Electrostatic spray drying of microorganisms
The present disclosure relates to a process for electrostatic spray drying of a living microorganism, the process comprising the following steps: a. Providing a suspension, comprising a number of components, including a microorganism, a solvent and an additive; b. Applying an electrostatic charge to said suspension; c. Forming droplets of said suspension; d. Drying said droplets, thereby forming dried particles; and e. (Optionally) collecting the dried particles.
1 . A process for electrostatic spray drying of a living microorganism, the process comprising:
applying an electrostatic charge to a suspension comprising a live microorganism, a solvent, and an additive, wherein the suspension comprises at least 35% by weight water;
forming droplets of said suspension;
drying said droplets, thereby forming dried particles; and
collecting the dried particles;
wherein the solvent has a higher dielectric constant than the additive, and the additive has a higher dielectric constant than the microorganism.
2 . The process according to claim 1 , wherein the electrostatic charge is applied by an electrode in contact with said suspension, wherein said electrode has an electric potential difference, with respect to ground, below about 40 kV.
3 . The process according to claim 2 , wherein the electric potential difference, with respect to ground, of the electrode varies over time.
4 . The process according to claim 1 , wherein the microorganism comprises facultative anaerobic bacteria or strict anaerobic bacteria.
5 . The process according to claim 1 , wherein forming droplets is carried with a two-fluid nozzle.
6 . The process according to claim 1 , wherein forming droplets is carried out with an atomizing gas selected from one or more of an inert gas, a noble gas, and an alkane gas.
7 . The process according to claim 1 , wherein the suspension comprises as at least 40% by weight water.
8 . The process according to claim 1 , wherein the additive comprises a drying protectant.
9 . The process according to claim 8 , wherein the dried particle comprises the drying protectant in an amount from about 50% by weight to about 90% by weight.
10 . The process according to claim 8 , wherein the additive comprises a drying protectant comprising one or more selected from cyclitols, monosaccharides, disaccharides, polysaccharides, magnesium stearate, peptides, proteins, sugar alcohols, hydrogenated starch hydrolysates, fatty acid esters, and alginates and salts thereof.
11 . The process according to claim 8 , wherein the additive comprises a drying protectant comprising one or more selected from inositol, dextrose, lactose, sucrose, trehalose, inulin, maltodextrin, starch, magnesium stearate, mannitol, sorbitol, and sodium alginate.
12 . The process according to claim 8 , wherein the dried particle comprises the drying protectant in an amount from about 50% by weight to about 75% by weight.
13 . The process according to claim 1 , wherein the dried particles have a size from about 10 micrometers to about 200 micrometers, measured as Dv50 values.
14 . The process according to claim 1 , wherein the size distribution of the dried particles is substantially unimodal.
15 . The process according to claim 1 , wherein the dried particles comprise a microorganism having a viability of at least 1.0×10E4 per gram, as determined by one or more of the most probable number (MPN), the number of colony forming units (CFU), and the number of viable cells as measured by flow cytometry.
16 . The process according to claim 1 , wherein the electrostatic charge is applied by an electrode in contact with said suspension, wherein said electrode has an electric potential difference, with respect to ground, below about 25 kV.
17 . The process according to claim 1 , wherein the electrostatic charge is applied by an electrode in contact with said suspension, wherein said electrode has an electric potential difference, with respect to ground, below about 10 kV.
18 . The process according to claim 1 , wherein the suspension comprises at least 50% by weight water.
19 . The process according to claim 1 , wherein the suspension comprises at least 70% by weight water.
20 . The process according to claim 1 , wherein the dried particles have a size from about 50 micrometers to about 200 micrometers, measured as Dv50 values.
21 . The process according to claim 1 , wherein the dried particles have a size from about 100 micrometers to about 200 micrometers, measured as Dv50 values.