Method for preparing carotenoids by rhodotorula and application thereof

Abstract

The application relates to the field of microbial technology, and discloses a method for preparing carotenoids by using rhodotorula and application, the method comprising the following steps: culturing rhodotorula in a fermentation medium, and culturing under blue light for 4 days; the fermentation medium comprises glucose, yeast powder, peptone, malt extract, potassium dihydrogen phosphate, magnesium sulfate, riboflavin and vitamin B; the mass concentration of the glucose in the fermentation medium is 20 g / L, the mass concentration of the yeast powder is 5 g / L, the mass concentration of the peptone is 5 g / L, the mass concentration of the malt extract is 3 g / L, the mass concentration of the potassium dihydrogen phosphate is 3 g / L, the mass concentration of the magnesium sulfate is 3 g / L, the mass concentration of the riboflavin is 3.6 mg / L, and the mass concentration ratio of the riboflavin and the vitamin B is 7:3. The liquid culture method is adopted, and the yield of carotenoids produced by rhodotorula is improved.

Description

[0001] This application claims priority to Chinese Patent Application No. 2024114272912, filed on October 14, 2024, the entire contents of which are incorporated herein by reference. TECHNICAL FIELD

[0002] The present application relates to the field of microbial technology, in particular to a method for preparing carotenoids by Rhodotorula and application thereof. BACKGROUND

[0003] Carotenoids are a class of important natural pigments, which are widely present in yellow, orange-red or red pigments of animals, higher plants, fungi and algae. Carotenoids are the main source of vitamin A in the body, and also have the effects of antioxidant, immune regulation, anticancer and anti-aging.

[0004] Currently, some researchers promote Rhodotorula to produce more carotenoids by using blue light, which can increase the yield of carotenoids, but also causes the number of Rhodotorula to decrease. Therefore, using blue light to promote Rhodotorula to produce more carotenoids is not a sustainable process. SUMMARY

[0005] In order to solve the above technical problems, the present application provides a method for preparing carotenoids by Rhodotorula and application thereof. The culture method of the present application can solve the damage caused by blue light, so that Rhodotorula can sustainably produce more carotenoids.

[0006] The present application provides a method for preparing carotenoids by Rhodotorula, which comprises: culturing Rhodotorula in a fermentation medium under blue light for 4 days.

[0007] The fermentation medium comprises glucose, yeast powder, peptone, malt extract, potassium dihydrogen phosphate, magnesium sulfate, riboflavin and vitamin B. The mass concentration of glucose in the fermentation medium is 20 g / L, the mass concentration of yeast powder is 5 g / L, the mass concentration of peptone is 5 g / L, the mass concentration of malt extract is 3 g / L, the mass concentration of potassium dihydrogen phosphate is 3 g / L, the mass concentration of magnesium sulfate is 3 g / L, the mass concentration of riboflavin is 3.6 mg / L, and the mass concentration ratio of riboflavin to vitamin B is 9-5:1-5.

[0008] Further, the Rhodotorula is BNCC119738 from North China Pharmaceutical and Biological Corporation (BNCC).

[0009] Further, the mass concentration ratio of riboflavin to vitamin B in the fermentation medium is selected from one of 9:1, 7:3 and 1:1.

[0010] Further, the mass concentration ratio of riboflavin and vitamin B in the fermentation medium is 7:3.

[0011] Further, the vitamin B includes one or more of vitamin B1 and vitamin B6.

[0012] Further, the vitamin B is vitamin B1 and vitamin B6.

[0013] Further, the mass concentration ratio of vitamin B1 and vitamin B6 is (1-7):(1-7).

[0014] Further, the mass concentration ratio of vitamin B1 and vitamin B6 is selected from one of 1:1, 3:7 and 7:3.

[0015] Further, the mass concentration ratio of vitamin B1 and vitamin B6 is 7:3.

[0016] Further, the intensity of blue light is 1000 lux, and the irradiation time of blue light is 4 days.

[0017] Further, the pH value of the fermentation medium is 6-6.4.

[0018] Further, the fermentation culture condition further includes aerobic culture at 30 DEG C.

[0019] Further, before culturing the red yeast in the fermentation medium, the red yeast needs to be activated in a YM medium.

[0020] Further, the components of the YM medium include yeast paste 3g / L, malt extract 3g / L, glucose 10g / L and peptone 5g / L.

[0021] Further, the pH value of the YM medium is 6-6.4.

[0022] Further, the activation condition includes aerobic culture at 30 DEG C for 24-48h.

[0023] Further, after the red yeast is activated in the YM medium, the red yeast is inoculated into the fermentation medium for culture, the activated red yeast in the YM medium is transferred into the fermentation medium, and the volume ratio of the transferred YM medium to the fermentation medium is 4%.

[0024] The application further provides application of the method for preparing carotenoids by the red yeast in production of carotenoids.

[0025] The application has the following technical effects:

[0026] 1. In the present application, by designing and selecting the liquid medium, in the liquid medium, blue light stimulates the synthesis pathway of carotenoids in Rhodotorula, thereby favorably increasing the yield of carotenoids, and in the culture medium of the present application, riboflavin and vitamin B are also added to stimulate the metabolic pathway of Rhodotorula and the growth of Rhodotorula; not only can solve the damage brought by blue light to yeast, promote the rapid growth of Rhodotorula in the liquid medium, make the number of viable Rhodotorula cells in the liquid medium increase, but also riboflavin and vitamin B can increase the yield of carotenoids.

[0027] 2. In the present application, by further selecting the mass concentration ratio between riboflavin and vitamin B, and the irradiation time and intensity of blue light, not only the number of viable Rhodotorula cells is further increased, but also the yield of carotenoids is further increased. DETAILED DESCRIPTION

[0028] To make the purpose, technical scheme and advantages of the present application clearer, the technical scheme of the present application will be described clearly and completely below. Obviously, the described embodiments are only some of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor belong to the scope of protection of the present application.

[0029] In some embodiments of the first aspect, the present application provides a method for preparing carotenoids by Rhodotorula, the method comprising: culturing Rhodotorula in a fermentation medium, and culturing under blue light for 4 days.

[0030] The fermentation medium comprises glucose, yeast powder, peptone, malt extract, potassium dihydrogen phosphate, magnesium sulfate, riboflavin and vitamin B, wherein the mass concentration of glucose in the fermentation medium is 20 g / L, the mass concentration of yeast powder is 5 g / L, the mass concentration of peptone is 5 g / L, the mass concentration of malt extract is 3 g / L, the mass concentration of potassium dihydrogen phosphate is 3 g / L, the mass concentration of magnesium sulfate is 3 g / L, the mass concentration of riboflavin is 3.6 mg / L, and the mass concentration ratio of riboflavin to vitamin B is (9-5):(1-5).

[0031] In some embodiments, the Rhodotorula is BNCC119738 from North China Pharmaceutical and Biological Corporation (BNCC).

[0032] In some embodiments, the mass concentration ratio of riboflavin to vitamin B in the fermentation medium is selected from one of 9:1, 7:3 and 1:1.

[0033] In some embodiments, the mass concentration ratio of riboflavin to vitamin B in the fermentation medium is 7:3.

[0034] In the present application, when the mass concentration ratio between riboflavin and vitamin B in the fermentation medium is 7:3, the synthesis of carotenoids by the red yeast and the growth of the live yeast are promoted.

[0035] In some embodiments, the vitamin B includes one or more of vitamin B1 and vitamin B6.

[0036] In some embodiments, the vitamin B is vitamin B1 and vitamin B6.

[0037] In some embodiments, the ratio of vitamin B1 and vitamin B6 by mass concentration is (1-7):(1-7).

[0038] In some embodiments, the ratio of vitamin B1 and vitamin B6 by mass concentration is selected from one of 1:1, 3:7 and 7:3.

[0039] In some embodiments, the ratio of vitamin B1 and vitamin B6 by mass concentration is 7:3.

[0040] Riboflavin and vitamin B can alleviate the damage to yeast cells caused by blue light from multiple dimensions.

[0041] On the one hand, riboflavin itself has the performance of antioxidant defense, which can scavenge ROS and maintain the redox homeostasis. Riboflavin itself is also a photosensitive molecule, which can absorb blue light energy and release it in the form of heat energy, reducing the generation of ROS caused by energy transmission to other molecules. As the precursor of flavin adenine dinucleotide (FAD) and flavin mononucleotide (FMN), FAD / FMN participates in the composition of antioxidant enzymes (such as catalase and glutathione reductase), directly scavenging H2O2 and regenerating reduced glutathione (GSH), and maintaining the intracellular antioxidant capacity. Studies have found that supplementing riboflavin can increase the GSH level in yeast cells and reduce the content of blue light-induced lipid peroxidation products (such as malondialdehyde). In addition, vitamin B1 also participates in the regulation of the activity of the intracellular antioxidant system. For example, it can affect the synthesis or activity of certain antioxidant enzymes (such as superoxide dismutase SOD, catalase CAT, etc.), enhancing the cell's ability to scavenge ROS. Studies have shown that vitamin B6 deficiency can increase the sensitivity of cells to oxidative stress, while supplementing vitamin B6 can enhance the antioxidant capacity of cells and reduce the accumulation of blue light-induced ROS.

[0042] On the other hand, blue light-induced lipid peroxidation can destroy the integrity and fluidity of the cell membrane. Vitamin B complex can maintain cell integrity, and it can maintain the normal structure and function of the cell membrane by inhibiting lipid peroxidation or participating in the synthesis and repair process of cell membrane lipids, thereby reducing the damage of blue light to cells. For example, vitamin Bl can regulate energy metabolism and maintain ATP supply under cell stress. Thiamine pyrophosphate (TPP) is a coenzyme of pyruvate dehydrogenase complex and a-ketoglutarate dehydrogenase complex, which promotes the products of glycolysis to enter the tricarboxylic acid cycle, ensures the energy supply of cells under blue light stress, and avoids repair dysfunction caused by ATP deficiency. Studies have shown that vitamin Bl deficiency can exacerbate blue light-induced mitochondrial membrane potential decline in yeast, and supplementing vitamin Bl can maintain mitochondrial integrity. Vitamin B2 participates in the cell cycle and regulates its stress response. FAD derived from vitamin B2 can act as a cofactor for transcription factors to regulate the expression of stress-related genes such as heat shock proteins (HSPs) and antioxidant enzymes, thereby enhancing the tolerance of cells to blue light. Nicotinic acid inhibits the expression of pro-apoptotic genes through NAD + dependent deacetylases (such as Sir2) to reduce blue light-induced programmed cell death. For example, in Saccharomyces cerevisiae, the addition of vitamin B complex can improve the cell survival rate after blue light irradiation.

[0043] Finally, riboflavin and vitamins Bl and B6 have a synergistic effect in cell metabolism and are involved in processes such as cell metabolism, energy production, antioxidant defense, and cell repair. Riboflavin can work synergistically with glutathione (GSH), vitamin Bl, B6, etc.: for example, ROS generated by riboflavin can promote the oxidation-reduction cycle of GSH (GSH→GSSG→GSH), enhancing the overall ability of cells to scavenge free radicals and forming multiple antioxidant defense lines. The sugar metabolism involving vitamin Bl provides energy and intermediates for the amino acid metabolism and nucleic acid synthesis involving vitamin B6, and the antioxidant system and protein synthesis regulated by vitamin B6 can support the physiological functions of vitamin Bl, and they work together to more effectively alleviate the damage of blue light to yeast cells.

[0044] In some embodiments, the intensity of the blue light is 1000 lux, and the time of blue light irradiation is 4 days.

[0045] In some embodiments, the pH value of the fermentation medium is 6-6.4.

[0046] In some embodiments, the fermentation culture conditions further include aerobic conditions at 30°C.

[0047] In some embodiments, before culturing the Rhodotorula in the fermentation medium, the Rhodotorula needs to be activated in a YM medium.

[0048] In some embodiments, the components of the YM medium include yeast extract 3 g / L, malt extract 3 g / L, glucose 10 g / L, and peptone 5 g / L.

[0049] In some embodiments, the pH value of the YM medium is 6-6.4.

[0050] In some embodiments, the activation condition includes culturing for 24-48 h at 30°C in an aerobic condition.

[0051] In some embodiments, the activated Rhodotorula is inoculated into a fermentation medium for culturing, and the activated YM medium is transferred into the fermentation medium, and the volume ratio of the transferred YM medium to the fermentation medium is 4%.

[0052] In the second aspect, the application provides the use of the method for preparing carotenoids by the Rhodotorula in the production of carotenoids.

[0053] The following describes some specific embodiments:

[0054] The activation process of the Rhodotorula: the Rhodotorula is BNCC119738 from the North China Pharmaceutical and Biological Engineering Corporation (BNCC), which is inoculated into a YM medium. The components of the YM medium include yeast extract 3 g / L, malt extract 3 g / L, glucose 10 g / L, and peptone 5 g / L, and the solvent is distilled water. The pH value is 6-6.4, and the sterilization is performed at 121°C for 20 min. The Rhodotorula is activated by culturing for 48 h at 30°C in an aerobic condition.

[0055] Embodiment 1:

[0056] A fermentation medium is prepared. In the fermentation medium, the components include yeast powder 5 g, glucose 20 g, peptone 5 g, malt extract 3 g, potassium dihydrogen phosphate 3 g, magnesium sulfate 3 g, riboflavin 3.6 mg, and vitamin B 1.54 mg (vitamin B includes vitamin B1 and vitamin B6, and the mass concentration ratio of vitamin B1 to vitamin B6 is 7:3). The pH value of the fermentation medium is adjusted to 6.2, and the sterilization is performed at 121°C for 20 min. The activated YM medium is transferred into the sterilized fermentation medium, and the volume ratio of the transferred YM medium to the sterilized fermentation medium is 4%. The irradiation culturing is performed for 4 days under the blue light intensity of 1000 lux, at 30°C in an aerobic condition.

[0057] Embodiment 2:

[0058] A fermentation medium was prepared, in which yeast powder 5 g, glucose 20 g, peptone 5 g, malt extract 3 g, potassium dihydrogen phosphate 3 g, magnesium sulfate 3 g, riboflavin 3.6 mg, vitamin B1 1.54 mg, distilled water 1 L, and the pH of the fermentation medium was adjusted to 6.2, and sterilized at 121°C for 20 min. The YM medium in which the Rhodotorula was activated was transferred to the sterilized fermentation medium, and the volume ratio of the transferred YM medium to the sterilized fermentation medium was 4%, and irradiation culture was performed under blue light intensity of 1000 lux, 30°C, and aerobic conditions for 4 days.

[0059] Example 3:

[0060] A fermentation medium was prepared, in which yeast powder 5 g, glucose 20 g, peptone 5 g, malt extract 3 g, potassium dihydrogen phosphate 3 g, magnesium sulfate 3 g, riboflavin 3.6 mg, vitamin B1 1.54 mg, distilled water 1 L, and the pH of the fermentation medium was adjusted to 6.2, and sterilized at 121°C for 20 min. The YM medium in which the Rhodotorula was activated was transferred to the sterilized fermentation medium, and the volume ratio of the transferred YM medium to the sterilized fermentation medium was 4%, and irradiation culture was performed under blue light intensity of 1000 lux, 30°C, and aerobic conditions for 4 days.

[0061] Example 4:

[0062] A fermentation medium was prepared, in which yeast powder 5 g, glucose 20 g, peptone 5 g, malt extract 3 g, potassium dihydrogen phosphate 3 g, magnesium sulfate 3 g, riboflavin 3.6 mg, vitamin B1 1.54 mg, distilled water 1 L, and the pH of the fermentation medium was adjusted to 6.2, and sterilized at 121°C for 20 min. The YM medium in which the Rhodotorula was activated was transferred to the sterilized fermentation medium, and the volume ratio of the transferred YM medium to the sterilized fermentation medium was 4%, and irradiation culture was performed under blue light intensity of 1000 lux, 30°C, and aerobic conditions for 4 days.

[0063] Example 5:

[0064] A fermentation medium was prepared, in which yeast powder 5 g, glucose 20 g, peptone 5 g, malt extract 3 g, potassium dihydrogen phosphate 3 g, magnesium sulfate 3 g, riboflavin 3.6 mg, vitamin B 1.54 mg (in which vitamin B is vitamin B1 and vitamin B6, and the mass concentration ratio of vitamin B1 and vitamin B6 is 3:7), and distilled water 1 L were contained. The pH value of the fermentation medium was adjusted to 6.2, and the fermentation medium was sterilized at 121°C for 20 min. The YM medium in which the Rhodotorula was activated was transferred into the sterilized fermentation medium, and the volume ratio of the transferred YM medium to the sterilized fermentation medium was 4%. The culture was irradiated under blue light with an intensity of 1000 lux, at 30°C, and in the presence of oxygen for 4 days.

[0065] Comparative Example 1

[0066] A fermentation medium was prepared, in which yeast powder 5 g, glucose 20 g, peptone 5 g, malt extract 3 g, potassium dihydrogen phosphate 3 g, magnesium sulfate 3 g, and distilled water 1 L were contained. The pH value of the fermentation medium was adjusted to 6.2, and the fermentation medium was sterilized at 121°C for 20 min. The YM medium in which the Rhodotorula was activated was transferred into the sterilized fermentation medium, and the volume ratio of the transferred YM medium to the sterilized fermentation medium was 4%. The culture was performed at 30°C, in the presence of oxygen, for 4 days, and was subjected to dark treatment.

[0067] Comparative Example 2

[0068] A fermentation medium was prepared, in which yeast powder 5 g, glucose 20 g, peptone 5 g, malt extract 3 g, potassium dihydrogen phosphate 3 g, magnesium sulfate 3 g, and distilled water 1 L were contained. The pH value of the fermentation medium was adjusted to 6.2, and the fermentation medium was sterilized at 121°C for 20 min. The YM medium in which the Rhodotorula was activated was transferred into the sterilized fermentation medium, and the volume ratio of the transferred YM medium to the sterilized fermentation medium was 4%. The culture was irradiated under blue light with an intensity of 1000 lux, at 30°C, and in the presence of oxygen for 4 days.

[0069] Comparative Example 3

[0070] The activation process of the Rhodotorula mucilaginosa was as follows. The Rhodotorula mucilaginosa was inoculated in a YM medium, and the YM medium contained yeast extract 3 g / L, malt extract 3 g / L, glucose 10 g / L, and peptone 5 g / L, and the pH value was 6-6.4. The YM medium was sterilized at 121°C for 20 min. The Rhodotorula mucilaginosa was activated by being cultured at 22°C for 48 h in the presence of oxygen.

[0071] The fermentation medium was prepared, in which yeast powder 5 g, glucose 20 g, peptone 5 g, malt extract 3 g, potassium dihydrogen phosphate 3 g, magnesium sulfate 3 g, distilled water 1 L, and the pH value of the fermentation medium was adjusted to 6.2, and sterilized at 121°C for 20 min. The YM medium in which the Rhodotorula mucilaginosa was activated was transferred to the sterilized fermentation medium, and the volume ratio of the transferred YM medium to the sterilized fermentation medium was 4%, and cultured at 30°C under oxygen for 4 days, and dark treatment.

[0072] Comparative Example 4

[0073] The activation process of the Rhodotorula mucilaginosa: the Rhodotorula mucilaginosa was BNCC336673, inoculated in the YM medium, the components of the YM medium were yeast extract 3 g / L, malt extract 3 g / L, glucose 10 g / L, peptone 5 g / L, and the solvent was distilled water; the pH value was 6-6.4, and sterilized at 121°C for 20 min. Cultured at 22°C for 48 h under oxygen, and the Rhodotorula mucilaginosa was activated.

[0074] The fermentation medium was prepared, in which yeast powder 5 g, glucose 20 g, peptone 5 g, malt extract 3 g, potassium dihydrogen phosphate 3 g, magnesium sulfate 3 g, distilled water 1 L, and the pH value of the fermentation medium was adjusted to 6.2, and sterilized at 121°C for 20 min. The YM medium in which the Rhodotorula mucilaginosa was activated was transferred to the sterilized fermentation medium, and the volume ratio of the transferred YM medium to the sterilized fermentation medium was 4%, and cultured at 30°C under oxygen for 4 days, and dark treatment.

[0075] Comparative Example 5

[0076] The activation process of the Rhodotorula mucilaginosa: the Rhodotorula mucilaginosa was BNCC336673, inoculated in the YM medium, the components of the YM medium were yeast extract 3 g / L, malt extract 3 g / L, glucose 10 g / L, peptone 5 g / L, and the solvent was distilled water; the pH value was 6-6.4, and sterilized at 121°C for 20 min. Cultured at 22°C for 48 h under oxygen, and the Rhodotorula mucilaginosa was activated.

[0077] A fermentation medium was prepared, in which the fermentation medium contained 5 g of yeast powder, 20 g of glucose, 5 g of peptone, 3 g of malt extract, 3 g of potassium dihydrogen phosphate, 3 g of magnesium sulfate, 3.6 mg of riboflavin, 1.54 mg of vitamin B (in which vitamin B is vitamin B1 and vitamin B6, and the mass concentration ratio of vitamin B1 and vitamin B6 is 7:3), 1 L of distilled water, the pH value of the fermentation medium was adjusted to 6.2, and the fermentation medium was sterilized at 121°C for 20 min. The activated YM medium of Phaffia rhodozyma was transferred to the sterilized fermentation medium, the volume ratio of the transferred YM medium to the sterilized fermentation medium was 4%, and the irradiation culture was carried out under the condition of blue light intensity of 1000 lux, 30°C, and aerobic condition for 4 days.

[0078] The examples and comparative examples were detected.

[0079] The test method of the biomass was a dry weight weighing method, 5 mL of bacterial liquid was centrifuged at 8000 rpm for 10 min, then washed with deionized water for 2 times to obtain wet bacterial bodies, and the wet bacterial bodies were dried at 60°C.

[0080] 1 mL of the fermentation liquid was taken and added into a 10 mL centrifuge tube, diluted by an appropriate multiple, 2 / 3 of the liquid amount was taken and added into a cuvette, and the OD was measured by using an ultraviolet spectrophotometer 600 , the measurement range was between 0.01 and 0.9, and the biomass of the fermentation liquid was calculated.

[0081] The test method of the carotenoid yield was as follows: 2 mL of the fermentation liquid was taken and added into a 10 mL centrifuge tube, centrifuged at 8000 rpm for 10 min, the bacterial bodies were collected and washed with sterile water for 3 times, at this time, the supernatant was discarded. Then, 4 mL of a prepared 3 mol / L hydrochloric acid solution was added into the washed bacterial bodies, oscillation immersion was carried out for 30 min to acid hydrolyze the yeast cell wall, heating was carried out in boiling water for 4 min, the bacterial bodies were quickly placed in ice water for cooling. The broken cell wall treated by the acid hydrolysis method and cooled was centrifuged at 8000 rpm for 10 min, the precipitate was collected and washed with distilled water for 2-3 times, the supernatant was discarded, 4 mL of acetone was added, oscillation extraction was carried out for 5 min in the dark, centrifugation was carried out at 8000 rpm for 10 min, a certain amount of supernatant was diluted by a certain multiple, and the absorbance A value of the acetone extract was measured at 450 nm by using a spectrophotometer; if the extraction was not complete, more acetone was added for extraction, until the bacterial bodies were colorless. The carotenoid yield was calculated according to the following formula:

[0082] The carotenoid yield of the unit volume of the fermentation liquid (μg / mL) = ;

[0083] The total carotenoid yield of the unit volume of the fermentation liquid = the carotenoid content of the unit volume of the fermentation liquid x W;

[0084] In the formula,

[0085] A - absorbance at the maximum wavelength of carotenoids;

[0086] D - dilution factor of the pigment extract;

[0087] V - total volume of the solvent used for extraction (mL);

[0088] W - volume of the fermentation broth used for extraction (mL);

[0089] 0.16 - molar extinction coefficient of carotenoids.

[0090] Results and analysis:

[0091] Table 1 - Biomass test results of examples and comparative examples

[0092]

[0093] Table 2 - Carotenoid production test results of examples and comparative examples

[0094]

[0095] In Table 2, it is found by comparing Comparative Example 1-Comparative Example 4 that although the production of carotenoids by Rhodotorula and Phaffia can be improved by blue light irradiation, the growth of Rhodotorula and Phaffia is inhibited by blue light. It is found that the damage to the yeast cells caused by blue light leads to the inhibition of the growth of the yeast, which can be verified in Table 1. In Table 1, the biomass of the yeast of Comparative Example 1 is significantly higher than that of Comparative Example 2 within 10 days of fermentation, and the addition of vitamin B can reduce the damage to the yeast caused by blue light, thereby improving the biomass of the yeast. Within 10 days of fermentation, the biomass of Examples 1-3 is significantly higher than that of Comparative Examples 1-2.

[0096] It can be found in Table 1 that the growth of the yeast is slow with the increase of the fermentation time, and therefore, the production of carotenoids within 4 days of fermentation is studied in the present application, as shown in Table 2.

[0097] On this basis, the synergistic effect between other vitamin B and riboflavin is further studied, and it is found that although they all belong to vitamin B group, the structure and mechanism of action of vitamin B are different, resulting in the difference between the effects. It is found by comparing Examples 1-5 that Example 1 has better effect, which may be that the synergistic effect of vitamin B1, riboflavin and vitamin B6 can better improve the damage to the yeast caused by blue light, thereby being conducive to the growth of the biomass of the yeast, and realizing the further increase of the production of carotenoids. Therefore, further optimization is made, and the vitamin B is vitamin B1 and vitamin B6, and the ratio of vitamin B1 and vitamin B6 is 7:3 in terms of mass concentration.

[0098] Finally, comparing from Example 1-Example 5 with Comparative Example 3-Comparative Example 4, it is found that although the yeast is damaged by blue light, there is difference between the effects due to different yeasts. It can be seen that the method of the present application is more suitable for Rhodotorula.

[0099] Finally, it should be noted that: the above examples are only used to illustrate the technical solutions of the present application, but not to limit them; although the present application has been described in detail with reference to the foregoing examples, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing examples, or make equivalent replacement for part or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the technical solutions of the embodiments of the present application.

Claims

1. A method for preparing carotenoids by Rhodotorula, characterized by, The method comprises: culturing the Rhodotorula in a fermentation medium, and culturing under blue light for 4 days. The fermentation medium comprises glucose, yeast powder, peptone, malt extract, potassium dihydrogen phosphate, magnesium sulfate, riboflavin and vitamin B, wherein the mass concentration of glucose in the fermentation medium is 20 g / L, the mass concentration of yeast powder is 5 g / L, the mass concentration of peptone is 5 g / L, the mass concentration of malt extract is 3 g / L, the mass concentration of potassium dihydrogen phosphate is 3 g / L, the mass concentration of magnesium sulfate is 3 g / L, the mass concentration of riboflavin is 3.6 mg / L, and the mass concentration ratio of riboflavin to vitamin B is 7:

3. The vitamin B is vitamin B1 and vitamin B6. The ratio of vitamin B1 to vitamin B6 is (1-7):(1-7) by mass concentration. The Rhodotorula is North Nai Biology BNCC119738.

2. The method of claim 1, wherein, The intensity of the blue light is 1000 lux, and the time of blue light irradiation is 4 days.

3. The method of claim 1, wherein, The pH value of the fermentation medium is 6-6.4, and the fermentation culture conditions further comprise oxygen at 30 DEG C.

4. The method of claim 1, wherein, Before culturing the Rhodotorula in the fermentation medium, the Rhodotorula needs to be activated in a YM medium.

5. The method of claim 1, wherein, After the Rhodotorula is activated in the YM medium, the activated Rhodotorula is inoculated into the fermentation medium for culture, the YM medium of the activated Rhodotorula is transferred into the fermentation medium, and the volume ratio of the transferred YM medium to the fermentation medium is 4%.

6. The method for preparing carotenoids by the Rhodotorula according to any one of claims 1-5 is applied in the production of carotenoids.

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