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The processes for production of indole alkaloids in shake flask suspension cultures of Catharanthus roseus cells using Zenk's alkaloid production medium (APM) were evaluated. The 1-stage process consisted of inoculating APM and incubating for 15 days. The 2-stage process involved 6 d of cultivation in growth medium followed by 15 d of incubation in APM. Growth, main nutrient consumption and alkaloid production were monitored. Both culture processes produced ∼ 20 g dw per 1 of biomass. However, 2-stage cultures yielded an inorganic nutrient richer and more active plant cell biomass, richer in inorganic nutrients, as indicated by higher (> 70%) nutrient availability and consumption. Total and individual indole alkaloid production were 10 times higher (740 mg l−1 and 25 to 4000 μg per g dw, respectively) for 2-stage than for 1-stage cultures. For both processes, highest alkaloid productivity coincided with complete extracellular consumption of major inorganic nutrients, especially nitrate, by the cells. Complete carbohydrate consumption in 2-stage cultures resulted in a 40% decline in production. Small but significant (∼ 10%) product release was observed for both culture regimes, which seemed not to be related to cell lysis. |
