Organic compounds -- part of the class 532-570 series – Organic compounds – Fatty compounds having an acid moiety which contains the...
Reexamination Certificate
2001-02-16
2002-02-26
Carr, Deborah D. (Department: 1621)
Organic compounds -- part of the class 532-570 series
Organic compounds
Fatty compounds having an acid moiety which contains the...
C554S193000
Reexamination Certificate
active
06350890
ABSTRACT:
Method for the preparative-scale production of fatty acids from biomass by in-situ extraction, reaction and chromatography using compressed gases
The invention relates to a method for the preparative-scale production of fatty esters—for producing fatty acids, preferably polyunsaturated fatty acids (PUFAS)—from biological sources by continuous in-situ extraction, reaction and chromatography using compressed gases.
In nature, PUFAs, in addition to oleic acid, occur in relatively high concentrations in linseed oil, hazelnut oil, poppy seed oil, hemp seed oil and fish oils. Numerous attempts have already been made to produce these valuable substances from biological sources of these types and to isolate them with a greater or lesser degree of purity. However, since the PUFAs are generally chemically bound as esters in lipids, in addition to extraction, conversion to the free acids (hydrolysis) or corresponding monoesters (transesterification) must be carried out.
Since the biological sources, in particular fish oil, are not available without restrictions, it is of interest to isolate the PUFAs from microorganisms, such as bacteria, algae etc., which have stored these fatty acids within the cells or in the cell membranes as lipids.
There is great industrial interest in industrial methods for the preparative-scale production of fatty esters, in particular of nutritionally important fatty esters, preferably polyunsaturated fatty esters. Lipids contain fatty acids, mostly bound in glycerides (mono-, di- and triglycerides), phosphatides, glycolipids and aminolipids. These bound fatty acids and free native fatty acids and their derivatives differ firstly in their frequency of occurrence in biological sources, and secondly in their activity on the human organism.
Native fatty acids and their derivatives are produced from biological sources, in addition to by classical solvent extraction of the corresponding lipids, in particular by extraction using compressed gases (for example supercritical carbon dioxide, etc.). This method termed SFE (supercritical fluid extraction), ensuring biological compatibility, is a mild much-described extraction method which is used in routine analysis and process engineering.
Extracted lipids cannot be separated directly by chromatography into the individual triglycerides, since generally a permutation of numerous naturally occurring fatty acids at the three positions of the triglyceride leads to a multiplicity of compounds which can only be separated chromatographically with difficulty.
The fatty acids are therefore extracted by means of a preceding or following reaction via cleavage of the lipids (fat cleavage) into the individual fatty acids by means of (catalytic) transesterification to form the esters of lower alcohols or by means of (catalytic) hydrolysis to give the free acids, also in the presence of a compressed gas in the reaction medium (SFR=supercritical fluid reaction).
The substances which serve as catalysts here are organic acids (formic acid, acetic acid, citric acid, etc. “Coupling chemical derivatisation reactions with supercritical fluid extraction”, J. A. Fields, J. Chromatog. A, 785 (1997), pp. 239-249) and solid catalysts (e.g. Ion-exchange resins (C. Vieville, Z. Mouloungui, A. Gaset; Colloq.—Inst. Natl. Rech. Agron. (1995), 71 (Valorisations Non-Alimentraires des Grandes Productions Agricoles), 179-82; acidic aluminum oxide (B. W. Wenclawiak, M. Krappe, A. Otterbach; J. Chromatogr. A (1997), 785, 263-267)) or combinations thereof (C. Vieville, Z. Mouloungui, A. Gaset; Ind. Eng. Chem. Res. (1993), 32(9), 2065-8).
Enzymatic reactions using lipases are also known which, either in solution, or immobilized, perform the fat cleavage with subsequent extraction in the presence of supercritical gases (R. Hashizume, Y. Tanaka, H. Ooguchi, Y. Noguchi, T. Funada; JP-196722 and A. Marty, D. Combes, J. S. Condoret; Prog. Biotechnol. (1992), 8 (Biocatalysis in Non-conventional Media), 425-32).
In principle, the SFE and SFR methods can be carried out as continuous flow or batch methods. King et al. carry out extraction and transesterification in the presence of compressed gases as a batch method (J. W. King, J. E. France, J. M. Snyder; Fresenius J. Anal. Chem. (1992), 344, 474-478). In this case, firstly, extraction of lipids from a biological source takes place (here seed grains), with subsequent transesterification on the catalyst to form methyl esters. The aluminum oxide catalyst is physisorbed with ethanol. However, a disadvantage is the complex use of the samples on the catalyst, as a result of which reaction only takes place at the catalyst/sample interface. This is inadequate in the context of a preparative reaction.
King et al. describe a virtually quantitative conversion (>98%) of triglycerides to the methyl esters on immobilized lipase which is carried out as a continuous flow method. In this case corn oil and, as modifier, methanol are pumped to the carbon dioxide. This is also carried out for consistent biological sources such as soybean flakes (M. A. Jackson, J. W. King; J. Am. Oil. Chem. Soc. (1996), 73(3), 353-6).
However, the use of lipases in the continuous flow method has the disadvantage of conversion rates which are low with time.
All of the procedures described in the prior art have the disadvantage that they exhibit a spatial separation between extraction and reaction and thus do not comply with in situ preconditions and therefore do not achieve quantitative conversion. (Cf. also in the case of an esterification JP 61261398, JP 07062385 A2 and in the case of a hydrolysis K. Fujita, M. Himi; Nippon Kagaku Kaishi (1995), (1)). In addition, in the prior art, there is no advantageous inexpensive combination of reaction, extraction and chromatography.
The object of the present invention is to provide a method for the preparative production of unsaturated and saturated fatty esters and their selective isolation from biological sources.
The object is achieved by a method for the preparation and isolation of fatty esters from biological sources using continuous in-situ extraction, reaction chromatography. In the presence of a compressed gas stream and a 0.5 to 5% strength C1-C5 alcohol modifier
(a) the reaction takes place on an inert catalyst in complete contact with the biological source;
(b) the reaction products are chromatographed on the inert catalyst from (a) which has chromatographic retention and exclusively desorbs and elutes the reaction products;
(c) the desorbed and eluted reaction products from (b) are extracted.
The present method has advantages compared with known procedures:
The reaction products produced are safe with regards to health and food chemistry, since
1.) ethanol is preferably used as modifier and reaction partner and
2.) solid inert aluminum oxide is used as catalyst/stationary phase and
3.) carbon dioxide is used as reaction/extraction medium and mobile phase. Neither the starting materials nor the product thus come into contact with toxic substances at any instant of the method.
Carbon dioxide serves as protecting gas atmosphere to prevent oxidations and for mild extraction and elution.
In contrast to the mentioned methods, in the present case the toxicity of the substances used is so low that these may safely be used for preparing food additives or pharmaceutical products.
The reaction products occur in pure form as solid substance or in high concentration in a suitable solvent and can readily be further processed.
In addition, the reaction products in the inventive method are selectively separated off from the starting materials, the intermediates and the byproducts.
The method can be carried out continuously. In the case of liquid starting materials, they can be fed into the flow system.
Owing to the preferred use of the inexpensive aluminum oxide as inert catalyst/stationary phase, an economically expedient, industrial preparative scale can be carried out.
The biological source can be used directly. It is not necessary to limit the amount of biomass from the biological source and the method i
Engelhardt Heinz
Fabritius Dirk
Kiy Thomas
Siffrin Christoph
AXIVA GmbH
Carr Deborah D.
McKenna & Cuneo LLP
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