Jiangnan University

Bo Pang

Li Zhou

Zhongmei Liu

Wenjing Cui

Zhemin Zhou

Bin Xu

Ting Xie

Haitao Zhang

Lianghong Liu

The present disclosure discloses a thermophilic recombinant type II pullulanase and the application thereof, and belongs to the technical field of genetic engineering. The present disclosure obtains a thermophilic recombinant type II pullulanase by heterologously expressing type II pullulanase in. Its optimum pH is 6.6, it has better pH tolerance under the conditions of pH 5.8-8.0, and its optimum temperature is 95° C. After incubating at 95° C. for 10 h, the remaining enzyme activity is greater than 50%. It can exhibit higher specific enzyme activity under strong reducing conditions. For example, adding DTT to the culture environment can increase the specific enzyme activity of Sumo-Pulby 237.2%. The present disclosure also provides the combined truncation mutant Δ28N+Δ791C of type II pullulanase Sumo-Pul. The specific enzyme activity of the enzyme mutant is 32.18±0.92 U/mg, which is 5.99 times as high as that of the wild-type enzyme, thereby having important industrial application value and potential.

Thermophilic recombinant type II pullulanase and application thereof

The present invention provides a preparation method of a gallium nitride single crystal based on a ScAlMgOsubstrate, comprising following steps: (1) providing a ScAlMgOsubstrate; (2) growing a buffer layer on a surface of the ScAlMgOsubstrate; (3) annealing the buffer layer; (4) growing a GaN crystal on the buffer layer; (5) performing cooling, so that the GaN crystal is automatically peeled off from the ScAlMgOsubstrate. The present invention does not need to use a complex MOCVD process for GaN deposition and preprocessing to make a mask or a separation layer, which effectively reduces production costs; compared with traditional substrates such as sapphire, it has higher quality and a larger radius of curvature, and will not cause a problem of OFFCUT non-uniformity for growing GaN over 4 inches; finally, the present invention can realize continuous growth into a crystal bar with a thickness of more than 5 mm, which further reduces the costs.

Method for growing a GaN single crystal film on a buffer layer on a ScAlMgO4 substrate and performing cooling so that the GaN film is peeled from the ScAlMgO4 substrate

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Wuxi, China

Bo Pang