Jiangnan University

Lingqia Su

Jing Wu

Kailin Yao

Jian Chen

Chun Lan Chen

Yan Huang

Yusheng Wang

Zhendong Wang

Ruoyu Hong

Junchen Dong

Li Du

Zirui Wang

Xiumei Tao

Jinyun Feng

Disclosed is a method for promoting extracellular expression of proteins inusing cutinase, which belongs to the technical fields of genetic engineering, enzyme engineering and microbial engineering. It teaches co-expressing a cutinase mutant and a target protein into promote extracellular expression of the target protein which is naturally located inside cells. The target protein includes xylose isomerase, 4,6-&#x3b1;-glucosyltransferase, 4-&#x3b1;-glucosyltransferase, trehalose synthase, branching enzyme and the like. The invention can achieve extracellular expression of intracellularly localized target protein, improve the production efficiency, reduce the production cost and simplify the subsequent extraction process.

Methods for promoting extracellular expression of proteins inusing a cutinase

The present invention discloses a mutant of cyclodextrin glycosyltransferase and belongs to the fields of gene engineering and enzyme engineering. According to the present invention, a mutant having higher disproportionation activity of cyclodextrin glycosyltransferase is obtained by mutating the cyclodextrin glycosyltransferase. The disproportionation activity of enzymes of mutants V6D, S90G, T168A, T171A, T383A, G608A, and V6D/S90G/T168A/T171A/T383A/G608A, is respectively 1.89 times, 1.21 times, 1.21 times, 1.22 times, 1.32 times, 2.03 times, and 3.16 times that of the wild type enzyme in shake flask fermentations.

Mutant of cyclodextrin glycosyltransferase

The present invention relates to preparation and application of a cyclodextrin glucosyltransferase mutant, belonging to the fields of gene engineering and enzyme engineering. By mutating amino acids of cyclodextrin glucosyltransferase, the enzyme activity of the obtained mutant can reach 2.5 times that of wild enzyme. In addition, the cyclodextrin glucosyltransferase mutant obtained in the present invention is simple in purification and suitable for industrial production.

Preparation and application of cyclodextrin glucosyltransferase mutant

The present disclosure discloses a maltooligosyl trehalose synthase mutant with improved thermal stability, and belongs to the technical fields of enzyme engineering and protein engineering. The residual enzyme activities of the MTSase mutants S361R, S444E, S361R/S444E, S361K/S444E, G415P/S361R/S444E and G415P consistent with the present disclosure after treatment at 60&#xb0; C. for 10 min are respectively 70.3%, 50.1%, 83.5%, 65.9%, 100% and 80.7%, which are respectively 1.6, 1.1, 1.9, 1.5, 2.3 and 1.9 times of that of the wild type. The half-lives of the S361R/S444E and G415P/S361R/S444E at 60&#xb0; C. are respectively 14.9 min and 90.8 min which are respectively 3.2 and 19.7 times of that of the wild type, indicating that the thermal stability of the MTSase mutant consistent with the present disclosure is significantly improved than that of the wild type.

Maltooligosyl trehalose synthase mutant with improved thermal stability

The present invention discloses a maltooligosyl trehalose trehalohydrolase (MTHase) mutant and application thereof, belonging to the technical fields of gene engineering and enzyme engineering. The present invention provides a series of MTHase mutants to prepare trehalose, having a better effect. Further, the MTHase mutant is expressed inBL21 (DE3) and the enzyme is optimized by fermentation, which can significantly increase the yield of enzymes.

Maltooligosyl trehalose trehalohydrolase (MTHase) mutant and application thereof

The present invention relates to the field of genetic engineering and enzyme engineering, and more particularly relates to a maltooligosyl trehalose synthase mutant and its application. The present invention provides a series of maltooligosyl trehalose synthase mutants with improved enzyme activity.

Maltooligosyl trehalose synthase mutant and its application

The present invention provides methods for deinking wastepaper by combined use of cutinase and chemical reagents, which relates to the field of enzyme engineering. The method comprises the following steps: pulp preparation, enzymatic hydrolysis, pulp washing and dewatering, and flotation. The enzyme for enzymatic hydrolysis is cutinase at a concentration of 10-20 U/g absolute dry pulp; and 0.5-4% NaSiO, 0.1-0.8% MgSO, 0.1-0.8% EDTA, 0.1-4% HOare used in the chemical treatment. With combined use of enzymatic and chemical treatment, the present invention has solved the problem of the current enzymatic method for deinking that requires large dosage of enzymes and thus high cost. Through proper choice of the kind and the amount of chemical reagents, synergistic effects of the enzymatic and chemical treatment can be achieved, thus increasing the effectiveness of the deinking process. In addition, this method does not require alkaline chemicals, which alleviates the problem of sewage treatment associated with conventional deinking methods.

Methods for deinking wastepaper by combined use of cutinase and chemical reagents

The present invention provides a method of increasing extracellular secretion of secretory proteins by co-expressing the secretory proteins with a mature cutinase. Cutinase can improve the permeability ofcell membrane without destroying the membrane, and thus facilitate cross-membrane transfer of the secretory proteins co-expressed in. Increased extracellular secretion of target proteins can shorten cell culture time, reduce the formation of inclusion bodies and increase production of target proteins.

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Wuxi, China

Lingqia Su