Chemistry: molecular biology and microbiology – Micro-organism – tissue cell culture or enzyme using process... – Preparing oxygen-containing organic compound
Patent
1996-05-21
1999-07-27
Lankford, Jr., Leon B.
Chemistry: molecular biology and microbiology
Micro-organism, tissue cell culture or enzyme using process...
Preparing oxygen-containing organic compound
562584, C12P 148, C07C 59265
Patent
active
059289112
DESCRIPTION:
BRIEF SUMMARY
The invention relates to a process for the manufacture of citric acid.
It also relates, by way of new industrial products, to certain raw materials which may be employed in the context of this manufacture.
Lastly, it relates to the application of certain amylaceous products to this process.
Citric acid is used mainly in the food industry, where its pleasant acid taste and its great solubility make it liked especially in drinks, jams and sweetmeats, but it is also used in the pharmaceutical and cosmetics industries and in the plastics and detergent industries.
Citric acid is now obtained almost exclusively by fermentation processes employing fermentation of various carbohydrates-based substrates in deep vats.
The microorganisms capable of producing and accumulating citric acid can belong to the Aspergillus, Citromyces, Penicillium, Monilia, Candida and Pichia species. The black Aspergillus species, and especially Aspergillus niger, are employed in particular in this type of production. The most effective strains are those which possess low isocitrate dehydrogenase and aconitate hydratase activities and high citrate synthase activity. These strains all have in common the feature of being very sensitive to traces of heavy metals.
The carbohydrates which are employed in these processes can be more or less refined. However, their state of purity gives rise to different constraints.
Thus, food grade crystallized sucrose or dextrose does not contain heavy metals. They furnish yields of citric acid greater than 70% but are expensive.
However, the recovery of the citric acid is greatly facilitated by the purity of such substrates.
Cane or beet molasses are cheap substrates. However, the large amount of impurities they contain create huge problems of treatment of the heavy metals and of purification of the citric acid.
Starch hydrolysates are a little more expensive than molasses. Irrespective of whether they are from maize, wheat, potato or rice, they contain less impurities than molasses and the purification of the citric acid is thereby facilitated. However, their use is limited because these substrates which have undergone little purification also contain substances of unknown nature which increase the adverse effects of heavy metals on citric fermentation.
It is thought that these substances which potentiate the effect of heavy metals, which are essentially iron, manganese and zinc, may be amino acid residues, peptides, enzymes or intermediate metabolites. Conversely, some substances which stimulate citric fermentation have sometimes been detected, although their chemical nature has not been clarified.
Methods exist which make it possible to combat the adverse effect on citric fermentation of the heavy metals present in substrates which have undergone little purification.
For example, they may be complexed using hexacyanoferrate, or their effects may be counteracted by adding copper.
MOYER (J. App. Microbio 1, 7-13), using an Aspergillus niger strain endowed with amylolytic properties, demonstrated that an unhydrolyzed native wheat starch could also be fermented successfully to citric acid by neutralizing the effect of heavy metals by adding an alcohol.
SWARTHOUT (U.S. Pat. No. 3,285,831) employed an enzyme hydrolysate of a crude maize flour to obtain citric acid by the action of Aspergillus niger. He got rid of heavy metals by trapping them on a cation exchange resin, and also suggested treating a wheat flour enzyme hydrolysate in the same way. Such hydrolysates obtained from whole cereal flours contain, however, a large amount of impurities, and in particular a large amount of proteins which interfere with the final recovery of the citric acid.
However, a cheaper substrate which is sufficiently pure not to cause problems of recovery of the citric acid or of removal of heavy metals, and which contains, furthermore, substances which stimulate citric fermentation, has not yet been identified or turned to good account.
It is to the credit of the Applicant Company that it recognized such a substrate in a hydrolysa
REFERENCES:
patent: 2492673 (1949-12-01), Woodward et al.
patent: 2970084 (1961-01-01), Schweiger et al.
patent: 3285831 (1966-11-01), Swarthout et al.
patent: 4165240 (1979-08-01), Enokizono et al.
J. App. Microbio, 1953, 1, 7-13 (Andrew J. Moyer).
"Starch : Chemistry and Technology" Second edition by Roy L. Whistler, pp. 491-506.
"Starch Production Technology" Radley J.A. (1976) pp. 175-187.
Prehrambeno-Tehnoloska Biotehnoloska Revija, 1994 32(1) 17-20.
"Food Acid Manufacture, Recent Developments" by A.A. Lawrence, published by Noyes Data Corp., 1974 edition pp. 2 to 74.
"Biotechnology, A Comprehensive Treatise in 8 volumes"by H.J. Rehm and G. Reed, vol. 3, Chapter 3d.
Brochures of Vogelbusch Ges. m.b.H., Austria : "Influence of Nutrient Concentration in the Fermentation Media on Production of Citric Acid By Industrially Used Strains of Aspergillus Niger".
Lankford , Jr. Leon B.
Roquette Freres
Tate Christopher R.
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