Fermentation industry propionic acid

Significant improvements in the yield, productivity, and selectivity of the fermentations producing propionic acid or butyric acid would be required if these methods were to become competitive with chemical synthesis methods used for industrial applications of these acids as commodity chemicals. 

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. 

Fermentation of lactic acid to yield propionic acid, carbon dioxide, acetic acid, and succinic acid is important for proper eye formation and flavor development in Emmental, Gruyere, and Swiss-type cheese varieties. This fermentation is associated with Propionibacterium spp. subspecies of Propionibacterium freudenreichii are of greatest significance. These organisms can also be used for industrial production of vitamin Bi2 and propionic acid. 

Propionic acid might be also produced by fermentation of Propionibac-terium acidipropionici, thus providing an attractive alternative that can also meet consumer s demand for natural preservatives used in the food industry. However, conventional batch propionic acid fermentation suffers from low... 

The production of substances that preserve the food from contamination or from oxidation is another important field of membrane bioreactor. For example, the production of high amounts of propionic acid, commonly used as antifungal substance, was carried out by a continuous stirred-tank reactor associated with ultrafiltration cell recycle and a nanofiltration membrane [51] or the production of gluconic acid by the use of glucose oxidase in a bioreactor using P E S membranes [52]. Lactic acid is widely used as an acidulant, flavor additive, and preservative in the food, pharmaceutical, leather, and textile industries. As an intermediate product in mammalian metabolism, L( +) lactic acid is more important in the food industry than the D(—) isomer. The performance of an improved fermentation system, that is, a membrane cell-recycle bioreactors MCRB was studied [53, 54], the maximum productivity of 31.5 g/Lh was recorded, 10 times greater than the counterpart of the batch-fed fermentation [54]. 

Many papers on continuous fermentation using electrodialysis have been reported.34 If ionic products produced in the fermentation broth amino acids, carboxylates, etc. are removed from the broth by electrodialysis, continuous fermentation becomes possible. The diffusion behavior of organic acids, such as, acetic, propionic, lactic, tartaric, oxalic, or citric acid through cation78 and anion79 exchange membranes has been studied in detail in connection with the removal of organic acids from the fermentation broth, and in applications in the food industry. 

The hydroxylation of aromatics serves as an example for a sussessfiiU industrial production of intermediates in a technical scale. BASF Ludwigshafen produces iso-merically pure (iJ)-2-(4-hydroxyphenoxy)-propionic acid (HPOPS) from (iJ)-2-phe-noxypropionic acid (POPS) in a 100 m fermenter for use as a herbicide intermediate (Eq. 4-19). 

The oxidation of phenols to catechols or hydroquinones by tyrosinase enzymes has been developed for biocatalysis. For example, the ortho-hydroxylation of L-tyrosine 162 (and also substituted variants) to give l-DOPA 163 has been extensively studied due to the importance of l-DOPA in the treatment of Parkinson s disease [92, 93]. An arene hydroxy lating enzyme having a broad substrate scope is 2-hydroxybiphenyl 3-monooxygenase from Pseudomonas azelaica, which is able to oxidize many ortho-substituted phenols 68 to the corresponding catechols 127 [94], as shown in Scheme 32.19. A notable example of an industrial biocatalytic arene hydroxylation that has been employed on very large scale (lOOm fermentation) is the pora-hydroxylation of R)-2-phenoxypropionic acid 164 by whole cells of Beauveria bassiana Lu 700 to give (R)-2-(4-hydroxyphenoxy)propionic acid 165, an important intermediate in herbicide manufacture [95]. 

If lactose-fermenting P. shermanii is used, cheese whey can be used as a substrate. From the whey containing 12% of dry substances, only 50% of lactose is utilized by P. shermanii, producing 1.6-2.2% solution of propionic acid (Bodie et al., 1987). In the combined batch culture, composed of P. shermanii and Lactobacillus casei, lactose is completely utilized and a 3% solution of propionic acid is produced in 52 h. When the medium is partially replaced during cultivation, a 4.5% solution of propionic acid is obtained by raising the concentration of dry substances in the whey up to 18% the production is increased up to 6.5% in mixed culture. For industrial production it is advisable to add a reducing agent to the medium (see above. Chapter 3), then the ratio of propionic to acetic acid will be increased (Emde and Schink, 1990). 

There are two technical problems that hmit industrial production of propionic acid by fermentation ... 

Diagram of an industrial scale pilot plant for production of propionic acid from whey permeate by sequential fermentation, ultrafiltration, and cell recycling (Redrawn with permission from Colomban et al. (1993))... 

Similarly, for commercial exploitation of PHB, it soon became apparent that a family of materials differing in properties was required to satisfy the variety of markets that were bound to develop. This was achieved by Imperial Chemical Industries (ICI) by a classical fermentation route using a pure carbohydrate substrate to which varying amounts of propionic acid was added to produce copolyesters containing only butyrate (HB) and valerate (HV) comonomers. ... 

Rodriguez, B.A., Stowers, C.C., Pham, V., Cox, B.M., 2013. The production of propionic acid, propanol and propylene via sugar fermentation an industrial perspective on the progress, technical challenges and further outlook. Green Chemistry, http / / dx.doi.org/10.1039 / c3gc42000k. 

---