Method of cultivating algae and photobioreactor

Patent metadata

Field	Value
Publication number	US-2023002721-A1
Application number	US-202217942812-A
Country	US
Kind code	A1
Filing date	Sep 12, 2022
Priority date	Feb 27, 2019
Publication date	Jan 5, 2023
Grant date	—

Abstract

A method of cultivating algal cells of an algae belonging to a class selected from Chlorophyceae, Euglenophyceae, Bacillariophyceae and Haptophyceae includes: irradiating the algal cells with an artificial light having a ratio of (i) photon flux density in a wavelength range of 520-630 nm to (ii) photosynthetic photon flux density, that is 65% or more; and measuring a cell size of the algal cells. Irradiation and non-irradiation of the algal cells with the artificial light are switched, or the photon flux density in the wavelength range of 520-630 nm is changed, according to the measured cell size.

First claim

What is claimed is:

1 . A method of cultivating algal cells of an algae belonging to a class selected from Chlorophyceae, Euglenophyceae, Bacillariophyceae and Haptophyceae, the method comprising:
irradiating the algal cells with an artificial light having a ratio of (i) photon flux density in a wavelength range of 520-630 nm to (ii) photosynthetic photon flux density, that is 65% or more; and measuring a cell size of the algal cells, wherein irradiation and non-irradiation of the algal cells with the artificial light are switched, or the photon flux density in the wavelength range of 520-630 nm is changed, according to the measured cell size.

2 . The method according to claim 1 , wherein:
the method comprises size-classifying the algal cells between relatively small-sized algal cells and relatively large-sized algal cells and subjecting the relatively small-sized algal cells to a step a 2 ) and the relatively large-sized algal cells to a step b 2 ), and the step of irradiating the algal cells with the artificial light comprises:
the step a 2 ) of irradiating the relatively small-sized algal cells with light in the range of 520-630 nm at a first photon flux density value, and
the step b 2 ) of irradiating the relatively large-sized algal cells with light in the range of 520-630 nm at a second photon flux density value that is smaller than the first photon flux density value.

3 . The method according to claim 1 , wherein:
the method comprises size-classifying the algal cells between relatively small-sized algal cells and relatively large-sized algal cells, and the relatively small-sized algal cells are subjected to a step a 2 ) of irradiation with the artificial light and the relatively large-sized algal cells are subjected to a step b 2 ) of placement in dim light or darkness.

4 . The method according to claim 3 , wherein the algal cells previously subjected to the step a 2 ) are size-classified.

5 . The method according to claim 3 , wherein the algal cells previously subjected to the step b 2 ) are subjected to the step a 2 ) without size-classification.

6 . The method according to claim 2 , wherein the first photon flux density value is in a range of 300-900 μmol/m 2 /s and the second photon flux density value is in a range of 50-300 μmol/m 2 /s.

7 . A method of cultivating algal cells, comprising further cultivating, in an open pond tank or a pond, the algal cells that have previously cultivated in a photobioreactor by the method according to claim 1 .

8 . The method according to claim 1 , wherein the algae belong to a class selected from Chlorophyceae or Euglenophyceae.

9 . The method according to claim 1 , wherein the artificial light has a ratio of (i) photon flux density in a wavelength range of 520-600 nm to (ii) photosynthetic photon flux density, that is 65% or more.

10 . The method according to claim 1 , wherein the ratio is 75% or more.

11 . The method according to claim 10 , wherein the ratio is 90% or more.

12 . The method according to claim 1 , wherein the artificial light has a maximum peak wavelength in a wavelength range of 520-600 nm.

13 . The method according to claim 1 , wherein each of the first photon flux density and the second photon flux density is in a range of 50-3000 μmol/m 2 /s.

14 . The method according to claim 1 , wherein the algal cells are irradiated with light in the wavelength range of 520-630 nm for a time period of 6-100 hours.

15 . The method according to claim 1 , wherein the artificial light comprises light having a wavelength spectrum with a peak wavelength in a wavelength range of 520-600 nm and a half-width of 0.1-50 nm.

16 . The method according to claim 1 , wherein the light in the wavelength range of 520-630 nm comprises light emitted by a light-emitting diode or a laser diode.

17 . The method according to claim 1 , wherein the first photon flux density value is in a range of 50-500 μmol/m 2 /s and the second photon flux density value is in a range of 300-3000 μmol/m 2 /s.

18 . The method according to claim 1 , wherein the algal cells are cultivated in a photobioreactor.

Assignees

• Nichia Corp

Inventors

• Hasunuma Tomohisa
• Kato Yuichi
• Fujikawa Yasuo
• Tsurumoto Tomohiro

Classifications

• C12N13/00

  Treatment of microorganisms or enzymes with electrical or wave energy, e.g. magnetism, sonic waves · CPC title

• C12M21/02

  Photobioreactors (culturing algae A01G33/00, A01H4/001, C12N1/12) · CPC title

• Y02A40/80

  in fisheries management · CPC title

• C12M41/34

  of gas · CPC title

• A01G33/00 Primary

  Cultivation of seaweed {or algae} · CPC title