ANTIBIOTIC FREE FERMENTATIONS, SYSTEMS AND METHODS FOR ACHIEVING ANTIBIOTIC FREE FERMENTATIONS, AND FERMENTATION BY-PRODUCTS GENERATED BY ANTIBIOTIC FREE FERMENTATIONS
Methods, compositions, and systems for antibiotic-free propagation and fermentation using hops and formic acid, particularly large-scale operations for production of a bioproduct are provided. Hops and formic acid are combined in amounts sufficient to minimize growth of contaminating bacteria.
1 . A method of ethanol fermentation comprising:
fermenting a feedstock with an ethanologen in the presence of formic acid and hop acids to produce ethanol and fermentation solids,
wherein the fermentation is antibiotic free.
2 . The method of claim 1 , wherein the ethanologen is a yeast or a bacterium.
3 . The method of claim 1 , wherein the feedstock is bacterially contaminated grain mash.
4 . The method of claim 1 , wherein the hop acids are present in a slurry tank, in a propagation tank, or a fermentation tank at a range of about 10 ppm to about 150 ppm, +/−20%.
5 . The method of claim 1 , wherein the hop acids are present in a slurry tank, in a propagation tank, or a fermentation tank at a range of about 20 ppm to about 30 ppm, +/−20%, or present at 16 ppm, 25 ppm, 84 ppm, or 125 ppm, +/−20%.
6 . The method of claim 1 , wherein the formic acid is present in a slurry tank, in a propagation tank, or a fermentation tank at a range of about 50 ppm to about 400 ppm, +/−20%, or present at 50 ppm, 60 ppm, 75 ppm, 100 ppm, 200 ppm, 300 ppm, or 400 ppm, +/−20%.
7 . The method of claim 1 , wherein the hop acids are added before the formic acid, after the formic acid, or together with the formic acid.
8 . The method of claim 1 , wherein the fermentation is a raw starch hydrolysis process.
9 . The method of claim 8 , wherein the hop acids are added to a propagator with the ethanologen, to a slurry tank before the ethanologen is added, to a slurry tank after the ethanologen is added, and/or to a fermenter.
10 . The method of claim 8 , wherein the formic acid is added to a propagator with the ethanologen, to a slurry tank before the ethanologen is added, to a slurry tank after the ethanologen is added, and/or to a fermenter.
11 . The method of claim 8 , wherein the formic acid is added to the slurry tank after the hop acids.
12 . The method of claim 1 , wherein the fermentation is a conventional cook process fermentation.
13 . The method of claim 12 , wherein the formic acid is added to the feedstock prior to cooking.
14 . The method of claim 12 , wherein the hop acids are added to the fermenter after the feedstock is cooled.
15 . The method of claim 8 , wherein the ethanol yield is increased relative to a fermentation performed in the presence of formic acid alone or performed in the presence of hop acids alone.
16 . The method of claim 8 , wherein levels of lactic acid are relative to a fermentation performed in the presence of formic acid alone or performed in the presence of hop acids alone.
17 . The method of claim 12 , wherein the ethanol yield is increased relative to a fermentation performed in the presence of formic acid alone or performed in the presence of hop acids alone.
18 . The method of claim 12 , wherein levels of lactic acid are relative to a fermentation performed in the presence of formic acid alone or performed in the presence of hop acids alone.
19 . A method of antibiotic free fermentation comprising (a) inoculating a feedstock with S. cerevisiae ; (b) adding formic acid and hop acids, and (c) fermenting the feedstock.
20 . The method of claim 19 , wherein the formic acid is added to a fermenter within 2 hours of yeast propagation.
21 . The method of claim 20 , wherein the formic acid is present in the fermenter at the end of fermenter fill to 60 ppm, +/−20%.
22 . The method of claim 19 , wherein the hop acids are added to a fermenter.
23 . The method of claim 19 , wherein the hop acids are present in the fermenter at a concentration of about 10 ppm to about 20 ppm, +/−20%.
24 . The method of claim 19 , wherein the hop acids are added to a slurry tank or propagation tank.
25 . The method of claim 19 , wherein the hop acids are present in a slurry tank or propagation tank at a concentration of about 50 ppm to about 130 ppm, +/−20%.
26 . A composition comprising: bacterially contaminated grain mash, a yeast, formic acid, hop acids, and water.
27 . A system for ethanol production comprising one or more fermenters comprising bacterially contaminated grain mash, an ethanologen, formic acid, hop acids, and water.
28 . The system of claim 27 , further comprises at least one of the following: a mill for preparation of feedstock; a propagator; and a distillation system.
29 . The system of claim 27 , which is antibiotic free.