Su Zhiguo

Suspension culture of compact callus aggregate of Rhodiola sachalinensis for improved salidroside production

Some level of cellular or tissue differentiation is needed for the biosynthesis of many important compounds in plant cell cultures. The culture of compact callus aggregates (CCA) consisting of spherical, smooth-surfaced clumps of 2-7 mm in diameter displaying some level of cellular and tissue differentiation was initiated from the stems of R. sachalinensis. Histochemical analysis showed that the CCA were structurally organized to facilitate nutrient transport. The kinetics for CCA growth and salidroside synthesis were measured in shake flasks. it was found that a short phase of exponential growth (mu = 0.137 day(-1)) and a relatively long phase of linear growth (growth rate = 0.60 g day(-1) l(-1) predominated over most of the the culture cycle. The salidroside yield of CCA after 24 days of culture was 0.68% on a dry weight basis, approximately six times as much as that of the dispersed cells; however, the growth rate of CCA was comparable to that of the dispersed cells. The CCA suspension culture was also successfully carried out ill a 5-l airlift bioreactor. The yield of salidroside was similar to that of shake-flask cultures though the biomass was relatively small. No foam buildup occurred in the reactor Since rite medium remained almost clear throughout the culture cycle

Trehalose extraction from Saccharomyces cerevisiae after microwave treatment

Fresh cells of Saccharomyces cerevisiae were disrupted after 60 s microwave irradiation, and trehalase activity was simultaneously destroyed. Trehalose could be extracted from microwave-treated yeast by water in 10 min at room temperature.

Improved HPLC method for taxol determination with Al2O3 solid-phase extraction

The closely eluting compounds of taxol, cephalomannine and N-debenzoyl-N-phenylacetyl taxol, were successfully removed from a sample of Taxus yunnanis by γ-Al2 O3 solid-phase extraction. A sensitive, selective, rapid and accurate C18 HPLC method for taxol determination was established.

Suspension nodule culture of the Chinese herb, Rhodiola sachalinensis, in an air-lift reactor: kinetics and technical characteristics

Suspension nodule culture of Rhodiola sachalinensis was carried out in a 10 l air-lift reactor for 30 days. The biomass of 13 gdry wt/l and salidroside content of 0.45% dry wt were obtained. No foaming was observed in the reactor since the broth remained almost clear throughout the culture. The O2 transfer coefficient kLa of the culture system increased firstly then dropped during the culture cycle. The significant increase in solid holdup of the culture system is suggested to be responsible for the variation of kLa.