A method for alkali flocculation harvesting and circular culture of microalgae

A cyclic culture, microalgae technology, applied in microorganism-based methods, biochemical equipment and methods, microorganisms, etc., can solve the problems of microalgae damage, cell debris, and high cost, so as to solve the problem of high cost and reduce harvesting costs. , the effect of a perfect match

Active Publication Date: 2021-11-02
DALIAN UNIV OF TECH
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Problems solved by technology

Taking Dunaliella salina as an example, a maximum of 35% NaCl is used for each cultivation, and if it cannot be recycled, the cultivation cost will be very expensive
But generally speaking, microalgae will secrete some extracellular products, or some cells will be lysed during the cultivation process, resulting in the leakage of intracellular substances and the generation of cell debris. These substances are generally harmful to microalgae. Substrates pose challenges, therefore, need to be treated to remove these inhibitors, otherwise the smooth progress of recirculating culture cannot be guaranteed
[0005] After the cultivation of microalgae, due to the characteristics of microalgae cells, harvesting is difficult and the cost is high, accounting for 20-30% of the entire production cost
The traditional harvesting methods of microalgae biomass are mainly centrifugation, filtration, adding inorganic or organic flocculants for flocculation, etc. Among these harvesting methods, centrifugal harvesting consumes a lot of energy and damages the algae, so it is not suitable for large-scale applications; Filtration is easy to cause membrane pollution and reduce recovery efficiency; when flocculant is harvested, adding flocculant to the water body will on the one hand introduce foreign compounds and cause water pollution, which will affect downstream operations and make separation difficult again; on the other hand, because the flocculant is expensive , the use of flocculants will increase production costs, and its use in large-scale commercial production of microalgae is limited
[0006] To sum up, there are problems of high cultivation cost, high harvest cost, and difficulty in recycling the culture medium for the production of microalgae using the method. At present, there is an urgent need for an overall production plan that can comprehensively consider these problems and solve them in a package. And this is the technical problem to be solved by the present invention

Method used

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  • A method for alkali flocculation harvesting and circular culture of microalgae
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  • A method for alkali flocculation harvesting and circular culture of microalgae

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Experimental program
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Effect test

Embodiment 1

[0053] Embodiment 1 circulation culture system

[0054] A method for alkali flocculation harvesting and circular culture of microalgae, the whole process is as follows figure 1 As shown, the method includes the following steps:

[0055] (1) The microalgae cultivation system is a bicarbonate-based carbon capture and microalgae cultivation system (BICCAPS), which utilizes a medium containing a certain concentration of bicarbonate to cultivate microalgae, and the cultured microalgae is Dunaliella salina, The medium formula is shown in Tables 1 and 2. The culture system is a 1L Erlenmeyer flask, used as a photobioreactor, the culture volume is 300mL, the inoculation density is 0.1g / L, the light intensity is 4000Lux, the temperature is 25°C, and the initial pH The value is 8.5, and the pH value is 10.3 after the cultivation ends; when the microalgae is cultivated to harvestable (0.8g / L), 50% of the volume of the algae liquid in the Erlenmeyer flask is taken out;

[0056] (2) Adju...

Embodiment 2

[0067] Embodiment 2: the circulating culture system of filter membrane treatment circulating liquid

[0068] The circulating fluid that is not treated cannot be reused for culturing microalgae. In this example, the semi-continuous microalgae circulation culture system of Example 1 is used to cultivate Dunaliella salina. The medium formula is shown in Table 1 and Table 2. The circulation culture time is 18 days, the light intensity is 3000 Lux, and the initial inoculation amount is 0.1g. / L, the temperature was 25°C, the initial pH value was 8.5, and the pH value was 10.37 after the cultivation. The circulating medium (experimental group) was compared with fresh medium (control group), ie the same volume of fresh medium was added when the medium was circulated. Three days after inoculation, 50% of the medium was removed for circulation, and the removed circulation medium was bubbled with CO 2, reduce the pH to 8.50, add other nutrient salts (except sodium chloride and sodium ...

Embodiment 3

[0069] Embodiment 3: the circulating culture of activated carbon treatment circulating liquid

[0070] In this example, the semi-continuous microalgae circulation culture system of Example 1 is used to cultivate Dunaliella salina. The medium formula is shown in Table 1 and Table 2. The circulation culture time is 18 days, the light intensity is 3000 Lux, and the initial inoculation amount is 0.1g. / L, the temperature was 25°C, the initial pH value was 8.5, and the pH value was 10.3 after the cultivation. After each circulation of the circulating medium, 50% of the volume of the circulating liquid was taken, treated with 0.5 and 5 g / L activated carbon for 24 hours, and then removed by centrifugation, and then the circulating liquid was bubbled into CO 2 , reduce the pH to 8.5, add other nutrient salts (except sodium chloride and sodium bicarbonate) to the initial medium concentration, and the specific addition amounts are: KNO 3 , 0.005mol / L; KH 2 PO 4 ·3H 2 O, 0.000237mol / ...

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Abstract

The invention discloses a method for harvesting and circularly cultivating microalgae by alkali flocculation. The invention utilizes the culture medium containing bicarbonate to cultivate microalgae, utilizes its high alkalinity, adds low-concentration flocculation ions to carry out flocculation and sedimentation, and harvests microalgae. Subsequently, CO was bubbled into the supernatant after flocculation and sedimentation 2 , to make it produce sodium bicarbonate again, and then use physical or chemical methods to treat the supernatant, which is used for the circular culture of microalgae, so as to achieve the purpose of reusing carbon source, nutrient salt and water. It also saves the cost of harvesting and cultivating microalgae, which has important application prospects for large-scale cultivation of microalgae. The invention is mainly used for the cultivation of Dunaliella salina.

Description

technical field [0001] The invention relates to the field of microalgae biotechnology, in particular to a method for harvesting and circularly cultivating microalgae by alkali flocculation. Background technique [0002] Microalgae have the characteristics of fast growth and high yield per unit area, and play an important role in various fields. Including health food, medicine, fine chemicals, aquatic bait and bioenergy, etc. At the same time, because it can use the nutrients in urban sewage to grow, it can also efficiently fix carbon dioxide, so it can slow down the current water pollution and carbon emission problems. [0003] Carbon dioxide is used as a raw material for the growth of microalgae, and its supply is one of the main costs of microalgae production. In microalgae culture, most culture systems provide carbon dioxide in the form of bubbling aeration, but in practical applications, there are problems of high energy consumption and high transportation costs for ca...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C12N1/12C12R1/89
CPCC12N1/12
Inventor 迟占有崔倩倩朱陈霸
Owner DALIAN UNIV OF TECH
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