US 12,291,737 B2
Schizochytrium strain and use thereof, microbial oil containing DHA at SN-2 position and preparation and use thereof
Yun Liang, Hunan (CN); Sheng Cao, Hunan (CN); and Shenjian Wang, Hunan (CN)
Assigned to Hanpeng Qu, Changsha (CN)
Filed by Hanpeng Qu, Hunan (CN)
Filed on Jul. 14, 2021, as Appl. No. 17/375,551.
Application 17/375,551 is a continuation of application No. PCT/CN2020/130385, filed on Nov. 20, 2020.
Claims priority of application No. 201911175787.4 (CN), filed on Nov. 26, 2019.
Prior Publication US 2021/0340583 A1, Nov. 4, 2021
Int. Cl. C12P 7/64 (2022.01); C12N 1/12 (2006.01); C12N 1/14 (2006.01); C12P 7/6434 (2022.01); C12P 7/6463 (2022.01); C12P 7/6472 (2022.01)
CPC C12P 7/6463 (2013.01) [C12N 1/14 (2013.01); C12P 7/6434 (2022.01); C12P 7/6472 (2013.01)] 3 Claims
 
1. A method for producing a microbial oil, comprising:
performing an atmospheric room temperature plasma (ARTP) mutagenesis on a starting strain in a form of a bacterial suspension for 5-60 seconds at a plasma mutagenesis power of 80-120 W, a gas flow rate of 8-12 standard liter per minute (SLM) and a treatment distance of 1-3 mm, followed by a screening to obtain a Schizochytrium strain; and
inoculating the Schizochytrium strain into a fermentation medium for fermentation to produce the microbial oil;
wherein the Schizochytrium strain is Schizochytrium sp. GDMCC No. 60733;
the fermentation is carried out at pH 6-7.5 and 27-31° C. for 4-8 days under a ventilation rate of 0.45-1.1 vvm;
the fermentation medium comprises 5-70 g/L of a carbon source, 15-45 g/L of a nitrogen source, 5-40 g/L of an inorganic salt, 0.01-0.04 g/L of a trace element and 0.01-0.04 g/L of a vitamin; and
the nitrogen source comprises glutamate; and a concentration of glutamate in the fermentation medium is 5-15 g/L; and
the method further comprising:
inoculating the Schizochytrium sp. GDMCC No. 60733 into an activation medium for activation to obtain an activated Schizochytrium suspension;
inoculating the activated Schizochytrium suspension into a seed culture medium for expansion culture to obtain a seed liquid; and
inoculating the seed liquid into the fermentation medium for the fermentation to produce the microbial oil;
wherein the activation is carried out at 27.5-28.5° C. and 150-200 r/min for 48-72 hours;
the activation medium comprises 30-50 g/L of a carbon source, 25-45 g/L of a nitrogen source, 25-40 g/L of an inorganic salt, 0.015-0.025 g/L of a trace element and 0.01-0.02 g/L of a vitamin;
the expansion culture is carried out at 27-28.5° C. under a ventilation rate of 0.5-0.8 vvm for 48-72 hours; and
the seed culture medium comprises 25-60 g/L of a carbon source, 10-30 g/L of a nitrogen source, 15-35 g/L of an inorganic salt, 0.01-0.02 g/L of a trace element and 0.01-0.02 g/L of a vitamin.