Isolation, Characterisation and Vitamin B12 Production Optimization of P. freudenreichii from Turkish Traditional Kars Gravyer

Abstract

In this study, nine differentPropionibacterium freudenreichiistrains were isolated from KarsGravyer produced by traditional methods in Turkey and identified by sequencing the16S–23Sintergenic region using species-specific primers. The isolated strains were ex-aminedin vitrofor the presence of theβ-galactosidase enzyme, autoaggregation ability,sensitivity against eight selected antibiotics and survivability under harsh conditions inorder to determine their potential probiotic properties. After probiotic potentials wereevaluated, an experimental design was made to optimize the production of vitamin B12in a 3 L glass bioreactorP. freudenreichiiNUV774. While all strains showed similar resis-tance (92–98%) to gastric juice (0.3% pepsin, pH 3.0), they showed resistance to intestinalfluid (0.1% pancreatin, 0.3% bile salt, pH 8.0) between 60% and 92%. It was determinedthat the viability after 3 and 6 h of incubation in 0.5% and 1% bile salt differed betweenstrains. All isolates exhibited resistance to ciprofloxacin, ampicillin, and trimethoprim–sulphamethoxazole; however, most were sensitive to ofloxacin. Overall,P. freudenreichiistrains showed resistance to the gastrointestinal tract, tolerance to pH 3.0, and high toleranceto bile salts. As a result of optimization, maximum vitamin B12 production was found to be156.8 mg/L. The optimum operating conditions were calculated astemperature = 36.9◦C,aeration = 2.430 vvm, and agitation = 159.120 rpm. Hence,P. freudenreichii,as future probi-otic strain candidates, will offer an alternative source toLactobacillus,BifidobacteriumandsomeBacillusspp. In addition, this study denoted that the alteration of the production ofactive vitamin B12 byP. freudenreichiioccurs in a strain-dependent manner.