Energy-saving and efficient high-temperature cyanobacteria UTEX 3222 continuous culture method

Abstract

The invention discloses an energy-saving and efficient high-temperature cyanobacteria UTEX 3222 continuous culture method, and belongs to the technical field of microalgae culture, the high-temperature cyanobacteria UTEX 3222 and a culture solution are placed in an annular flat-plate reactor, a lamp is arranged in the annular reactor, and air is introduced; a light source used for cultivation is electrically-driven LED light, and the LED light is red light or white light; the power of the lamp is adjusted by the duty ratio, and when the duty ratio is 15-20%, the ratio of the power of the lamp to the volume of the reactor is 1.0-1.5 w / L; the dilution rate of continuous culture is 0.5 to 1.0 day <-1 >. According to the method, low energy consumption and high volume production can be realized.

Description

Technical Field

[0001] This invention belongs to the field of microalgae cultivation technology, specifically relating to an energy-saving and efficient method for continuous cultivation of the high-temperature cyanobacterium UTEX 3222. Background Technology

[0002] Cyanobacteria exhibit extremely high growth rates and, under suitable conditions, short cell division cycles, enabling rapid biomass accumulation. Compared to most microalgae, they can reproduce on a large scale in a shorter time, providing a highly efficient raw material supply for industrial production. Furthermore, cyanobacteria can survive in various extreme environments, including high salinity, high temperature, and high alkalinity. This broad environmental adaptability allows for industrial production in diverse geographical regions, including areas unsuitable for traditional agriculture, reducing dependence on specific natural conditions. Simultaneously, cyanobacteria possess a highly efficient photosynthetic system, efficiently converting solar energy into chemical energy and exhibiting a strong ability to fix carbon dioxide, helping to mitigate greenhouse gas emissions. They also achieve biomass growth with relatively low energy input, reducing production costs. Moreover, cyanobacteria can synthesize various valuable products such as proteins and polysaccharides, finding wide applications in numerous industries, including food and medicine, creating abundant market demand for their industrial production. Summary of the Invention

[0003] This invention addresses the problems in the prior art by providing an energy-saving and efficient method for continuous cultivation of cyanobacteria at high temperatures, specifically UTEX 3222. This method enables pilot-scale continuous cultivation of cyanobacteria with low energy consumption and high production volume.

[0004] This invention is achieved through the following technical solution: A method for continuous cultivation of the thermophilic cyanobacterium UTEX 3222, characterized by energy efficiency and high efficiency, involves placing the UTEX 3222 and its culture medium in a ring-shaped flat-plate reactor. Lighting fixtures are positioned inside the reactor, and air is introduced. The light source used for cultivation is electrically driven LED light, which can be red or white. The lamp power is adjusted by the duty cycle; at a duty cycle of 15-20%, the ratio of lamp power to reactor volume is 1.0-1.5 W / L. The dilution rate for continuous cultivation is 0.5-1.0 days. -1 .

[0005] Preferably, the spectral wavelength of the red light is 580-700nm.

[0006] Preferably, the spectral wavelength of the white light is 400-800nm.

[0007] Preferably, the initial inoculation density of the high-temperature cyanobacteria UTEX 3222 is 0.05-0.1 g / L.

[0008] Preferably, the ventilation rate when air is introduced is 0.15-0.2 vvm.

[0009] Preferably, the daily replenishment of culture medium is 50-100 L.

[0010] Preferably, the ratio of lamp height to reactor height is 1:2; the optical path of the annular flat plate reactor is 4-6 cm.

[0011] Preferably, the culture medium has the following composition: 2.5 g / L -1 NaHCO3, 1.5 g L -1 NaNO3, 18.0 g / L - 1 NaCl, 3.6 g L -1 CaCl•2H2O, 0.6 g L -1 KCl, 0.33 g / L -1 KH2PO4, 0.75 g / L -1 MgSO4•7H2O, 0.036 g / L -1 FeCl3•6H2O, 1 g L -1 Na2EDTA, 1 ml / L -1 D7, 3 ml / L -1 VB 12 .

[0012] Preferably, the D7 comprises 2.86 g L -1 H3BO3, 1.81g / L -1 MnCl2•4H2O, 0.222g L -1 ZnSO4•7H2O, 0.079g / L -1 CuSO4•5H2O, 1.26 g L -1 Na2MoO4•2H2O, 0.0403 g / L -1 Co (NO3)2•6H2O.

[0013] Preferably, the culture temperature is 35-45℃, the pH is controlled within the range of 8.0-8.5, and the light intensity is controlled within the range of 500-760 μmol / m². 2 / s.

[0014] Compared with the prior art, the present invention has the following advantages and beneficial effects: I. This invention provides an energy-saving and efficient continuous cultivation method for high-temperature cyanobacteria UTEX 3222, in which the cultivation process simultaneously achieves a production efficiency greater than 0.6 g / L / day and an electro-algal conversion rate of less than 100 kWh / kg.

[0015] II. This invention provides an energy-saving and efficient continuous cultivation method for the high-temperature cyanobacteria UTEX 3222, employing a modified BGA medium. Compared to the traditional MAD2 nutrient-rich medium, this method not only optimizes the nutrient composition but also significantly reduces the preparation cost of the medium. Simultaneously, this modified medium effectively meets the growth efficiency and biomass yield requirements of microalgae, enabling low-cost, high-efficiency large-scale production, and possesses promising application prospects and economic value.

[0016] Third, the present invention provides an energy-saving and efficient continuous culture method for high-temperature cyanobacteria UTEX 3222. By setting special culture conditions of high temperature, high salinity and high light intensity, it not only significantly improves the growth efficiency of cyanobacteria, but also reduces the risk of pollution in the culture process from multiple dimensions. In particular, it effectively inhibits the reproduction of protozoa and the growth of most competing algae, thereby ensuring the purity and stability of the culture system. Attached Figure Description

[0017] Figure 1 A comparison of the growth rates of the high-temperature cyanobacterium UTEX3222 under different light intensities; Figure 2 This is a comparison chart of the energy consumption of the high-temperature cyanobacteria UTEX3222 under different light intensities. Detailed Implementation

[0018] The present invention will be further described in detail below with reference to embodiments, but the implementation of the present invention is not limited thereto.

[0019] Example A method for continuous cultivation of the thermophilic cyanobacterium UTEX 3222, characterized by energy efficiency and high efficiency, involves placing the UTEX 3222 and its culture medium in a ring-shaped flat-plate reactor. Lighting fixtures are positioned inside the reactor, and air is introduced. The light source used for cultivation is electrically driven LED light, which can be red or white. The lamp power is adjusted by the duty cycle; at a duty cycle of 15-20%, the ratio of lamp power to reactor volume is 1.0-1.5 W / L. The dilution rate for continuous cultivation is 0.5-1.0 days. -1 .

[0020] The wavelength of the red light is 580-700nm.

[0021] The wavelength of the white light is 400-800nm.

[0022] The initial inoculation density of the thermophilic cyanobacterium UTEX 3222 was 0.05-0.1 g / L.

[0023] The ventilation rate during air introduction is 0.15-0.2 vvm.

[0024] The daily replenishment of culture medium is 50-100 L.

[0025] The ratio of lamp height to reactor height is 1:2 (the volume of the annular plate reactor is 100 L); the optical path of the annular plate reactor is 4-6 cm.

[0026] The culture medium consists of: 2.5 g / L -1 NaHCO3, 1.5 g L -1 NaNO3, 18.0 g / L -1 NaCl, 3.6 g L -1 CaCl•2H2O, 0.6 g L -1 KCl, 0.33 g / L -1 KH2PO4, 0.75 g / L -1 MgSO4•7H2O, 0.036 g / L - 1 FeCl3•6H2O, 1 g L -1 Na2EDTA, 1 ml / L -1 D7, 3 ml / L -1 VB 12 .

[0027] Wherein, D7 comprises 2.86 g L -1 H3BO3, 1.81g / L -1 MnCl2•4H2O, 0.222g L -1 ZnSO4•7H2O, 0.079g / L -1 CuSO4•5H2O, 1.26 g L -1 Na2MoO4•2H2O, 0.0403 g / L -1 Co (NO3)2•6H2O.

[0028] The cultivation temperature was 35-45℃, the pH was controlled within the range of 8.0-8.5, and the light intensity was controlled within the range of 500-760 μmol / m². 2 / s.

[0029] Experiment Example 1: Culture Medium Screening Experiment BG11 and MAD2 media were selected as the base media to screen for suitable media for continuous culture of this high-UTEX3222 strain. The PB method was used to screen for NaCl, NaNO3, KH2PO4, CaCl2·2H2O, MgSO4·7H2O, FeCl3·6H2O, Na2EDTA, Tris, KCl, Na2CO3, and VB. 12 The main influencing factors and concentrations of various nutrients on the growth rate of thermophilic cyanobacteria were investigated. Based on the above, considering the optimal pH range for cyanobacterial growth (6.5–10), Na₂CO₃ was replaced with NaHCO₃ to improve the pH buffering capacity of the culture medium while supplementing the carbon source to promote cyanobacterial growth. Finally, the optimal concentration was determined to be 2.5 g / L. -1 NaHCO3, 1.5 g L - 1 NaNO3, 18.0 g / L -1 NaCl, 3.6 g L -1 CaCl•2H2O, 0.6 g L -1 KCl, 0.33 g / L -1 KH2PO4, 0.75 g / L - 1 MgSO4•7H2O, 0.036 g / L -1 FeCl3•6H2O, 1 g L -1 Na2EDTA, 1 ml / L -1 D7, 3 ml / L -1 VB 12 The culture medium consists of [a specific type of medium], and this comprehensive culture medium is called MBGA.

[0030] D7 includes 2.86 g L -1 H3BO3, 1.81g / L -1 MnCl2•4H2O, 0.222g L -1 ZnSO4•7H2O, 0.079g / L -1 CuSO4•5H2O, 1.26 g L -1 Na2MoO4•2H2O, 0.0403 g / L -1 Co (NO3)2•6H2O.

[0031]

[0032] Experiment Example 2: Light Intensity Optimization Experiment The energy input per unit volume was determined to be 2.5–3.5 W / L, and the dilution rate was determined to be 0.8 d⁻¹. Based on this, a pilot-scale continuous culture experiment with a working volume of 100 L was conducted. The experiment used white light illumination, duty cycles of 42% and 56%, a dilution rate of 0.8 d⁻¹, precise temperature control at 40±2℃, continuous aeration in the reactor, and pH control at 8.0–8.5, with CO2 injection adjusted via pH feedback. The system operated stably for 10 days, and the experimental results are as follows: Figure 1 and Figure 2 As shown.

[0033] Table 1 Experimental conditions for light intensity optimization

[0034] Experiment Example 3: Energy Consumption Measurement Experiment (1) Experimental setup Energy consumption of UTEX3222 was measured in continuous culture mode. MBGA culture medium was selected, light intensity was set to two groups of 520 μmol / m² / s and 760 μmol / m² / s, dilution rate was 0.8, and temperature was 40±2℃.

[0035] (2) Vaccination and initiation UTEX3222 was inoculated into a loop reactor, and modified MBGA medium was added, setting the initial inoculation density to OD. 720 =4.196, the spectrum is a full wavelength spectrum (400~800nm), the illumination frequency is 100 Hz, and the average incident light intensity is 520 μmol / m². 2 / s, the average transmitted light intensity is 7.5μmol / m² / s, and the average transmitted light intensity is 760μmol / m² / s. 2 / s, 11μmol / m 2 / s, dilution rate 0.8 days -1 The pH range is 8.0~8.5, and the temperature is controlled by a heating belt, with a temperature range of 40~45 ℃. Turn on the peristaltic pump, set the flow rate, and keep the outflow rate of the liquid collection unit consistent with the inflow rate of the feed addition unit to start the continuous culture mode, so as to realize the continuous culture and collection of algal solution.

[0036] (3) Cultivation and harvesting The experiment lasted for 22 days. During the experiment, samples were taken daily to monitor the growth of microalgae, and the dry weight of UTEX3222 and the actual daily power consumption were measured. The daily growth rate, algal yield, and electro-photon conversion rate of UTEX3222 were calculated. The comparison results of various parameters of UTEX3222 under different light intensities are shown in Table 2.

[0037] Table 2 Comparison of parameters for continuous culture of UTEX3222 under different light intensities.

[0038] (4) Results and Analysis Referring to Table 2, UTEX3222 at 520 μmol / m 2 The dry weight value of the culture at / s was higher than that of a light intensity of 760 μmol / m² / s. 520 μmol / m² / s 2 The dry weight of the / s experimental group was 0.6067 g / L, compared to 760 μmol / m 2 The concentration of 0.4353 g / L in the experimental group increased by 35.67% during the experimental period. At 520 μmol / m 2 The average growth rate of the experimental group was 0.5020 g / L / day, and the average growth rate of the experimental group was 760 μmol / m². 2 The average growth rate of the experimental group was 0.3737 g / L / day; 520 μmol / m 2 The electrophoton conversion rate of the / s experimental group was 121.3 kWh / kg, compared to 760 μmol / m 2 The growth rate of the experimental group was 233.8 kWh / kg, an increase of 48.12%. The decrease in growth rate under high light intensity may be a result of high light inhibition. The results show that UETX3222 can grow normally under high light intensity and high temperature conditions, but considering the overall energy consumption, the conversion rate of electrophoton algae can be improved by increasing the light intensity and thus reducing the power consumption.

[0039] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Any simple modifications or equivalent changes made to the above embodiments based on the technical essence of the present invention shall fall within the protection scope of the present invention.

Claims

1. An energy-saving and efficient method for continuous cultivation of the high-temperature cyanobacterium UTEX 3222, characterized in that: The high-temperature cyanobacterium UTEX3222 and its culture medium were placed in a ring-shaped flat-plate reactor. Lighting fixtures were arranged inside the reactor, and air was introduced. The light source used for cultivation was electrically driven LED light, which could be red or white. The lamp power was adjusted by the duty cycle; at a duty cycle of 15-20%, the ratio of lamp power to reactor volume was 1.0-1.5 W / L. The dilution rate for continuous cultivation was 0.5-1.0 days. -1 .

2. The energy-saving and efficient continuous cultivation method for high-temperature cyanobacteria UTEX 3222 according to claim 1, characterized in that: The spectral wavelength of the red light is 580-700nm.

3. The energy-saving and efficient continuous cultivation method for high-temperature cyanobacteria UTEX 3222 according to claim 1, characterized in that: The wavelength of the white light is 400-800nm.

4. The energy-saving and efficient continuous cultivation method for high-temperature cyanobacteria UTEX 3222 according to claim 1, characterized in that: The initial inoculation density of the thermophilic cyanobacterium UTEX 3222 was 0.05-0.1 g / L.

5. The energy-saving and efficient continuous cultivation method for high-temperature cyanobacteria UTEX 3222 according to claim 1, characterized in that: The ventilation rate when air is introduced is 0.15-0.2 vvm.

6. The energy-saving and efficient continuous cultivation method for high-temperature cyanobacteria UTEX 3222 according to claim 1, characterized in that: The daily replenishment of culture medium is 50-100 L.

7. The energy-saving and efficient continuous cultivation method for high-temperature cyanobacteria UTEX 3222 according to claim 1, characterized in that: The ratio of lamp height to reactor height is 1:2; the optical path of the annular flat plate reactor is 4-6 cm.

8. The energy-saving and efficient continuous cultivation method for high-temperature cyanobacteria UTEX 3222 according to claim 1, characterized in that: The culture medium has the following composition: 2.5 g / L -1 NaHCO3, 1.5 g L -1 NaNO3, 18.0 g / L -1 NaCl, 3.6 g / L -1 CaCl•2H2O, 0.6 g L -1 KCl, 0.33 g / L -1 KH2PO4, 0.75 g / L -1 MgSO4•7H2O, 0.036 g / L -1 FeCl3•6H2O, 1 g L -1 Na2EDTA, 1 ml / L -1 D7, 3 ml / L -1 VB 12 .

9. The energy-saving and efficient continuous cultivation method for high-temperature cyanobacteria UTEX 3222 according to claim 8, characterized in that: The D7 comprises 2.86 g L -1 H3BO3, 1.81g / L -1 MnCl2•4H2O, 0.222g L -1 ZnSO4•7H2O, 0.079g / L -1 CuSO4•5H2O, 1.26 g L -1 Na2MoO4•2H2O, 0.0403 g / L -1 Co (NO3)2•6H2O.

10. The energy-saving and efficient continuous cultivation method for high-temperature cyanobacteria UTEX 3222 according to claim 1, characterized in that: The cultivation temperature was 35-45℃, the pH was controlled within the range of 8.0-8.5, and the light intensity was controlled within the range of 500-760 μmol / m². 2 / s.

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