响应面法优化鹿角菜中岩藻多糖的提取工艺

在单因素试验的基础上,利用Box-Benhnken中心组合实验设计,采用响应面法对鹿角菜(Pelvetia siliquosa)中岩藻多糖的提取工艺进行优化。结果表明,液料比、水浴温度和水浴时间对岩藻多糖提取率均有显著影响;最佳提取工艺条件为:液料比(m L/g)32、水浴温度90℃、水浴时间8.4 h,此时岩藻多糖最高提取率为5.2005%,与理论值5.2153%相比,相对误差很小。响应面模型与实际情况拟合良好,采用响应面法对鹿角菜中岩藻多糖提取条件进行优化合理可行。     

His260残基的替代改变食鹿角菜假交替单胞菌芳香基硫酸酯酶的热稳定性

This study aimed to improve the thermostability of arylsulfatase from Pseudoalteromonas carrageenovora. A library of P. carrageenovora arylsulfatase mutants was constructed by introducing random mutagenesis using error-prone PCR. After screening, two mutants of H260 L and D84 A/H260 L showed enhanced thermal stability than the wild-type predecessor(WT). Site-directed mutagenesis demonstrated that only amino acid residue at Position 260 plays an important role in the thermostability of P. carrageenovora arylsulfatase. Thermal inactivation analysis showed that the half-life(t_(1/2)) values at 55°C for H260 L, H260 I, H260 Q, H260 F and H260 R were 40.6, 48.4, 30.9, 29.1 and 34.5 min, respectively, while that of WT was 9.1 min. Structure modeling demonstrated that the additional hydrogen bonds and/or optimization of surface charge-charge interactions could be responsible for the increased thermostability imparted by H260 L, H260 I, H260 Q, H260 F and H260 R.