title: Control of cell morphology of probiotic Lactobacillus acidophilus for enhanced cell stability during industrial processing.
abstract: The viability of bacteria during industrial processing is an essential quality criterion for bacterial preparations, such as probiotics and starter cultures. Therefore, producing stable microbial cultures during proliferation is of great interest. A strong correlation between the culture medium and cellular morphology was observed for the lactic acid bacterium Lactobacillus acidophilus NCFM, which is commonly used in the dairy industry as a probiotic supplement and as a starter culture. The cell shapes ranged from single short rods to long filamentous rods. The culture medium composition could control this phenomenon of pleomorphism, especially the use of peptone in combination with an adequate heating of the medium during preparation. Furthermore, we observed a correlation between the cell size and stability of the microorganisms during industrial processing steps, such as freeze-drying, extrusion encapsulation and storage following dried preparations. The results revealed that short cells are more stable than long cells during each of the industrially relevant processing steps. As demonstrated for L. acidophilus NCFM, the adaptation of the medium composition and optimized medium preparation offer the possibility to increase the concentration of viable cells during up- and survival rate during down-stream processing.
authors.affiliation: Berlin University of Technology, Department of Applied and Molecular Microbiology, Berlin, Germany; Research and Teaching Institute for Brewing in Berlin, Research Institute for Special Microbiology, Berlin, Germany. Electronic address: martin.senz@tu-berlin.de.
authors.forename: Martin
authors.initials: M
authors.lastname: Senz
authors.affiliation: General Mills, Inc., Minneapolis, USA.
authors.forename: Bernhard
authors.initials: B
authors.lastname: van Lengerich
authors.affiliation: Beuth University of Applied Sciences, Department of Biotechnology, Berlin, Germany.
authors.forename: Johannes
authors.initials: J
authors.lastname: Bader
authors.affiliation: Berlin University of Technology, Department of Applied and Molecular Microbiology, Berlin, Germany; Research and Teaching Institute for Brewing in Berlin, Research Institute for Special Microbiology, Berlin, Germany.
authors.forename: Ulf
authors.initials: U
authors.lastname: Stahl
mesh_terms: D048430:Cell Shape / Q000502:physiology; D002470:Cell Survival; D003470:Culture Media; D005511:Food Handling; D007779:Lactobacillus acidophilus / Q000166:cytology*; D019936:Probiotics
chemical_list: D003470:Culture Media
keywords: Cell stability; Extrusion encapsulation; Lactobacillus acidophilus NCFM; Maillard reaction products; Medium composition; Morphology