SUBJECTS lactic acid

A process of subjecting lactic acid or a mixture of lactic acid... 

A process of producing a polyester by subjecting lactic acid to dehydration polycondensation in the presence of a catalyst, in which solid-phase polymerization is carried out at least in part of the steps... 

Phenyl-ethyl alcohol can be prepared by numerous methods, several of which are the subject-matter of patents. It may be prepared, for example, by the conversion of phenyl-bromo-lactic acid into phenyl-acetaldehyde, and then reducing this body with sodium. Or it may be prepared by reducing phenyl-acetic esters with sodium and absolute alcohol in the folio-wing manner —... 

Thus, while these two polymers differ greatly in their rate of hydrolytic chain cleavage, gel permeation chromatography (GPC) analysis of a 1 1 blend of PCL and poly(glycolic acid-co-lactic acid) in pH 7.4 buffer showed that both components of the blend were subject to the same rate of chain cleavage (65). 

These new fermentation processes often require high costs for recovering the product from the fermentation broth. For instance, the production of lactic acid requires the neutralization of the product during the fermentation, to avoid acidification of the medium, and the subsequent re-acidification of the lactate [65]. Similarly, the recovery of 1-butanol implies the distillation of large amounts of water. Alternative recovery processes are therefore the subject of intensive research. 

D-[l- C]Xylose was subjected to boiling in 4 M aqueous sodium hydroxide. The resulting mixture contained 2,4-dihydroxybutanoic acid, lactic acid, and D-a,j8-xylometasaccharinic acid. The almost uniform distribution of the C label among the carbon atoms of 2,4-dihydroxybutanoic acid indicated that this acid is probably formed by the recombination of completely isomerized, two-carbon fragments. Fragmentation of D-xylose occurred mainly at one of the central bonds, C-2-C-3 or C-3-C-4. 

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]. 

The action of alkaline reagents on sugars has been the subject of much study since Lobry de Bruyn s researches in 1896. Many complex changes are induced in the sugar molecule by alkaline reagents, as is exemplified by the researches of Evans.Here, however, mention will be made only of the production of lactic acid by the action of alkali on sucrose. 

Lactose is readily fermented by lactic acid bacteria, especially Lactococcus spp. and Lactobacillus spp., to lactic acid, and by some species of yeast, e.g. Kluyveromyces spp., to ethanol (Figure 2.27). Lactic acid may be used as a food acidulant, as a component in the manufacture of plastics, or converted to ammonium lactate as a source of nitrogen for animal nutrition. It can be converted to propionic acid, which has many food applications, by Propionibacterium spp. Potable ethanol is being produced commercially from lactose in whey or UF permeate. The ethanol may also be used for industrial purposes or as a fuel but is probably not cost-competitive with ethanol produced by fermentation of sucrose or chemically. The ethanol may also be oxidized to acetic acid. The mother liquor remaining from the production of lactic acid or ethanol may be subjected to anaerobic digestion with the production of methane (CH4) for use as a fuel several such plants are in commercial use. 

In the manufacture of chamois leather the skins are prepared by passing through the lime vats, scraping on the home, et cetera, in the ordinary way and when these preliminaries are effected, and the lime removed in the lactic acid or bran vat, ns muc]i as possible, they are subjected to the frizing operation. This consists In rubbing them with pumice-stone, or the blunt end of a round knife, till the grain Is entirely removed, the surface softened, and an equal thickness obtained throughout. After this the skins are squeezed or pressed, in order to remove as much water as possible. 

In a small test group of only five subjects erosion times of the dry skin of the calves were determined before and after four weeks of treatment with either a water-in-oil cream or a 12% lactic acid lotion (Figure 37.1). The assay was performed on four adjacent spots per leg. Spot-to-spot variation was on average less than one minute. In the majority of subjects erosions formed within two minutes. Erosion times on the legs treated with the water-in-oil cream were strongly increased, whereas the opposite legs, treated with the lactic acid lotion showed only slight improvement. This is not unexpected since alpha-hydroxy acids are known for their keratolytic activity which will weaken the... 

There is no doubt that catalytic asymmetric synthesis has a significant advantage over the traditional diastereomeric resolution technology. However, it is important to note that for the asymmetric hydrogenation technology to be commercially useful, a low-cost route to the precursor olefins is just as crucial. The electrocarboxylation of methyl aryl ketone and the dehydration of the substituted lactic acids in Figures 5 and 6 are highly efficient. Excellent yields of the desired products can be achieved in each reaction. These processes are currently under active development. However, since the subjects of electrochemistry and catalytic dehydration are beyond the scope of this article, these reactions will be published later in a separate paper. 

The Finnish fermented milk drink Evolus is fermented with a L. helveticus strain and contains the same tripeptides as Calpis . The Evolus drink has been demonstrated to exert a significant reduction in blood pressure of mildly hypertensive human subjects upon daily intake of 150 ml during a 21-week intervention period (Seppo et al., 2003). A fermented low-fat hard cheese Festivo was developed in Finland (Ryhanen et al., 2001) with probiotic lactic acid bacteria and was found to produce during maturation, high amounts of ACE-inhibitory peptides derived from asi-casein. The peptides emerged at the age of three months and their level remained rather stable at least for six months. 

NS), respectively, cytochrome oxidase decreased 9%(NS). Treatment-related effects in wmn muscle citrate synthetase decreased 19% (NS), cytochrome oxidase increased 23% (NS), muscle lactate and lactic acid dehydrogenase affected. Subjects reported no adverse health effects after exposure. 

Disposition in the Body. Rapidly and completely absorbed after oral administration, but subject to extensive first-pass metabolism bioavailability about 25%. The main metabolic reaction is conjugation with sulphate at the phenol position minor metabolites formed are jS-(4-hydroxyphenoxy)lactic acid and prenalterol glucuronide. About 90% of a dose is excreted in the urine in 24 hours. After an intravenous dose, about 60% is excreted unchanged with about 35% as the sulphate after oral administration, about 15% is excreted unchanged, with about 80% as the sulphate. 

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