阅读说明：本技术 一种强化微藻固碳与甘油三酯积累的方法 (Method for enhancing carbon sequestration and triglyceride accumulation of microalgae ) 是由 耿媛媛 沈倩 聂煜东 张贤明 于 2021-08-25 设计创作，主要内容包括：本发明公开了一种强化微藻固碳及甘油三酯积累的方法,涉及微藻培养、微藻固碳以及微藻生物柴油领域。本发明主要是将体积分数为5％CO-(2)气体作为唯一碳源,向微藻培养液中添加具有固碳效果与促进光合作用的聚乙二醇溶液以及具有固碳作用的单乙醇胺溶液,该方法显著提高了微藻培养液中溶解性无机碳的浓度,微藻固碳效率,以及提升微藻生物量产率和甘油三酯含量。本发明提供聚乙二醇的主要作用是提高CO-(2)从气相到液相传质速率,提供单乙醇胺主要作用是提高微藻培养液对CO-(2)气体固定效率,继而为微藻生长和甘油三酯积累提供充足碳源。(The invention discloses a method for strengthening microalgae carbon sequestration and triglyceride accumulation, and relates to the fields of microalgae culture, microalgae carbon sequestration and microalgae biodiesel. The invention mainly uses 5 percent of CO by volume fraction 2 Adding polyethylene glycol solution with carbon fixing effect and photosynthesis promoting effect and carbon fixing monomer into microalgae culture solution with gas as sole carbon sourceThe method obviously improves the concentration of soluble inorganic carbon in the microalgae culture solution, the carbon fixation efficiency of the microalgae, and the biomass yield and the triglyceride content of the microalgae. The main function of the polyethylene glycol provided by the invention is to improve CO 2 The main effect of providing monoethanolamine is to improve the CO content of microalgae culture solution by the mass transfer rate from gas phase to liquid phase 2 Gas fixation efficiency, in turn, provides an adequate carbon source for microalgae growth and triglyceride accumulation.)

1. A method for strengthening carbon fixation and triglyceride accumulation of microalgae is characterized by comprising the step of respectively adding polyethylene glycol and monoethanolamine aqueous solution into microalgae culture solution with the pH of 6-8 to be used as strengthened CO₂The gas is converted into microalgae which can utilize a carbon source in the fields of microalgae carbon sequestration efficiency and microalgae biodiesel.

2. The method for enhancing microalgae carbon sequestration and triglyceride accumulation according to claim 1, wherein the concentration of the added polyethylene glycol is 0-2 mg/L.

3. The method for enhancing microalgae carbon sequestration and triglyceride accumulation according to claim 1, wherein monoethanolamine is added at a concentration of 0-500 mg/L.

4. The method for enhancing microalgae carbon sequestration and triglyceride accumulation according to claim 1, wherein the aqueous solution of polyethylene glycol and monoethanolamine is added after the culture medium is sterilized and cooled.

5. The method for enhancing microalgae carbon sequestration and triglyceride accumulation according to claim 1, further comprising introducing CO into microalgae culture fluid₂Introducing CO of 0-30% volume fraction into microalgae culture solution under gas condition₂A gas. The aeration time is 0-24 h.

6. The method of claim 5, wherein the CO is added to enhance microalgae carbon sequestration and triglyceride accumulation₂The gas is industrial discharged CO₂Gases, flue gases, or containing CO₂One or more combinations in air of gas。

7. The method for enhancing carbon sequestration and triglyceride accumulation of microalgae according to claims 1-6, wherein the culture medium is carbon-source-free BG11 culture medium, carbon-source-free Zarrouk culture medium, SE culture medium, f/2 culture medium.

8. The method for enhancing carbon sequestration and triglyceride accumulation in microalgae according to claims 1-7, wherein the microalgae is marine microalgae, freshwater microalgae, marine/freshwater microalgae, respectively, botryococcus, dunaliella, chlorella, scenedesmus, chlamydomonas reinhardtii, crypthecodinium, cylindracea, pavlova, chlorella, isochrysis galbana, phaeodactylum tricornutum, spirulina, botryococcus braunii, nannochloropsis minitans, etc.

Technical Field

The invention belongs to the field of microalgae culture, particularly relates to a method for enhancing carbon sequestration and triglyceride accumulation of microalgae, and particularly relates to CO utilization through physical-chemical absorption and biological utilization₂The method of (1).

Background

The microalgae carbon sequestration technology is a process for converting a large amount of carbon dioxide into biomass by using microalgae cells. The microalgae is one of organisms capable of fixing carbon, has the advantages of high photosynthetic rate, high propagation speed, strong environment adaptability and the like, and is equivalent to 10-50 times of the carbon fixing capacity of a forest. Carbon dioxide fixed by photosynthesis of microalgae accounts for 40% of the global carbon dioxide fixation every year. However, CO₂Some technical bottlenecks still exist in microalgae carbon sequestration, such as low-concentration CO₂Low solubility of gas in water and limited photosynthetic efficiency of microalgae.

Currently, chemical absorption processes have higher CO due to their higher CO content₂The collection efficiency is of great concern. Among them, the most common chemical absorbents include alcohol amine solutions, ammonia, hot caustic soda, amino acid salts, and the like. In recent years, owing to its excellent absorption activity and high CO efficiency₂The removal efficiency is gradually increased in the field of strengthening microalgae carbon sequestration. Literature (KIM G, C HOI W, LEE C, et al₂ absorbents[J]Biochemical l Engineering Journal,2013,78:18-23.) when culturing green algae Sce nephus sp by introducing carbon dioxide into a cylindrical photobioreactor, Monoethanolamine (MEA) was added to the microalgae culture solution, and the MEA was mixed with the introduced CO₂The chemical reaction is carried out to generate R-NHCOO-, the total inorganic carbon concentration in the microalgae culture solution is improved, and the R-NHCOO-can be gradually dissociated to generate CO along with the consumption of carbon source in the culture solution by microalgae cells₂Further provides a carbon source required by the microalgae cells. Although the method can improve the concentration of total inorganic carbon sources in the culture solution, the high-concentration monoethanolamine can generate carbamate intermediates which have toxic action on microalgae cells, and further the microalgae biological yield is reduced.

Polyethylene glycol is a CO₂Physical absorbents, low cost, non-toxicity and relatively high CO₂The advantages of solubility and the like are of great concern. Literature (Lee Y.H., Yeh Y.L.Using polyethylene glycol as a nonoisonicomatic um to a promoter growing and lipidproduction of marine microalgae Nannochloropsis oculata [J]Bioprocess biosystem Eng,2014,37(8):1669-₂The fixing effect is good. Literature (Li J., Ye Y., Chen L., et al. solublities of CO)₂ in Poly(ethylene glycols)from(303.15to 333.15)K [J].Journal of Chemical&Engineering Data,2012,57(2): 610-₂Has good prospect in the aspects of capturing and reducing energy consumption. In order to further improve the carbon fixation effect and oil accumulation of microalgae, the inventor utilizes polyethylene glycol as a non-ionic penetrant to reduce the solubility of oxygen in a culture medium, further promote photosynthesis, utilizes the excellent absorption activity of monoethanolamine, and utilizes microalgae to absorb CO₂The characteristics of resource utilization are combined, and the finding shows that when the mixed solution of polyethylene glycol and monoethanolamine is added into the microalgae culture solution, the carbon fixing efficiency of microalgae and the total inorganic carbon source in the culture solution are obviously increased, the toxic action of microalgae cells under high-concentration monoethanolamine is reduced, and the biomass of microalgae is further promoted.

Disclosure of Invention

The invention aims to overcome the defect that the prior chemical absorbent (alcohol amine solution) can treat CO in the process of culturing microalgae₂Low absorption and conversion efficiency, and the toxic action of the high-concentration alcohol amine solution on microalgae cells, and provides a method for strengthening carbon fixation and oil accumulation of microalgae.

The polyethylene glycol provided by the invention is polyethylene glycol 200, and mainly has the function of enhancing CO₂The process of mass transfer from gas phase to liquid phase.

The method for strengthening carbon fixation and triglyceride accumulation of microalgae comprises the step of adding a monoethanolamine solution with the concentration of 0-2mg/L and the concentration of 0-100mg/L into a microalgae culture solution with the pH of 6-8.

According to the method for enhancing carbon sequestration and triglyceride accumulation of microalgae, the polyethylene glycol and monoethanolamine aqueous solution is added into the culture solution after the microalgae is inoculated into the culture solution.

Specifically, the microalgae culture medium is sterilized before the microalgae species are inoculated according to the requirement. The culture medium sterilization specifically comprises the steps of placing the culture medium in a conical flask, and performing high-temperature steam sterilization for 20min at 121 ℃ and 0.1 Mpa.

According to the method for enhancing microalgae carbon sequestration and triglyceride accumulation, 0-30% of CO in volume fraction needs to be introduced into the conical flask₂A gas.

The invention relates to a method for strengthening microalgae carbon sequestration and triglyceride accumulation, which adopts aeration stone to bubble and introduce CO₂The time of the gas is 0-24 h.

Specifically, bubbling CO-containing gas through aeration stone₂Said gas containing CO₂Industrial emission of CO₂Gases, flue gases, or containing CO₂One or more combinations of gases in air.

The method for strengthening carbon sequestration and triglyceride accumulation of microalgae is suitable for various oil-producing microalgae varieties including marine microalgae, freshwater microalgae and marine/freshwater microalgae. Preferably microalgae is one or more of Vibrio, Dunaliella, Chlorella, Scenedesmus, Chlamydomonas reinhardtii, Crypthecodinium, Cylindrocarpon, Schiff algae, Chlorococcus microalga, Isochrysis galbana, Phaeodactylum tricornutum, Spirulina, Botryococcus braunii, and Nannochloropsis minitans.

According to the method for strengthening carbon fixation and triglyceride accumulation of microalgae and the method for measuring the concentration of triglyceride, a proper amount of algae liquid is mixed with a cosolvent, after water bath treatment at a certain temperature is carried out for a period of time, Nile red with a certain concentration is added, light-shielding dyeing is carried out, and after a certain period of time, a fluorescence value of the mixture at 480nm is measured by using a fluorescence spectrophotometer.

Further preferably, the cosolvent mixed with the algae liquid can adopt organic solvents such as dimethyl sulfoxide, methanol, ethanol and acetone to change the permeability of microalgae cell membranes.

According to the method for enhancing the carbon sequestration and triglyceride accumulation of the microalgae, the harvesting condition of the microalgae is the period when the biomass of the microalgae tends to be stable.

According to the method for enhancing the accumulation of carbon fixation and triglyceride of the microalgae, the microalgae recovery method can be conventional centrifugal collection or flocculant collection.

According to the method for strengthening microalgae solid carbon and triglyceride accumulation and the related method for measuring the total inorganic carbon concentration, the microalgae culture solution is collected and filtered by using a 0.45-micron filter head, and an appropriate amount of filtrate is collected for measuring the total inorganic carbon concentration.

The invention has the technical characteristics that:

(1) during microalgae cultivation, carbon source is one of the main factors affecting microalgae biomass yield. The method of the invention is to add polyethylene glycol and monoethanolamine aqueous solution into the microalgae culture solution respectively with the introduced CO₂The gas undergoes a chemical reaction. On one hand, the polyethylene glycol can be used as a non-ionic penetrant to reduce the oxygen solubility in a culture medium and relieve the inhibition of oxygen on the growth of microalgae, thereby promoting the photosynthesis of the microalgae. Another aspect is the polyethylene glycol pair C O passed into the medium₂The gas also has adsorption effect, thereby further strengthening CO₂The dissolution and mass transfer of molecules from a gas phase to a liquid phase improve the content of inorganic carbon in the whole culture system. In addition, the addition of polyethylene glycol can reduce the adverse effect of monoethanolamine on microalgae cell biomass.

(2) The method of the invention adds monoethanolamine aqueous solution into microalgae culture solution, and introduces CO₂The gas generates chemical reaction to generate R-NHOO^-Obviously improves the concentration of total inorganic carbon in the microalgae culture solution, and along with the consumption of carbon source by the growth of microalgae, the R-NHOO^-Can slowly dissociate free CO₂For growth of microalgae cells.

Compared with the prior art, the invention has the beneficial effects that:

the invention uses CO-containing₂Adding polyethylene glycol and monoethanolamine aqueous solution into microalgae culture solution with gas as carbon source, wherein the polyethylene glycol and monoethanolamine aqueous solution are both used for treating CO₂Has adsorption effect, and can maximally fix CO introduced into microalgae culture solution₂The gas obviously improves the concentration of total inorganic carbon in the microalgae culture solution, thereby improving the biomass of the microalgae. And therewithMeanwhile, compared with patents CN104805016A and CN11195942A, the polyethylene glycol has the characteristics of low price and harmlessness, and is more favorable for establishing carbon capture and biodiesel production technologies with better effect and lower cost. In addition, the addition of polyethylene glycol can alleviate the negative effect of monoethanolamine on algal cell biomass.

Drawings

FIG. 1 shows the biomass concentration of a general chlorella culture solution cultured by adding polyethylene glycol with different concentrations into BG11 culture medium.

FIG. 2 shows the total inorganic carbon concentration of BG11 in general Chlorella culture medium cultured by adding polyethylene glycol of different concentrations.

FIG. 3 shows the triglyceride concentration of Chlorella vulgaris cultured in BG11 medium by adding polyethylene glycol of different concentrations.

FIG. 4 shows the biomass concentrations of Chlorella vulgaris cultured in BG11 medium with monoethanolamine added at different concentrations.

FIG. 5 shows the total inorganic carbon concentration in the culture solution of general Chlorella cultured by adding monoethanolamine of different concentrations into BG11 culture medium.

FIG. 6 shows triglyceride concentrations of Chlorella vulgaris cultured in BG11 medium with monoethanolamine added at different concentrations.

FIG. 7 shows the biomass concentration of Chlorella vulgaris cultured in BG11 medium by adding 0.6mg/L polyethylene glycol and monoethanolamine.

FIG. 8 shows the total inorganic carbon concentration in the culture solution of general Chlorella cultured by adding 0.6mg/L polyethylene glycol and monoethanolamine into BG11 culture medium.

FIG. 9 shows triglyceride concentration of Chlorella vulgaris cultured in BG11 medium by adding 0.6mg/L polyethylene glycol and monoethanolamine.

Detailed Description

The invention is further illustrated by the following examples.

Example 1

The method for enhancing carbon sequestration and triglyceride accumulation of microalgae in the embodiment comprises the following specific steps:

1. culturing microalgae: the cultured algae is Chlorella vulgaris, and is from fresh water algae seed bank of aquatic organism research institute of Chinese academy of sciences. The chlorella vulgaris in the logarithmic growth phase is inoculated to a BG-11 culture medium rich in nutrition according to the initial inoculation concentration of about 100mg/L, and due to the study of the carbon fixation characteristic, the invention improves the BG-11 culture medium, removes a carbon source in the original culture medium, and has the initial pH value of 7.5. The culture temperature is 30 ℃, the illumination intensity is 6000Lux, the illumination period is 14h:10h (light: dark), and the whole culture period is 7 days.

2. Adding a polyethylene glycol solution: adding polyethylene glycol solution into 3 conical flasks filled with common Chlorella culture solution respectively, wherein the final concentration of polyethylene glycol is 0-0.6 mg/L.

3. Supplying carbon dioxide: in the embodiment, aeration stone (with the aperture of 30-60 mu m) which is the most common in the field is adopted for aeration, and the embodiment adopts CO with the volume ratio of 5 percent₂Aeration was performed at a flow rate of 100mL/min for 14h during the light culture period.

4. The growth of Chlorella vulgaris was measured daily during the cultivation, and the inorganic carbon content and triglyceride concentration were measured daily.

As shown in figure 1, in the whole culture period, the biomass of the chlorella vulgaris can reach 422mg/L in the control group without adding polyethylene glycol solution after 7 days of culture, the biomass of the chlorella vulgaris can reach 652mg/L, 715mg/L and 512mg/L after adding polyethylene glycol at concentrations of 0.2mg/L, 0.4mg/L and 0.6mg/L and 1mg/L respectively after 7 days of culture, and the biomass of the chlorella vulgaris is respectively improved by 54.5%, 69.4% and 21.3% compared with the control group.

As shown in FIG. 2, the total inorganic carbon concentration of Chlorella vulgaris was 25.885mg/L in the control group without polyethylene glycol solution after 7 days of culture, and the total inorganic carbon concentrations of 63.99mg/L, 89.92mg/L and 96.51mg/L in the Chlorella vulgaris culture solution were continuously increased after 7 days of culture with polyethylene glycol solution at 0.2mg/L, 0.4mg/L and 0.6mg/L, respectively. Wherein the concentrations of polyethylene glycol added are 0.2mg/L, 0.4mg/L and 0.6mg/L, respectively, and the concentrations of inorganic carbon accumulated in the chlorella culture solution are 30.68mg/L, 50.19mg/L and 53.81mg/L, respectively, which are 2.58 times, 4.23 times and 4.53 times of those of the control group. In addition, the maximum carbon fixing rates of the added polyethylene glycol are 266.075mg/L/d, 286.26mg/L/d and 170.655mg/L/d which are respectively 0.2mg/L, 0.4mg/L and 0.6mg/L, and are respectively improved by 57.56%, 69.57% and 11.95% compared with the control group.

As shown in FIG. 3, the concentration of triglyceride in the Chlorella vulgaris was 18.69mg/L after 7 days of culture in the control group without addition of the polyethylene glycol solution during the whole culture period. The concentrations of the added polyethylene glycol are respectively 0.2mg/L, 0.4mg/L and 0.6mg/L, and the concentrations of the common chlorella triglyceride are respectively 20.21mg/L, 21.88mg/L and 24.35mg/L which are respectively 1.08 times, 1.17 times and 1.30 times of the control group.

Example 2

1. Culturing microalgae: the cultured algae is Chlorella vulgaris, and is from fresh water algae seed bank of aquatic organism research institute of Chinese academy of sciences. The chlorella vulgaris in the logarithmic growth phase is inoculated to a BG-11 culture medium rich in nutrition according to the initial inoculation concentration of about 100mg/L, and as the carbon fixation characteristic of the chlorella vulgaris is researched, the chlorella vulgaris is improved in the BG-11 culture medium, and a carbon source in the original culture medium is removed. The initial pH value of the culture medium is 7.5, the culture temperature is 30 ℃, the illumination intensity is 6000Lux, the illumination period is 14h:10h (light: dark), and the whole culture period is 7 days.

2. Adding a polyethylene glycol reagent: respectively adding monoethanolamine solution into 4 conical flasks filled with common chlorella culture solution, wherein the final concentration of the monoethanolamine solution is 0-100 mg/L.

3. Supplying carbon dioxide: in the embodiment, aeration stone (with the aperture of 30-60 mu m) which is the most common in the field is adopted for aeration, and the embodiment adopts CO with the volume ratio of 5 percent₂Aeration was performed at a flow rate of 120mL/min at the beginning of the light culture and continued for 14 h.

4. The growth of Chlorella vulgaris was measured daily during the cultivation, and the inorganic carbon content and triglyceride concentration were measured daily.

As shown in figure 4 of the drawings,

in the whole culture period, the biomass of the control group without adding the monoethanolamine solution can reach 422mg/L at most after the control group is cultured for 7 days, the concentrations of the added monoethanolamine are respectively 25mg/L, 50mg/L, 75mg/L and 100mg/L, and the biomass of the control group after the control group is cultured for 7 days reaches 443.28mg/L, 571.49mg/L, 491.83mg/L and 387.11 mg/L. The contents of 50mg/L, 75mg/L and 100mg/L monoethanolamine in the culture medium are respectively increased by 5.04%, 35.42% and 16.55% compared with the control group, and the monoethanolamine solution with the high concentration of 100mg/L has the inhibition effect on the biomass of the chlorella vulgaris.

As shown in FIG. 5, in the Chlorella vulgaris in the whole culture period, the total inorganic carbon concentration of the control group without addition of monoethanolamine solution was 25.885mg/L after 7 days of culture, and the total inorganic carbon concentrations of the culture solution of Chlorella vulgaris in the culture solution of Chlorella vulgaris were continuously increased at 25mg/L, 50mg/L, 75mg/L, and 100mg/L after 7 days of culture, respectively, 29.875mg/L, 34.37 mg/L, 34.96mg/L, and 39.805 mg/L. Wherein, the concentrations of the added monoethanolamine are respectively 25mg/L, 50mg/L, 75mg/L and 100mg/L, the concentrations of the inorganic carbon accumulated in the chlorella culture solution are respectively 14.065mg/L, 14.875m g/L, 8.9mg/L and 7.87mg/L, wherein, the addition of the monoethanolamine with low concentration of 25mg/L and 50mg/L is respectively 1.06 times and 1.12 times of the addition of the monoethanolamine with low concentration of the control group. In addition, when the concentrations of the added monoethanolamine are respectively 25mg/L, 50mg/L and 75mg/L, the highest carbon fixing rates are 179.92mg/L/d, 254.24mg/L/d and 198mg/L/d, which are respectively improved by 6.58%, 50.6% and 17.28% compared with the control group.

As shown in FIG. 6, the concentration of triglyceride in the case of the Chlorella vulgaris control group cultured for 7 days without addition of monoethanolamine solution was 18.69mg/L throughout the whole culture period. When the concentrations of monoethanolamine added are respectively 25mg/L, 50mg/L, 75mg/L and 100mg/L, the concentrations of triglyceride of chlorella vulgaris are respectively 25.07mg/L, 28.61mg/L, 21.94mg/L and 23.09 mg/L, which are respectively 1.34 times, 1.53 times, 1.17 times and 1.23 times of those of the control group.

Example 3

1. Culturing microalgae: the cultured algae is Chlorella vulgaris, and is from fresh water algae seed bank of aquatic organism research institute of Chinese academy of sciences. The chlorella vulgaris in the logarithmic growth phase is inoculated to a BG-11 culture medium rich in nutrition according to the initial inoculation concentration of about 100mg/L, and due to the study of the carbon fixation characteristic, the invention improves the BG-11 culture medium, removes a carbon source in the original culture medium, ensures that the initial pH value of the culture medium is 7.5, the culture temperature is 30 ℃, the illumination intensity is 6000Lux, the illumination period is 14h:10h (light: dark), and the whole culture period is 7 days.

2. Adding a polyethylene glycol solution: 0.6m g/L polyethylene glycol solution and 25mg/L, 50mg/L, 75mg/L and 100mg/L monoethanolamine solution were added to 4 flasks, respectively, containing a common chlorella culture.

3. Supplying carbon dioxide: in the embodiment, aeration stone (with the aperture of 30-60 mu m) which is the most common in the field is adopted for aeration, and the embodiment adopts CO with the volume ratio of 5 percent₂Aeration was performed at a flow rate of 120mL/min at the beginning of the light culture and continued for 14 h.

4. The growth of Chlorella vulgaris was measured daily during the cultivation, and the inorganic carbon content and triglyceride concentration were measured daily.

As shown in FIG. 7, in the whole culture period, the highest biomass of the chlorella vulgaris can reach 422mg/L after 7 days of culture in the control group without adding polyethylene glycol and monoethanolamine solution, the biomass respectively reaches 1098.25mg/L, 1289.64 mg/L, 1008.33mg/L and 791.51mg/L after 7 days of culture in the polyethylene glycol solution of 0.6mg/L and the monoethanolamine solution of 25mg/L, 50mg/L, 75mg/L and 100mg/L, and is respectively improved by 160.25%, 205.6%, 138.94% and 87.56% compared with the control group.

As shown in FIG. 8, in the Chlorella vulgaris in the whole culture period, the total inorganic carbon concentration of the control group without polyethylene glycol and monoethanolamine solution after 7 days of culture was 25.885mg/L, and the total inorganic carbon concentration of the Chlorella vulgaris culture solution was continuously increased after 7 days of culture by adding 0.6mg/L polyethylene glycol solution and 25mg/L, 50mg/L, 75mg/L, 100mg/L monoethanolamine solution, and was 98.41mg/L, 131.45mg/L, 149.46mg/L, and 174.49mg/L, respectively. Wherein, the concentration of the inorganic carbon accumulated in the chlorella culture solution is 49.15mg/L, 73.84mg/L, 79.68mg/L and 90.2mg/L respectively, which are 3.69 times, 5.55 times, 5.99 times and 6.78 times of the control group respectively. In addition, the highest carbon fixing rate after adding 0.6mg/L polyethylene glycol solution and 25mg/L, 50mg/L, 75mg/L and 100mg/L monoethanolamine solution for culturing for 7 days is 559.675 mg/L/d, 651.425mg/L/d, 529.287mg/L/d and 393.772mg/L/d, which are respectively 255.22%, 285.87%, 213.52% and 133.25% higher than the control group.

As shown in FIG. 9, the concentration of triglyceride in the case of the Chlorella vulgaris control group cultured for 7 days without addition of polyethylene glycol and monoethanolamine solution was 18.69mg/L throughout the whole culture period. The triglyceride concentrations of Chlorella vulgaris after 7 days of culture by adding 0.6mg/L polyethylene glycol solution and 25mg/L, 50mg/L, 75mg/L, 100mg/L monoethanolamine solution were 40.92 mg/L, 52.63mg/L, 58.02mg/L, 63.00mg/L, which were 2.18 times, 2.82 times, and 3.37 times of the control group, respectively.