Lactic acid purification

Madzingaidzo, L., Danner, H., and Braun, R. 2002. Process development and optimisation of lactic acid purification using electrodialysis. J. Biotechnol. 96, 22-239. 

Removal of sulfanilic acid from wastewater Lactic acid purification and concentration Enrichment of bisphenol A Phenol recovery from aqueous solutions Zinc(ll) recovery from HCI solution Hydrogen separation from methane steam conversion products... 

TABLE 1.2 Summary of Lactic Acid Purification Methods ... 

Lactic Acid Purification Method Advantages Disadvantages... 

Table 2.6 Lactic Acid Purification Technology (Henton et al., 2005, Published with Permission)—cont d...

Salts of Organic Acids. Calcium salts of organic acids may be prepared by reaction of the carbonate hydroxide and the organic acid (9). Calcium lactate [814-80-2] is an iatermediate ia the purification of lactic acid from fermentation of molasses. Calcium soaps, soaps of fatty acids, ate soluble ia hydrocarbons, and are useful as waterproofing agents and constituents of greases (9). 

E Allemann, E Doelker, R Gurny. Drug loaded poly (lactic acid) nanoparticles produced by a reversible, salting-out process purification of an injectable dosage form. Eur J Pharm Biopharm 39 13-18, 1992. 

De Vuyst L and Leroy F. 2007. Bacteriocins from lactic acid bacteria production, purification, and food applications. J Mol Microbiol Biotechnol 13 194-199. 

The biodegradable polymer available in the market today in largest amounts is PEA. PEA is a melt-processible thermoplastic polymer based completely on renewable resources. The manufacture of PEA includes one fermentation step followed by several chemical transformations. The typical annually renewable raw material source is com starch, which is broken down to unrefined dextrose. This sugar is then subjected to a fermentative transformation to lactic acid (LA). Direct polycondensation of LA is possible, but usually LA is first chemically converted to lactide, a cyclic dimer of LA, via a PLA prepolymer. Finally, after purification, lactide is subjected to a ring-opening polymerization to yield PLA [13-17]. 

Waste Acid Recovery via Purification Lactic Acid Production Recovery of Na-CO, from Trona... 

They stated further that, the new adaptive enzyme catalyzing Reaction 3 appears to be similar to the malic enzyme of pigeon liver, although strictly DPN (instead of TPN)-specific. The coenzyme specificity explains the ready occurrence of Reaction 1. Therefore, the authors showed that exogenous NAD was required for the overall reaction (malic acid -> lactic acid), but because this activity was measured manometrically, they never demonstrated the formation of reduced NAD. Similarly, they did not attempt to show that pyruvic acid was the intermediate between L-malic acid and lactic acid. Instead, the formation of pyruvic acid was inferred from the NAD requirement and because the malic acid dissimilation activity remained constant during purification while the lactate dehydrogenase activity decreased (14). In fact, attempts to show any appreciable amounts of pyruvic acid intermediate failed (22). 

Hensel, R., Mayr, R., Stetter, K. 0. and Kandler, O. 1977. Comparative studies of lactic acid dehydrogenase in lactic acid bacteria. I. Purification and kinetics of the allosteric L-lactic acid dehydrogenase from Lactobacillus casei spp. casei and, Lactobacillus curvatus. Arch. Microbiol 112, 81-93. 

Berrama T, Pareau D, Stambouli M, Durand G. Purification and concentration of lactic acid by emulsion liquid membrane extraction. In Cox, Hidalgo M, Valiente M, eds. Solvent Extraction for the 21st Century, Proceedings of ISEC 99, Barcelona. London Society of Chemical Industry, 2001 983-987. 

Martak, J. and Schlosser,. (2007) Extraction of lactic acid by phosphonium ionic liquids. Separation and Purification Technology, 57, 483. 

Many industrial organic acids can be produced by fermentation, such as acetic, citric, and lactic acids. Succinic acid is a dicarboxylic acid of potential industrial interest as a platform chemical (1-3). Separation and purification of succinic acid by adsorption was tested to replace current precipitation methods and their associated waste disposal problems. Succinic acid is a valuable intermediate value chemical with a moderate market. For succinic acid to have an economic and energy impact, it will need to become a commodity chemical intermediate with a much lower price. This target price hasbeen estimated to be between 0.22 and 0.30 / lb ( 0.48- 0.66/kg) and is potentially achievable with advanced technology (1). At this price, succinic acid can be catalytically upgraded into other higher valued chemicals suchastetrahydrofuran, 1,4-butanediol, y-butyrolactone, 2-pyrrolidinone, and N-methylpyrrolidinone. 

Calcium lactate is sold for use in medicines and in foods as a source of calcium and as an intermediate in the purification of lactic acid from fermentation processes. 

The use of these asymmetric hydrogenation catalysts gives the C-2 chiral center in about 80% optical purity. The same value would apply also to the chiral methyl. For further purification, a crystallization process was used. The optically impure lactic acid (an oil) was dissolved in an approximately equal volume of boiling diethylether diisopropyl ether, 1 1 on standing at 5°C large, colorless, crystals of optically pure chiral methyl chiral lactic acid, 162, were deposited. The recovery of the purified material was 60%. Because of the inherent relationship between the two chiral centers, optical purity at C-2 guarantees optical purity at C-3. 

Lactic acid is produced chemically from acetaldehyde, by hydrocyanation, followed by acid hydrolysis of the cyanohydrin (Fig. 8.6 a). The cmde lactic acid is purified via esterification with methanol, distillation of the ester and hydrolysis with recycling of the methanol [34]. Major drawbacks are the production of an equivalent of ammonium sulfate and the cumbersome purification procedure that is required to obtain food-grade lactic acid. 

Acidification of the culture supernatant, filtration, treatment with active charcoal and concentration usually result in food-grade lactic acid, if the feedstock was pure glucose. Otherwise, more extensive purification may be required. 

The growing interest in renewable raw materials spurred, from the mid-1980s onwards, interest in the development of highly integrated, low-waste procedures for the fermentation, primary purification and processing of lactic acid. Continuous removal of lactic acid, via solvent extraction or otherwise, would obviate the need for adding base but is not feasible at pH 5.5-6.5, however, because only 2% of the lactic acid (pKa 3.78) is uncharged at pH 5.5. 

Ethyl lactate is produced by the esterification of lactic acid with ethanol in the presence of a little mineral oil, or by combination of acetaldehyde with hydrocyanic acid to form acetaldehyde cyanhydrin. This is followed by treatment with ethanol (95%) and hydrochloric or sulfuric acid. Purification is achieved using fractional distillation. The commercial product is a racemic mixture. 

The cross-axis CPC (coil planet centrifuge), with column holders at the off-center position on the rotary shaft, enables retention of the stationary phase of aqueous-aqueous polymer-phase systems such as PEG 1000-potassium phosphate and PEG 8000-dex-tran T500 [3,4], Since the last decade, various types of cross-axis CPC (types XL, XLL, XLLL, and L) have been developed for performing CCC with highly viscous aqueous polymer-phase systems. The separation and purification of protein samples, including lactic acid dehydrogenase [5], recombinant enzymes, profiUn-actin complex, and so on, were achieved using these cross-axis CPCs [6]. 

The performance of the XL cross-axis CPC, equipped with a pair of columns with a 165-mL capacity, was evaluated for purification of lactic acid dehydrogenase (LDH) from a crude bovine heart filtrate. Successful separation of the LDH fraction was achieved with 16% (w/w) PEG 1000-12.5%(w/w) potassium phosphate at pH 7.3. The separation was performed at 500 rpm at a flow rate of 1.0 mL/min using the potassium phosphate-rich lower phase as a mobile phase. The sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) analysis of the LDH fractions showed no detectable contamination by other proteins. The enzymatic activity was also preserved in these fractions. 

One of the drawbacks in the current commercial fermentation process is that the predominant form of the product is the deprotonated lactate rather than lactic acid, requiring more expensive and wasteful product purification steps. This is because the Lactobacillus fermentation operates at a minimum pH of 5.0-5.5 which is above the pA a of lactic acid (3.87). To overcome this limitation, a powerful strain improvement method, genome shuffling, was used to improve the acid tolerance of a poorly characterized industrial strain of LactobacillusA population of strains with subtle improvement in pH tolerance was isolated using classical strain improvement methods such as chemostats, and were then shuffled by recursive pool-wise protoplast fusion to create mutant strains that grow at substantially lower pH than does the wild-type strain. 

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