The preparation method who the purpose of this invention is to provide a kind of microbial oil by mutagenesis, screening mutant strain, has improved the content of thalline oleaginousness and unsaturated fatty acids.
In order to achieve the above object, the present invention takes following technical measures:
The bacterial classification that is used for producing microbial oil of the present invention is to belong to the deep yellow genus mortierella, and it has the higher thalline oleaginousness and the content of polyunsaturated fatty acid.At first the bacterium that sets out has been carried out mutagenesis screening, deep yellow mortierella Mortierella isabllina AS3.3410 strain is through twice mutagenesis of UV-light, next is to add twice complex mutation of LiCl through UV-light, through fermentation test, filter out Mortierella isabllina AS3.3410 mutant strain 5-1-6 strain.This bacterial strain on August 1st, 2000 in China's typical culture collection center preservation, deposit number is CCTCC NO.M200017.This strain is through the dried mycelia of fermentation biomass 49g/L fermented liquid, oil length about 60%, and produce oil 19.7g/L fermented liquid, linolenic acid 6.18%-7.32%, the polyunsaturated fatty acid that contains 18 carbon polyenoic acids accounts for 44% of total fatty acids.About from mycelia, obtaining grease, adopted and squeezed out most of crude oil earlier, crude oil can reach the first-grade edible oil standard after refining.Residual oil in the bacterium cake with the solvent oil extraction, has so just reduced solvent oil consumption and solvent-extracted workload again.This substep obtains the method for microbial oil can carry out suitability for industrialized production.The characteristics higher according to the mycelium oleaginousness take the pre-mode that leaches of pressing to obtain grease; The 3rd be to the exsiccant mycelium through 90~115 ℃, after 25-35 minute steaming is fried, squeezing, can obtain major part have thalline the pre-oil expression fat of intrinsic fragrance, pre-pressed crude oil does not wherein contain organic solvent.The remaining 10% greasy bacterium cake of having an appointment that contains is with organic solvent-normal hexane or the extraction of its isomer.The organic solvent content volume ratio of extraction is 0.6-1: 1, and temperature 45-60 ℃, 30-60 minute; The 4th is concentrated, and the indirect steam of extraction liquid in long-tube evaportor is heated to 80-100 ℃, the open steam 95-120 in the dish formula stripping tower ℃, concentrates and can obtain to leach crude oil; The 5th is that pre-pressed crude oil and leaching crude oil are squeezed into two aquation pots respectively, the salts solution that adds 1/10 volume 1-5%, heated and stirred continues 10-30 minute to 70-90 ℃, leaves standstill cooling 4-24 hour, the crude oil that aquation is good pumps in the precipitation pot respectively, feed 110-150 ℃ of open steam, the atmospheric indirect steam of 3-5, vacuum tightness is-650~-750mmHg, obtain finished product oil, by leach in the oil that the crude oil refining goes out residual molten≤50 * 10
-6, by in the refining oil in the pre-pressed crude oil residual molten be 0.
Embodiment 1
The bacteria suspension 4ml that dilution is prepared moves in the sterile petri dish of 60ml, puts into aseptic magnetic stirring bar, puts on the magnetic stirring apparatus, and 45 " and 60 " are shone at the 30cm place respectively under the 20W ultraviolet lamp, and entire operation is all carried out in Bechtop.
Each 0.5ml of bacteria suspension that gets non-irradiated bacteria suspension (comparing) respectively and shone under lamp carries out dilution in various degree, getting last 3 dilution diluent 0.2ml is applied on the potato culture medium flat plate, with preparing the aseptic rod coating that is coated with, cultivated 3-4 days, and caused mortality ratio more than 90% for 28 ℃.
The bacterial strain that grows transferred shake bottle in the inclined-plane simultaneously, cultivate, microscopic examination is to the stand density and the fat particle of thalline, collect dry mycelium, oven dry, survey biomass, survey oleaginousness, select the better bacterial strain of two strains in view of the above, repeat above-mentioned ultraviolet mutagenesis again, screening, obtained strains is again behind uv irradiating, bacteria suspension, be coated on the potato substratum that is contained in LiCl and cultivate, screening so repeats twice, promptly obtains the prominent bacterial strain 5-1-6 strain of high yield of Mortierellaisabellina AS3.3410 strain, the mutant strain of gained is inoculated on the PDA substratum, cultivated 7 days.
With spore inoculating in the seeding tank that 50L material is housed 40-45 hour, 28 ℃ of temperature all moved in the fermentor tank that the 500L material is housed again, can obtain the dry mycelium of 24.5kg after 72-96 hour, dry mycelium is steamed stir-fry 30 minutes, and after the indirect steam temperature was 105 ℃, squeezing can obtain the 10kg pre-pressed crude oil.
12.5kg the bacterium cake, the solvent that adds 13L soaked 1 hour at 55 ℃, collect extraction liquid, extraction liquid concentrates in the dish formula vapour tower and can obtain 1.5kg leaching crude oil through long-tube evaportor, to leach crude oil and go into 70 ℃ of addings of heating 0.15kg3%NaCl solution in the pump aquation pot, stir cooling in 20 minutes and left standstill 24 hours, skim upper strata oil, pump into precipitation pot vacuum tightness-700mmHg, pass to 130 ℃ of open steams, can get residual solvent at last is 50 * 10
-6Following processed oil 1.45kg.
Pre-pressed crude oil aquation dehydration with leaching the crude oil treating processes, can obtain the processed oil about 11.5kg, and two kinds of oil contents are opened, and the local flavor of pre-pressed crude oil is better.
Embodiment 2
Spore inoculating is cultivated 40-45 hour whole the immigration in the fermentor tank that the 1200L material is housed in the seeding tank that the 120L material is housed, put jar in 72-96 hour and can obtain the 50kg dry mycelium, steam stir-fry 30 minutes for thalline, indirect steam is 105 ℃, and squeezing can obtain the prediction press for extracting juice crude oil of 20.55kg then.
28.4kg the bacterium cake, the solvent oil that adds 28.4L soaked 1 hour at 55 ℃, collect extraction liquid, extraction liquid concentrates through long-tube evaportor, dish formula stripping tower and can obtain 3.32kg and leach crude oil, will leach crude oil and pump in the aquation pot 70 ℃ of heating and add 0.32kg3%NaCl solution, stirs minute to cool off to leave standstill 24 hours, skim upper strata oil, pump into precipitation pot vacuum tightness-700mmHg, pass to 130 ℃ of open steams, can obtain residual solvent at last is 50 * 10
-6Following processed oil 3.18kg.
Pre-oil expression aquation dehydration with going out the crude oil treating processes, can obtain the processed oil of 19.8kg.
Implementation step is identical with embodiment 1.
Embodiment 3
With spore inoculating in the seeding tank that 500L material is housed, cultivate and all moved in 40-45 hour in the fermentor tank that the 2500L material is housed, put in 72-96 hour and jar can obtain the 102kg dry mycelium, dry mycelium is steamed fried 30 minutes, indirect steam is 105 ℃, and squeezing can obtain the prediction press for extracting juice crude oil of 38.8kg then.
The bacterium cake of 62kg, the solvent oil that adds 62L soaked 1 hour at 55 ℃, collect extraction liquid, extraction liquid concentrates through long-tube evaportor, dish formula stripping tower and can obtain 7.1kg and leach crude oil, will leach crude oil and pump into and heat 70 ℃ and add 0.7kg3%NaCl solution in the aquation pot, stirred 20 minutes, left standstill 24 hours, the upper strata oil pump is gone into precipitation pot, vacuum tightness-700mmHg, pass to 130 ℃ of open steams, can obtain residual solvent at last is 50 * 10
-6Following processed oil 6.9kg.
Pre-oil expression aquation dehydration with going out the crude oil treating processes, can obtain the processed oil of 37.2kg.
Implementation step is identical with embodiment 1.