GROWTH-CHARACTERISTICS OF PLANT HAIRY ROOTS AND THEIR CULTURES IN BIOREACTORS

Plant hairy roots from horseradish, carrots, etc. transformed by the soil bacterium Agrobacterium rhizogenes showed active growth in the phytohormone-free Murashige-Skoog medium with sucrose as a carbon source. Reticulate polyurethane foam was an appropriate support for the immobilization of hairy root cells. The hairy roots of 11 kg-dry cells&middotm-3 (110 kg-fresh cells&middotm-3) were obtained in a 31-d culture in an airlift column bioreactor with immobilized horseradish cells. A linear relationship was observed between the dry cell mass grown and medium conductivity decrease for hairy root cultures. Thus, it was possible to monitor cell mass concentration during the hairy root culture by on-line measurement of conductivity in the bioreactor system.