A method for improving the biomass of scenedesmus under light culture and application thereof

Abstract

This invention relates to a method for increasing the biomass of *Scenedesmus* under light and its application. The method includes the following steps: inoculating *Scenedesmus* stock solution into a sterile liquid culture medium, and culturing the *Scenedesmus* under light using a composite spectrum of white and red light. This invention develops a novel method for culturing *Scenedesmus*, namely, culturing the *Scenedesmus* under light using a composite spectrum of white and red light. This method is simple to operate and easy to implement. It can significantly improve the growth rate and biomass accumulation of *Scenedesmus*, enabling high-quality, large-scale production; it can also improve light and electrical energy utilization efficiency, reduce energy costs, and solve the technical challenge of simultaneously increasing production and reducing energy consumption in *Scenedesmus* cultivation.

Description

Technical Field

[0001] This invention belongs to the field of microalgae cultivation technology, and relates to a light cultivation method for increasing the biomass of Scenedesmus and its application. Background Technology

[0002] Scenedesmus is a type of green algae widely distributed in freshwater environments. Rich in nutrients and metabolic products, it has significant value and broad applications in ecological restoration, energy development, aquaculture, food health, and scientific research. In environmental remediation, Scenedesmus can efficiently absorb nutrients such as nitrogen and phosphorus from water bodies, degrade organic pollutants, and significantly improve eutrophic water bodies. Its cell walls have a strong adsorption capacity for heavy metals such as lead and cadmium, making it suitable for the remediation of industrial wastewater and polluted water bodies. Simultaneously, Scenedesmus has high photosynthetic efficiency, fixing carbon dioxide and playing an ecological role in carbon sequestration, emission reduction, and carbon neutrality. In the energy and chemical industries, Scenedesmus has a high oil content, making it a high-quality raw material for biodiesel production and a renewable clean energy alternative to traditional oils. It can also accumulate high-value-added substances such as astaxanthin, carotenoids, polysaccharides, and unsaturated fatty acids, which can be applied in the food, cosmetics, and chemical industries. In aquaculture, *Scenedesmus* is rich in protein and nutritionally complete, making it a high-quality live feed for fish, shrimp, and shellfish fry, improving their survival rate and growth rate. Its algal powder can also be used as a feed additive to enhance the quality of livestock and poultry products. In the food and health sector, *Scenedesmus* is rich in high-quality protein, dietary fiber, and antioxidants, making it suitable for development into nutritional supplements and functional foods. Its active substances also possess anti-inflammatory and immunomodulatory potential, providing materials for pharmaceutical research. Overall, *Scenedesmus* possesses ecological, economic, and scientific value, making it an important biological resource in the green and low-carbon industry.

[0003] In the large-scale cultivation of Scenedesmus, the core contradiction of balancing increased production and reduced energy consumption remains difficult to resolve, becoming a key bottleneck for industrialization. Increased production relies on high density, high light intensity, high aeration, and sufficient nutrients: high density can increase biomass per unit volume, but it will exacerbate light shading and reduce deep photosynthetic efficiency, requiring a significant increase in light and aeration energy consumption; high light intensity and high aeration can accelerate photosynthetic carbon fixation, but significantly increase electricity and equipment operating costs; sufficient nitrogen and phosphorus nutrients can ensure rapid proliferation, but increase raw material input and subsequent wastewater treatment costs. On the other hand, reducing energy consumption requires simplifying conditions and reducing energy and nutrient input: weak light, low aeration, and limited nitrogen and phosphorus can reduce costs, but they will directly inhibit cell division and biomass accumulation, and may even lead to algal collapse due to metabolic imbalance.

[0004] Therefore, developing a cultivation method that simplifies conditions, reduces energy consumption, and can improve the growth rate and biomass accumulation of Scenedesmus is of significant technical and economic value for breaking through industry bottlenecks and achieving sustainable, low-cost, high-quality, large-scale production of Scenedesmus resources. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the present invention aims to provide a light-based cultivation method for increasing the biomass of Scenedesmus and its application.

[0006] To achieve this objective, the present invention employs the following technical solution:

[0007] In a first aspect, the present invention provides a method for increasing the biomass of Scenedesmus under light cultivation, the method comprising the following steps:

[0008] The Scenedesmus stock solution was inoculated into a sterile liquid culture medium, and the Scenedesmus was cultured under light using a composite spectrum of white and red light.

[0009] This invention develops a novel cultivation method for Scenedesmus, which uses a composite spectrum of white and red light to cultivate the algae. Red light ensures high light energy capture and electron transfer efficiency, while white light (especially the blue / green bands) provides the light signal and spectral components necessary to maintain the balance between photochemical quenching and photoprotection. The combination of the two avoids both the over-excitation and photoinhibition of pure red light and overcomes the relatively low average quantum efficiency of pure white light, thus enabling Scenedesmus to exhibit optimal growth promotion effect.

[0010] This cultivation method is simple to operate and easy to implement. It can significantly improve the growth rate and biomass accumulation of Scenedesmus, enabling high-quality large-scale production of Scenedesmus. It can also improve light energy utilization efficiency and electrical energy utilization efficiency, reduce energy consumption costs, and solve the technical problem of balancing increased production and reduced energy consumption in the cultivation of Scenedesmus.

[0011] Preferably, the wavelength of the red light is 630-660 nm, such as 630 nm, 635 nm, 640 nm, 645 nm, 650 nm, 655 nm, 660 nm, etc. Other specific values ​​not listed in this range can be selected, all of which are within the protection scope of this invention, and will not be described in detail here.

[0012] Preferably, the color temperature of the white light is 4000-4500 K.

[0013] In the light cultivation method involved in this invention, when the wavelength of red light is selected as 630-660 nm and the color temperature of white light is selected as 4000-4500 K, the combined spectral light irradiation has a better effect on improving the growth rate and biomass accumulation of Scenedesmus.

[0014] Preferably, the ratio of photon flux density of white light to red light in the composite spectrum is 4:3-2:1, such as 4:3, 3:2, 2:1, etc. Other specific values ​​not listed in this range can be selected, all of which are within the protection scope of this invention, and will not be described in detail here.

[0015] In the light cultivation method involved in this invention, when the photon flux density ratio of white light to red light in the composite spectrum is 1:1 to 2:1, it has a better effect on improving the growth rate and biomass accumulation of Scenedesmus compared to other ratios.

[0016] Preferably, the light-based culture method further includes: adjusting the light intensity to 180-280 μmol / (m²). 2 ·s), for example 180 μmol / (m 2 ·s), 190 μmol / (m 2 ·s), 200 μmol / (m 2 ·s), 210 μmol / (m 2 ·s), 220 μmol / (m 2 ·s), 230 μmol / (m 2 ·s), 240 μmol / (m 2 ·s), 250 μmol / (m 2 ·s), 260 μmol / (m 2 ·s), 270μmol / (m 2 ·s), 280 μmol / (m 2 ·s), 290 μmol / (m 2 Other unlisted point values ​​within this range, such as ·s), are all acceptable and fall within the scope of protection of this invention; therefore, they will not be elaborated upon here. More preferably, 220-260 μmol / (m 2 ·s).

[0017] Compared to other light intensities, adjusting the light intensity to 180-280 μmol / (m 2 ·s) especially 220-260 μmol / (m 2 ·s), which is more effective in increasing the growth rate and biomass accumulation of Chlorella proteoglycans.

[0018] Preferably, the light-induced culture method further includes adjusting the photoperiod to 16L:8D-24L:0D, more preferably 22L:2D-24L:0D. Here, "16L:8D" refers to a "16-hour light period and an 8-hour dark period," and the specific settings within "16L:8D-24L:0D" can be 16L:8D, 18L:6D, 20L:4D, 22L:2D, 24L:0D, etc.

[0019] Compared to other photoperiods, adjusting the photoperiod to 16L:8D-24L:0D, especially 22L:2D-24L:0D, is more effective in improving the growth rate and biomass accumulation of Chlorella proteoglycans.

[0020] Preferably, the light cultivation method further includes adjusting the flash frequency to 40-70 Hz, such as 40 Hz, 45 Hz, 50 Hz, 55 Hz, 60 Hz, 65 Hz, 70 Hz, etc. Other specific values ​​not listed within this range can be selected, all of which are within the protection scope of this invention and will not be elaborated here. More preferably, 55-65 Hz.

[0021] Compared to other flash frequencies, adjusting the flash frequency to 40-70 Hz, especially 55-65 Hz, is more effective in improving the growth rate and biomass accumulation of Chlorella proteoglycans.

[0022] Preferably, the light cultivation method further includes adjusting the light duty cycle to 75%-100%, such as 75%, 80%, 85%, 90%, 95%, 100%, etc. Other specific values ​​not listed within this range can be selected, all of which are within the protection scope of this invention, and will not be elaborated here.

[0023] Preferably, the inoculation amount of the Scenedesmus stock solution is 0.1-0.3 g / L based on cell dry weight, such as 0.1 g / L, 0.12 g / L, 0.14 g / L, 0.15 g / L, 0.16 g / L, 0.18 g / L, 0.2 g / L, 0.25 g / L, 0.28 g / L, 0.3 g / L, etc. Other specific values ​​not listed within this range can be selected, all of which are within the protection scope of this invention, and will not be elaborated here.

[0024] Preferably, the liquid culture medium is BG-11 liquid culture medium.

[0025] Preferably, the liquid culture medium has the following formulation (per liter):

[0026] NaNO3 1-2 g / L, K2HPO4·3H2O 0.01-0.08 g / L, MgSO4·7H2O 0.5-1 g / L, CaCl2·2H2O 0.01-0.05 g / L, Citric acid 0.002-0.01 g / L, Ferric ammonium citrate 0.001-0.01 g / L, Na2EDTA·2H2O 0.002-0.01 g / L, Na2CO3 0.01-0.05 g / L, A5 trace element solution 0.8-1.2 mL (containing: H3BO3 1-5 g / L, MnCl2·4H2O 1-3 g / L, ZnSO4·7H2O 0.1-0.4 g / L, CuSO4·5H2O 0.05-0.1 g / L). (g / L, Na2MoO4·2H2O 0.1-0.5 g / L, Co(NO3)2·6H2O 0.02-0.08 g / L); solvent is deionized water.

[0027] In this invention, the cultivation temperature of the Scenedesmus is 34-36℃, such as 34℃, 34.5℃, 35℃, 35.5℃, 36℃, etc. Other specific values ​​not listed in this range can be selected and are all within the protection scope of this invention, and will not be described in detail here.

[0028] Preferably, the spirulina is kept aerated and 1-5% CO2 is introduced during the cultivation process.

[0029] Secondly, the present invention provides the application of the light cultivation method according to the first aspect in improving the growth rate and biomass accumulation of Scenedesmus.

[0030] Thirdly, the present invention provides the application of the light cultivation method according to the first aspect in improving the light energy utilization efficiency and electrical energy utilization efficiency of Scenedesmus.

[0031] Compared with the prior art, the present invention has the following beneficial effects:

[0032] This invention develops a novel cultivation method for Scenedesmus, which uses a composite spectrum of white and red light to cultivate Scenedesmus. This cultivation method is simple to operate and easy to implement. It can significantly improve the growth rate and biomass accumulation of Scenedesmus, enabling high-quality large-scale production of Scenedesmus. It can also improve light energy utilization efficiency and electrical energy utilization efficiency, reduce energy consumption costs, and solve the technical problem of balancing increased production and reduced energy consumption in the cultivation of Scenedesmus. Detailed Implementation

[0033] To further illustrate the technical means and effects of the present invention, the following describes the technical solution of the present invention in conjunction with preferred embodiments of the present invention. However, the present invention is not limited to the scope of the embodiments.

[0034] The formulation (per liter) of BG-11 liquid culture medium used in the following examples or comparative examples is as follows: NaNO3 1.5 g, K2HPO4·3H2O 0.04 g, MgSO4·7H2O 0.75 g, CaCl2·2H2O 0.036 g, citric acid 0.006 g, ferric ammonium citrate 0.006 g, Na2EDTA·2H2O 0.006 g, and A5 trace element solution 1 mL (containing: H3BO3 2.86 g / L, MnCl2·4H2O 1.81 g / L, ZnSO4·7H2O 0.22 g / L, CuSO4·5H2O 0.08 g / L, Na2MoO4·2H2O 0.39 g / L, Co(NO3)2·6H2O 0.05 g / L).

[0035] In the following examples or comparative examples, the final biomass concentration (g / L) was calculated using the filtration-drying-weighing method. The specific procedure was as follows: 10 mL of algal solution was measured, and the filter membrane was pre-dried in a 105°C oven until constant weight. After cooling, the initial mass of the filter membrane (m1, g) was recorded. The algal solution was slowly filtered using a vacuum filtration device to ensure complete retention of algal cells on the filter membrane surface. The algae on the filter membrane were washed twice with deionized water. The filter membrane with attached algal sludge was removed and placed in a 105°C oven for further drying until constant weight. After cooling, the total mass (m2, g) was weighed. The final biomass concentration (DCW, g / L) of the algae was calculated using the following formula:

[0036] DCW = (m2 – m1) / 10 × 1000;

[0037] The maximum specific growth rate (μmax) in the following examples or comparative examples was calculated by monitoring the dynamic changes in biomass, using the following formula:

[0038] μ=[ln(DCW2) – ln(DCW1)] / (t2 – t1);

[0039] DCW2 and DCW1 represent the stem cell weights (g / L) at times t2 and t1, respectively.

[0040] Example 1

[0041] This embodiment provides a method for culturing Scenedesmus, as detailed below:

[0042] An adjustable spectral light source consisting of an independently controllable 4000K white LED module and a red LED module with a center wavelength of 630 nm is used. Through a precision drive controller, the ratio of photon flux density of white light to red light is adjusted and maintained at 2:1.

[0043] The total illuminance of the aforementioned light source was precisely set and maintained at 240 μmol / (m²). 2 •s); adopts optical periodic (24L:0D) mode; applies pulse modulation with a frequency of 60 Hz and a duty cycle of 100% to the light source through a high-frequency programmable driver.

[0044] Using BG-11 medium as the culture medium, Scenedesmus was inoculated until the initial stem cell weight was 0.18 g / L. The culture volume was 250 mL / bottle. The culture was placed in a constant temperature environment of 35℃, with sterile air continuously introduced at a ventilation rate of 0.5 vvm and 2% CO2 introduced.

[0045] Example 2

[0046] This embodiment provides a method for culturing Scenedesmus, as detailed below:

[0047] An tunable spectral light source consisting of an independently controllable 4300K ​​white LED module and a red LED module with a center wavelength of 650 nm is used. Through a precision drive controller, the ratio of photon flux density of white light to red light is adjusted and maintained at 3:2.

[0048] The total illuminance of the aforementioned light source was precisely set and maintained at 220 μmol / (m²). 2 •s); adopts optical periodicity (22L:2D) mode; applies pulse modulation with a frequency of 55 Hz and a duty cycle of 90% to the light source through a high-frequency programmable driver.

[0049] Using BG-11 medium as the culture medium, Scenedesmus was inoculated until the initial stem cell weight was 0.18 g / L. The culture volume was 250 mL / bottle. The culture was placed in a constant temperature environment of 34℃, with sterile air continuously introduced at a ventilation rate of 0.5 vvm and 2% CO2 introduced.

[0050] Example 3

[0051] This embodiment provides a method for culturing Scenedesmus, as detailed below:

[0052] An tunable spectral light source consisting of an independently controllable 4500K white LED module and a red LED module with a center wavelength of 660 nm is used. Through a precision drive controller, the ratio of photon flux density of white light to red light is adjusted and maintained at 4:3.

[0053] The total illuminance of the aforementioned light source was precisely set and maintained at 260 μmol / (m²). 2 •s); adopts optical periodic (24L:0D) mode; applies pulse modulation with a frequency of 65 Hz and a duty cycle of 75% to the light source through a high-frequency programmable driver.

[0054] Using BG-11 medium as the culture medium, Scenedesmus was inoculated until the initial stem cell weight was 0.18 g / L. The culture volume was 250 mL / bottle. The culture was placed in a constant temperature environment of 36℃, with sterile air continuously introduced at a ventilation rate of 0.5 vvm and 2% CO2 introduced.

[0055] Examples 4-7

[0056] This embodiment provides a method for cultivating Scenedesmus, which differs from Example 1 only in that the ratio of photon flux density of white light to red light in the composite spectrum is 3:1, 1:1, 1:2, and 1:3, respectively, while other conditions remain unchanged.

[0057] Examples 8-11

[0058] This embodiment provides a method for cultivating Scenedesmus, which differs from Example 1 only in that the total light intensity is precisely set and maintained at 180 μmol / (m²). 2 ·s), 280 μmol / (m 2 ·s), 140 μmol / (m 2 ·s), 300 μmol / (m 2 ·s), with other conditions remaining unchanged.

[0059] Examples 12-14

[0060] This embodiment provides a method for cultivating Scenedesmus, which differs from Example 1 only in that the photoperiods (16L:8D), (14L:10D), and (12L:12D) modes are used respectively, while other conditions remain unchanged.

[0061] Examples 15-18

[0062] This embodiment provides a method for cultivating Scenedesmus, which differs from Embodiment 1 only in that: a high-frequency programmable driver is used to apply pulse modulation with frequencies of 70 Hz, 40 Hz, 10 Hz and 100 Hz, all with a duty cycle of 100%, to the light source, while other conditions remain unchanged.

[0063] Examples 19-20

[0064] This embodiment provides a method for culturing Scenedesmus, which differs from Example 1 only in that the culturing temperatures are 30℃ and 38℃, respectively, while other conditions remain unchanged.

[0065] Comparative Example 1

[0066] This comparative example provides a method for cultivating Scenedesmus, which differs from Example 1 only in that: an adjustable spectral light source consisting of an independently controllable 4000K white LED module and an orange-yellow LED module with a center wavelength of 590 nm is used. The ratio of photon flux density of white light to red light is adjusted and maintained at 2:1 by a precision drive controller, while other conditions remain unchanged.

[0067] Comparative Example 2

[0068] This comparative example provides a method for cultivating Scenedesmus, which differs from Example 1 only in that: an adjustable spectral light source consisting of an independently controllable 4000K white LED module and a green LED module with a center wavelength of 525 nm is used. The ratio of photon flux density of white light to red light is adjusted and maintained at 2:1 by a precision drive controller, while other conditions remain unchanged.

[0069] Comparative Example 3

[0070] This comparative example provides a method for cultivating Scenedesmus, which differs from Example 1 only in that: an adjustable spectral light source consisting of an independently controllable 4000K white LED module and a blue LED module with a center wavelength of 450 nm is used. The ratio of photon flux density of white light to red light is adjusted and maintained at 2:1 by a precision drive controller, while other conditions remain unchanged.

[0071] Comparative Example 4

[0072] This comparative example provides a method for cultivating Scenedesmus, which differs from Example 1 only in that: an adjustable spectral light source consisting of an independently controllable 4000K white LED module and a violet LED module with a center wavelength of 410 nm is used. The ratio of photon flux density of white light to red light is adjusted and maintained at 2:1 by a precision drive controller, while other conditions remain unchanged.

[0073] Comparative Example 5

[0074] This comparative example provides a method for cultivating Scenedesmus, which differs from Example 1 only in that the light source is replaced by a single 4000K white LED module instead of a composite light source. The total light intensity, photoperiod mode, light source application frequency, and duty cycle remain unchanged. Other conditions also remain unchanged.

[0075] Comparative Example 6

[0076] This comparative example provides a method for cultivating Scenedesmus, which differs from Example 1 only in that the light source is replaced by a single red LED module with a center wavelength of 630 nm, while the total light intensity, photoperiod mode, light source application frequency, and duty cycle remain unchanged. Other conditions also remain unchanged.

[0077] Test Example 1

[0078] After culturing *Scenedesmus* for 48 h according to the methods of Examples 1-20 and Comparative Examples 1-6, the final biomass concentration (g / L) and maximum specific growth rate (μmax, d) of each group were measured. -1 The results of the detection are shown in Table 1.

[0079] Table 1

[0080]

[0081] As shown in Table 1, compared with Comparative Examples 1-6, Examples 1-20, namely the Scenedesmus cultivation method involved in this invention, use a composite spectrum of white and red light for illumination cultivation. The two light sources work together to enhance each other, which can significantly improve the growth rate and biomass accumulation of Scenedesmus.

[0082] Further comparison of the data results of Examples 1-3 and Examples 4-20 shows that the ratio of photon flux density of white light to red light, light intensity, flash frequency, photoperiod, and culture temperature also affect the growth rate and biomass accumulation of Scenedesmus to varying degrees.

[0083] Test Example 2

[0084] Comparative experiment of optimized light formulation and traditional white light culture of Scenedesmus:

[0085] (1) Training setup:

[0086] Experimental group: The optimized light formula determined in Example 1 was used, and the electro-optical efficiency of the luminaire was 38%.

[0087] Control group: Ordinary white light (PPFD 240 μmol / (m)) was used. 2 The luminaire's electro-optical efficiency is 44.81%.

[0088] The two groups were kept under the same basic conditions: temperature 35℃, BG11 medium, initial inoculation DCW of 0.120 g / L, 2% CO2 purging, culture volume of 150 mL, and three replicates per group. The basic experimental parameters are shown in Table 2.

[0089] Table 2

[0090]

[0091] (2) Results:

[0092] After 48 hours, the final dry weight (g / L) of each group was measured. The results showed that the final DCW of the optimized light formulation experimental group was 0.883±0.019 g / L, while that of the white light control group was 0.838±0.007 g / L. The biomass yield of the experimental group was significantly increased by 5.37% compared with that of the control group (see Table 3).

[0093] Table 3

[0094]

[0095] (3) Optimization of formulation and analysis of white light energy consumption

[0096] Based on the results measured by the integrating sphere spectrometer, the optimal red and white light formulations and white light parameters were systematically compared, and the results are shown in Table 4.

[0097] Table 4

[0098]

[0099] As shown in Table 4, under the same initial light intensity and volume, the light conversion efficiency of white light is 6.81% higher than that of red-white light. Even under these conditions, because Scenedesmus absorbs red-white light more fully, its light energy utilization efficiency is higher, and therefore its biomass accumulation is higher than that of white light.

[0100] Based on the data results in Table 2, the energy consumption parameters for the two sets were calculated. Detailed parameters are shown in Table 5.

[0101] Table 5

[0102]

[0103] As shown in Table 5, the biomass growth rate in the experimental group was 0.703 g / L, while that in the control group was 0.658 g / L. The total power consumption of the experimental group was 0.631 kWh, and that of the control group was 0.544 kWh. The energy consumption per unit of biomass in the experimental group was 897.86 Wh / g, while that in the control group was 827.23 Wh / g. The similar energy consumption per unit of biomass between the two groups is directly related to the difference in electro-optical conversion efficiency between the two types of lamps.

[0104] The light energy utilization rate of microalgae was calculated based on radiation energy. The total radiation energy of the experimental group was 239.83 Wh, and that of the control group was 243.84 Wh. The light energy utilization rate of the experimental group was 0.00293 g / Wh, while that of the control group was 0.00267 g / Wh. The radiation energy utilization efficiency of the experimental group was 1.1 times that of the control group.

[0105] The above results indicate that although the luminous efficiency of white light fixtures is higher than that of composite light in the experimental group, Scenedesmus has a greater advantage in absorbing and converting composite light, and its biomass accumulation effect is better than that of white light.

[0106] (4) Equivalent photoelectric conversion efficiency

[0107] Based on this, assuming the electro-optical efficiency of the composite luminaire remains consistent with that of white light at 44.81%, an equivalent comparison is conducted while maintaining constant radiant power and only improving electro-optical efficiency. The equivalent composite light input power can be reduced to 11.158 W, the equivalent total power consumption of the composite light is 535.59 Wh, and the equivalent energy consumption per unit biomass of the composite light is 761.87 Wh / g, further enhancing the energy-saving potential.

[0108] This invention, through systematic light regulation experiments and verification, proposes a lighting scheme for the cultivation of *Scenedesmus* with clearly defined parameters, strong operability, and high energy efficiency. This scheme can significantly improve the growth rate, biomass yield, and light energy utilization efficiency of *Scenedesmus*, possessing good reproducibility and potential for large-scale application. It has significant practical value for promoting energy conservation, emission reduction, and efficiency improvement in related industries.

[0109] The applicant declares that the technical solution of this invention is illustrated by the above embodiments, but this invention is not limited to the above embodiments, that is, it does not mean that this invention must rely on the above embodiments to be implemented. Those skilled in the art should understand that any improvements to this invention, equivalent substitutions of raw materials for the products of this invention, addition of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of this invention.

[0110] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, and these simple modifications all fall within the protection scope of the present invention.

[0111] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not describe the various possible combinations separately.

Claims

1. A method for increasing the biomass of Scenedesmus under light, characterized in that, The light-based culture method includes the following steps: The Scenedesmus stock solution was inoculated into a sterile liquid culture medium, and the Scenedesmus was cultured under light using a composite spectrum of white and red light.

2. The light-based culture method according to claim 1, characterized in that, The wavelength of the red light is 630-660 nm; Preferably, the color temperature of the white light is 4000-4500 K; Preferably, the ratio of photon flux density of white light to red light in the composite spectrum is 4:3-2:

1.

3. The light-based culture method according to claim 1 or 2, characterized in that, The light-induced culture method further includes: adjusting the light intensity to 180-280 μmol / (m²). 2 ·s), more preferably 220-260 μmol / (m 2 ·s).

4. The light-based culture method according to any one of claims 1-3, characterized in that, The light-induced culture method further includes adjusting the light cycle to 16L:8D-24L:0D, more preferably 22L:2D-24L:0D.

5. The light-based culture method according to any one of claims 1-4, characterized in that, The light-based cultivation method further includes adjusting the flash frequency to 40-70 Hz, more preferably 55-65 Hz.

6. The light-based culture method according to any one of claims 1-5, characterized in that, The light-based culture method further includes adjusting the light duty cycle to 75%-100%.

7. The light-based culture method according to any one of claims 1-6, characterized in that, The inoculation amount of the Scenedesmus stock solution is 0.1-0.3 g / L based on cell dry weight; Preferably, the liquid culture medium is BG-11 liquid culture medium.

8. The light-based culture method according to any one of claims 1-7, characterized in that, The culture temperature of the Scenedesmus is 34-36℃.

9. The application of the light cultivation method according to any one of claims 1-8 in improving the growth rate and biomass accumulation of Scenedesmus.

10. The application of the light cultivation method according to any one of claims 1-8 in improving the light energy utilization efficiency and electrical energy utilization efficiency of Scenedesmus.

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