Extraction of DHA process technology by microbial fermentation method
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Last Update: 2020-06-21
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Source: Internet
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Author: User
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DHA (Docosahexenoic acid, 22:6 4.7.10.13.16.19, full name 22 carbon hexale acid) is an important long-chain polyunsaturated fatty acid (polyunsaturated acid, or PUFA), belonging to the s-3 series (the first double bond in the molecular structure is located on the side of the COOH-hexavalent, i.e., the third seriesHumans and other mammals have only desaturation enzymes of 4, 5, 6 and 9, and lack the desaturated enzymes of s9 or more, so they cannot synthesize DHA on their own and must be provided by foodDHA has been a major focus of children's nutrition since the 1990sProfessor Croft of the British Institute of Brain Nutrition and professor Oyu Zhanmei, a renowned Japanese nutritionist, first revealed the mystery of DHA, their findings show that DHA is one of the most important substances in the development and growth of the human brainDHA, as a fatty acid, enhances memory and thinking ability, improves intelligence and so onThe study found that people with high dHA content had strong psychological tolerance and high ersocym of intellectual developmentIn view of the deepening understanding of DHA, the development and use of DHA technology continues to improve, how to get high-quality, high content DHA, has been the goal of people to pursueNow, the use of microbial fermentation (hidden algae) can get 50% of the oil production rate, with nhexane extraction and prepared fermentation liquid, concentrated at low temperature, refined, can get the content of 40 to 45% of the total oil DHAThe following small section for you to introduce its processthe first fermentationthe second extraction process, here is mainly introduced extraction process:hexanesacline heatingstrain secondary treatmentfermentation liquid, dehydration concentration, extraction tank, broken wall, rapid stirring, still, upper clear liquid , low temperature vacuum concentration, rich in DHA fat-soluble liquid 1, fermentation liquid concentration dehydrationfermentation liquid contains a large amount of water (more than 90%), the first is to dehydrateWith the large build-up of non-dehydrated bacteria liquid and the large space occupied by the extraction tank, it is necessary to increase the volume of the extraction tank, and also increase the investment cost accordingly At present, according to our transfer of technology manufacturers to see there are two main: ceramic membrane filtration, centrifuge separation ceramic membrane filtration, membrane filtration technology is a branch of modern separation technology, the main role is to remove (intercept) colloids, bacteria and solid substances from the gas phase or liquid phase material, in order to achieve purification, separation and concentration process purposes The membrane has many advantages, such as smooth film surface, no debris, thin thickness, low adsorption filter, high pore rate, uniform microporous structure, good filtration effect and fast filtration speed, and has been widely used in food and beverage, medicine, chemical industry, electronics, energy, environmental protection and inspection and other fields The filtration method includes positive and negative pressure filtration, are so that water and smaller particles or molecules sothat sothat so that the solute can pass through a certain aperture of the membrane, large particles or molecular solutes can not pass through, so that large particles or polymer substances dehydrated, concentrated, improve the purpose of detection rate Membrane filtration is very good at the beginning of use, filtering is also fast But after a few hours of use, it was found that the filtering speed and filtering effect were not as good as before Causes algal oil spores to break up and oil emulsifying is serious Analysis of the reason: after a period of filtration, it may be that some bacteria or other substances blocked the filter hole, increased the load of the pump, the pump body to the fermentation fluid shear, resulting in the rupture of algal oil spores and centrifugal dehydrated disc separator is one of the settling centrifuges used to separate materials that are difficult to separate The disc separator is a vertical centrifuge, the drum is mounted on the upper end of the vertical shaft, and the transmission is driven by the motor and rotates at high speed There is a set of disc-shaped parts stacked on each other in the drum -- discs There is a small gap between the disc and the disc The suspension (or emulsion) is added to the drum by the feeding tube located at the center of the drum When the suspension (or emulsion) flows through the gap between the discs, the solid particles (or droplets) sink down the centrifuge to the disc to form a slag (or fluid layer) The slag slides along the surface of the disc and detaches from the disc and accumulates in the largest diameter part of the drum, where the separated liquid is discharged from the outlet The role of the disc is to shorten the settlement distance of solid particles (or droplets), expand the settlement area of the drum, the drum because of the installation of the disc and greatly improve the production capacity of the separator Solids accumulated in the drum are removed by hand after the separator is stopped or drained from the drum without stopping through the slag removal mechanism The disc separator can perform two operations: liquid-solid separation (i.e separation of bottom concentration suspension), called clarification operation, liquid-liquid separation (or liquid-solid) separation (i.e., separation of emulsion), called separation operation Centrifuge separation, can solve the emulsification phenomenon very well, but if the adjustment is not good, will re-discharge water at the same time take away part of the algal oil spores, resulting in unnecessary losses This process can remove 35 to 50% of the water 2, extraction extraction methods are two: First, the extraction tank is first added to the preparation of the bacteria 2 to 3 times the volume of n-hexane (temperature of 50 degrees C), and then put into the wall-breaking bacteria, side input side stirring (mixing speed 45r.p.m) After the solution has been cast, stir for 5min, then separate at rest The second method is to extract a certain amount of bacteria in the extraction tank, and then add a certain amount of wall breaker, stirring the broken wall Then, add 2 to 3 times the volume of n-hexane (temperature of 50 degrees C), quickly stir (mixing speed of about 60r.p.m) 10min, so that the liquid and solvent deep mixture, and then static separation After separation, either the lower scum is put into another extraction tank for a second extraction, or the upper liquid is removed and a second extraction is put into the solvent The upper liquid is placed in a mixture oil staging tank, which is stationary and separated The heavy phase part is put into the extraction tank, the extraction is used, and the light phase part concentrates and evaporates at low temperature When extracting, the amount of solvent added, stirring speed and time are important parameters, should be mastered according to small tests If the control is not good, emulsification may occur Once emulsification occurs, it is used to break the milk with alcohol of more than 90 degrees Now, according to the actual needs, we have designed a continuous extraction DHA process It not only increases the output and reduces the investment cost, but also improves the quality of the product, reduces the labor intensity, is the preferred process for future production 3, broken walls I contact to extract DHA process, the use of wall-breaking methods are mainly: mechanical method, chemical method two Mechanical method is physical, relying on mechanical energy to achieve the effect of breaking walls The main use of grinding method, high-pressure homogeneity In the broken wall, because there is no timely contact with the solvent, will cause oil particles and water mixed, under the action of external forces to emulsify The chemical method is mainly enzyme dissolution It destroys the cell wall and releases the oil particles in the cell The wall-breaking effect, to be observed under a microscope, the enzyme protein method can reach 100% of the wall breaking rate 4, concentrated concentrate can be divided into intermittent, continuous and two types according to the yield size The temperature is required to be 50 degrees C and the vacuum degree is above -0.085MPa The total gross oil of DHA produced by the above process is: 12.5g/L fermentation liquid above; summary: the production of DHA by positive hexane solvent method is a mature process, we have built three enterprises in China, each has achieved good economic and social benefits For the improvement of national quality and the next generation of intellectual level, to achieve due contribution
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