【摘 要】
：
The glutaraldehyde cross-linked chitosan beads were prepared under microwave irradiation and urease was immobilized onto the beads. The activity and the yield o
【机 构】
：
School of Chemical Engineering and Technology
论文部分内容阅读
The glutaraldehyde cross-linked chitosan beads were prepared under microwave irradiation and urease was immobilized onto the beads. The activity and the yield of enzyme activity of the immobilized urease were 10.83 U/g carrier and 47.7%, respectively. The optimum conditions of immobilization were 1% of glutaraldehyde volume fraction, 10 mg/g of urease/beads weight ratio, 24 h of the processing time and pH 6.5 of the reaction medium for immobilization. The properties of the immobilized urease were investigated and compared with those of the free enzyme. The optimum pH values were 6.5 and 7.0 for the immobilized and free urease, respectively. The optimum temperature was 60 ℃ for the free urease, while it shifted to 65 ℃ for the immobilized enzyme. The Michaelis constant K m was 9.1 mmol/L for the immobilized and 12.5 mmol/L for the free urease. The immobilized urease retained 40% of its initial enzyme activity even after 10 repeated uses. The immobilized urease stored at 4 ℃ retained 46% of its initial activity even after 35 d.
其他文献
Common displays such as CRT or LCD screens have limited capabilities in displaying most color spectra correctly. The main disadvantage of these devices is that
Given a graph G and a non-negative integer h, the h-restricted connectivity κh (G) of G is the minimum cardinality of a set of vertices of G, in which at least
将沟道辐射与自由电子激光进行类比,讨论了电子轴沟道辐射作为γ激光的可能性.引入等效磁场描述电子的运动行为,并通过等效磁场与辐射场相互作用描述了电子的纵向运动,导出了
为探究吕家坨井田地质构造格局,根据钻孔勘探资料,采用分形理论和趋势面分析方法,研究了井田7
Calculations of energies and absolute intensities of Auger electron and X-ray arising from electron capture are introduced briefly. The calculation codes and ma
Yarn quality characteristics are affected by processing parameters. A 36 tex rotor spun yarn of 50/50 Basofil/cotton (B/C) blended yarn was spun, and the spinni
In this paper, the asymptotic properties of the quadratic forms and the T statistic of the skew elliptical variables are studied. Consistent estimators of some
A real-time transaction service aims at ensuring the consistency of real-time and transactional Grid applications. This paper proposes an efficient real-time tr
The HCPB concept has been a European DEMO reference concept for nearly one decade. Detailed thermal-hydraulic study on the control behavior of the whole system