Establishment of forskolin yielding transformed cell suspension cultures of Coleus forskohlii as controlled by different factors

Suspension cultures derived from gall calli which were obtained following i nfection with Agrobacterium tumefaciens (C58) were established in Coleus fo rskohlii. Cell line selection following single cell cloning or cell aggrega te cloning was carried out to select cell lines capable of fast growth and for producing high level of forskolin. A fast growing cell line (GSO-5/7) t hus selected was found to accumulate 0.021% forskolin in 42 days. The effec t of cultural conditions on cell growth was studied to identify factors inf luencing biomass yield. Cell growth in suspension was found to be influence d significantly by carbon source, initial cell density and light or dark co ndition. Optimal cell growth (20 fold increase in biomass in a 42 day perio d) was obtained when the cells were grown in dark condition in B5O media co ntaining 3% sucrose as sole carbon source with an initial cell density of 1 .5 x 10(5) cells per mi. Forskolin accumulation was maximum (0.021%) in the stationary phase of cell growth. These suspension cultures showed continuo us and stable production of forskolin. (C) 2000 Elsevier Science B.V. All r ights reserved.