Mannitol-enhanced survival of Lactococcus lactis subjected to drying

• Published in: Applied microbiology and biotechnology 1999-01, Vol.51 (1), p.100-104
• Main Authors: EFIUVWEVWERE, B. J. O, GORRIS, L. G. M, SMID, E. J, KETS, E. P. W
• Format: Article
• Language: English
• Subjects: Acidification; Agrotechnological Research Institute; Bacteria; Biological and medical sciences; Biotechnology; Drying; Fundamental and applied biological sciences. Psychology; Instituut voor Agrotechnologisch Onderzoek; Methods. Procedures. Technologies; Microbiology; Others; Survival; Various methods and equipments
• ISSN: 0175-7598; 1432-0614
• DOI: 10.1007/s002530051369

Survival of Lactococcus lactis subjected to different drying conditions was investigated. Mannitol most remarkably enhanced the survival of dried cells to a level almost equalling that of viable cells [log^sub 10^ (cfu ml^sup -1^)=9.42] as was found prior to the drying process (log^sub 10^=9.6). In the absence of mannitol, a survival was reduced by a factor of 10^sup 4^. Drying of cells at 20°C led to higher survival rates than drying at 30°C. Mannitol enhanced the survival rate at both temperatures, and at both 20°C and 30°C the highest reduction in survival occurred when cells were dried at a water activity of 0.76. In the presence of mannitol, differences in survival after drying at different water activities were less pronounced. Rehydration of cells dried in the presence of mannitol resulted in an extended lag phase of 4h compared to fresh cells. No growth or acidification of the culture medium was observed for 12h in the case of rehydrated cells dried in the absence of mannitol. It was hypothesized that a radical scavenging activity of mannitol could partly explain these observations.[PUBLICATION ABSTRACT]