KR101484732B1 - Method for Cultivation of Microalgae Using Wastewater Pretreated by Polymer Film - Google Patents

Abstract

The present invention relates to a microalgae culture method comprising the steps of forming a polymer thin film, pretreating wastewater using the polymer thin film, and culturing a microalgae using the pretreated wastewater as a medium. According to the present invention, pretreatment of wastewater with a cationic polymer reduces the number of bacteria in the wastewater, thereby increasing productivity of microalgae and effectively removing pollutants from wastewater.

Description

TECHNICAL FIELD The present invention relates to a method for culturing microalgae using wastewater pretreated with a polymer thin film,

The present invention relates to a method for culturing microalgae using wastewater pretreated with a polymer thin film, and more particularly, to a method for culturing a microalgae by pretreating wastewater using a polymer thin film and using the pretreated wastewater as a medium .

Unlike general wastewater, livestock wastewater contains high concentrations of organic pollutants and nutrients. As a result, the pollutant loading rate of the wastewater is only about 0.5% of total wastewater generated in Korea. have. Such high concentration of livestock wastewater causes deterioration of water quality and eutrophication of river, threatening drinking water source, and accelerating pollution of soil and groundwater.

However, compared with the rapidly increasing production of livestock wastewater, the wastewater treatment facility has been deteriorated and the selection of improper construction methods has resulted in poor efficiency of treatment or discharge of the wastewater to rivers without maintaining legal standards. In recent years, the discharge standards for organic substances and nitrogen / phosphorus compounds that cause eutrophication of rivers have been strictly applied, and it is urgent to develop advanced treatment technology therefor.

Conventionally, various physical, chemical and biological methods such as activated sludge method and biofilm method have been used to remove nutrients from livestock wastewater. Using these methods singly or in combination can remove nutrients to a satisfactory level, but has drawbacks such as high operating costs, high chemical requirements, and excessive sludge generation. Therefore, a treatment system using microalgae instead of the conventional wastewater treatment method is considered as an alternative to the organic and nutrient removal methods.

On the other hand, microalgae grow faster than other photosynthetic plants and exhibit high productivity per unit area, and are attracting attention as sustainable bioenergy sources. Despite many advantages, however, there are some problems to be solved for the commercial production of avian-based biodiesel. For example, the limitations of light penetration for mass culture, the high harvesting cost of algae biomass, and the amount of enormous water required by photosynthetic organisms due to water-dependent cultivation have been pointed out as problems (Gerbens-Leenes et al , 2009. PNAS 106, 10219-10223).

The nutrients in the wastewater, such as nitrogen and phosphorus, must be removed before they are released into the environment, which can be removed by absorption into the biomass from photosynthesis of microalgae. Thus, wastewater has already been used to cultivate microalgae, but its main purpose is to remove nutrients (Lim et al., 2010, Bioresour. Technol. 101, 7314-7322). In recent years, microalgae cultivation in wastewater has been extended not only to the removal of nutrients but also to the supply of water and nutrients required for the mass culture of microalgae as a feed fuel for biodiesel (Chinnassamy et al , 2012, Bioresour Technol., 101, 3097-3105).

It is known that in the production of bio-energy based on photosynthesis, an enormous amount of water is required for the cultivation of photosynthetic organisms such as microalgae, but fortunately, it is known that microalgae can utilize various sources such as wastewater, seawater or fresh water (NREL report, 1998, National Renewable Energy Laboratory report / TP-580-24190, p. However, generally reused wastewater contains an enormous number of bacteria that can inhibit the growth of microalgae, and the growth of bacteria is faster than the growth of microalgae. Residual bacteria in the wastewater feed on microalgae and are present in the vicinity of microalgae, which can interfere with microalgae growth by inhibiting the use of light.

Korean Patent No. 10-1061035 provides a method for culturing microalgae comprising culturing microalgae using organic waste resources. However, since ultrasonic degradation or ozone sterilization must be performed in order to solubilize wastewater, facility costs and operating expenses It is expensive and not economical. Korean Patent Laid-Open Publication No. 10-2012-0016800 discloses a novel strain, Chlorella vulgaris, which is capable of removing nitrogen and phosphorus from wastewater due to its high resistance to wastewater and is highly effective in producing high-quality biodiesel. However, It has not been disclosed.

The present inventors have made intensive efforts to solve the above problems. As a result, the present inventors have found that the pretreatment of wastewater using the polymer thin film reduces the bacteria in the wastewater. Further, when the microalgae are cultured in the pretreated wastewater, It is confirmed that the productivity is increased as compared with the conventional method.

It is an object of the present invention to provide a method for culturing microorganisms in wastewater pretreated with a thin film of a polymer in order to increase the productivity of microalgae.

(I) depositing a cationic polymer on the surface of the support to form a polymer thin film; And (ii) stirring the wastewater and the polymer thin film to remove the bacteria in the wastewater. The present invention also provides a method for pretreating wastewater using the polymer thin film.

Another object of the present invention is to provide a method of manufacturing a semiconductor device, comprising: (i) depositing a cationic polymer on a surface of a support to form a polymer thin film; (Ii) stirring the wastewater and the polymer thin film to remove bacteria in the wastewater; And (iii) culturing the microalgae using the wastewater from which the bacteria have been removed as a medium.

The method for culturing microalgae according to the present invention is useful for treating bacteria that interfere with the growth of microalgae, is economical because it can cultivate microalgae in a large amount, and can utilize animal wastewater which is continuously required to be treated useful. In addition, it is possible to treat wastewater at a low cost and is particularly useful because it can maximize the productivity of microalgae useful for the production of biocompounds, pharmaceuticals, health functional foods, biofuels and protein hydrolysis products.

Figure 1 shows the effect of livestock wastewater on cell viability when treated with pDMAMS.
2 is 1) livestock waste is not a pre-treatment, 2) livestock waste water pre-treatment to an autoclave, and 3) filter (pore size = 0.2 ㎛) respectively in a livestock waste, and 4) a livestock waste water pre-treatment to pDMAMS pretreated with Chlorella The results are shown in Fig.
3 is 1) that is livestock waste water to a pre-treatment, 2) livestock waste water pre-treatment to an autoclave, and 3) filter (pore size = the livestock waste water pre-treatment with 0.2 ㎛), 4) in a pre-treatment by livestock wastewater pDMAMS Chlorella The content of chlorophyll when cultivating vulgaris is shown.
Figure 4 is 1) that is livestock waste water to a pre-treatment, 2) livestock waste water pre-treatment to an autoclave, and 3) filter (pore size = the livestock waste water pre-treatment with 0.2 ㎛), 4) in a pre-treatment by livestock wastewater pDMAMS Chlorella and the chemical oxygen demand before and after cultivation of vulgaris .
Figure 5 is 1) that is livestock waste water to a pre-treatment, 2) livestock waste water pre-treatment to an autoclave, and 3) filter (pore size = the livestock waste water pre-treatment with 0.2 ㎛), 4) in a pre-treatment by livestock wastewater pDMAMS Chlorella The change in nitrogen concentration when cultivating vulgaris is shown.

Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. In general, the nomenclature used herein is well known and commonly used in the art.

In the present invention, it was confirmed that microalgae cultured in wastewater pretreated with a cationic polymer not only increases the productivity of microalgae, but also has an effect on the removal of pollutants in wastewater.

Accordingly, in one aspect, the present invention provides a method of manufacturing a semiconductor device, comprising: (i) depositing a cationic polymer on a surface of a support to form a polymer thin film; And (ii) stirring the wastewater and the polymer thin film to remove the bacteria in the wastewater. The present invention also provides a method for pretreating wastewater using the polymer thin film.

According to another aspect of the present invention, there is provided a method of manufacturing a semiconductor device, comprising: (i) depositing a cationic polymer on a surface of a support to form a polymer thin film; (Ii) stirring the wastewater and the polymer thin film to remove bacteria in the wastewater; And (iii) culturing the microalgae using the bacterial-depleted wastewater as a medium.

In the step of culturing the microalgae, nutrients (nitrogen and phosphorus) necessary for the growth of microalgae are sufficiently supplied from the wastewater, so that microalgae can be mass-cultured without supplying additional nutrients. In the step of culturing the microalgae, carbon dioxide necessary for photosynthesis can be further supplied by using any method commonly used in the art.

In the present invention, the polymer thin film is formed on the surface of the support. The support is not particularly limited, but may be glass, metal, metal oxide, wood, paper, fiber, plastic, rubber, leather, silicon wafer or the like depending on the purpose of use. The plastic may be made of polyethylene (PE), polypropylene (PP), polystyrene (PS), polyethylene terephthalate (PET), polyamides (PA) PES, polyvinyl chloride (PVC), polyurethanes (PU), polycarbonate (PC), polyvinylidene chloride (PVDC), polytetrafluoroethylene (PTFE) Polyetheretherketone (PEEK), polyetherimide (PEI), and the like.

In the present invention, the cationic polymer has a positive charge, and any polymer capable of binding to the surface of the cell wall of a negative charge and destroying the cell wall can be used. Polydimethylaminomethylstyrene (PDMS) PDMAMS), polyvinylamine, polyaminoamide, poly-2-dimethylaminoethyl methacrylate (pDMAEMA), poly-1-vinylpyrrolidone (p1-VP), polydiethylaminoethyl acrylate (pDEAEA) And may be polydimethylaminoethyl acrylate (pDMAEA) or polydiethylaminoethyl methacrylate (pDEAMA), preferably polydimethylaminomethylstyrene (PDMAMS). In the polymer, a tertiary amine containing nitrogen positively charged at its terminal comes into contact with a negatively charged bacterium, causing charge disruption in the cell wall to destroy the cell wall, Making it in a favorable condition for cultivation.

The polymer thin film can be formed using a chemical vapor deposition (CVD) method or a plasma chemical vapor deposition (PECVD) method. In the present invention, a polymer thin film is formed by using an initiated chemical vapor deposition method. Pretreatment of wastewater with a cationic polymer thin film can eliminate contamination by bacteria and increase the uptake rate of nutrients in wastewater by microalgae.

The polymer thin film formed by the present invention may have a thickness of 200 nm to 5 탆, and when the thickness of the thin film is less than 200 nm, the efficiency of destroying the microorganisms of the waste water is inferior. When the thickness exceeds 5 탆, There is a problem that it takes.

In the present invention, wastewater refers to sewage sludge, purified water sludge, inflow water for sewage treatment plant, effluent water, industrial wastewater, livestock wastewater and the like, including contaminated water quality including a large amount of nitrogen and phosphorus. In the present invention, livestock wastewater having the composition shown in Table 1 below was used.

variable density( mg / L) pH 7.75 Total solids
(Total solid) 19,560 ± 156 Volatile solids
(Volatile solid) 13,070 ± 184 Total suspended solids
(Total suspended solid) 15,913 ± 641 Volatile suspended solids
(Volatile suspended solid) 11,183 ± 401 chemical oxygen demand
(Chemical oxygen demand) 24,050 ± 495 Solubility Chemical Oxygen Demand
(Soluble chemical oxygen demand) 8,320 ± 424

Total nitrogen 1,544.3 ± 1.0 -NH ₄ ⁺ -N 1,499.6 ± 1.0 -NO ₃ ^- N 44.7 ± 0.0 -NO ₂ ^- N Not detected Total phosphorous 88.2 ± 2.0 Al ⁺ 0.1 Ca ^{2 +} 77.7 Fe ^{2 +} 0.2 K ⁺ 487.8 Mg ^{2 +} 7.0

In the present invention, microalgae can be any microalgae that are resistant to wastewater, have rapid growth in wastewater, and are capable of removing phosphorus and nitrogen, and can be any of microalgae such as Chlorella sp., Scenedesmus sp. Duanliella sp., Nannochloris sp., Biddulphia sp., Chaetoceros sp., Monodus sp., Spodoptera sp.), Duanliella sp. , Parietochloris sp., Emiliania sp., Isochrysis sp., Phaemonas sp., Glossomastrix sp. , Aphanocapsa sp., Spirulina sp., Trichodesmium sp., Hemiselmis sp., Rhodomonas sp., Jimnodi sp. be titanium in (Gymnodinium sp.), upon subscription in Ella (Scrippsiella sp.) However, this Article Not necessarily to be, preferably in chlorella (Chlorella sp.).

The chlorella genus is Chlorella vulgaris , Chlorella protocode protothecoides , Chlorella kessleri ), chlorella rutheoviridis ( Chlorella luteoviridis , Chlorella sphaerica , Chlorella pyrenoidosa , Chlorella salina), Chlorella Maxima (Chlorella maxima , or Chlorella platensis , but is not limited thereto, preferably chlorella bulgaris.

The cultivation of C. vulgaris in livestock wastewater pretreated with polydimethylaminomethylstyrene (PDMAMS) showed significant differences in chemical oxygen demand (COD) before and after culture (FIG. 4). After the completion of the culture, the residual COD concentration was measured at a level of about 10% of the initial COD, and it was confirmed that C. vulgaris culture can remove about 90% of the nitrogen present in the livestock wastewater. Also, it can be seen from FIG. 5 that as the C. vulgaris is cultivated in the livestock wastewater, the concentration of nitrogen contained in the livestock wastewater is decreased. This shows that cultivation of the microalgae according to the present invention is effective for removing pollutants in livestock wastewater.

That is, microbial growth can be promoted by removing bacteria through the pretreatment of wastewater using a polymer thin film, and nitrogen depletion can proceed quickly. It is possible to provide microalgae in which the accumulation of lipid in the microalgae is recognized by the microalgae to be depleted of nitrogen and thereby the lipid content is increased.

[Example]

Hereinafter, the present invention will be described in more detail with reference to Examples. It is to be understood by those skilled in the art that these embodiments are only for illustrating the present invention and that the scope of the present invention is not construed as being limited by these embodiments.

Example  1: Production of polymer thin film

Dimethylaminomethylstyrene (DMACS) (DMAMS) was placed in a monomer vessel of an iCVD (initiated chemical vapor deposition) reactor (manufactured by Atihitotei) and heated to 50 캜. TBPO (tert-butyl peroxide, Aldrich) was used as an initiator, which was placed in an initiator bottle and kept at room temperature. Thereafter, a monomer and an initiator were mixed in a ratio of 2: 1 and allowed to flow in an iCVD reactor. The temperature of the filament in the reactor was maintained at 200 占 폚. The substrate temperature in the reactor was maintained at 30 캜, and a nylon mesh (100 탆, edge wire mesh) cut into 10 cm * 10 cm was placed on the substrate and fixed flat. The pressure in the chamber was maintained at 200 mTorr. Over time, a nylon mesh with 1 μm thick pDMAMS (poly-DMAMS) stack was obtained. The same method was used to deposit pDMAMS on the backside of the nylon mesh.

Example  2: Pretreatment of wastewater using polymer thin film

30 ml of livestock wastewater (Livestock Promotion Agency, National Livestock Science Institute) mixed with livestock manure and slaughter by-products were placed in a 50 ml Falcon tube, and a nylon mesh coated with pDMAMS was cut into a 2.5 cm * 5 cm size, and the lid was closed. Next, the mixture was stirred at 200 rpm using a green siseriker (Vision Science).

The samples were sampled immediately after stirring, 1 hour, 2 hours, 4 hours, 6 hours, and 9 hours, and then they were diluted 100 times and then sprayed on TYG (Tryptone-Yeast extract-Glucose) medium and LB medium. After incubation at room temperature for 24 hours, the number of colonies produced in each medium was checked using a CFU method (Colony Forming Unit). All analyzes were repeated.

As a result, as shown in Fig. 1, it was confirmed that the number of bacterial populations was reduced when livestock wastewater was treated with pDMAMS. Approximately 51.1% of the bacteria were reduced in the TYG medium and about 50.8% in the LB medium. This is due to the action of the pDMAMS polymer coated on the nylon mesh membrane. The principle of destruction of the cell wall of the bacteria by the pDMAMS polymer is as follows. Polymeric amine groups coated on a nylon mesh have a positive charge, which can bind to the negative charge on the surface of the bacterial cell wall. At this time, due to the agitation effect due to the natural fluidity of the pDMAMS polymer deposited in the form of a long chain on the membrane surface, physical destruction of the cell wall bound to the polymer occurs.

Example  3: Cultivation of microalgae in wastewater

Chlorella The strain of vulgaris UTEX 264 was cultured in 100 ml of liquid TAP medium for 5 days. 2) livestock wastewater pretreated with autoclave; 3) livestock wastewater pretreated with filtering (pore size = 0.2 ㎛); 4) livestock wastewater pretreated with pDMAMS had an initial inoculum of 0.1 g / L. The TN concentration of the livestock wastewater was adjusted to 240 mg / L. The cells were cultured for 8 days under a shaking condition of 140 rpm while injecting 2% of carbon dioxide prepared by mixing 100% of carbon dioxide and air. Growth of microalgae was confirmed by cell counting while observing with a microscope using a hemocytometer. The chlorophyll concentration of the culture was measured using PL (Photo Luminescence) analyzer.

Fig. 2 is a graph showing the distribution that showing the results of culturing vulgaris, were able to confirm that the C. vulgaris in a livestock waste water pre-treatment in an autoclave, showing the highest productivity, the C. vulgaris cultured in livestock waste water pre-treatment as pDMAMS contact is not pre Livestock The productivity was 28.1% higher than that of wastewater.

The results of measurement of chlorophyll content proportional to the number of microalgae (FIG. 3) also confirmed that C. vulgaris in livestock wastewater treated with pDMAMS showed higher productivity than that of untreated livestock wastewater. By measuring chlorophyll content, it is possible to estimate how much C. vulgaris has grown indirectly. It can be seen that chlorophyll was increased by about 37.8% when cultured in livestock wastewater treated with pDMAMS than when cultivated in untreated livestock wastewater.

While the present invention has been particularly shown and described with reference to specific embodiments thereof, those skilled in the art will readily appreciate that many modifications are possible in the exemplary embodiments without materially departing from the novel teachings and advantages of this invention. something to do. Accordingly, the actual scope of the present invention will be defined by the appended claims and their equivalents.

Claims (16)

delete delete delete delete delete delete delete delete A microalgae culture method comprising the steps of:
(i) depositing a cationic polymer on the surface of a support selected from the group consisting of glass, metal, metal oxide, wood, paper, fiber, plastic, rubber, leather and silicon wafer to form a polymer thin film;
(Ii) stirring the wastewater and the polymer thin film to remove bacteria in the wastewater; And
(Iii) culturing the microalgae using the wastewater from which the bacteria have been removed as a medium.
delete delete The method of claim 9, wherein the cationic polymer is selected from the group consisting of polydimethylaminomethylstyrene (PDMAMS), polyvinylamine, polyaminoamide, poly-2-dimethylaminoethyl methacrylate (pDMAEMA) (P1-VP), polydiethylaminoethyl acrylate (pDEAEA), polydimethylaminoethyl acrylate (pDMAEA) and polydiethylaminoethyl methacrylate (pDEAMA). Microalgae culture method. 10. The method of claim 9, wherein the deposition is performed by chemical vapor deposition (CVD) or plasma enhanced chemical vapor deposition (PECVD). The method of claim 9, wherein the polymer thin film has a thickness of 200 nm to 5 탆. 10. The method of claim 9, wherein the microalgae is selected from the group consisting of Chlorella sp.). < / RTI > 16. The method of claim 15, wherein the chlorella genus is selected from the group consisting of Chlorella vulgaris , Chlorella protocode protothecoides , Chlorella kessleri ), chlorella rutheoviridis ( Chlorella luteoviridis , Chlorella sphaerica , Chlorella pyrenoidosa , Chlorella salina , Chlorella maxima , and Chlorella platensis . The microalgae culture method according to claim 1,

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