Coupling process for preparing biodiesel and enriching polyunsaturated fatty acid esters

Abstract

The invention relates to a coupling process for preparing biodiesel and enriching polyunsaturated fatty acid esters. The coupling process comprises the following steps: reacting grease, short-chain alcohol, water and liquid lipase in a reactor, and then dividing reaction liquid into a heavy phase and a light phase; recycling and reusing enzyme in the heavy phase; and distilling the light phase so as to separate out a C14-C18 fatty acid ester which serves as the biodiesel. A tower oil phase is applied to subsequent immobilized enzyme transformation, and meanwhile, online dehydration is introduced to a reaction course. The process, without conducting pre-treatment on the grease raw material in a previous reaction process of liquid enzyme catalysis, can achieve the effective transformation of the grease, which is C14-C18 in fatty acid carbon-chain length, into corresponding fatty acid ester, with a transformation rate reaching 90% or above; and tower liquid is applied to immobilized lipase catalysis in the second stage, and polyunsaturated fatty acid esters higher than C19 are effectively transformed into corresponding fatty acid ester, with a transformation rate reaching 98% or above. The process has the advantages of being strong in grease raw material adaptability, environment-friendly and clean in process, high in product yield and the like.

Description

technical field [0001] The invention belongs to the field of biochemical industry, and in particular relates to a coupling process of biodiesel preparation and polyunsaturated fatty acid ester enrichment. Background technique [0002] Polyunsaturated fatty acids (PUFAs) refer to long-chain fatty acids with more than one double bond in the molecule. They are essential fatty acids for the human body and need to be ingested from food. According to the position of the PUFA double bond, it is divided into ω-3 and ω-6 series, counting from the carbon atoms of the methyl segment farthest from the carboxyl group in the fatty acid molecule, the first double bond appears at the third and fourth carbon Between atoms is called ω-3PUFA, such as α-linolenic acid (C18:3), docosahexaenoic acid (DHA, C22:6), eicosapentaenoic acid (EPA, C20:5), etc. ; The first double bond between the sixth and seventh carbon atoms is called ω-6PUFA, such as linoleic acid (C18:2) and arachidonic acid (C20:4)...

AI Technical Summary

Problems solved by technology

Among them, the urea inclusion method is more commonly used. In organic solvents, urea can form urea inclusion complexes with straight-chain saturated fatty acids and crystallize at low temperatures. However, this process requires the use of a large amount of organic solvents, which adds subsequent purification steps; Vaporization of the separated matter at low temperature, strictly controlling the temperature to obtain fractions at different temperatures, can obtain higher ω-3PUFAs, but the process consumes a lot of energy; in the anion complexation method, silver nitrate anion can be complexed with ω-3PUFAs, and the product is hydrophilic Therefore, ω-3PUFAs can enter the water phase in the form of anion complexes to achieve separation, but silver nitrate is expensive, so it is limited to a small amount of preparation in the laboratory; using supercritical CO 2 Extraction has the advantages of no oxidation of omega-3PUFA, but it has relatively high requirements for equipment

In short, the above physical or chemical methods for enriching ω-3PUFA have problems such as poor selectivity and high energy consumption in the process. It is urgent to develop a highly selective and environmentally friendly biological enzymatic process for the enrichment of ω-3PUFAs

However, the current enzymatic process for enriching polyunsaturated fatty acids is cumbersome, with high cost and poor selectivity, and the prospect of industrial application is unclear.

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