不同阴离子组成的离子液体对产紫青霉生长、代谢及催化特性的影响

Effects of Ionic Liquids with Different Anion Composition on Cell Growth,Metabolism and Catalysis Characteristics of Penicillium purpurogenum Li-3

研究了6种不同阴离子分别与1-丁基-3-甲基咪唑阳离子[Bmim]+组成的6种离子液体对产紫青霉(Penicillium purpurogenum Li-3)细胞生长、代谢、细胞膜透性和催化活性的影响.结果表明,[Bmim]Ac和[Bmim]Tf2N对菌体细胞的生长和代谢具有明显的抑制作用;6种离子液体均改善了细胞膜透性,其中以[Bmim]Ac最明显;全细胞催化反应实验表明,在分别含25%的疏水性离子液体[Bmim]PF6和[Bmim]Tf2N的2种介质体系中,甘草酸(GL)生物转化合成单葡萄糖醛酸基甘草次酸(GAMG)的转化率分别为82.73%和89.84%,GAMG的产率分别为68.65%和76.23%,与不含离子液体的纯缓冲溶液体系相比(GL转化率和GAMG产率分别为81.82%和33.31%),GL的转化率均略有提高,而GAMG的产率则提高了2倍多,表明2种疏水性离子液体对全细胞催化反应的定向性具有明显促进作用;亲水性离子液体[Bmim]Ac,[Bmim]Cl和[Bmim]NO3对细胞的催化活性具有明显的抑制作用,而[Bmim]BF4的抑制作用则较弱.

The wild-type Penicillium purpurogenum Li-3 strain is capable of expressing highly β-glucuroni-dase, a intracellular enzyme with excellent ability to biotransform glycyrrhizin（GL） into glycyrrhetinic acid monoglucuronide （ GAMG ） possessing best biological function. To improve the production of GAMG, the effects of ionic liquids with different anion composition on Penicillium purpurogenum Li-3 cells properties of growth, metabolism, permeability of cell membrane and catalysis were studied in this paper. The results showed that [ Bmim] Ac and [ Bmim] Tf2 N had obvious inhibitory effects on cell growth and metabolism. Six kinds of ionic liquids all improved the permeability of cell membrane, and [ Bmim] Ac was the most remarka-ble. In the two catalytic medium respectively containing 25% hydrophobic [Bmim]PF6 and [Bmim]Tf2N, conversion rates of substrate GL were 82. 73% and 89. 84%, and the yields of GAMG were 68. 65% and 76. 23%, respectively. Thus, the substrate GL conversion increased slightly, but the yield of GAMG were about two times higher than that in the pure buffer solution without ionic liquids （ conversion rate of GL 81. 82%, yield of GAMG 33. 31%） . It was obvious that hydrophobic [ Bmim] PF6 and [ Bmim] Tf2 N were ca-pable of promoting the selectivity of the whole cell catalysis. While hydrophilic [ Bmim] Ac, [ Bmim] Cl and [ Bmim] NO3 obviously had inhibition in different degrees on the cell’ s catalytic activity. These results indica-ted that the anions in ionic liquids played a crucial role as biological catalytic medium.