Separation of l-glutamine (l-Gln) from Gln fermentation broth by nanofiltration (NF) was investigated with NTR7450 NF membrane. The effects of various experimental parameters such as transmembrane pressure, pH and concentration of broth on the rejection of l-Gln and l-glutamate (l-Glu) showed that NTR7450 was able to effectively separate l-Gln and l-Glu when the appropriate conditions were chosen. Moreover, the rejection of l-Gln and l-Glu in a single amino acid solution was also studied with the variation of pH, concentration, and physicochemical parameters. It was demonstrated that deviations in the rejection of fermentation broth from a single l-Gln or l-Glu solution were mainly caused by the complex ionic composition of the real fermentation broth.

A non-linear cascade model is proposed to describe the signal transduction pathway in suspension cultures of Taxus chinensis var. mairei induced by an oligosaccharide from Fusarium oxysporum. The oxidative burst intensity, which was defined as the amount of the free radicals including superoxide anion (O2·), H2O2 and OH− and measured by ESR spectrometry, was used as the signal characteristic and the theory of electronic signal transduction cascade was then applied to derive the initial model. The model shows that the signal transduction cascade process is composed of three cascade nets, represented by the phosphorylation of a G-protein, activation of an ion channel and phospholipase C, and phosphorylation of protein kinase C. The three reactions were calculated as beginning at 30.5, 48.8 and 141.4min after elicitation, and the maximum variation rates of the signal intensity in the three nets occurred at 43.2, 80.6 and 192.6min, respectively. The validity of the model predictions was verified by experimental data.

研究了谷氨酰胺发酵液中盐离子对纳滤分离提取谷氨酰铵的作用，系统地考察了操作温度和发酵液组成对纳滤分离透过特性的影响，确定了纳滤分离时发酵液最佳稀释倍数和操作温度。结果表明，二价阳离子通过改变膜面电荷密度对谷氨酸的透过特性产生很大影响，使其截留率降低了8%。发酵液中较高浓度的（NH4）2SO4使谷氨酸和谷氨酰胺的截留率和透过通量明显降低，但较高浓度的NH4Cl影响较小，这体现了纳滤膜对不同离子排斥力的差异。当发酵液稀释至谷氨酰胺浓度为1%，pH调至7时，发酵液中的其它盐离子和残糖因浓度较低而对纳滤分离影响不显著。