Immobilization of Rubia tinctorum L. suspension cultures and its effects on alizarin and purpurin accumulation and biomass production

The present study is investigating the immobilization of Rubia tinctorum L. suspension cultures. The effects of three inoculation volumes and three immobilization materials (loofa, sisal and jute) on fresh and dry weights of biomass as well as on alizarin and purpurin production were determined in this study. Two grams of four-week old callus tissue were transferred to liquid medium to establish suspension cultures. After four weeks, suspension cultures of R. tinctorum at concentration of 8 x 10(5) living cells/ml were immobilized with lignocellulosic materials and the cells were attached to all immobilization materials at the end of the first week and started to form aggregates on them. At the fourth week of these batch systems, biomass was measured approximately three times higher than the starting suspension cultures. The highest fresh weight was obtained (339.40 g/l) from sisal with A1/2 inoculation ratio. Immobilization materials and inoculation volumes had an effect on dry weights, and accordingly, the most effective combinations were jute with A1/4 (J3) and A1/2 (J1) inoculation volumes with 7.86 and 7.82 g/l dry weights, respectively. Alizarin and purpurin contents of immobilized cells, analyzed with U-HPLC method, were 6.05 and 22.91 times higher than inoculated cells. All immobilization materials used in this study had no negative effect on to cells and biomass accumulation was enhanced. Concomitantly with rapid biomass increase, alizarin and purpurin production was ascended.