L(+)-Lactic acid
[CAS# 79-33-4]

Identification

• Classification: Chemical reagent >> Organic reagent >> Fatty acid
• Name: L(+)-Lactic acid
• Synonyms: (S)-(+)-2-Hydroxypropanoic acid; Sarcolactic acid
• Molecular Formula: C₃H₆O₃
• Molecular Weight: 90.08
• CAS Registry Number: 79-33-4
• EC Number: 201-196-2
• SMILES: C[C@@H](C(=O)O)O

Properties

• Density: 1.206
• Melting point: 18 °C
• Boiling point: 125 °C
• Refractive index: 1.427
• Flash point: 110 °C
• alpha: -13 °
• Water solubility: SOLUBLE

Safety Data

• Hazard Symbols: GHS05;GHS07 Danger
• Risk Statements: H314-H315-H318
• Safety Statements: P260-P264-P264+P265-P280-P301+P330+P331-P302+P352-P302+P361+P354-P304+P340-P305+P354+P338-P316-P317-P321-P332+P317-P362+P364-P363-P405-P501

Hazard Classification

Hazard	Class	Category Code	Hazard Statement
Serious eye damage	Eye Dam.	1	H318
Skin irritation	Skin Irrit.	2	H315
Skin corrosion	Skin Corr.	1C	H314
Eye irritation	Eye Irrit.	2	H319
Specific target organ toxicity - single exposure	STOT SE	3	H335
Skin corrosion	Skin Corr.	1	H314
Skin corrosion	Skin Corr.	1B	H314
Skin corrosion	Skin Corr.	1A	H314
Substances or mixtures corrosive to metals	Met. Corr.	1	H290
Respiratory sensitization	Resp. Sens.	1	H334

Discovery and Applications

L(+)-lactic acid is an important chemical compound with a wide range of applications in various fields. L(+)-lactic acid was first isolated from yogurt in 1780 by Swedish chemist Carl Wilhelm Scheele. Its discovery marked an early understanding of fermentation processes in biological systems and laid the foundation for the understanding of microbial metabolism and the production of organic acids. Chemically, L(+)-lactic acid is a hydroxycarboxylic acid, the L-enantiomer of lactic acid, with the molecular formula C3H6O3. Its structure consists of hydroxyl groups adjacent to the carboxylic acid group on a three-carbon backbone.

In biological systems, L(+)-lactic acid plays a vital role in anaerobic metabolism and is a byproduct of glycolysis during strenuous exercise in various organisms, including humans. Its presence contributes to muscle fatigue and the subsequent recovery process. Industrially, L(+)-lactic acid is mainly produced by microbial fermentation, using bacteria such as Lactobacillus and Lactococcus. This method is favored for its efficiency, sustainability, and ability to produce high-purity lactic acid suitable for a wide range of applications.

The main application of L(+)-lactic acid is in the food and beverage industry. It can be used as an acidulant, pH adjuster and flavor enhancer for a wide range of products, including dairy products, baked goods, beverages and confectionery. Its mild taste and natural origin make it a top choice for regulating acidity and enhancing food preservation, helping to improve taste and extend shelf life without compromising product quality.

In the pharmaceutical field, L(+)-lactic acid can be used as an ingredient in drug delivery systems and topical preparations. Its biocompatibility and biodegradability make it ideal for controlled-release formulations and bioresorbable medical implants. In addition, L(+)-lactic acid derivatives are used in cosmetic formulations for their moisturizing and exfoliating properties, meeting consumers' growing demand for natural and sustainable skin care agents.

The biodegradability and non-toxic nature of L(+)-lactic acid allow it to be used in environmentally friendly products. It is a precursor for the production of biodegradable polymers such as polylactic acid (PLA), which can be used in bioplastics, packaging materials and agricultural mulches. These materials offer a renewable alternative to traditional plastics, reducing dependence on fossil fuels and mitigating environmental impact.

References

2020. Lactic Acid Production and Its Application in Pharmaceuticals. Bioactive Natural products in Drug Discovery, 1(16).
DOI: 10.1007/978-981-15-1394-7_16

1991. L-lactate uptake by rat liver. Effect of food deprivation and substrate availability. The Biochemical journal, 273(1).
DOI: 10.1042/bj2730195

1991. Kinetic mechanism of the endogenous lactate dehydrogenase activity of duck epsilon-crystallin. Archives of Biochemistry and Biophysics, 284(2).
DOI: 10.1016/0003-9861(91)90297-v