Effect of Nitrogen, Phosphorus and Medium pH to Enhance Alkaloid Production from Catharanthus roseus Cell Suspension Culture

Abstract

Several elevated levels of nitrogen and phosphate at varying pH of the medium which impart a major influence on callus and biomass development and subsequent production of alkaloids was investigated using suspension culture system of Catharanthus roseus in the present study. The B5 medium was buffered at pH 4.51, 5.82 and 7.32 by addition of different levels of (A) diammonium hydrogen phosphate (NH4)2HPO4 and (B) ammonium dihydrogen orthophosphate (NH4H2PO4) representing the enhanced and varied supply of total nitrogen (NH4++NO3ˉ) and phosphate compared to MS medium (as control) for cell biomass production and alkaloid yield. The pH of the medium have shown significant effects with maximum biomass fresh wt., dry wt. and total alkaloid yield at 5.82 medium pH with elevated phosphate levels and total nitrogen concentration of 3710.10 mg/L compared to control MS medium with 2850 mg/L total nitrogen. At 3667.33 and 3752.48 mg/L of total nitrogen with enhanced phosphate supply showed reduced biomass fresh wt., dry wt. and total alkaloid yield at lower (4.51) and higher (7.32) medium pH respectively. Inclusion of 200 mg/L of tryptophan or phenylalanine as reduced nitrogen source in B5 medium buffered at 5.82 ± 0.2 pH showed enhanced biomass and alkaloid production. Hence, addition of nitrogen, phosphate, tryptophan, phenylalanine as nutrient in suspension culture stimulate their uptake to enhance cell biomass and total alkaloids production but as a function of pH of the medium.