The complete genome of Propionibacterium freudenreichii CIRM 1 a hardy actinobacteria with food and probiotic applications

Propionibacterium freudenreichii is essential as ripening culture in Swiss-type cheese manufacture and is also considered for its probiotic use. The type strain of this species, P. freudenreichii subsp shermanii CIRM 1 (CIP 103027 or ATCC 9614), was sequenced using a whole genome shotgun strategy. The whole genome was sequenced with an elevenfold coverage. The circular chromosome of 2.7 Mb has a GC-content of 67 % and contains 34 loci corresponding to integrase sequences. IS sequences cover 3.5 % of the genome. The automatic and manual annotation, based on homology and conserved domain research has been done for the complete genome. The annotation revealed (1) the genetic basis of hardiness: sequences involved in immunity against phages, genes belonging to metabolism of different carbon and nitrogen sources, genes encoding enzymes of the vitamins and amino acids synthesis, genes involved in the management of polyphosphate and glycogen storage, several copies of chaperones, genes encoding proteins coping with oxidative stresses (2) genes responsible for aroma compound synthesis: Wood-Werkman pathway forming propionic and acetic acids, esterase/lipase involved in the formation of free fatty acids and esters, pathways of branched chain amino acids degradation resulting in the formation of branched chain volatile fatty acids (3) genes potentially involved in probiotic activity: complete biosynthesis pathway for the bifidogenic compound, a high number of surface proteins present in other probiotic bacteria and involved in the interaction with the host. The perspectives opened by post genomic research for cheese technology and health applications of P. freudenreichii will be discussed.