摘要
高山红景天（ＲｈｏｄｉｏｌａｓａｃｈａｌｉｎｅｎｓｉｓＡ．Ｂｏｒ．）培养细胞中，甙元酪醇在细胞生长静止期大量积累，而此时糖基化反应的效率很低，因而红景天甙（ｓａｌｉｄｒｏｓｉｄｅ）产量较低。考虑到培养细胞中酪醇葡萄糖基转移酶的活性在指数生长期达到最高，考察了在指数生长期添加外源酪醇生物转化生产红景天甙的可能性，并探讨了酪醇添加浓度、添加方法及细胞密度对酪醇转化率及红景天甙产量的影响。结果表明，细胞在酪醇浓度为１ｍｍｏｌ／Ｌ的培养基中培养２４ｈ后可使酪醇转化率达到９５％；过高的酪醇浓度（＞３ｍｍｏｌ／Ｌ）对细胞生长及酪醇转化率都有明显抑制作用；通过较低浓度酪醇的３次重复添加，可使细胞密度为６ｇＤＷ／Ｌ、１２ｇＤＷ／Ｌ及１８ｇＤＷ／Ｌ的培养物中的红景天甙产量分别达到１３２０ｍｇ／Ｌ、１７４０ｍｇ／Ｌ和１９８０ｍｇ／Ｌ。
In Rhodiola sachalinensis A. Bor. cell cultures, low yields of salidroside was supposed to be associated with the low efficiency of glucosylation reaction at the stationary phase of cell growth, when large amounts of the substrate, aglycon tyrosol, were accumulated. Considering the activity of tyrosol glucosyltransferase being the highest at the exponential growth phase, the author added exogenous tyrosol into the cultures at this time so as to produce salidroside through biotransformation. The effects of tyrosol concentration, the way of tyrosol addition as well as the cell density on the transformation rate and salidroside yield were investigated. It was found that the transformation rate attained 95% after cells were incubated in the medium containing 1 mmol/L tyrosol for 24 h. Excess high concentrations of tyrosol in medium (>3 mmol/L) caused inhibition of transformation rate and cell growth. By 3 repeated additions of tyrosol in low concentrations, the salidroside yields of 1320 mg/L, 1740 mg/L and 1980 mg/L to the cell densities of 6 g DW/L, 12 g DW/L and 18 g DW/L were obtained respectively.
基金
国家自然科学基金
关键词
高山红景天
红景天甙
酪醇
生物转化
Rhodiola sachalinensis, salidroside, tyrosol, Biotransformation
