Chitosanases EAG1, a classical glycoside hydrolase from Bacillus ehimensis, is relatively unstable with higher temperature. This shortcoming seriously restricts its industrial application. Therefore, it is crucial to ...Chitosanases EAG1, a classical glycoside hydrolase from Bacillus ehimensis, is relatively unstable with higher temperature. This shortcoming seriously restricts its industrial application. Therefore, it is crucial to clarify the theoretical basis of thermo stability and to produce enzymes with high activity and stability. Using the structural modeling and molecular dynamical simulation, residues Leu84, Gly113, Asp116, Ala207 and Leu286 were believed to be the key residues for structural stability. Then the predicted residue Leu84 was mutated to ALA. It was shown that the L84A mutation can improve the thermal stability of chitosanases EAG1. Together with previous studies, mutations of G113C, D116C, A207C and L286C forms two sulfur bonds can change the thermal stability of EAG1. The results suggest that the thermal stability of EAG1 could be engineered by site-directed mutagenesis on the conserved residues. This protocol could be employed for improving thermal stability of other chitosanases EAG1.展开更多
The main aroma component of Luzhou-flavor Liquor is ethyl caproate, which is combined with appropriate amount of ethyl butyrate, ethyl acetate, ethyl lactate and so on. By adding the marine bacillus BC-2 (Accession nu...The main aroma component of Luzhou-flavor Liquor is ethyl caproate, which is combined with appropriate amount of ethyl butyrate, ethyl acetate, ethyl lactate and so on. By adding the marine bacillus BC-2 (Accession number: MK811408) to substrate sludge, the bacillus complex bacterial liquid (pit Mud Functional Bacterial liquid) has been modified. The complex bacterial liquid was used in the production of Luzhou-flavor Liquor and it dramatically promoted the content of health-beneficial ingredients in the new workshop. These results demonstrated that the marine bacillus BC-2 can effectively improve the quality and health benefit of Luzhou-flavor Liquor.展开更多
Phytase is a kind of enzyme that hydrolyzes phytic acid and its salts to produce inositol and phosphoric acid. As a new feed additive, phytase has great potential in animal nutrition and environmental protection. Beca...Phytase is a kind of enzyme that hydrolyzes phytic acid and its salts to produce inositol and phosphoric acid. As a new feed additive, phytase has great potential in animal nutrition and environmental protection. Because of its good stability, large-scale production and high activity, microbial phytase has become a hot spot in industrial application. Here, we reported the predicted structure and enzymatic properties of a phytase from Bacillus subtilis, which was named as phyS. It was clear that the optimal temperature is 35°C, and the optimal pH is 8. Meanwhile, the enzyme activity was kept at above 90% in the range of pH 8 - 9, this result demonstrated that phyS is an alkaline phytase. This study lays a foundation for the extensive application of phyS.展开更多
Electromagnetic waves carrying an orbital angular momentum (OAM) are of great interest. However, most OAM antennas presentdisadvantages such as a complicated structure, low efficiency, and large divergence angle, whic...Electromagnetic waves carrying an orbital angular momentum (OAM) are of great interest. However, most OAM antennas presentdisadvantages such as a complicated structure, low efficiency, and large divergence angle, which prevents their practicalapplications. So far, there are few papers and research focuses on the problem of the divergence angle. Herein, a metasurfaceantenna is proposed to obtain the OAM beams with a small divergence angle. The circular arrangement and phase gradient wereused to simplify the structure of the metasurface and obtain the small divergence angle, respectively. The proposed metasurfaceantenna presents a high transmission coefficient and effectively decreases the divergence angle of the OAM beam. All thetheoretical analyses and derivation calculations were validated by both simulations and experiments. This compact structurepaves the way to generate OAM beams with a small divergence angle.展开更多
文摘Chitosanases EAG1, a classical glycoside hydrolase from Bacillus ehimensis, is relatively unstable with higher temperature. This shortcoming seriously restricts its industrial application. Therefore, it is crucial to clarify the theoretical basis of thermo stability and to produce enzymes with high activity and stability. Using the structural modeling and molecular dynamical simulation, residues Leu84, Gly113, Asp116, Ala207 and Leu286 were believed to be the key residues for structural stability. Then the predicted residue Leu84 was mutated to ALA. It was shown that the L84A mutation can improve the thermal stability of chitosanases EAG1. Together with previous studies, mutations of G113C, D116C, A207C and L286C forms two sulfur bonds can change the thermal stability of EAG1. The results suggest that the thermal stability of EAG1 could be engineered by site-directed mutagenesis on the conserved residues. This protocol could be employed for improving thermal stability of other chitosanases EAG1.
文摘The main aroma component of Luzhou-flavor Liquor is ethyl caproate, which is combined with appropriate amount of ethyl butyrate, ethyl acetate, ethyl lactate and so on. By adding the marine bacillus BC-2 (Accession number: MK811408) to substrate sludge, the bacillus complex bacterial liquid (pit Mud Functional Bacterial liquid) has been modified. The complex bacterial liquid was used in the production of Luzhou-flavor Liquor and it dramatically promoted the content of health-beneficial ingredients in the new workshop. These results demonstrated that the marine bacillus BC-2 can effectively improve the quality and health benefit of Luzhou-flavor Liquor.
文摘Phytase is a kind of enzyme that hydrolyzes phytic acid and its salts to produce inositol and phosphoric acid. As a new feed additive, phytase has great potential in animal nutrition and environmental protection. Because of its good stability, large-scale production and high activity, microbial phytase has become a hot spot in industrial application. Here, we reported the predicted structure and enzymatic properties of a phytase from Bacillus subtilis, which was named as phyS. It was clear that the optimal temperature is 35°C, and the optimal pH is 8. Meanwhile, the enzyme activity was kept at above 90% in the range of pH 8 - 9, this result demonstrated that phyS is an alkaline phytase. This study lays a foundation for the extensive application of phyS.
基金The authors acknowledge the support of the National Natural Science Foundation of China(Grant Nos.61774020,51788104,51802023,61690195,61605015,61575028,51532004,and 51802021)the Science and Technology Plan of Shenzhen City(Grant No.JCYJ20180306173235924)the Ph.D.Student’s Short-Term Overseas Study and Exchange Program of BUPT.
文摘Electromagnetic waves carrying an orbital angular momentum (OAM) are of great interest. However, most OAM antennas presentdisadvantages such as a complicated structure, low efficiency, and large divergence angle, which prevents their practicalapplications. So far, there are few papers and research focuses on the problem of the divergence angle. Herein, a metasurfaceantenna is proposed to obtain the OAM beams with a small divergence angle. The circular arrangement and phase gradient wereused to simplify the structure of the metasurface and obtain the small divergence angle, respectively. The proposed metasurfaceantenna presents a high transmission coefficient and effectively decreases the divergence angle of the OAM beam. All thetheoretical analyses and derivation calculations were validated by both simulations and experiments. This compact structurepaves the way to generate OAM beams with a small divergence angle.
