Microbial compositions
Provided herein are various microbial compositions and methods for preparing these compositions.
1 . A method for preparing a microbial composition comprising encapsulated microbial particulates, the method comprising:
atomizing a feed mixture comprising a gram-negative bacterium, a conductive carrier, and a solvent via an electrostatically charged nozzle to form a charged spray of the feed mixture wherein the conductive carrier and solvent migrate to an outer surface of the droplets and the conductive carrier at least partially encapsulates the gram-negative bacterium;
contacting the charged spray of the feed mixture with a drying fluid to remove at least a portion of the solvent from the charged droplets of the feed mixture and to form the encapsulated microbial particulates; and
recovering the encapsulated microbial particulates to form the microbial composition, wherein the composition has a gram-negative bacterium titer of at least about 1×10 4 colony-forming units per gram after about 180 days following preparation of the composition.
2 . The method of claim 1 , wherein the drying fluid comprises a nitrogen-containing gas or air.
3 . The method of claim 1 , wherein the drying fluid is at a temperature from about 50° C. to about 140° C., from about 50° C. to about 80° C., from about 70° C. to about 140° C., from about 80° C. to about 100° C., from about 100° C. to about 140° C. or from about 80° C. to about 90° C. prior to contact with the charged spray of the feed mixture.
4 . The method of claim 1 , wherein the feed mixture is atomized with an atomizing fluid at a temperature from about 25° C. to about 60° C., from about 40° C. to about 60° C., from about 40° C. to about 50° C., or from about 50° C. to about 60° C.
5 . The method of claim 1 , wherein the moisture content of the composition is no greater than about 5 wt. %, no greater than about 4 wt. %, no greater than about 3 wt. %, no greater than about 2 wt. %, or no greater than about 1 wt. %.
6 . The method of claim 1 , wherein the weight ratio of the carrier to the bacterium is at least about 2:1, at least about 5:1, at least about 10:1, at least about 25:1, or at least about 50:1.
7 . The method of claim 1 , wherein the carrier has a glass transition temperature in the range of from about 30° C. to about 120° C., from about 50° C. to about 120° C., from about 70° C. to about 120° C., from about 30° C. to about 100° C., from about 50° C. to about 100° C., from about 70° C. to about 100° C., from about 30° C. to about 80° C., from about 50° C. to about 80° C., or from about 70° C. to about 80° C.
8 . The method of claim 1 , wherein the carrier comprises a saccharide compound.
9 . The method of claim 8 , wherein the saccharide compound is a polysaccharide.
10 . The method of claim 9 , wherein the polysaccharide comprises maltodextrin.
11 . The method of claim 1 , wherein the gram-negative bacterium is a Methylobacterium or Methylorubrum.
12 . The method of claim 2 , wherein the heated drying fluid comprises a nitrogen-containing gas or air at a temperature of about 100° C. to about 140° C. prior to contact with the charged spray of the feed mixture.
13 . The method of claim 1 , wherein the gram-negative bacterium comprises a methanotroph and/or a methylotroph.
14 . The composition of claim 10 , wherein the maltodextrin has a dextrose equivalent of from about 13 to about 25.