66results about How to "Higher than vitality" patented technology

The invention discloses a mutant of endoglucanase, coding gene and application thereof. A protein provided by the invention is artificially synthesized and named as celA-mut(3F-6) or celA-mut(C3-13); the protein is a protein 1) or protein 2) as below: 1) a protein consisting of amino acid residue sequence in a sequence 2 in the sequence table; 2) a protein consisting of amino acid residue sequence in a sequence 4 in the sequence table; 3) a protein obtained by replacement and / or deletion and / or addition of one or a plurality of amino acid residues on the amino acid residue of the sequence2 or a sequence 4 in the sequence table, and with endoglucanase activity and derived from 1). Experiments of the invention have proved that the mutant of endoglucanase obtained by the invention has increased vitality compared with a wild type thereof and wide operational temperature range while maintaining an optimum reaction temperature (75 DEG C), therefore the mutant of endoglucanase has good industrial application prospect.

The invention relates to the field of genetic engineering, and discloses a xylanase mutant with high specific enzyme activity and application thereof. The invention uses the xylanase XYN of the GH11 family derived from Bacillus subtilis Lucky9 as the mother parent, carries out amino acid mutation and expression by molecular biological technology. Compared with the original xylanase XYN, the specific enzyme activity of the mutant N36Y is increased by 180%, reaching 150U / mg, which has achieved unexpected technical effects. The improvement of the specific activity of the xylanase mutant in the invention is beneficial to reduce the production cost of the xylanase, further expands the wide application of the enzyme in the field of functional sugars, and has broad market prospects.

The invention belongs to the field of biological medicine, and relates to a preparation method of a lactococcus lactis product expressing phenylalanine ammonia lyase, and the method orderly comprises the following steps: 1) obtaining a gene which expresses phenylalanine ammonia lyase; 2) connecting the gene which expresses phenylalanine ammonia lyase with a expression vector which is suitable forlactococcus lactis transformation so as to form a recombinant expression vector; 3) transforming competent lactococcus lactis by the recombinant expression vector; 4) screening to obtain a lactococcus lactis strain which highly expresses phenylalanine ammonia lyase; 5) fermenting the lactococcus lactis and inducing the expression of phenylalanine ammonia lyase; 6) drying the obtained fermented strain; wherein the pH of the fermentation liquid is adjusted to be 6.0-6.5 before the induction of fermentation in step 5); the pH is adjusted to be 6.5-7.5 after the induction; the strain is continued to be cultured till the fermentation is finished. With the technical scheme of the invention, the living bacteria number of the obtained lactococcus lactis and the specific activity of phenylalanine ammonia lyase are greatly increased, wherein the former reaches up to above 1012 CFU / ml, and the later reaches up to above 80 U / g.