枇杷叶多糖酶法提取工艺优化及其离子交换层析纯化

单因素试验和响应面试验得到酶法提取枇杷叶多糖最佳条件为提取时间2.95 h、提取温度41 ℃、酶用量15.6 mg/g，多糖提取率为8.03%。研究枇杷叶多糖在离子交换填料DEAE Sepharose CL-6B上的吸附行为，考察缓冲液pH值和离子强度对吸附等温线的影响。结果表明，在实验范围内，吸附平衡数据符合单分子层吸附的Langmuir方程，枇杷叶多糖在DEAE-Sepharose CL-6B上的吸附量随着缓冲液pH值的上升而增加，低离子强度的缓冲液有利于多糖的吸附。实验确定枇杷叶多糖离子交换柱层析进样条件为pH 8.0条件下，选取不含NaCl的缓冲液，通过离子交换柱层析后枇杷叶多糖被分为3 个组分，得率分别为32.66%、1.22%和3.12%。

Optimization of Enzymatic Extraction of Polysaccharides from Loquat Leaves and Purification by Ion Exchange Chromatography

Using one-factor-at-a-time method and response surface methodology (RSM), the optimal conditions for enzymatic
extraction of polysaccharides from loquat leaves with cellulase were determined as follows: temperature, 41 ℃; time, 2.95 h;
and cellulase amount, 15.6 mg/g. Under these optimal conditions, the extraction yield of polysaccharides was 8.03%.
The adsorption properties of loquat leaf polysaccharides (LLP) on the ion exchange adsorbent DEAE Sepharose CL-6B
were studied. Effects of pH and ion strength on isotherms were examined through static adsorption experiments. The
results showed that equilibrium sorption data could be described by the Langmuir isotherm equation with high correlation
coefficients, implying the existence of the monomolecular sorption in these systems. After fitting the experimental data
with Langmuir equation, several adsorption parameters, which directly reflected the influences of pH and ion strength, were
obtained. The adsorbent exhibited better adsorption performance for LLP at higher pH and lower ion strength of buffer
solution. The suitable conditions for ion chromatography were obtained with pH 8.0 of buffer solution without NaCl. Three
fractions named as LLPS-1, LLPS-2 and LLPS-3 were obtained through ion chromatography, and their yields were 32.66%,
1.22% and 3.12%, respectively.