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US 4,698,303 AGranted
Production of lactic acid by continuous fermentation using an inexpensive raw material and a simplified method of lactic acid purification
AssigneeEngenics, Inc.
InventorsRichard B. Bailey, Dilip K. Joshi, Stephen L. Michaels, Richard A. Wisdom
Life of this patent
Estimating the term…
Abstract
The invention provides a method for producing lactic acid by continuous fermentation utilizing particular methods of media pretreatment, cell-recycle fermentation, fermentation broth acidification, and lactic acid separation.
Claims29
A process for producing lactic acid from whey comprising the steps of:
- (a) providing a whey composition at an acidic pH from which a substantial portion of proteins having a molecular weight over 10,000 have been removed;
- (b) treating said composition with a protease at a temperature in the range of 40.degree. C. to 65.degree. C. for a period sufficient to degrade proteins to smaller peptides and amino acids, said smaller peptides and amino acids characterized as being nonpercipitable when subjected to heat-sterilization, increased salt concentration or contact with organic solvents;
- (c) fermenting the composition resulting from step (b) with a lactic acid or lactic acid salt-producing microorganism in a fermentation zone;
- (d) continuously removing a product-containing broth from said zone, removing cells of said microorganism from said broth to form a cell-free product-containing stream and recycling said cells to said zone;
- (e) contacting said cell-free product-containing stream at an acidic pH with a water-immiscible liquid consisting essentially of trialkyl tertiary amines of at least 24 carbon atoms and a water-immiscible organic solvent for a sufficient time and temperature, whereby lactic acid and lactic acid salt are extracted from said stream into a water-immiscible phase, said liquid characterized by a distribution coefficient in excess of 1.0 for lactic acid and lactic acid salt in said liquid versus water;
- (f) separating said water-immiscible phase from the mixture formed in step (e);
- (g) contacting said water-immiscible liquid from step (f) with a material selected from the group consisting of aqueous ammonium hydroxide, solid alkalis, solid alkaline earth compounds, and aqueous non-homogenous suspensions of solid alkalis or solid alkaline earth compounds for a sufficient time and temperature, whereby lactic acid and lactic acid salt are removed from said water-immiscible phase.
4 more elements
A process for producing lactic acid from whey comprising the steps of:
- (a) providing a whey composition at an acidic pH from which a substantial portion of proteins having a molecular weight over 10,000 have been removed;
- (b) treating said composition with a protease at a temperature in the range of 40.degree. C. to 65.degree. C. for a period sufficient to degrade proteins to smaller peptides and amino acids, said smaller peptides and amino acids characterized as being nonprecipitable when subject to heat-sterilization, increased salt concentration or contact with organic solvents;
- (c) fermenting the composition resulting from step (b) with a lactic acid or lactic acid salt-producing microorganism in a fermentation zone;
- (d) removing a product-containing broth from said zone, removing cells of said microorganism from said broth to form a cell-free product-containing stream;
- (e) contacting said cell-free product-containing stream at an acidic pH with a water-immiscible liquid consisting essentially of trialkyl tertiary amines of at least 24 carbon atoms and a water-immiscible organic solvent for a sufficient time and temperature, whereby lactic acid and lactic acid salt are extracted from said stream into a water-immiscible phase, said liquid characterized by a distribution coefficient in excess of 1.0 for lactic acid and lactic acid salt in said liquid versus water;
- (f) separating said water-immiscible phase from the mixture formed in step (e);
- (g) contacting said water-immiscible liquid from step (f) with a material selected from the group consisting of aqueous ammonium hydroxide, solid alkalis, solid alkaline earth compounds, and aqueous non-homogenous suspensions of solid alkalis or solid alkaline earth compounds for a sufficient time and temperature, whereby lactic acid and lactic acid salt are removed from said water-immiscible phase.
4 more elements
Dependencies are inferred from the claim text.