Novel process for producing lactobacillus rhamnosus

A process for the production of bacterial particles of Lactobacillus rhamnosus or a composition comprising bacterial particles of Lactobacillus rhamnosus, wherein the process comprises the steps of:

• (a) fermenting the Lactobacillus rhamnosus in a lactose-free, optionally milk-free, medium in a fermentor, and removing a fermentation broth from the fermentor, wherein the fermentation is carried out in the presence of ammonium;
• (b) applying shear to the fermentation broth and optionally concentrating the fermentation broth, wherein when concentrating the fermentation broth, optionally comprising the addition of one or more additives, optionally cryoprotectants and/or stabilizers, to said concentrated fermentation broth.

The process according to claim 1, wherein the fermentation is carried out in the presence of ammonium acetate and wherein the fermentation is carried out at a pH point, or the fermentation is directed towards an end pH point, that is equal to or more than pH 3.0, wherein the pH is controlled by addition of a titrant, wherein the titrant is selected from the group consisting of sodium hydroxide and potassium hydroxide.

The process according to claim 1, wherein the fermentation medium is a solution, suspension or dispersion, optionally an aqueous solution, suspension or dispersion, wherein optionally acetate is present as a disassociated or a non-disassociated ammonium acetate salt.

The process according to claim 1, wherein the fermentation medium has a volume of equal to or more than 50 liter.

The process according to claim 1, wherein step (b) comprises homogenization of an unconcentrated fermentation broth, wherein such homogenization is carried out at a rate in the range from more than 10000 rounds per minute (rpm) to equal to or less than 50000 rounds per minute (rpm), for a period in the range from equal to or more than 1 minute to less than 5 minutes.

The process according to claim 1, wherein a shear rate is applied in the range from equal to or more than 0.5 s−1, optionally from equal to or more than 1.0 s−1, optionally from equal to or more than 10 s−1, optionally from equal to or more than 100 s−1, optionally from equal to or more than 500 s−1, to equal to or less than 500000 s−1, optionally equal to or less than 100000 s−1, optionally equal to or less than 50000 s−1, optionally equal to or less than 10000 s−1, optionally equal to or less than 5000 s−1.

The process according to claim 1, wherein a shear stress is applied in the range from equal to or more than 1·10−9 Pascal, optionally from equal to or more than 1·10−8 Pascal, optionally from equal to or more than 1·10−7 Pascal, optionally from equal to or more than 1·10−6 Pascal, optionally from equal to or more than 1·10−5 Pascal, to equal to or less than 1·10−1 Pascal, optionally equal to or less than 1·10−2 Pascal, optionally equal to or less than 1·10−3 Pascal, optionally equal to or less than 1·10−4 Pascal.

The process according to claim 1, wherein the shear is applied by subjecting the fermentation broth to a homogenization and/or a centrifugation step.

The process according to claim 1, wherein the process comprises spray-drying or freeze-drying of a concentrated fermentation broth.

Lactobacillus rhamnosus bacterial particles or a composition comprising Lactobacillus rhamnosus bacterial particles, obtained or obtainable by the process according to claim 1.

Lactobacillus rhamnosus bacterial particles or compositions comprising Lactobacillus rhamnosus bacterial particles obtained by the method according to claim 1, wherein equal to or more than 90% w/w, optionally equal to or more than 95% w/w, optionally equal to or more than 99% w/w, optionally equal to or more than 99.5% w/w, optionally equal to or more than 99.9% w/w and optionally equal to or more than 100.0% w/w of the bacterial particles have a particle size, as determined by laser diffraction particle size analysis, of equal to or less than 8.0 micrometer, optionally equal to or less than 7.5 micrometer, optionally equal to or less than 7.0 micrometer, optionally equal to or less than 6.5 micrometer and optionally equal to or less than 6.0 micrometer, and the bacterial particles optionally have a cell viability, optionally viable cell count, of equal to or more than 2.00·1010 CFU/gram, optionally of equal to or more than 2.10·1010 CFU/gram, optionally of equal to or more than 1.50·1011 CFU/gram and optionally of equal to or more than 2.00·1011 CFU/gram.