KR101842591B1 - Method for microalgae harvesting using Poly-Lysine - Google Patents

Abstract

The present invention relates to a method for microalgae harvesting using poly-lysine, in which the poly-lysine is applied as a coagulant to effectively coagulate and harvest the microalgae, and to eliminate harmful toxins and prevent microalgae from being biologically contaminated by microorganisms. The method comprises the following steps: preparing a microalgae solution in which microalgae are cultured; introducing poly-lysine into the microalgae solution; inducing flocculation of microalgae with the poly-lysine by agitating the microalgae solution to which poly-lysine is introduced; and precipitating microalgae aggregates flocculated by the poly-lysine.

Description

[0001] The present invention relates to a method for harvesting microalgae using polylysine,

The present invention relates to a method for harvesting microalgae using polylysine, and more particularly, to a method for harvesting microalgae using polylysine as a coagulant to effectively collect and harvest microalgae, The present invention relates to a microalgae harvesting method using polylysine capable of inhibiting biological contamination of harvested microalgae by microorganisms.

In producing microalgae biomass, the cost of harvesting microalgae accounts for 20-30% of the total production cost. Various methods such as centrifugation, flocculation, membrane filtration, electrolysis, floatation, ultrasonic wave and pH control are used for harvesting microalgae. Because harvest conditions are different depending on microalgae species or culturing conditions, There is no established optimal technology. Among them, microalgae harvesting method using coagulant can be used alone, but when used as a pretreatment method such as centrifugation or membrane filtration, the economical efficiency of the existing physical harvesting method can be improved.

On the other hand, the chemical and biological contamination of microalgae in the production of microalgae biomass has a great influence on the biomass yield and quality. Chemical contamination means pollution caused by chemicals that are added during microalgae biomass production. Typically, coagulant for flocculating microalgae is a typical source of chemical pollution. Metal coagulants such as aluminum and iron are widely used because they are inexpensive and highly efficient. However, since they are toxic to humans and the environment, there is limited utilization of fine-grained biomass harvested through these metal coagulants. Various natural coagulants (eg, moringa seed, γ-PGA, starch, etc.) have been studied to escape the risk of these metal flocculants. Second, biological contamination inhibits the quality and storage of microalgae biomass produced by zooplankton or bacteria as they grow with microalgae. In particular, microalgae biomass cultivated in an open pond has no way of avoiding contamination by various microorganisms.

 Zheng, Hongli, Zhen Gao, Jilong Yin, Xiaohong Tang, Xiaojun Ji, and He Huang. "Harvesting of Microalgae by Flocculation with Poly (γ-Glutamic Acid)." Bioresource Technology 112 (2012): 212-20.  Peng, Chengrong, Shuangshuang Li, Jiaoli Zheng, Shun Huang, and Dunhai Li. "Harvesting Microalgae with Different Sources of Starch-Based Cationic Flocculants." Applied Biochemistry and Biotechnology 181 (2017): 112-24.  Rashid, Naim, Saif Ur Rehman, and Jong-In Han. "Rapid Harvesting of Freshwater Microalgae Using Chitosan." Process Biochemistry 48 (2013): 1107-10.

Disclosure of the Invention The present invention has been devised to solve the above-mentioned problems, and it is an object of the present invention to effectively collect and harvest microalgae by applying poly-lysine as a coagulant in harvesting microalgae, It is an object of the present invention to provide a microalgae harvesting method using polylysine capable of inhibiting biological contamination of harvested microalgae by microorganisms.

According to another aspect of the present invention, there is provided a method for harvesting microalgae using polylysine, comprising: preparing a microalgae solution in which microalgae are cultured; Introducing poly-lysine into the microalgae solution; Stirring the microalgae solution to which the polylysine has been added to induce flocculation of microalgae by polylysine; And precipitating microalgae aggregates flushed by polylysine.

The polylysine is any one of? -Poly-lysine and? -Poly-lysine. In addition, the polylysine may be a mixture of? -Poly-lysine and? -Poly-lysine.

When α-poly-lysine or ε-poly-lysine is added, the pH of the microalgae solution can be adjusted to 4 or more.

The polylysine may be selected from the group consisting of α-PLL (α-Poly-L-Lysine), α-PDL (α-Poly-D-Lysine), ε- -D-Lysine) or a mixture of at least two or more thereof.

The method for harvesting microalgae using polylysine according to the present invention has the following effects.

By applying poly-lysine, which has cell adhesion properties and preservative properties, to microalgae harvesting, microalgae flocculation efficiency can be improved and chemical pollution and biological contamination of microalgae can be minimized. The microalgae biomass thus produced can be widely used as a high value-added raw material.

Unlike the conventional metal coagulant, polyol is used to coagulate the microalgae. Therefore, pH control of the microalgae solution is not required because the hydroxide ion is not consumed and reuse is possible.

1 is a flow chart for explaining a microalgae harvesting method using polylysine according to an embodiment of the present invention;
Fig. 2 shows experimental results showing microalgae harvesting efficiency depending on the molecular weight and concentration of alpha-polylysine.
FIG. 3 shows the results of microscopic algae growth and photosynthetic efficiency of microalgae cultured using a residual medium after microalgae harvesting using α-polylysine.
FIG. 4 is a photograph showing the contamination state of microalgae biomass harvested using? -Poly-lysine according to the storage time. FIG.
FIG. 5 is a photograph of the evaluation of the toxicity of a flea to a concentration of microalgae biomass harvested using? -Poly-lysine.
FIG. 6 shows experimental results showing changes in harvesting efficiency depending on the stirring speed and the concentration of ε-polylysine in the microalgae harvesting using ε-polylysine.
7 is a photograph showing the contamination state of microalgae biomass harvested with? -Polyisin according to the storage time.
8 shows the results of experiments showing the effect of photosynthesis efficiency of microalgae cells on the concentration of ε-polylysine in microalgae harvesting using ε-polylysine.
FIG. 9 shows experimental results showing pH-dependent harvesting efficiency of microalgae solution when microalgae were harvested using? -Poly-lysine.
FIG. 10 shows experimental results showing pH-dependent harvesting efficiency of microalgae solution when microalgae were harvested using? -Poly-lysine.
FIG. 11 shows experimental results showing microalgae harvesting efficiency using a conventional natural coagulant, Moringa seed powder, aluminum chloride, and cationic guar gum.

The present invention provides a technique for harvesting microalgae using poly-lysine as an aggregating agent in producing microalgae biomass.

As mentioned in the Background of the Invention, in order to increase the production and quality of microalgae biomass in the production of microalgae biomass, the coagulation efficiency of the microalgae must be improved, and the chemical pollution of the microalgae And biological contamination must be minimized.

The present invention can minimize the chemical contamination and biological contamination of microalgae by applying poly-lysine as a flocculant, and it has little harmful toxicity to human body and adversely affects the activity of microalgae such as photosynthesis of microalgae It is possible to exclude the influence factor.

Poly-lysine is a cationic polymer and has a form in which a lysine is bonded by an amide bond. Such poly-lysine is classified into PLL (Poly-L-Lysine) and PDL (Poly-D-Lysine) according to the binding type. In addition, poly-lysine is divided into α-poly-lysine produced by artificial synthesis and ε-poly-lysine which is biologically present. α-poly-lysine has characteristics such as heavy metal adsorption and cell adhesion, and ε-poly-lysine is used as a natural preservative. Therefore, poly-lysine can be synthesized from α-PLL (α-Poly-L-Lysine), α-PDL (α- -L-Lysine), and ε-PDL (ε-Poly-D-Lysine). Such poly-lysine is known to be toxic to humans and the environment.

The present invention focuses on the above-mentioned characteristics of poly-lysine, that is, cell attachment and preservation characteristics, and suggests a technique for applying this to microalgae harvesting. Micro-algae can be aggregated through the cell attachment properties of poly-lysine, and bio-contamination of harvested microalgae can be prevented by the antiseptic properties of poly-lysine.

In the aggregation of microalgae using poly-lysine, α-PLL (α-Poly-L-Lysine), α-PDL (α-Poly- -L-Lysine) and ε-PDL (ε-Poly-D-Lysine) are used as coagulants.

In order to effectively exhibit the cell adhesion and preservation properties of poly-lysine, α-poly-lysine having excellent cell adhesion properties and ε-polylysine (ε- poly-L-lysine), ε-PLL (ε-Poly-L-Lysine), and α-PLL L-Lysine), and? -PDL (? -Poly-D-Lysine) may be mixed and injected as a coagulant.

As described above, it is known that? -Poly-lysine is relatively excellent in cell adhesion property and? -Poly-lysine is relatively excellent in antiseptic properties, In the case of α-poly-lysine, which can be produced by artificial synthesis, preservation characteristics can be enhanced by controlling the molecular weight and the input concentration. As the molecular weight increases, the preservative effect increases, but when the concentration required for harvest is low, the preservative effect may not be efficiently exerted. According to the experimental example to be described later,? -Poly-lysine having a molecular weight of 4 to 15 kDa is? -Polylysine having a different molecular weight (1 to 5 kDa, 30 to 70 kDa, 70 to 150 kDa) -lysine), it has been found that the composition has excellent antiseptic properties, and this will be described in detail with reference to the following experimental examples.

Hereinafter, a method for harvesting microalgae using polylysine according to an embodiment of the present invention will be described in detail with reference to the drawings.

Referring to FIG. 1, in step S101, poly-lysine is injected into the microalgae solution in a state in which the microalgae solution in which the microalgae are cultured is prepared (S102). Then, micro-algae solution into which poly-lysine is injected is stirred at a constant speed to induce flocculation of microalgae by poly-lysine (S103). As described above, when poly-lysine is added to a microalgae solution due to its cell attachment property, poly-lysine adheres to micro-algae cells in poly-lysine, . Microalgae flocculated by poly-lysine is precipitated (S104). In this state, the microalgae harvesting method according to one embodiment of the present invention is completed when the precipitated microalgae aggregates are collected. The collected microalgae agglutinates may be further subjected to centrifugation, membrane filtration, and the like.

In the microalgae harvesting method described above, the poly-lysine may be added to the microalgae solution in any one of α-poly-lysine and ε-poly-lysine, Lt; / RTI > That is, when α-poly-lysine or ε-poly-lysine is added as a flocculant or α-poly-lysine and ε-poly- -lysine can be mixed and injected as a flocculant.

As mentioned earlier, poly-lysine has cell attachment and preservation properties, and α-poly-lysine is relatively more soluble than ε-poly-lysine Ε-poly-lysine is superior to α-poly-lysine in terms of preservative properties.

Taking these characteristics into consideration, it has been found that when α-poly-lysine or ε-poly-lysine is added singly or α-poly-lysine and ε- (α-poly-lysine) and ε-poly-lysine (ε-poly-lysine) in consideration of characteristics of microalgae, microalgae harvesting environment and preservation environment of harvested microalgae. -Epoly-lysine or a mixture thereof may be added as a coagulant. More specifically,? -Polyl-L-Lysine,? -Poly-Lysine,? -Polyl-Lysine, Poly-D-Lysine) or at least two kinds of poly-lysine may be mixed and added as a coagulant.

The method for harvesting microalgae using polylysine according to an embodiment of the present invention has been described above. Hereinafter, the present invention will be described in more detail with reference to experimental examples.

<Experimental Example 1>

Experiments were carried out on microalgae harvesting efficiency according to the molecular weight of α-poly-lysine.

Microalgae were used by Chlorella ellipsoidea (KMMCC-1987) from the Korea Marine Microalgae Bank. Chlorella ellipsoidea was used after 2 weeks of culture in photoautotrophic conditions. Α-polylysine having a molecular weight of 1 to 5 kDa, 4 to 15 kDa, 30 to 70 kDa and 70 to 150 kDa was prepared as a concentrated solution of 10 g / L and used for microalgae harvesting experiments.

 Polylysine having a molecular weight as described above was added to the 25 ml microalgae solution and the mixture was stirred at 400 rpm for 5 minutes and at 80 rpm for 10 minutes and then precipitated for 1 hour. The microbial harvesting efficiency was calculated by sampling the solution at the point. The harvesting efficiency was calculated using the UV-Spectrophotometer at 680 nm as shown in the following equation.

(1) Harvest efficiency = (1 - ( OD _f / OD _i )) * 100 (%)

( OD _i : initial microalgae concentration, OD _f : residual microalgae concentration after flocculation)

Referring to FIG. 2, it can be seen that as the molecular weight of? -Polysin increases, the final harvesting efficiency is increased and the amount of polylysine required for harvesting decreases. It can be seen that the molecular weight of polylysine has an important influence on microalgae harvesting.

<Experimental Example 2>

After the microalgae harvesting using α-polylysine, experiments were conducted on the possibility of reusing microalgae culture.

Microalgae and alpha-polylysine were prepared under the same conditions as in Experimental Example 1, and microalgae harvesting was carried out. Next, the supernatant of the microalgae solution was separated, and the byproducts were removed and supplemented with insufficient nutrients to be used as a microalgae culture solution. Photosynthetic efficiency of microalgae cells was measured by measuring the efficiency of photosystem II.

Referring to FIG. 3, the remaining α-polylysine except the longest chain length α-polylysine shows the same cell growth as the control group. Photosynthetic efficiency also showed a constant value except for α-polylysine of 70-150 kDa similar to the culture results. As a result, it is possible to reuse the medium left after harvesting with polylysine, which makes it possible to develop economical microalgae biomass production process.

<Experimental Example 3>

The micro-algae contamination of α-polylysine with molecular weight was investigated.

Microalgae and alpha-polylysine were prepared under the same conditions as in Experimental Example 1.

In order to confirm the degree of biological contamination of microalgae biomass harvested with α-polylysine of various molecular weights, α-polylysine was injected into 400 mL of microalgae solution at various concentrations and settled for 24 hours. After the supernatant was removed by centrifugation, the color and morphological changes of microalgae were observed at room temperature.

Referring to FIG. 4, in the case of the α-polylysine-treated group, contamination by microorganisms estimated to be bacteria and fungi was observed from about 9 days after storage. Even with α-polylysine treatment, some contamination was observed at a lower frequency than the untreated group. Notably, no contamination was observed 40 days after storage when harvested with 5 mg / L of α-polylysine with a molecular mass of 4-15 kDa. It is known that the larger the molecular weight of? -Polylysine is, the greater the preservative effect is. Also, as the molecular weight increases, the amount of the feed required for microalgae harvesting is reduced. Experimental Example 2 confirmed that? When applied to the algae harvesting, it is possible that the preservation effect is not exerted on the microalgae harvested because the amount is small. In the case of applying α-polylysine for effective harvesting and reduction of contamination of biomass produced at the same time, α-polylysine having optimal molecular weight suitable for microalgae species and medium characteristics and aggregation and preservation effect It was confirmed that it is important to select the input amount.

<Experimental Example 4>

Experiments were conducted on the toxicity of daphnia to α-polylysine.

Microalgae and alpha-polylysine were prepared under the same conditions as in Experimental Example 1, and microalgae harvesting was carried out. Then, the harvested microalgae were lyophilized and powdered, then injected into a daphnia culture medium at a concentration of 0.1 to 100 mg / L, and then observed for type inhibition and lethality for 48 hours to evaluate acute toxicity of daphnia.

Referring to Fig. 5, no dwarf toxicity was observed in the microalgae harvested using alpha-polylysine at all concentrations and all molecular weights. This confirms the low toxicity of microalgae biomass produced via α-polylysine.

<Experimental Example 5>

Experiments were conducted on microalgae harvesting efficiency according to the injection concentration of ε-poly-lysine.

Microalgae were prepared under the same conditions as in Experimental Example 1. Poly-Lysine having a molecular weight of 3.5 to 4.5 kDa was prepared in a concentrated solution of 10 g / L and used for microalgae harvesting experiments.

The effects of stirring speed and ε-polylysine concentration on microalgae harvesting using ε-polylysine were confirmed, and for the statistical analysis, the reaction was carried out at a stirring speed of 50~500 rpm and an epsilon-polylysine concentration range of 5~25 mg / L A face-centered central composite design was performed.

Polylysine was injected into the 25 ml microalgae solution at different concentrations and stirred for 5 minutes and then sedimented for 1 hour and the solution was sampled at the surface of the water to calculate the microalgae harvesting efficiency. The harvesting efficiency was calculated as follows at 680 nm using a UV-Spectrophotometer.

(Equation 2) Harvest efficiency = (1 - ( OD _f / OD _i )) * 100 (%)

( OD _i : initial microalgae concentration, OD _f : residual microalgae concentration after flocculation)

Referring to FIG. 6, as the injection concentration of ε-polylysine increased, the harvesting efficiency was increased and the stirring speed showed the highest harvesting efficiency in the range of about 250-350 rpm. In the statistical analysis, ε-polylysine concentration was found to have a greater effect than the stirring speed, and statistically, it was confirmed that ε-polylysine of about 19 mg / L was required when the harvest efficiency of about 95% was predicted.

<Experimental Example 6>

The micro-algae contamination according to the injection concentration of ε-polylysine was examined.

Microalgae and epsilon-polylysine were prepared under the same conditions as in Experimental Example 5.

In order to confirm the degree of biodegradation of microalgae biomass harvested at various concentrations of ε-polylysine, ε-polylysine was injected into 400 mL of microalgae solution at various concentrations and then settled for 24 hours. After the supernatant was removed by centrifugation, the color and morphological changes of microalgae were observed at room temperature.

As a result of the experiment, as compared with the results using α-polylysine as shown in FIG. 7 (see Experimental Example 3 and FIG. 4), ε-polylysine has a relatively small injection amount (concentration of 2.375 mg / L) It can be confirmed that the pollution can be suppressed. In the ε-polylysine-treated group, there was no significant morphological change (appearance and color), whereas in the ε-polylysine treated group, 2.375 mg / L It can be confirmed that biological contamination can be sufficiently prevented even by the concentration.

<Experimental Example 7>

The toxicity of ε-polylysine to microalgae was tested.

Microalgae and epsilon-polylysine were prepared under the same conditions as in Experimental Example 5. To investigate the toxicity of ε-polylysine to algae, ε-polylysine was injected into a microalgae solution at a concentration of 0 to 100 mg / L, and after 3, 6 and 24 hours, Respectively.

As shown in Fig. 8, it was confirmed that? -Polyisin had no effect on the photosynthetic efficiency of microalgae up to a concentration of 100 mg / L. This shows that ε-polylysine is a safe substance and microalgae biomass harvested through ε-polylysine is also safe.

<Experimental Example 8>

The effect of the pH of the microalgae solution on the harvesting efficiency in the microalgae harvesting using α-polylysine was tested.

Microalgae and alpha-polylysine were prepared under the same conditions as in Experimental Example 1. Microalgae were harvested by adding α-polylysine while changing the pH of the microalgae solution to 2-12. The concentration of each α-polylysine was used to indicate the peak of harvest efficiency obtained in Experimental Example 1.

As shown in FIG. 9, it can be seen that the harvest efficiency increases with increasing pH regardless of the molecular weight of alpha-polylysine. In particular, except for alpha-polylysine at 1 to 5 kDa at pH 4 or higher, - Polylysine showed a harvesting efficiency of over 90%. The high harvesting efficiency maintained in this wide pH range means that if α-polylysine is used, it can be harvested without any pH adjustment, which makes it possible to harvest economically. Since the conventional metal coagulant is harvested by binding with the hydroxide ion of the medium, the pH is changed from the neutral to the acidic region, whereas the polylysine is harvested without consuming the hydroxide ion, There is also an advantage in that.

<Experimental Example 9>

The effect of the pH of the microalgae solution on the harvesting efficiency in harvesting microalgae using ε-polylysine was tested.

Microalgae and epsilon-polylysine were prepared under the same conditions as in Experimental Example 5, and the harvesting efficiency was measured 2 hours after the addition of 15 mg / L of epsilon-polylysine. The microalgae were harvested by adding ε-polylysine while changing the pH of the microalgae solution to 2 to 12, and the harvesting efficiency was measured 1 hour after the coagulant was added. The concentration of ε-polylysine was fixed at a concentration of 15 mg / L.

As shown in FIG. 10, the harvesting efficiency was 78% at pH 2, 87% at pH 4, and 96-99% at pH 6 and above, as shown in FIG. A characteristic showing a satisfactory harvesting efficiency in such a wide pH range (pH 4 to 12) is that when ε-polylysine is utilized similarly to the result of Experimental Example 8, economical harvesting is possible without adjusting pH separately. The pH change is not large and it is advantageous to reuse the medium.

&Lt; Comparative Example 1 &

When microscopic algae were harvested using microalgae harvesting efficiency using α-polylysine (see Experimental Example 1 and FIG. 2) and the existing natural coagulant, Moringa seed powder, aluminum chloride and cationic guar gum (see FIG. 11) .

2 and 11, except for the lowest molecular weight α-polylysine (1 to 5 kDa), α-polylysine of the remaining molecular weight is capable of harvesting microalgae even at a lower concentration than conventional flocculants .

&Lt; Comparative Example 2 &

The efficiency of microalgae harvesting using epsilon-polylysine (see Experimental Example 5 and Fig. 6) and the efficiency of microalgae harvesting using conventional natural coagulants (see Table 1 below) were compared. The efficiency of the coagulant itself was evaluated by calculating the ratio of the amount of coagulant needed and the initial microalgal concentration required to achieve a harvest efficiency of at least about 90%.

Referring to FIG. 6 and Table 1, it can be seen that epsilon-polylysine can be harvested satisfactorily at a concentration of 2-6 times less than conventional natural flocculants. High coagulant efficiency means that coagulant consumption is low and economic harvesting is feasible. Also, utilization of microalgae biomass that is finally produced is less influential (component change and toxicity).

<Coagulation characteristics of ε-polylysine (ε-PLL) and conventional natural coagulant> Coagulant Type Target microalgae Microalgae concentration (mg / L) Flocculant concentration
(mg / L) Math efficiency
(%) Flocculant efficiency ^* references γ-PGA C. vulgaris 570 22.03 91 23.55 [One] C. protothecoides 600 19.82 98 29.67 Cationic wheat starch C. pyrenoidosa 1,000 89 91 10.22 [2] B. braunii 1,000 119 94 7.90 Cationic potato starch C. pyrenoidosa 1,000 89 93 10.45 B. braunii 1,000 119 90 7.56 Cationic corn starch C. pyrenoidosa 1,000 89 96 10.79 B. braunii 1,000 119 93 7.82 Chitosan C. vulgaris 1,000 120 99 8.25 [3] Cationic guar gum Chlorella sp . CB4 780 40 90 18.43 [4] ε-PLL C. ellipsoidea 1,000 19 95 50

( ^* Coagulant Efficiency = Microalgae Concentration / Coagulant Concentration * Harvesting Efficiency / 100)

&Lt; Comparative Example 3 &

The economic efficiency of microalgae harvesting method using ε-polylysine and the economical efficiency of microalgae harvesting method using natural coagulant were compared.

Referring to Table 2, in the case of microalgae harvesting using ε-polylysine, about 20 US $ is required to harvest about 1 ton of microalgae biomass. This is one of the most economical methods among the harvesting techniques compared to the method using slaked lime.

<Cost of harvesting microalgae biomass according to harvesting technology> Harvest technology Target microalgae Mathematical efficiency (%) Items included in cost calculation ¹ Cost of harvest
(US $ / biomass ton) references Continuous centrifugation - - E, P 119 - 740 ^2,3 [5] Tangential flow filtration T. suecica ~ 100 P 343 [6] High pH by slaked lime C. vulgaris - M 18 [7] Low pH by HNO3 C. nivale
C. ellipsoideum
Scenedesmus sp. > 90 M 61
62
72 [8] Electro-coagulation-flotation N. oculata 96 - 100 P 68 - 101 [9] Flocculation by γ-PGA C. vulgaris
C. protothecoides 91
98 M 228
168 [One] Flocculation by ε-PLL C. ellipsoidea 95 M, P 20 ⁴

¹ E: Equipment, P: Power, and M: Material

² Difference according to kind of culture facility

³ US $ 1 = € 0.86

⁴ ε-PLL Price per kg = US $ 1, purity = 95%

&Lt; References listed in Table 1 and Table 2 > [1] Zheng, Hongli, Zhen Gao, Jilong Yin, Xiaohong Tang, Xiaojun Ji, and He Huang. "Harvesting of Microalgae by Flocculation with Poly (γ-Glutamic Acid)." Bioresource Technology 112 (2012): 212-20.

[2] Peng, Chengrong, Shuangshuang Li, Jiaoli Zheng, Shun Huang, and Dunhai Li. "Harvesting Microalgae with Different Sources of Starch-Based Cationic Flocculants." Applied Biochemistry and Biotechnology 181 (2017): 112-24.

[3] Rashid, Naim, Saif Ur Rehman, and Jong-In Han. "Rapid Harvesting of Freshwater Microalgae Using Chitosan." Process Biochemistry 48 (2013): 1107-10.

[4] Banerjee, Chiranjib, Sandipta Ghosh, Gautam Sen, Sumit Mishra, Pratyoosh Shukla, and Rajib Bandopadhyay. "Study of Algal Biomass Harvesting Using Cationic Guar Gum from the Natural Plant Source as Flocculant." Carbohydrate Polymers 92 (2013): 675-81.

[5] Norsker, Niels-Henrik, Maria J. Barbosa, Marian H. Vermu ㅻ, and Ren ㅹ H. Wijffels. "Microalgal Production - a Close Look at the Economics." Biotechnology Advances 29 (2011): 24-27.

[6] Danquah, Michael K., Li Ang, Nyomi Uduman, Navid Moheimani, and Gareth M. Forde. "Dewatering of Microalgal Culture for Biodiesel Production: Exploring Polymer Flocculation and Tangential Flow Filtration." Journal of Chemical Technology and Biotechnology 84 (2009): 1078-83.

[7] Vandamme, Dries, Imogen Foubert, lse Fraeye, Boudewijn Meesschaert, and Koenraad Muylaert. "Flocculation of Chlorella Vulgaris Induced by High Ph: Role of Magnesium and Calcium and Practical Implications." Bioresource Technology 105 (2012): 114-19.

[8] Liu, Jiexia, Yi Zhu, Yujun Tao, Yuanming Zhang, Tao Li Aifen Li, Ming Sang, and Chengwu Zhang. "Freshwater Microalgae Harvested Via Flocculation Induced by Ph Decrease." Biotechnology for Biofuels 6 (2013): 98.

[9] Kim, Jungmin, Byung-Gon Ryu, Kyochan Kim, Bo-Kyong Kim, Jong-In Han, and Ji-Won Yang. "Continuous Microalgae Recovery Using Electrolysis: Effect of Different Electrode Pairs and Timing of Polarity Exchange." Bioresource Technology 123 (2012): 164-70.

Claims (6)

Preparing a microalgae solution in which microalgae have been cultured;
Introducing poly-lysine into the microalgae solution;
Stirring the microalgae solution to which the polylysine has been added to induce flocculation of microalgae by polylysine; And
A method for harvesting microalgae using polylysine, comprising the steps of: precipitating microalgae flocculated by polylysine.
The method for harvesting microalgae according to claim 1, wherein the polylysine is any one of? -Poly-lysine and? -Poly-lysine.
The method for harvesting microalgae according to claim 1, wherein the polylysine is a mixture of? -Poly-lysine and? -Poly-lysine.
The method according to claim 2, wherein the pH of the microalgae solution is adjusted to 4 or more when? -Poly-lysine or? -Poly-lysine is added. Microbial harvesting method using lysine.
The method according to claim 3, wherein, when a mixture of? -Poly-lysine and? -Poly-lysine is added, the pH of the microalgae solution is adjusted to 4 or more A microalgae harvesting method using polylysine.
The polylysine according to claim 1, wherein the polylysine is at least one selected from the group consisting of? -Poly-L-Lysine,? -PDL,? -Poly-Lysine, -PDL (? -Poly-D-Lysine), or a mixture of at least two kinds or more of the polylysine.

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