Strain producing pullulan, application thereof and pullulan production method

Abstract

The invention relates to the field of microorganisms and discloses aureobasidium pullulans.The preservation number of the aureobasidium pullulans is CGMCC No.11937.The aureobasidium pullulans with the preservation number being CGMCC No.11937 uses wild aureobasidium pullulans with the preservation number being CGMCC No.3.4580 as an original strain, chemical induced mutation is performed, the aureobasidium pullulans is obtained through screening, the capacity that the aureobasidium pullulans ferments to generate pullulans is remarkably improved, compared with the original strain, the yield of the pullulans is increased by 80%, and the glucose conversion rate is increased by 68%.The color of the finished pullulans becomes lighter obviously.Thus, the aureobasidium pullulans with the preservation number being CGMCC No.11937 can be widely applied to pullulans fermentation.

Description

technical field

[0001] The invention relates to the field of microorganisms, in particular to a pullulan-producing strain and application thereof, and a production method of pullulan. Background technique

[0002] Pullulan is also known as pullulan, pullulan, pullulan or pullulan. It is an exopolysaccharide produced by Aureobasidium pullulans. It is mainly composed of a-1,6-glycosidic bonds combined with maltotriose to form homopolysaccharides, that is, glucose is combined with a-1,4-glycosidic bonds to form maltotriose. Then combine with other maltotriose by α-1,6-glucosidic bond, so that it can be connected repeatedly to form a high molecular polysaccharide. Molecular weight 4.8×1O 4 ~2.2×10 6 (The average molecular weight of commercial pullulan polysaccharide is 2×10 5 , composed of about 480 maltotriose).

[0003] Pullulan is a colorless, odorless polymer substance, and its properties can be manifested in the following aspects. Safety: Animal experiments show that ...

Examples

Embodiment 1

[0039] Embodiment 1: the screening of Aureobasidium pullulans MHZ-2101 belonging to the present invention

[0040] Inoculate the starting strain Aureobasidium pullulans CGMCCNo.3.4580 into solid PDA medium, culture at 28°C for 3 days, add 0.9% sterile saline, and shake fully to obtain a bacterial suspension, and calculate the concentration of the spore suspension by a hemocytometer. Normal saline diluted to 10 6 NTG / mL, the final concentration of 0.5mol / LNTG was treated for 2 hours, washed with normal saline for 3 times, and finally diluted to 10 with normal saline 5 1 / mL, spread 100 μL on a PDA plate, incubate at 28°C in the dark for 7 days, pick a single colony with normal morphology, whitish color, and the largest colony diameter, and name it MHZ-2101.

[0041] The formula of PDA medium is as follows: Peel 200g potatoes, cut into cubes, cook in boiling water for 15min, filter through eight layers of gauze, add 20g of glucose to the filtrate, distill water to 1L, pack in tr...

Embodiment 2

[0043] Embodiment 2: The production method of pullulan polysaccharide according to the present invention and the comparison experiment of pullulan polysaccharide fermentation

[0044] 1. Fermentation method

[0045] Inoculate Aureobasidium pullulans MHZ-2101 into solid PDA medium, culture at 28°C for 3 days, pick a large loop with an inoculation loop and inoculate it into the seed medium, culture at 28°C, 150rpm reciprocating shaker for 20hrs, 1:10 rotation Received the fermentation medium, cultured on a reciprocating shaker at 28° C. for 72 hours at 180 rpm, and measured the content of glucose and pullulan.

[0046] Seed medium: 40g / L glucose, 2.8g / L yeast powder, 6.5g / L potassium dihydrogen phosphate, 0.3g / L magnesium sulfate.

[0047] Fermentation medium: 120g / L glucose, 10g / L yeast powder, 130g / L potassium dihydrogen phosphate, 10g / L magnesium sulfate, 15g / L ammonium sulfate, sodium hydroxide to adjust the pH value to 6.5.

[0048] Glucose content detection: the fermenta...

technical field

[0001] The invention relates to the field of microorganisms, in particular to a pullulan-producing strain and application thereof, and a production method of pullulan. Background technique

[0002] Pullulan is also known as pullulan, pullulan, pullulan or pullulan. It is an exopolysaccharide produced by Aureobasidium pullulans. It is mainly composed of a-1,6-glycosidic bonds combined with maltotriose to form homopolysaccharides, that is, glucose is combined with a-1,4-glycosidic bonds to form maltotriose. Then combine with other maltotriose by α-1,6-glucosidic bond, so that it can be connected repeatedly to form a high molecular polysaccharide. Molecular weight 4.8×1O 4 ~2.2×10 6 (The average molecular weight of commercial pullulan polysaccharide is 2×10 5 , composed of about 480 maltotriose).

[0003] Pullulan is a colorless, odorless polymer substance, and its properties can be manifested in the following aspects. Safety: Animal experiments show that ...

Examples

Embodiment 1

[0039] Embodiment 1: the screening of Aureobasidium pullulans MHZ-2101 belonging to the present invention

[0040] Inoculate the starting strain Aureobasidium pullulans CGMCCNo.3.4580 into solid PDA medium, culture at 28°C for 3 days, add 0.9% sterile saline, and shake fully to obtain a bacterial suspension, and calculate the concentration of the spore suspension by a hemocytometer. Normal saline diluted to 10 6 NTG / mL, the final concentration of 0.5mol / LNTG was treated for 2 hours, washed with normal saline for 3 times, and finally diluted to 10 with normal saline 5 1 / mL, spread 100 μL on a PDA plate, incubate at 28°C in the dark for 7 days, pick a single colony with normal morphology, whitish color, and the largest colony diameter, and name it MHZ-2101.

[0041] The formula of PDA medium is as follows: Peel 200g potatoes, cut into cubes, cook in boiling water for 15min, filter through eight layers of gauze, add 20g of glucose to the filtrate, distill water to 1L, pack in tr...

Embodiment 2

[0043] Embodiment 2: The production method of pullulan polysaccharide according to the present invention and the comparison experiment of pullulan polysaccharide fermentation

[0044] 1. Fermentation method

[0045] Inoculate Aureobasidium pullulans MHZ-2101 into solid PDA medium, culture at 28°C for 3 days, pick a large loop with an inoculation loop and inoculate it into the seed medium, culture at 28°C, 150rpm reciprocating shaker for 20hrs, 1:10 rotation Received the fermentation medium, cultured on a reciprocating shaker at 28° C. for 72 hours at 180 rpm, and measured the content of glucose and pullulan.

[0046] Seed medium: 40g / L glucose, 2.8g / L yeast powder, 6.5g / L potassium dihydrogen phosphate, 0.3g / L magnesium sulfate.

[0047] Fermentation medium: 120g / L glucose, 10g / L yeast powder, 130g / L potassium dihydrogen phosphate, 10g / L magnesium sulfate, 15g / L ammonium sulfate, sodium hydroxide to adjust the pH value to 6.5.

[0048] Glucose content detection: the fermenta...

Images