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US 4,771,001 AGranted
Production of lactic acid by continuous fermentation using an inexpensive raw material and a simplified method of lactic acid purification
AssigneeNeurex Corporation
InventorsRichard B. Bailey, Dilip K. Joshi, Stephen L. Michaels, Richard A. Wisdom
Life of this patent
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Abstract
The disclosure describes a method for producing lactic acid from carbohydrate-containing media by continuous fermentation utilizing particular methods of media pretreatment, cell-recycle fermentation, fermentation broth acidification, and lactic acid separation.
Claims21
A process for producing lactic acid from a carbohydrate-containing medium comprising the steps of:
- (a) fermenting said carbohydrate-containing medium with a lactic acid or lactic acid salt-producing microorganism in a fermentation ot form a broth;
- (b) continuously removing a product-containing both 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;
- (c) 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 period of time and at a temperature sufficient to extract lactic acid and lactic acid salt 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;
- (d) separating said water-immiscible phase from the mixture formed in step (c);
- (e) contacting said water-immiscible liquid from step (d) 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, whereby lactic acid and lactic acid salt are removed from said water-immiscible phase.
2 more elements
A process for producing lactic acid from a carbohydrate-containing medium comprising the steps of:
- (a) fermenting said carbohydrate-containing medium with a lactic acid or lactic acid salt-producing microorganism in a fermentation zone;
- (b) removing a product-containing both from said zone, removing cells of said microorganism from said broth to form a cell-free product-containing stream;
- (c) 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 period of time and at a temperature sufficient to extract lactic acid and lactic acid salt 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;
- (d) separating said water-immiscible phase from the mixture formed in step (c);
- (e) contacting said water-immiscible liquid from step (d) 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, whereby lactic acid and lactic acid salt are removed from said water-immiscible phase.
2 more elements
Dependencies are inferred from the claim text.