Recombined hansenula polymorpha fermentation technology

Abstract

The invention provides a recombined hansenula polymorpha fermentation technology which includes a fermentation culture stage, a fed-batch fermentation stage and a foreign gene induced expression stage. Recombined hansenula polymorpha is cultured by means of a special basic salt culture medium, and the wet bacteria weight reaches 120 g / L-150 g / L after fermentation is conducted for about 24 h; fed-batch (glucose) is adopted so that density of hansenula polymorpha can be further increased till the wet bacteria weight reaches 220 g / L-230 g / L; in the induction stage, a special mixed induction agent composed of a mixture of glucose and methyl alcohol in different proportions and a mixture of a mixed salt solution and methyl alcohol is used for induced expression. By means of the special basic salt culture medium, the special mixed induction agent and a feeding method, growth of hansenula polymorpha can be promoted, so the bacteria density of a fermentation tank is increased, induction efficiency is improved, and the proportion of dead cells is reduced. According to the recombined hansenula polymorpha fermentation technology, the yield of phytase is greatly increased on the original bases, and enzyme activity of phytase reaches about 2368 U / ml in 3L of a fermentation solution. The technology has good application prospects in research and practical production of feed enzyme preparations.

Description

technical field [0001] The invention relates to the field of fermentation engineering, in particular to a recombinant Hansenula fermentation process. Background technique [0002] Phytic acid (Phytate, Phytic, IP6), also known as phytate, contains 6 phosphate groups and is an important storage form of phosphorus in feed. The molecular formula of phytic acid is C 6 h 18 o 24 P 6 , the molecular weight is 660.09. Phytase (Phytase) can catalyze the hydrolysis of phytic acid and phytate into inositol and phosphoric acid (or phosphate). [0003] Phytic acid mainly exists in plant seeds in the form of calcium, magnesium, and potassium phytate, and also exists in nucleated red blood cells of animals. Phytase is found in enzymes secreted by soil, plants, and microorganisms to the outside of the cell. Therefore, phytase plays an important role in the metabolic cycle of phosphorus in the natural environment. In addition, phytic acid has a strong complexing ability for most meta...

AI Technical Summary

Problems solved by technology

Under normal circumstances, the phosphate bond in phytic acid is very stable. There are generally two methods for the degradation of phytic acid. One is chemical methods, but it is extremely difficult to degrade phytic acid by chemical methods; the other method is Enzymatic hydrolysis, the currently known enzyme that can effectively degrade phytic acid is only phytase

[0004] Monogastric animals lack phytase to decompose phytic acid. Phosphorus in the form of phytic acid is difficult to be absorbed and utilized by animals, which brings the following problems: First, the presence of phytic acid in feed has anti-nutritional effects. Phytic acid Phosphorus itself is difficult to be hydrolyzed and utilized by the digestive tract of pigs, poultry and aquatic animals; phytic acid will combine with various metal ions and proteins during the digestion process of animals' gastrointestinal tract to form insoluble complexes, which will hinder the action of some digestive enzymes. Inhibition, which greatly reduces the digestibility of mineral elements and other nutrients in the feed

This not only greatly increases the cost of feed production, but also directly excretes a large amount of phosphorus that is not used by animals, resulting in waste of phosphorus sources and serious environmental problems.

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