Method for producing lactic acid from organic waste
Aspects of the invention relate to methods for producing lactic acid from organic waste, comprising contacting organic waste with a microbial community to form a fermentation mixture, and fermenting the fermentation mixture under controlled pH and temperature conditions for a time sufficient to produce lactic acid.
1. A method for producing lactic acid from organic waste, comprising
contacting organic waste with a controlled microbial community to form a fermentation mixture,
controlling the pH and temperature conditions of the controlled microbial community in the fermentation mixture, and
fermenting the fermentation mixture under the controlled pH and temperature conditions for a time sufficient to produce lactic acid,
wherein the controlled microbial community comprises Firmicutes, Bacteroides and Spirochetes,
wherein the fermentation mixture has a solid content,
wherein the pH is controlled to between 3.0 and 6.0,
wherein the temperature is controlled to between 20° C. and 50° C., and
wherein the method does not comprise sterilization of the organic waste.
2. The method of claim 1 , wherein the method does not comprise enzyme addition to the fermentation mixture.
3. The method of claim 1 , wherein the organic waste is food waste or agricultural waste.
4. The method of claim 1 , wherein prior to fermentation, the organic waste is mechanically disrupted to a particle size of approximately 1 mm or smaller.
5. The method of claim 4 , wherein the mechanical disruption comprises shredding or grinding.
6. The method of claim 1 , wherein the pH is adjusted by addition of sodium hydroxide or other bases.
7. The method of claim 1 , wherein the temperature of the fermentation mixture is about 37° C.
8. The method of claim 1 , further comprising shifting the pH to between pH 3.86 and pH 4.75, inclusive, at or near the end of fermentation.
9. The method of claim 1 , wherein 60-100 grams of lactic acid per liter is produced.
10. The method of claim 1 , wherein the pH is adjusted to between pH 5.0 to pH 6.0.
11. The method of claim 10 , wherein the pH is adjusted to about pH 5.5.
12. The method of claim 1 , wherein the pH is controlled to be at or below 6.0 and above the pKa of lactic acid.
13. A method for producing lactic acid from organic waste, comprising
contacting organic waste with a controlled microbial community to form a fermentation mixture,
controlling the pH and temperature conditions of the controlled microbial community in the fermentation mixture, and
fermenting the fermentation mixture under the controlled pH and temperature conditions for a time sufficient to produce lactic acid,
wherein the controlled microbial community comprises Firmicutes, Bacteroides and Spirochetes,
wherein the fermentation mixture has a solid content,
wherein the temperature is controlled to between 20° C. and 50° C., and
wherein the pH is controlled to be at or below 6.0 and above the pKa of lactic acid.
14. The method of claim 13 , wherein at least 60 or more grams of lactic acid per liter are produced.
15. The method of claim 13 , wherein 60-100 grams of lactic acid per liter or 60-150 grams of lactic acid per kilogram of organic waste is produced.
16. A method for producing lactic acid from organic waste, comprising
contacting organic waste with a controlled microbial community to form a fermentation mixture,
controlling the pH and temperature conditions of the controlled microbial community in the fermentation mixture, and
fermenting the fermentation mixture under the controlled pH and temperature conditions for a time sufficient to produce lactic acid,
wherein the controlled microbial community comprises Firmicutes, Bacteroides and Spirochetes,
wherein the fermentation mixture has a solid content,
wherein the pH is controlled to between 3.0 and 6.0,
wherein the temperature is controlled to between 20° C. and 50° C., and
wherein 60 or more grams of lactic acid per liter are produced.
17. The method of claim 16 , wherein 60-100 grams of lactic acid per liter or 60-150 grams of lactic acid per kilogram of organic waste is produced.
18. The method of claim 17 , wherein the organic waste is food waste.