Production method and application of special dietary protein

Abstract

The invention provides a production method and application of special dietary protein. A protease protein sequence from bacillus is used as a template, phenylalanine is knocked out and replaced, and part of amino acids is rearranged, so that it is ensured that phenylalanine-free protein has protease specific activity in the fermentation process, and other impure protein is degraded or growth of other impure protein is inhibited; a fed-batch fermentation process is adopted, so that the logarithmic growth period of a strain is prolonged, and the protein expression index is increased; besides, apost-treatment process is optimized, and the obtained protein powder is high in purity and good in mouth feel. The ratio of LNAA to Phe in the obtained recombinant phenylalanine-free protein exceeds 100 times, so that the situation that phenylalanine in blood enters the brain can be effectively reduced. According to the method, the production cost of the phenylalanine-free or low-phenylalanine protein powder can be reduced to reach the cost of a common protein product, and the protein powder has great practical application value and broad market prospects.

Description

technical field [0001] The present invention relates to the field of genetic engineering, in particular to a method for expression in Bacillus licheniformis and production of a recombinant protein suitable for patients with phenylketonuria, which includes using the protease protein sequence derived from Bacillus as a template when designing the recombinant protein, Knock out and replace phenylalanine, and rearrange some amino acids, so as to ensure that the newly designed phenylalanine-free protein has protease activity during the fermentation process, and can be simply processed during post-fermentation treatment It permanently loses its protease activity, thereby ensuring the safety of dietary protein. Background technique [0002] Phenylketonuria (PKU) is a rare genetic disease of amino acid metabolism. The incidence rate in Chinese newborns is about 1:11800, and the total number of PKU patients in China is about 120,000. PKU is autosomal recessive and is due to key enzy...

AI Technical Summary

Problems solved by technology

There are many disadvantages in the traditional phenylalanine-restricted diet therapy: (1) Since the protein of most foods contains phenylalanine, the food that can be selected is very limited, and you can only choose protein-free or very low-protein foods. (2) Using amino acid compound powder as a substitute for dietary protein, because many amino acids have a strong bitter taste and special unpleasant smell, resulting in amino acid compound powder The taste of the food is poor, and the patient's treatment compliance is poor; in addition, due to oral administration of a large amount of free amino acids, the osmotic pressure of the intestinal tract is disturbed, causing intestinal discomfort and intestinal metabolic disorders; thirdly, the food form that amino acid powder can be made into is very limited , long-term use leads to a decline in the quality of life of patients

(3) Continuous neurological and psychological problems due to poor quality of life; (4) Long-term dietary restrictions or single choices lead to nutritional deficiencies; (5) The cost of special foods and nutrients is relatively high, and the family burden is heavy

Because patients with phenylketonuria need to use it for a long time and consume at least 15-75g of protein per day, if the expression efficiency is low or the production and purification process is complicated, the production will be limited and the price will be expensive. Ordinary patients with phenylketonuria If it is unaffordable economically, such a product cannot meet the market demand

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