Assessement of preservation methods applied to dairy and cutaneous propionibacteria with industrial relevance

NEME SCHEIJ L.; PÉREZ CHAIA A. Y ZÁRATE, G.

San Miguel de Tucumán

Congreso; XXIX Annual Scientific Meeting of Tucumán Biology Society; 2013

Asociaciación de BIología de Tucumán

Propionibacteria are divided into ?dairy? and ?cutaneous? based on habitat and are used as cheese starters, nutraceutical producers and probiotics. Industrial application of microorganisms greatly relies on preservation methods that guarantee cultures with long term functionality. Our objective was to assess the effect of different preservation methods on viability and stability during storage of 2 dairy and cutaneous strains of propionibacteria. P. freudenreichii and P. avidum strains were harvested at stationary phase (1010 CFU/mL) and preserved by hypobiotic: storage under mineral oil and anabiotic methods: freezing at -20ºC and lyophilization with/without crioprotectors. Samples were stored during 9 months at 4ºC and the number of viable cells, re-activation in fresh medium and cellular damage (release of proteins, nucleic acids and β-gal) were determined at intervals. The strains survived to treatments and long-term storage. After 9 months, 104 CFU/mL and 109 CFU/g were recovered under the best conditions of hypobiotic and anabiotic methods respectively. Glycerol, DMSO and LEL were successful protectors and suspension media for propionibacteria preserved by freezing whereas glutamate and trehalose were the best protectors for lyophilized cells. The protectors assayed also prevented cell inactivation and damage caused by preservation.