Use of microbial cell lines to maximize organic acid production
Described herein are methods, microbial cell lines, and media used in co-culture to augment propionic acid production using an optimized fermentation medium and methods for increasing propionic acid yield, e.g., by co-culturing Lacticbacillus Casei and high-acid tolerant A. Acidipropionici.
1 . A method for producing propionic acid, the method comprising:
providing acid-tolerant propionic acid excreting microbes selected from the group consisting of Propionibacterium, Anaerovibrio, Bacteroides, Clostridium, Fusobacterium, Megasphaera, Propionispira, Selenomonas, Veillonella , and combinations thereof;
providing acid-tolerant lactic acid producing microbes selected from the group consisting of Lactococcus, Pediococcus, Oenococus, Enterococcus, Leuconostoc, Bifidobacterium, Bacillus, Lactobacillus, Clostridium, Paenibacillus , Sporolactobacillus, and combinations thereof;
providing a growth medium comprising a glucose carbon source and a lactose carbon source, and having a pH of between 5.8 and 6.5;
adding the acid-tolerant propionic acid excreting microbes and the acid-tolerant lactic acid producing microbes to the growth medium, wherein the acid-tolerant lactic acid producing microbes are added to the growth medium 6-36 hours after the acid-tolerant propionic acid excreting microbes are added to the growth medium, thereby producing a co-culture;
incubating the co-culture in fermentation, thereby producing propionic acid; and maintaining the co-culture for a time sufficient to produce a desired amount of propionic acid.
2 . The method of claim 1 , wherein the Propionibacterium genus microbes are Acidipropionibacterium acidipropionici (NF S-2018).
3 . The method of claim 1 , wherein the acid-tolerant propionic acid excreting microbes are provided as a growing culture.
4 . The method of claim 1 , wherein the acid-tolerant lactic acid producing microbes are selected from the group consisting of Lactococcus, Pediococcus, Oenococus, Enterococcus, Leuconostoc, Bifidobacterium , and Bacillus.
5 . The method of claim 4 , wherein the acid-tolerant lactic acid producing microbes are provided as a growing culture.
6 . The method of claim 1 , wherein the acid-tolerant lactic acid producing microbes are selected from the group consisting of Bacillus, Lactobacillus, Clostridium, Paenibacillus, Sporolactobacillus , and combinations thereof.
7 . The method of claim 6 , wherein the acid-tolerant lactic acid producing microbes are Lactobacillus casei.
8 . The method of claim 6 , wherein the acid-tolerant lactic acid producing microbes are provided as spores.
9 . The method of claim 8 , wherein the spores are provided as part of the carbon source.
10 . The method of claim 1 , wherein the pH of the growth medium is 6.0.
11 . The method of claim 1 , wherein the growth medium further comprises a nitrogen source, vitamins, MgSO 4 , NaPO 4 , and KPO 4 .
12 . The method of claim 11 , wherein the nitrogen source is selected from yeast extract, peptides, ammonia sulfate, ammonia hydroxide, amino acids, and combinations thereof.
13 . The method of claim 12 , wherein the nitrogen source is yeast extract.
14 . The method of claim 11 , wherein the vitamin is vitamin B12.
15 . The method of claim 1 , wherein the glucose carbon source and the lactose carbon source are the same.
16 . The method of claim 1 , wherein the glucose carbon source and the lactose carbon source are different.
17 . The method of claim 1 , wherein the glucose carbon source is a plant-based glucose carbon source.
18 . The method of claim 17 , wherein the plant-based glucose carbon source is selected from the group consisting of hydrolyzed wheat, hydrolyzed corn, hydrolyzed beans, hydrolyzed starch, and combinations thereof.
19 . The method of claim 1 , wherein the lactose carbon source is whey.
20 . The method of claim 1 , wherein the acid-tolerant lactic acid producing microbes are added to the growth medium 12-24 hours after the acid-tolerant propionic acid excreting microbes are added to the growth medium;
and maintaining the co-culture for a time sufficient to produce a desired amount of propionic acid.