CN101864470B - Method for increasing yield of extracellular polysaccharide produced by submerged fermentation of long thread moss cells - Google Patents

Abstract

The invention belongs to the field of submerged fermentation of microalgae cells, and particularly discloses a method for increasing the yield of extracellular polysaccharides produced by submerged fermentation of Nostocchis cells. The method provided by the present invention for increasing the yield of the cell polysaccharides of Nostocella sativa by controlling the light intensity in stages and the fermentation process of the culture medium has a simple process and high production efficiency, and is suitable for scale-up industrial production. Used as a natural antiviral drug or food raw material.

Description

Method for improving the yield of extracellular polysaccharides produced by submerged fermentation of Nostocatis cells

(1) Technical field

The invention belongs to the field of submerged fermentation of microalgae cells, and in particular relates to a method for increasing the yield of exopolysaccharide produced by submerged fermentation of Nostocchis cells.

(2) Background technology

Fa Cai is a terrestrial economic cyanobacteria that grows in the arid regions of Northwest and North my country, and has high nutritional value. Due to its harsh growth environment, the cells of Nostocia spp. secrete a large amount of colloidal substances to the outside of the cells during the growth process, wrapping the cells and algal filaments outside the body to form a colloidal sheath to protect the cells of Nostia sativa from drought, high temperature, and ultraviolet radiation. harm. The main components of colloids are polysaccharides, and these polysaccharides are of great biological significance for the resistance of the unfavorable growth environment of the Nostocs and the normal growth of the cells of the Nostocs.

Studies have found that the acidic polysaccharide-nosoflan extracted from wild Nostoconia spp. cells has strong antiviral activity against influenza virus, human cytomegalovirus, herpes simplex virus and other viruses with envelopes, and is a potential antiviral agent. Drugs; and the polysaccharides produced by submerged liquid fermentation are highly similar to natural polysaccharides in terms of physical and chemical properties, appearance and antiviral properties, and can replace natural polysaccharides as raw materials for industrial production. A new polysaccharide-producing resource.

The method of submerged fermentation of Nostoc chinensis cells to produce polysaccharides of Nostoc sativa has a short production cycle and low cost, and does not need to consume wild Nostoc sativa resources, which is in line with the national policy of protecting the ecology of Nostoc sativa resources. At present, the research on the production of Nostocchia polysaccharides by submerged fermentation of Nostocchis cells mainly focuses on the optimization of fermentation conditions, such as the optimization of the medium and the optimization of the culture conditions; however, there is no relevant literature report on the use of controlled culture conditions to increase the yield of Nostocs polysaccharides .

(3) Contents of the invention

In order to make up for the deficiencies of the prior art, the present invention provides an easy and effective method for increasing the yield of extracellular polysaccharides produced by submerged fermentation of Nostocella cells.

The present invention is achieved through the following technical solutions:

A method for increasing the yield of extracellular polysaccharides produced by submerged fermentation of Nostocchis cells, using Nostocs cells as raw materials, mainly comprising the following steps:

(1) In the first stage of cultivation for 4 days, the BG-11 medium with nitrogen source added with glucose was used, and the light intensity was controlled at 40-60 μmol/m ² ·s;

(2) In the second stage of cultivation for 3 days, the compound nitrogen-free BG-11 medium supplemented with glucose and sodium acetate was used, and the light intensity was controlled at 60-160 μmol/m ² ·s.

In the step (1), the concentration of the glucose is 4g/L; in the step (2), the concentration of the sodium acetate is 2g/L, the concentration of the glucose is 3～4g/L, the pH of the medium is more than or equal to 9, and the light intensity is controlled At 100-160 μmol/m ² ·s.

Nostocia cells are photoautotrophic organisms, and they can also grow in mixed nutrition and heterotrophs. The light intensity is an important factor in the growth process. For the polysaccharides of Nostocchia, especially the exopolysaccharides secreted into the medium, it is the most important factor for development. The primary metabolites during the growth of lettuce cells increase very rapidly in the later stage. Therefore, by controlling the light intensity and medium composition in stages, the growth of Nostocchis cells can be improved in the early stage, and the nitrogen-free medium with compound carbon sources is used for the growth of Nostocs polysaccharides in the later stage. rapid accumulation.

By adopting the technology of the invention, the yield of the cell polysaccharide of the hairy vegetables is significantly improved, and the yield is increased to 3-4 g/L.

The invention has the advantages of simple process and high production efficiency, can significantly increase the yield of the Nostocella cell polysaccharide, is suitable for scaled-up industrial production, and the obtained Nostocci cell polysaccharide can be used as a natural antiviral drug or a food raw material after being separated and purified.

(4) Specific implementation methods

Embodiment 1: comparative example

The Nostocella cell species used in the present invention is isolated and preserved by Tianjin Key Laboratory of Industrial Microbiology (Chinese patent ZL031191101.0, inventor: Jia Shiru, Su Jianyu, Qiao Changsheng, date of authorization: March 8, 2006).

This invention separates and obtains the long-term preservation of Nostocchia cell species from the wild Nostocchis algae, carries out the suspension culture of Nostocys cells, adopts high-density culture technology, and adds the mixed nutrition mode of organic carbon source (Chinese patent 2006100113589.4, inventor: Jia Shiru Yu Haifeng, Su Jianyu, and Lin Yongxian, published), used BG-11 medium supplemented with glucose, cultured for 7 days, the temperature was 24°C, the rotation speed was 140rpm, the light intensity was 40-90μmol/m ² ·s, and the polysaccharide yield of Nostocchi sativa was 2.25g/L.

Example 2:

The light reactor adopts the method of controlling light intensity and culture medium in stages, and the conditions such as temperature and rotation speed are the same as those in Comparative Example 1.

In the 4th day of the first stage of fermentation, nitrogenous BG-11 medium with 4g/L glucose was used, and the light intensity was controlled at 40-60μmol/m ² ·s. On the 5th day of culture, 2g/L sodium acetate was fed Nitrogen-free BG-11 medium with 3-3.5 g/L glucose, adjust the pH above 9.0, and control the average light intensity of the liquid surface at 100-160 μmol/m ² ·s.

Using this step-by-step control strategy to produce polysaccharides from Nostoconia spp., the yield of polysaccharides obtained by ethanol precipitation was 3.5g/L.

Example 3:

The light reactor adopts the method of controlling light intensity and culture medium in stages, and the conditions such as temperature and rotation speed are the same as those in Comparative Example 1.

In the 4th day of the first stage of submerged fermentation, the aerobic BG-11 medium supplemented with 4g/L glucose was used, and the light intensity was controlled at 40-60μmol/m ² ·s. In the nitrogen-free BG-11 medium of 2g/L sodium acetate and 4g/L glucose, the pH of the medium was adjusted to be above 9.0, and the light intensity (average value of the liquid level) was controlled at 100-160 μmol/m ² ·s.

Using this step-by-step control strategy to produce the polysaccharides of Nostoconia spp., the yield of polysaccharides obtained by the two-stage fermentation broth was 4g/L by ethanol precipitation.

Claims (3)

1. a method that improves yield of extracellular polysaccharide produced by submerged fermentation of long thread moss cells take hair weeds cells as raw material, is characterized in that: mainly comprise the steps:

(1) fs cultivated 4 days, adopt add glucose nitrogenous source BG-11 substratum arranged, intensity of illumination is controlled at 40 ~ 60 μ mol/m ²S;

(2) subordinate phase was cultivated 3 days, adopted that to add concentration be the compound without nitrogenous source BG-11 substratum of the glucose of 3 ~ 4g/L and sodium acetate that concentration is 2g/L, medium pH 〉=9, and intensity of illumination is controlled at 60 ~ 160 μ mol/m ²S.

2. the method for raising yield of extracellular polysaccharide produced by submerged fermentation of long thread moss cells according to claim 1, it is characterized in that: in the step (1), the concentration of described glucose is 4g/L.

3. the method for raising yield of extracellular polysaccharide produced by submerged fermentation of long thread moss cells according to claim 1 and 2, it is characterized in that: in the step (2), described intensity of illumination is controlled at 100 ~ 160 μ mol/m ²S.