Plant lactobacillus and with the method for this bacterium biological preparing conjugated linoleic acid
Technical field
Plant lactobacillus CCTCC No.M206033 and with the method for this bacterium biological preparing conjugated linoleic acid, particularly a kind of free linoleic acid that transforms is produced the lactobacterium plantarum strain of conjugated linolic acid and is transformed the method for producing, and belongs to technical field of bioengineering.
Background technology
Linolic acid (be called for short LA) be a kind of contain suitable-9, the octadecadienoic acid of suitable-12 conformations.Conjugated linolic acid (be called for short CLA) is the various common names that contain the linoleic acid isomers of conjugated double bond, is the human most important function lipid acid of finding over nearly 20 years, wherein suitable-9, anti--11 and trans-10, and suitable-12 isomer biologically actives.Conjugated linolic acid extensively is present in all kinds of natural foods, mainly is present in the butterfat and meat product of cud animal ox, sheep etc., and CLA content does not wait from 2~25mg in every gram butterfat, and the content of CLA increases with the age growth of milk cow.
1978, the scientists of the hot nutrient research of University of Wisconsin-Madison institute during the carcinogenic mutagenic compound of generation, chanced on a kind of linoleic isomer and can suppress mutagenesis in research meat bake process.Studies show that, conjugated linolic acid is except having very strong anti-cancer function, also have lowering blood-fat and reducing weight, regulate body metabolism, improve immunizing power, reducing blood-fat, decreasing cholesterol, atherosclerosis, blood sugar regulation, prevent and treat diabetes, anti-oxidant, improve functions such as skeleton density, antifatigue, improvement sleep.Therefore the mid-90 in 20th century, conjugated linolic acid takes the lead in after U.S.'s list marketing as nutrient supplement food, rapidly in the North America, minority developed country such as Europe and Japan and area be fast-selling, formed the new fashion of health-nutrition material consumption.
The artificial conjugated linolic acid that obtains can perhaps transform two kinds of main paties of natural acid by certain micro-organisms by chemical method synthetic (Wu Jihua, 2001).Biological process mainly is to utilize that the synthetic enzyme acts on substrate in the microorganism growth process, transforms linolic acid and generates conjugated linolic acid.Kepler in 1967 and Tove (J.Biol.Chem., 242:5686-5692 (1967)) point out, and be suitable-9, and anti-11-18:2 is first intermediate product that rumen bacteria such as Butyrivibrio fibrisolvens (Butyrivibrio fibrisolvens) act on LA.Contain linoleate isomerase in the rumen bacteria, explained the reason that higher CLA is arranged in the ruminating animal tissue.Someone will can carry out enrichment to the bacterium that LA is converted into CLA in the cud, and to synthesizing trans-10 in a large number, along the bacterial strain of 12-18:2 according to bacterial concentration carried out sorting (Park Y.et al., Lipids., 34 (3): 234-248 (1999)).In addition, isolating 5 kinds of strict anaerobes from sheep rumen (l strain Ruminococcus albus, 2 strain Eubacterium spp, 2 strain Fusocillus spp), can both be converted into CLA to LA by hydrogenization, but CLA shared ratio in gross product differs just.But rumen bacteria strictly anaerobic such as Butyrivibrio fibrisolvens is not suitable for suitability for industrialized production CLA.In addition. rumen bacterias such as Butyrivibrio fibrisolvens also contain and are unfavorable for CLA synthetic reductase enzyme, and this reductase enzyme can further change into other compounds to CLA, and some ruminates bacterium can also make the LA hydrogenation become stearic acid.(Applied Microbiology. such as Jiang in 1998,85:95-102 (1998)) makes the primary election substratum with MRS and detected the ability that 7 strain Bacterium lacticum, 4 strain galactococcuses, 2 strain suis and 6 strain bacterium acidi propionicis are converted into LA CLA, found that, under the condition that the experimenter adopted, only have 3 strain bacterium acidi propionici cell cultures that the ability of synthetic CLA is arranged, the factors such as substratum composition, tween 80, protein of finding in addition can influence the synthetic of CLA.1999, U.S. scientist Pariza M W, Yang X.Y. ([P] U.S.:5856149 (1999)) has reported that at first a strain lactobacillus (Lactobacillus reuteri) has a kind of cytolemma desmoenzyme, and it can be the synthetic CLA of raw material with the free linolic acid.
Calendar year 2001 Japan (Appli.Envir.Microbiol. such as scientist Ogawa, 67:1246-1252 (2001)) reported that Lactobacillus acidophilus AKU 1137 is that feedstock conversion is that the process of CLA is not to turn to conjugated double bond from one step of unconjugated double bond isomery with LA, but related to the synthetic of hydroxy fatty acid (10-hydroxyl-12 is suitable-octadecenoic acid and 10-hydroxyl-12 be anti--octadecenoic acid) intermediate product.This is to disclose the mechanism that LA transforms to CLA first, and the product that this Lactobacillus acidophilus transforms mainly is suitable-9, anti-11-18:2; Instead-9, along 11-18:2 and anti--9, anti-11-18:2 almost all is present in the thalline or links to each other with thalline with the form of free fatty acids.
Compare with chemical synthesis, the transformation efficiency of biological process is relatively low, but the biological process synthesis of conjugated linoleic acid has specificity, biologically active is suitable in the product-9, and anti-11-18:2 content of isomer is very high, and other content of isomer is few, and biological process transforms conjugated linolic acid reaction conditions gentleness, energy consumption is low, pollutes for a short time, and security of products is higher.People such as Pariza ([P] U.S.:5856149 (1999)) studies show that, utilize lactobacillus (Lactobacillus reuteri PYR8) to transform conjugated linolic acid, and every gram cell transformation produces the 7.8mg conjugated linolic acid.Suitable among the CLA that obtains-9, the content of anti--11 isomer is more than 98%, only has a spot of suitablely-9, and along 11 and anti--9, suitable-11 isomer exist.
Studies show that: Butyrivibrio fibrisolvens rumen bacterias such as (Butyrivibrio fibrisolvens) is then because strictly anaerobic can't drop into industrial application.Lactobacillus fermentation transforms produces conjugated linolic acid, is having the oxygen existence that the activity of isomerase and the productive rate of isomer are not all had influence, and Bacterium lacticum is stronger for the tolerance of conjugated linolic acid in addition, and has the potential using value at field of food.Bacterium lacticum becomes the research focus that industrial fermentation prepares conjugated linolic acid gradually.
Summary of the invention
The purpose of this invention is to provide a kind of plant lactobacillus CCTCC No.M206033 and with the method for this bacterium biological preparing conjugated linoleic acid.
Technical scheme of the present invention: a kind of is the bacterium pearl of conjugated linolic acid with the free linoleic acid bio-transformation, its classification called after plant lactobacillus (Lactobacillus plantarum) ZH008, and deposit number is CCTCCNo.M206033.
Method with CCTCC No.M206033 biological preparing conjugated linoleic acid
By the selection of conditions such as pre-incubation time, medium pH, conversion incubation time, conversion inoculum size, the method that sums up this bacterium conversion linolic acid biological preparing conjugated linoleic acid is:
(1) bacterial strain of bio-transformation employing is CCTCC No.M206033;
(2) substratum is:
Pre-culture medium is the MRS substratum that contains the 0.5mg/ml free linoleic acid;
The conversion substratum is: contain the 1.0mg/ml free linoleic acid pH6.5 the MRS substratum or contain the potassium phosphate buffer of the 0.1mol/L pH6.5 of 1.0mg/ml free linoleic acid;
(3) pre-culture condition: 1% inoculum size, cultivated 12-14 hour for 37 ℃;
(4) transform culture condition: the thalline after pre-the cultivation is with 2.0 * 10
10The cell concentration of cfu/ml is transferred in the MRS substratum of the pH6.5 that contains the 1.0mg/ml free linoleic acid, cultivates 36 hours for 37 ℃;
Or the thalline after pre-the cultivation is with 2.0 * 10
10The cell concentration of cfu/ml is transferred in the potassium phosphate buffer of the 0.1mol/L pH6.5 that contains the 1.0mg/ml free linoleic acid, cultivates 24 hours for 37 ℃.
Beneficial effect of the present invention: we are by a large amount of screening operations, separate from three kinds of sources of yoghourt from raw milk, pickles juice and Xinjiang herdsman and to obtain a kind of bacterium pearl that free linoleic acid generates conjugated linolic acid that transforms, confirm that through identifying it is plant lactobacillus, called after plant lactobacillus (Lactobacillus plantarum) ZH008, deposit number CCTCC No.M206033.The substrate linolic acid directly contacts with lactobacillus cell during the fermentation of this bacterium, and under membrane-bound linoleate isomerase effect, it is suitable-9 that linolic acid is converted into conjugated linolic acid, instead-11 isomer.This bacterium well-grown in aerobic environment.The present invention has determined the fermentation condition of conjugated linolic acid high yield also by a series of experiments.For preparing conjugated linolic acid, domestic biological process conversion linolic acid provides a kind of production technique efficiently.Therefore the present invention has crucial commercial value and application prospect.
Description of drawings
Fig. 1 CCTCC NO.M206033 different growing stages transforms the ability of CLA.
Fig. 2 transforms incubation time transforms the CLA productive rate to CCTCCNO.M206033 influence in MRS substratum (containing 1.0mg/mlLA).
Biological sample preservation explanation
Plant lactobacillus (Lactobacillus plantarum) ZH008 has been deposited in Chinese typical culture collection center, and depositary institution is called for short CCTCC, preservation date on April 10th, 2006, deposit number CCTCCNO.M206033.
Embodiment
Embodiment 1, the production technique of plant lactobacillus CCTCC No.M206033 biological preparing conjugated linoleic acid
Pre-incubation time is to the influence of CLA transformation efficiency:
Insert CCTCC No.M206033 in MRS substratum (contain 0.5mg/ml LA or do not contain LA) with 1% inoculum size, in collecting respectively through 0,6h, 12h, 18h and 24h, 37 ℃ of cultured cells are with 2.0 * 10
10The final concentration of cfu/ml is transferred to 37 ℃ of cultivation 24h among the 1ml MRS (containing 1.0mg LA) with above-mentioned cell, and gas chromatographic detection is CLA content wherein, the results are shown in Figure 1.
As can be seen from Figure 1, the ability of cultivating CCTCC No.M206033 cell transformation CLA by LA in advance generally is improved, particularly be in the cell of logarithmic phase latter stage (12h), it is the most remarkable that its ability that transforms CLA increases, and its CLA average conversion brings up to 11.7% from 3.9%.
Above experimental verification is with 1% inoculum size, and under the situation that 0.5mg/ml LA exists, it is the most favourable to transforming CLA during latter stage to be cultured to logarithmic phase in advance, and bacterial strain transforms produces conjugated linolic acid than strong without the ability under the LA inducing culture.
Transform and cultivate of the influence of pH value the CLA transformation efficiency:
Through 12h, (the bacterium number is about 2.0 * 10 to 37 ℃ of pre-incubated cells to collection CCTCC No.M206033 in MRS (containing 0.5mg/ml LA)
10Cfu/ml), add above-mentioned cell to 1ml, the LA addition is 1.0mg, and pH is respectively in 6.0,6.5,7.0,7.5 or 8.0 MRS and phosphate buffered saline buffer (KPB) reaction system 37 ℃ and cultivates 24h, and vapor-phase chromatography detects that wherein the CLA content results is as shown in table 1.
Under the table 1 substratum different pH condition and different pH damping fluid CLA conversion results
No matter can know from table 1, be to react at MRS or in KPB, and pH6.0~7.0 are more suitable pH value in reaction, and pH6.5 is optimal reaction pH value.
Transform the influence of incubation time to the CLA transformation efficiency:
(1) be substratum with the MRS that contains 1mg/ml LA:
Collection is cultivated the CCTCC No.M206033 cell of 12h in advance through 0.50mg/ml LA, with 2.0 * 10
10The final concentration of cells of cfu/ml transfer above-mentioned cell in the MRS substratum (containing 1.0mgLA) of 1ml pH6.5 37 ℃ cultivate 0 respectively, 12h, 24h, 36h, 48h, 60h, 72h, gas chromatographic detection is CLA content wherein, result such as Fig. 2.
As can be seen from Figure 2, in 0~36h scope, it is more remarkable that the CLA that produces in the MRS system along with the increase plant lactobacillus CCTCC No.M206033 of incubation time increases.When incubation time surpasses 36h, what CLA content increased in the MRS system is just very slow.(FoodChemistry such as this result and Lin T.Y, 1999,67:1-5.) experimental result similar, also illustrate simultaneously under the condition that we adopt, obtain the culture of high CLA content, 36h is proper incubation time, and output is 221.5 μ g/ml, prolongs incubation time again and there is no need.
Or (2) are substratum with the potassium phosphate buffer of the 0.1mol/L pH6.5 that contains 1mg/ml LA:
Collect in the 400mlMRS substratum plant lactobacillus CCTCCNO.M206033 through linolic acid induced growth 12h.Be suspended in the buffer solution of potassium phosphate of 40ml 0.1mol/lpH6.5, making cell concentration is 2.0 * 10
10Cfu/ml adds 40mgLA emulsion, 120rpm, and 37 ℃ are reacted 12h respectively, 24h, 36h and 90h..Separation and Extraction lipid acid is formed with gas chromatographic analysis lipid acid.
The result shows that plant lactobacillus CCTCC NO.M206033 intact cell can effectively be converted into CLA with LA in buffer solution of potassium phosphate (0.1mol/l pH6.5), mainly is along 9, anti-11-CLA, as reaction 24h, it is suitable-9 that 31.24% LA is converted into, anti-11-CLA; Suitable-9, the output of anti-11-CLA is 312.4 μ g/ml.
Transform the influence of inoculum size to the CLA transformation efficiency:
In order to investigate the cell addition CCTCC No.M206033 is transformed the influence of CLA ability, we collect and cultivate the CCTCC NO.M206033 cell of 12h in advance through 0.5mg/ml LA (cell concentration is respectively 1.0 * 10
9, 2.0 * 10
9, 8.0 * 10
9, 2.0 * 10
10Or 4.0 * 10
10Cfu/ml), add above-mentioned cell in the 1ml MRS (containing 1.0mg LA) 37 ℃ cultivate 36h, gas chromatographic detection is CLA content wherein, result such as table 2.
CLA transformation efficiency under the different cell concns of table 2
As can be seen from Table 2, along with the content of CLA in the increase MRS reaction system of biomass and transformation efficiency also increase thereupon, when cell concentration from 1.0 * 10
9Cfu/ml is increased to 2.0 * 10
10What the transformation efficiency of CLA increased during cfu/ml is the most obvious, and transformation efficiency is increased to 28.7% from 1.3%.But along with the continuation of biomass increases, the CLA transformation efficiency descends on the contrary to some extent.So we select 2 * 10
10The cell concn of cfu/ml is as the more satisfactory cell addition of CCTCCNO.M206033 cell transformation CLA.
In sum, plant lactobacillus CCTCC NO.M206033 is with 1% inoculum size, at the MRS substratum inducing culture that contains 0.5mg/mlLA to logarithmic phase latter stage (12-14h), with 2.0 * 10
10The cfu/ml cell concentration is transferred to pH6.5, contains in the MRS substratum of 1.0mg/ml LA, and the CLA transformation efficiency is the highest during 37 ℃ of effect 36h.Pre-culture also can be transferred in the potassium phosphate buffer of the 0.1mol/LpH6.5 that contains 1mg/ml LA by identical cell concentration, 37 ℃ of effects after 24 hours the CLA transformation efficiency the highest.