Lactic Acid

Abstract

Lactic acid is a naturally occurring C 3 α‐hydroxycarboxylic acid that is a product of anaerobic metabolism of sugars in virtually all living things. It is a colorless to slightly yellow, hydroscopic liquid commercially available in 50 – 90 wt % solutions. Lactic acid is made industrially by fermentation of carbohydrates or synthetically via the hydrolysis of lactonitrile. Production by fermentation has increased over the last decade as it produces the highly enantiopure l ‐lactic acid that is needed for food and polymer applications. Historically, foods have been the largest volume application, as lactic acid is a mild‐tasting acidulant and food preservative. The use of lactic acid based polymers has increased significantly since ca. 2002. These polymers have the potential to develop into a million‐tonne industry over the next 20 years. The commercial lactic acid processes use a variety of sugar for raw materials (sucrose from sugar beets and sugar cane, dextrose from corn), depending on price and availability of these sugars near the plant location. There are also a number of purification processes that are used commercially (lactate ester distillation, distillation, liquid – liquid extraction). The article contains sections titled: 1. Introduction 2. Properties 2.1. Physical Properties 2.2. Chemical Properties 2.2.1. Internal Esterification 2.2.2. Esterification 2.2.3. Other Reactions 3. Production 3.1. Lactic Acid Fermentation 3.2. Lactic Acid Purification 3.3. Synthesis of Lactic Acid 3.4. Construction Materials 4. Uses 4.1. Food Uses 4.2. Polymers 4.3. Industrial Uses 5. Quality Specifications 6. Analysis 7. Storage and Transportation 8. Legal Aspects 9. Economic Aspects 10. Environmental Protection 11. Toxicology and Occupational Health

Anaerobic Membrane Bioreactor for Continuous Lactic Acid Fermentation

“…Industrial research has, therefore, focused on strategies to increase the productivity of LA fermentations and reduce the costs. LA is usually produced by the microbial conversion of carbohydrates, such as dextrose, lactose, and sucrose, under anaerobic conditions because this yields a particular stereoisomer rather than the racemic mixture produced by chemical synthesis [20,21,22]. Therefore, we used the Gram-positive, thermophilic, and facultative anaerobic bacterium Bacillus coagulans to produce l -LA in the laboratory because this species can achieve high yields under anaerobic fermentation conditions [23,24,25,26].…”

Direct conversion of cellulose to α-hydroxy acids (AHAs) over Nb2O5-SiO2-coated magnetic nanoparticles

“…Moreover, its polymerization to biodegradable poly(lactic) acid is one of the most promising and rapidly growing application [6]. However, its current relatively high price precludes many of the applications listed above, because it is produced almost exclusively through the fermentation of sugars, a process that generates a significant amount of wastes [7]. Therefore, the identification of more efficient and less costly production methods compared with the current fermentation procedure is one of the most important tasks of current researchers in the field of biomass transformation.…”

Microbial metabolites in nutrition, healthcare and agriculture

“…The poly lactic acid polymer is biodegradable and biocompatible, and used in pharmaceutical industry for the synthesis of prosthetic devices, sutures and internal drug dosing (San-Martin et al 1992; Chahal and Starr 2006). The poly lactic acid has several applications in packaging, agriculture, automobile, healthcare, electronics, textile, and other industries (Ghaffar et al 2014; Singhvi et al 2010; Martinez et al 2013).…”