JP2008043321A - Chlorella vulgaris, method of bioremediation by using the same, and also bioreactor and method for removing harmful substance by using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for removing harmful compounds by using Chlorella vulgaris bearing an outside disturbance such as heating treated materials to a high temperature, a bioremediation method by using the same, and a bioreactor and a method for removing harmful substances by using the same. <P>SOLUTION: This method for removing the harmful compounds having phenolic hydroxy groups contained in waste water or soil is provided by using the Chlorella vulgaris having a removing capacity of the harmful compounds having the phenolic hydroxy groups and bringing the Chlorella vulgaris cultured at 15 to 42°C temperature range in contact with the waste water or soil containing the harmful compounds having the phenolic hydroxy groups. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to Chlorella vulgaris having the ability to remove harmful compounds having a phenolic hydroxyl group, a bioremediation method using the same, a bioreactor, and a method for removing harmful substances using the same.

  Examples of removing harmful compounds having phenolic hydroxyl groups using microalgae have already been reported by domestic and foreign researchers. For example, Non-Patent Documents 1 and 2 report methods for removing 2,4-dichlorophenol and bisphenol A using the microalgae Chlorella fasca, respectively.

  In general, the use of microorganisms as a bioreactor for waste liquid treatment is known, for example, from Non-Patent Document 3. Non-patent documents 4 and 5 report the results of removing phosphoric acid and ammonia with immobilized microalgae.

N. Tsuji et al. , Photosynthesis-dependent removal of 2,4-dichlorophenol by Chlorella fusca var. vacolata. Biotechnology Letters, Vol. 25, p. 241-244. (2003). T.A. Hirooka et al. Biodegradation of bisphenol A and discovery of it's estrogenic activity by the green alga Chlorella fusca var. vacolata. Environmental Toxicology and Chemistry, Vol. 24, p. 1896-1901. (2005). Edited by Ryuichi Sudo, Experimental Method for Environmental Microorganisms, pp. 154 to 189 (published by Kodansha, 1988). N. F. Y. Tam and Y.M. S. Wong, Effect of Immobilized Microbead Concentrations on Wastewater Nutrient removal. Environmental Pollution, Vol. 107, p. 145-151 (2000). L. E. de-Bashan et al. , Romaval of ammonium and phosphorous ions, and the bioaspirating algebraic energized belgium in the form of the biomaterials. Water Research, Vol. 36, p. 2941-2948 (2002).

In the removal of harmful compounds having phenolic hydroxyl groups such as chlorophenol, which shows endocrine disrupting effects, when the microorganisms proposed so far are used, the water to be treated containing harmful compounds has a high temperature of about 40 ° C. due to disturbance. Since the microorganisms are almost killed in the treated water, the harmful compounds cannot be removed by the microorganisms even if the treated water is lowered to an appropriate temperature of 25 ° C. to 35 ° C. There is a problem.
Accordingly, an object of the present invention is to provide Chlorella vulgaris that can withstand disturbances such as high temperature of an object to be processed in removing harmful compounds, and a bioremediation method using the same.

  As a result of intensive research to solve the above-mentioned problems, the present inventor has isolated and cultured cultivated samples separated from sample water (all fresh water) collected from ponds, rivers, paddy fields, hot springs, etc. in Miyazaki Prefecture and neighboring prefectures. In the algae strain (Chlorella vulgaris), a photosynthetic microorganism having the ability to remove harmful compounds having a phenolic hydroxyl group such as chlorophenol and capable of growing at 42 ° C. has been found, and the present invention has been achieved.

  That is, the present invention is a chlorella vulgaris having the ability to remove harmful compounds having a phenolic hydroxyl group, and is characterized by being able to grow in a temperature range of 15 to 42 ° C.

Further, Chlorella vulgaris of the present invention is characterized in that it is able to grow in ₂ under aeration 5~15v / v% CO.
If this Chlorella vulgaris is used, the removal of harmful compounds and the fixation of CO ₂ are possible, so the removal of harmful compounds and the reduction of CO ₂ can be carried out in parallel.

  In addition, as a result of research on the isolated microalgal strain, the present inventor, in particular, Chlorella vulgaris having the accession number FERM P-20906 and Chlorella vulgaris having the reception number FERM AP-20963, It was found that the compound has an excellent ability to remove harmful compounds having a phenolic hydroxyl group.

  In addition, the present inventor added and stirred the chlorella bulgaris of the present invention in an aqueous solution containing a harmful compound having a phenolic hydroxyl group, or the chlorella of the present invention in soil containing a harmful compound having a phenolic hydroxyl group.・ It was clarified that harmful compounds having phenolic hydroxyl groups immediately decrease immediately after the addition of Bulgaris.

  That is, the bioremediation method of the present invention comprises a step of bringing at least the chlorella vulgaris in any one of the first to fourth inventions of the present application into contact with wastewater containing a harmful compound having a phenolic hydroxyl group. To do.

  In addition, the bioremediation method of the present invention includes a step of contacting at least the chlorella vulgaris according to any one of the first to fourth inventions of the present application with soil containing a harmful compound having a phenolic acid group. It is characterized by.

  Also, the bioreactor of the present invention is characterized in that it is filled with beads carrying a microalga of Chlorella sp. Formed by an acidic polysaccharide gel and capable of removing harmful compounds having a phenolic hydroxyl group. . In particular, the microalga of the genus Chlorella is preferably the Chlorella vulgaris described in any one of the first to fourth inventions of the present application.

  The hazardous substance removal method of the present invention is characterized in that the bioreactor is immersed in an aqueous solution containing a harmful compound having a phenolic hydroxyl group, and the harmful compound is removed from the aqueous solution.

  Conventionally, as a form of a support on which microalgae belonging to the genus Chlorella are supported, a sheet-like or net-like form is known, but such a form of support is sufficient for a long period of time. Since it is difficult to maintain the mechanical strength, if these carriers are used as a bioreactor for removing harmful compounds contained in wastewater, the carriers are likely to collapse, and over a long period of time There is a problem that the removal cannot be performed sufficiently. However, according to the present invention, the mechanical strength of each bead is higher than when using the microalgae of the genus Chlorella supported on a sheet-like or net-like one. Even when immersed in an aqueous solution containing a harmful compound having a phenolic hydroxyl group, the shape of the beads is maintained without collapsing, and the harmful compounds contained in the wastewater can be removed over a long period of time.

  In addition, since the beads carrying chlorella microalgae have sufficient mechanical strength, they can be easily recovered after they have been used to remove harmful compounds. Processing can also be performed. In addition, since the microalgae belonging to the genus Chlorella are carried on the beads, the centrifugation operation associated with the collection of the microalgae belonging to the genus Chlorella is not required when the removal treatment is repeated, and thus the operation is facilitated.

  In addition, in order to give the sheet-like or net-like carrier sufficient strength, the sheet-like or net-like shape is formed on a substrate having sufficient mechanical strength when removing harmful compounds contained in the wastewater. Although it is conceivable to form a carrier, the method for forming the carrier is complicated. However, according to the present invention, beads carrying chlorella microalgae can be obtained, for example, by dropping an acidic polysaccharide gel in which chlorella microalgae are suspended into a predetermined solution. Easy to manufacture. Further, by forming the beads, the surface area in contact with the aqueous solution containing the harmful compound can be increased as compared with the case of forming a sheet or a net, and the treatment capacity of the harmful compound can be increased.

  The microalgae of the genus Chlorella are collected from the culture solution by centrifugation, and are prepared into beads to be used. As a method for supporting microalgae belonging to the genus Chlorella, an entrapment method, a physical adsorption method, a microcapsule method, or the like can be used. When using the inclusion method, as the carrier, a polysaccharide such as carrageenan alginate, a curable resin, a gelling agent such as polyacrylamide, or the like can be used.

  As the acidic polysaccharide, it is preferable to use calcium alginate. Calcium alginate is easy to handle and bead formation is also easy.

  Examples of the harmful compound having a phenolic hydroxyl group include harmful compounds exhibiting endocrine disrupting action, for example, chlorophenols such as 4-chlorophenol (4CP), bisphenol A, and the like.

According to the present invention, chlorella has the ability to remove harmful compounds having a phenolic hydroxyl group, and can grow even in a temperature range that is relatively high in the culture and growth of microalgae, that is, at a temperature of about 30 to 42 ° C.・ Because it is Bulgaris, if this Chlorella vulgaris is used, even if the object to be treated is heated to a high temperature of about 40 ° C. due to disturbance, it can grow without dying and remove harmful compounds. Can do. In addition, Chlorella vulgaris derived by fixing CO ₂ contained in the high-temperature combustion gas can be effectively used. Moreover, by using this, emission reduction by CO ₂ fixation and bioremediation can be performed in parallel.

  Hereinafter, a method for removing harmful compounds having a phenolic hydroxyl group using Chlorella vulgaris according to an embodiment of the present invention will be described in detail. Chlorella vulgaris used for removing harmful compounds having a phenolic hydroxyl group according to an embodiment of the present invention is chlorella vulgaris having an accession number FERM P-20906 (hereinafter referred to as “Chlorella vulgaris MKJ-34”). Or the Chlorella Bulgaris (hereinafter referred to as the following) having the receipt number FERM AP-20963 received on July 18, 2006, deposited by the National Institute of Advanced Industrial Science and Technology Patent Biological Deposit Center. "Chlorella Bulgaris C-1"). Hereinafter, the isolation method and the result of morphological analysis of Chlorella vulgaris MKJ-34 and Chlorella vulgaris C-1 will be described. Moreover, the bioreactor using these and the removal method of a harmful substance using the same are demonstrated in detail.

(Example 1) Isolation method of Chlorella vulgaris MKJ-34 1-1: Medium Microalgae contained in test water collected from paddy fields in Kikuchi City, Kumamoto Prefecture were accumulated and cultured in MBM medium. As the MBM medium, x1 MBM medium was sterilized by autoclave, and x100 Fe mixture and x100 A5 metal mix sterilized by filtration were each added in an amount of 1/100. Each composition is shown below.
xl MBM medium:
KNO ₃ 25 mg, MgSO ₄ · 7H ₂ O 7.5 mg, K ₂ HPO ₄ 7.5 mg, KH ₂ PO ₄ 17.5 mg, NaCl 2.5 mg, CaCl ₂ · 2H ₂ O 1 mg, NaHCO ₃ 50 mg, Fe mixture 0 .1 ml, A5 metal mixture 0.1 ml,
Distilled water 99.8 ml, pH 6.0
x100 Fe mixture: 1 g of FeSO ₄ · 7H ₂ O, 500 ml of distilled water, 2 drops of H ₂ SO ₄ x100 A5 metal mixture: H ₃ BO ₃ 286 mg, MnSO ₄ · 7H ₂ O 250 mg, ZnSO ₄ · 7H ₂ O 22.2 mg , CuSO ₄ .H ₂ O 7.9 mg, Na ₂ MoO ₄ 2.1 mg, distilled water 100 ml

  On the other hand, for high-density culture and long-term storage of microalgae, use YPD medium (glucose 2%, polypeptone (manufactured by Wako Pure Chemical Industries) 2%, yeast extract (manufactured by Wako Pure Chemical Industries) 2%)) for 2 days. Shaking culture was performed.

1-2: Isolation method The collected sample water was subjected to static accumulation culture at 40 ° C. for 2 weeks under sunlight (indirect light) irradiation. The enrichment culture solution is diluted 100-1000 times with sterilized water and inoculated into MBM plate medium containing ampicillin with a final concentration of 50 mg / l and 2% agar, and then statically cultured at 30 ° C. under light irradiation for 2 weeks. The microalgae were separated from the resulting green colonies. Then, this green colony was transferred again to the MBM plate medium, and single colony isolation was repeated to obtain an isolated microalgae strain.

  When the base sequence of the 18S-rRNA gene of the isolated microalgae strain was determined and the homology was searched, it showed 99.9% homology with the known Chlorella vulgaris 18S-rRNA gene. The isolated microorganism was considered to be a new species of Chlorella vulgaris from the nucleotide sequence and morphological characteristics of the 18S-rRNA gene and its physiological properties, and this isolated microorganism was named Chlorella vulgaris MKJ-34.

1-3: Morphological characteristics FIG. 1 shows an optical micrograph of the isolated Chlorella vulgaris MKJ-34 strain. When the isolated microorganism is observed with an optical microscope, as shown in FIG. 1, the cell morphology is spherical, the cell membrane is smooth, the size is 4-6 μm, and 2-8 daughter cells are found in the spontaneous sporangia. Observed and showed the characteristics of Chlorella vulgaris.

1-4: Physiological characteristics (1) It has the ability to remove phenol (2) It can grow under 5-15 v / v% CO ₂ aeration (3) Both autotrophic conditions (under light irradiation) and heterotrophic conditions Can grow in

  The long-term storage of Chlorella vulgaris strain MKJ-34 is cultured at 30 ° C on a YPD slant medium, and colony formation is confirmed with the naked eye (5-7 days), and then stored at a low temperature (eg, 4 ° C). It is desirable to do. Colony formation is visually confirmed (about 4 days), and then stored at a low temperature (for example, 4 ° C.) to obtain a preserved strain. This stock is replanted on a new YPD agar plate every few months, typically every 6 months.

(Example 2) Isolation method of Chlorella vulgaris C-1 In the same procedure as in Example 1, from the test water collected from the pond of Osaki-cho, Kagoshima Prefecture, the above-mentioned Chlorella vulgaris MKJ-34 and Isolated another microalgal strain.

2-1: Isolation method More specifically, the test water was first inoculated into the MBM medium, and algae were accumulated and cultured at 25 ° C. for 2 weeks under sunlight (indirect light) irradiation. The enrichment culture solution was diluted 2500 times to 10,000 times, and the enrichment culture was repeated again at 25 ° C. for 2 weeks. Next, the enriched culture solution was inoculated into an MBM plate medium containing ampicillin having a final concentration of 50 mg / l and 2% agar, followed by stationary culture under light irradiation at 30 ° C. for 2 weeks. From the resulting colonies showing green color, Algae separation was performed. This green colony was again transferred to the MBM plate medium, and single colony isolation was repeated to obtain an isolated microalgae strain.

  When the nucleotide sequence of the 18S-rRNA gene of the isolated microalgae strain was determined and the homology was searched, it showed 99% homology with the known 18S-rRNA gene of Chlorella vulgaris. The isolated microorganism was considered to be a new species of Chlorella vulgaris from the base sequence and morphological characteristics and physiological properties of the 18S-rRNA gene, and this isolated microorganism was named Chlorella vulgaris C-1.

2-2: Morphological characteristics FIG. 2 shows an optical micrograph of the isolated Chlorella vulgaris C-1 strain. When the isolated microorganism is observed with an optical microscope, as shown in FIG. 2, the cell morphology is spherical, the cell membrane is smooth, the size is 6-9 μm, the chloroplast is arm-shaped, and the characteristics of Chlorella vulgaris Was showing.

2-3: Physiological characteristics (1) It has the ability to remove phenol (2) It can grow under 5-15 v / v% CO ₂ aeration (3) Both autotrophic conditions (under light irradiation) and heterotrophic conditions Can grow in

  For long-term storage of Chlorella vulgaris C-1, as in Example 1, it is desirable to store algal cells cultured at 30 ° C. on a YPD slant medium at 15 to 20 ° C. Chlorella vulgaris C-1 was found to be unable to grow when left at 4 ° C. for 2 months or longer.

(Example 3) Evaluation of the ability to remove harmful compounds having a phenolic hydroxyl group of Chlorella vulgaris MKJ-34

3-1: Method for quantifying phenols First, a method for quantifying various phenols in a reaction solution will be described below.
764 μl of Reagent A (0.32% 4-aminoantipyrine aqueous solution, aqueous solution of harmful compound having 0.32N ammonia, distilled water mixed in a ratio of 1: 3.28: 6.33) in 1 ml of the test solution , And Reagent B (0.32% potassium hexacyanoferrate (III) aqueous solution (potassium ferricyanide)) was added in an amount of 236 μl and allowed to stand at room temperature for 5 minutes, and then the absorbance at 490 nm was measured. In addition, the thing which added the harmful compound to the buffer solution which does not contain Chlorella vulgaris was made to color, and it was set as the comparison control, and the disappearance rate of the harmful compound was computed from this. The results obtained by this colorimetric method correlated well with the results obtained by the quantitative method using high performance liquid chromatography.

3-2: Evaluation of removal ability of Chlorella vulgaris MKJ-34 Colonies were scraped from the stock strain stored in Example 1 using a platinum loop, transplanted to a YPD liquid medium, and preferably cultured at 30 ° C. for 3 days. did. This was used as a precultured alga body, which was transplanted to another YPD medium, and cultured under shaking under the same culture conditions. This culture solution was separated by centrifugation at 8000 rpm for 10 minutes, and the collected alga bodies were used for removing harmful compounds having phenolic hydroxyl groups. In this example, the removal ability of 4CP of Chlorella vulgaris MKJ-34 was measured using an aqueous solution containing 4-chlorophenol (4CP) which is one of harmful compounds having a phenolic hydroxyl group.

  Removal of 4CP was attempted from an aqueous solution containing 4CP by using algal cells of Chlorella vulgaris MKJ-34 prepared in advance by the method shown in 3-2. The 4CP concentration in the aqueous solution used for the evaluation was measured by colorimetric determination after coloring with 4-aminoantipyrine according to the method shown in 3-1. Different amounts of algal cells were suspended in 3 ml of 50 mM phosphate buffer (pH 7.0), and 4CP was added to a final concentration of 0.1 mM (13 ppm) at 160 rpm at 30 ° C. For 24 hours. As shown in FIG. 3, the disappearance of 4CP depends on the concentration of alga bodies. When the algal body content in the solution is about 4.0 mg dry weight / ml, the disappearance rate of 4CP is 20% or less at the maximum. However, the disappearance rate could be increased to 53% by increasing the concentration of algal cells.

  After incubation of algal bodies with 4CP for 24 hours, the algal bodies were collected and repeatedly incubated with 4CP. As a result, at least 7 times, 4CP could be removed without significantly reducing the removal rate.

(Example 4) Evaluation of the ability to remove harmful compounds having a phenolic hydroxyl group of Chlorella vulgaris C-1 By the same method as Chlorella vulgaris MKJ-34, an algal body of Chlorella vulgaris C-1 was prepared. The removal of 4CP was examined. As shown in FIG. 4, 0.1 mM (13 ppm) of 4CP could be lost up to 76% after 16 hours by increasing the concentration of algal cells. In addition, when Chlorella vulgaris C-1 is used, 4CP can be efficiently eliminated at a lower algal body concentration than that of MKJ-34 strain, that is, an algal body concentration of 15 mg-dry cells / ml or less. I understood it.

(Example 5) Comparative Example For known microalgae of the genus Chlorella other than Chlorella vulgaris MKJ-34 and Chlorella vulgaris C-1, 4CP removal ability was also obtained by the same procedure as in Example 3 or Example 4. Tested. As the known microalgae of the genus Chlorella, the following 6 algae strains were randomly selected from the type culture of IAM Culture Collection, Institute for Molecular Cell Biology, University of Tokyo.

Chlorella sorokiniana IAM C-212 (Chlorella sorokiniana IAM C-212)
Chlorella kesleri IAM C-531 (C. kessleri IAM C-531)
Chlorella vulgaris IAM C-536 (C. vulgaris IAM C-536)
Chlorella vulgaris IAM C-547 (C. vulgaris IAM C-547)
Chlorella sp. IAM C-628 (Chlorella sp. IAM C-628)
Chlorella vulgaris IAM C-629 (C. vulgaris IAM C-629)
As a result of the test, it was found that the above 6 types of algal strains did not show significant 4CP removal ability.

(Example 6) Growth characteristics of Chlorella vulgaris MKJ-34 and Chlorella vulgaris C-1 under high temperature 30-45 ° C relative to the growth of Chlorella vulgaris MKJ-34 and Chlorella vulgaris C-1 The effect of temperature in the range was investigated. Both algae strains were shaken and cultured for 4 days in a 20 ml MBM liquid medium prepared in an L-shaped test tube under light irradiation with a fluorescent lamp (5000 lux, 12 hours dark, 12 hours light repeat). The amount of algal bodies grown was measured by measuring the degree (OD ₆₆₀ ). Both algae strains were confirmed to be able to grow at least in the range of 30 to 42 ° C. Growth in the range of 30 to 45 ° C. is shown in FIG.

(Example 7) Growth characteristics of Chlorella vulgaris MKJ-34 and Chlorella vulgaris C-1 under high CO ₂ concentration About Chlorella vulgaris MKJ-34 and Chlorella vulgaris C-1, CO ₂ The growth under aeration with high concentration gas was examined. Light irradiation with a fluorescent lamp (5000 lux, 12 hours dark, 12 hours light repeat), conditions under 35 ° C. in 280 ml MBM liquid medium (without NaHCO ₃ ) prepared in 300 ml Erlenmeyer flasks The amount of grown alga bodies was measured by culturing for 5 days while aerated with a mixed gas of 100 v / v% CO ₂ and air (0.038 v / v% CO ₂ ) and measuring turbidity (OD ₆₆₀ ). It was measured. As shown in FIG. 6, the growth of both algae strains was slight when aerated with only air, but grew well under aeration of 5-10 v / v% CO ₂ , with 15 v / v% CO ₂ . It was confirmed that growth was possible even under aeration.

(Example 8) Bioremediation method As a bioremediation method, the above chlorella vulgaris may be brought into contact with waste water containing a harmful compound having a phenolic hydroxyl group, or soil. It is preferable to immerse a bioreactor filled with algal body beads in waste water by supporting them in a salt of an acidic polysaccharide such as calcium alginate by the inclusion method. Below, the bioreactor and the preparation method of alga body beads in a present Example are demonstrated.

  As shown in FIG. 7, the bioreactor supports chlorella microalgae having the ability to remove harmful compounds having phenolic hydroxyl groups on a calcium alginate gel, which is one of acidic polysaccharides, and this is loaded with alga beads 1 Are packed in a cylindrical column 2.

  The cylindrical column 2 has a diameter of 3.8 cm, an inner diameter of 1.8 cm, and a height of 32 cm, and an upper part is provided with an inlet for injecting a solution containing toxic compounds (treated water), and a lower part is provided with an inlet. It has a discharge port through which treated water is discharged. In this example, the water to be treated injected into the bioreactor is prepared so that the final concentration of the harmful compound as the decomposition substrate is 0.1 mM (13 ppm) while maintaining the temperature at 30 ° C. By pouring at about 0.1 ml / min, the treatment can be performed continuously. The column 2 is not limited to a cylindrical one, and may be any container that can be filled with the algal beads 1.

  Known methods for supporting microorganisms include the entrapment method, the physical adsorption method, the microcapsule method, and the like. In this embodiment, microalgae are supported by the entrapment method. In addition, as a carrier for the inclusion method, a salt of an acidic polysaccharide such as calcium alginate is used. By using an acidic polysaccharide salt, a bead-like form can be easily imparted.

  When using calcium alginate as a carrier, the algal beads 1 can be prepared by the following procedure. For example, in this example, a liquid obtained by suspending a predetermined concentration of Chlorella vulgaris MKJ-34 in a 2% sodium alginate solution was dropped into a 5% calcium chloride aqueous solution while stirring. Then, a spherical solid gel was obtained, and the algal body beads 1 could be obtained by washing this with distilled water.

  3 g of the algal body beads obtained by the above method, 3 ml of water containing a substrate to be decomposed (hazardous compound having a phenolic hydroxyl group) in which 0.1 mM phenols are suspended in a phosphate buffer or MOPS buffer of pH 7.0. In addition, when placed in a test tube at a temperature of 30 ° C. and agitated by reciprocal shaking, Chlorella vulgaris MKJ-34 supported on alga body beads 1 was able to remove harmful compounds.

  After shaking the algal beads 1 with 3 ml of 4CP-containing water for 24 hours, the recovery of the beads was repeated, and how the 4CP disappearance ability changed depending on the number of times was examined. As shown in FIG. 8, 4CP could be removed at least seven times without a significant decrease in the removal rate. As is clear from this result, the algal beads 1 filled in the bioreactor can be used repeatedly. If the algal beads 1 are used for a long period of time, the equilibrium between the algal beads 1 and the water to be treated may collapse and swell, and in this case, the water to be treated may contain calcium salts or other algal beads. It is better to use a suitable amount of salt for maintaining an equilibrium state between 1 and the water to be treated. Thereby, the algal beads 1 can be used for a long time.

  When the algal beads 1 are filled into a cylindrical column 2 to form a bioreactor, and this is immersed in water to be treated containing 4CP, 4CP contained in 700 ml of water to be treated as shown in FIG. Could be removed continuously for 3 days with a disappearance rate of 40-80%.

  Since the present invention has an excellent ability to remove harmful compounds having a phenolic hydroxyl group and can grow even at a temperature of about 30 to 42 ° C., it can be used as a chlorella bulgaris that can withstand the disturbance of high temperature of the object to be treated. Can be used. In addition, by incorporating this Chlorella vulgaris into, for example, a bioreactor, bioremediation or harmful compounds in a closed system such as treatment of harmful compound-containing water contained in waste liquid discharged from pulp factories, synthetic organic chemical factories, etc. It can be used for open-type bioremediation that is performed outdoors, such as for the purification of soil containing sucrose.

It is an optical microscope photograph of isolated Chlorella vulgaris MKJ-34. It is an optical microscope photograph of isolated Chlorella vulgaris C-1. It is a figure which shows the loss | disappearance rate (%) of the harmful compound which has 13 ppm phenolic hydroxyl group in the to-be-processed water which added Chlorella vulgaris MKJ-34 of different density | concentration. It is a figure which shows the loss | disappearance rate (%) of the harmful compound which has 13 ppm phenolic hydroxyl group in the to-be-processed water which added chlorella vulgaris C-1 of different density | concentration. It is a figure which shows the growth condition under the temperature of the range of 30-45 degreeC of Chlorella vulgaris MKJ-34 and Chlorella vulgaris C-1. Chlorella vulgaris MKJ-34 and Chlorella vulgaris C-1 of CO ₂ is a diagram showing a state of growth under gas vent containing a high concentration. It is a front view of the bioreactor in the embodiment of the present invention. It is the figure which showed the process of repeated removal of 4CP by the alga body bead. It is the figure which showed the result of the continuous removal of 4CP by the bioreactor filled with the alga body bead.

Explanation of symbols

1 Algae beads 2 columns

Claims (11)

  Chlorella vulgaris having the ability to remove harmful compounds having a phenolic hydroxyl group and capable of growing in a temperature range of 15 to 42 ° C. 5~15v / v% CO ₂ Chlorella vulgaris viable claim 1 under aeration.   3. Chlorella vulgaris according to claim 1 or 2, having the deposit number FERM P-20906.   3. Chlorella vulgaris according to claim 1 or 2, having the receipt number FERM AP-20963.   A bioremediation method comprising a step of contacting at least chlorella vulgaris according to any one of claims 1 to 4 with wastewater containing a harmful compound having a phenolic hydroxyl group.   A bioremediation method comprising a step of bringing the chlorella vulgaris according to any one of claims 1 to 4 into contact with soil containing a harmful compound having a phenolic hydroxyl group.   A bioreactor filled with beads carrying microalgae of the genus Chlorella that is formed by acidic polysaccharide gel and has the ability to remove harmful compounds with phenolic hydroxyl groups.   The bioreactor according to claim 7, wherein the microalga of the genus Chlorella is the chlorella bulgaris according to any one of claims 1 to 4.   A method for removing harmful substances, comprising immersing the bioreactor according to claim 7 or 8 in an aqueous solution containing a harmful compound having a phenolic hydroxyl group, and removing the harmful compound from the aqueous solution.   The method for removing harmful substances according to claim 9, wherein the acidic polysaccharide is calcium alginate.   The harmful substance removing method according to claim 9 or 10, wherein the harmful compound having a phenolic hydroxyl group is a harmful compound exhibiting an endocrine disrupting action.

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