	US 11,667,885 B2
	Method of cultivating algae
Reijo Tanner, Hikiä (FI); Jukka Seppälä, Jokela (FI); Timo Tamminen, Espoo (FI); Kristian Spilling, Helsinki (FI); Pasi Ylöstalo, Jokela (FI); and Pauliina Uronen, Kerava (FI)
Assigned to NESTE OYJ, Espoo (FI); and SUOMEN YMPÄRISTÖKESKUS SYKE, Helsinki (FI)
Appl. No. 15/525,206
Filed by NESTE OYJ, Espoo (FI); and SUOMEN YMPÄRISTÖKESKUS SYKE, Helsinki (FI)
PCT Filed Nov. 4, 2015, PCT No. PCT/FI2015/050760 § 371(c)(1), (2) Date May 8, 2017, PCT Pub. No. WO2016/071570, PCT Pub. Date May 12, 2016.
Claims priority of application No. 14192180 (EP), filed on Nov. 7, 2014.
Prior Publication US 2017/0335274 A1, Nov. 23, 2017
Int. Cl. C12N 1/12 (2006.01); C12P 7/64 (2006.01); C12N 1/38 (2006.01); C12P 7/6463 (2022.01)

CPC C12N 1/12 (2013.01) [C12N 1/38 (2013.01); C12P 7/6463 (2013.01)]

13 Claims

1. A method of producing algal cells comprising steps of:

a) cultivating algal cells in culture conditions, using a day-night cycle containing a light period and a dark period and in an amount of light that support growth, and determining the time required for one cell division of the alga in said culture conditions;

b) depleting the algal cells of at least one inorganic nutrient, wherein the inorganic nutrient contains inorganic nitrogen;

c) exposing the algal cells continuously during a light period of a day-night light cycle to an amount of light which is higher than in step a) wherein the amount of light has an intensity corresponding to or exceeding a light level of 1.5×E_kof the alga and which is higher than in step a); and

d) collecting the algal cells after the lipid:chlorophyll ratio has increased at least 3-fold when compared to the lipid:chlorophyll ratio before step c);

wherein step b) and step c) are started at the same time at a time point that occurs one cell division before and one cell division after the time when the inorganic nutrient is under a detection limit in a culturing medium.