8099 / VPI 0405) has 22 insertion sequences, 72 different transposases and a few prophages. No pathogenicity factors from the related acne-causing P.acnes were detected in P.freundenreichii. It is able to synthesize all amino acids and nucleotides, and all vitamins except pantothenate and biotin; while the thiamine pathway seems complete this bacteria requires thiamine for growth. This bacteria grows only poorly in milk, and grows in cheese mainly due to its ability to ferment lactic acid anaerobically. It can survive the cheese cooking step (heating to 54 degrees Celsius for about 30 minutes) in a strain dependent fashion (adapted from PMID 20668525). (HAMAP: PROFC)