The Viability and Biosynthetic Activity of Cells of Capsicum frutescens Mill. cv. annuum Immobilized in Reticulate Polyurethane

Cells of C. frutescens Mill. cv. annuum, immobilized in reticulatepolyurethane foam, retained a high level of viability aftera 23 d period of entrapment, as determined by respiratory activity,esterase activity (staining with fluorescein diacetate), nutrientuptake and secondary metabolic activity (capsaicin production).Esterase activity and the ability to accumulate capsaicin wereretained during prolonged culture periods (of up to 12 weeks'duration), and although certain precursors to capsaicin (phenylalanine,ferulic acid and isocapric acid), when supplied to immobilizedcells at a concentration of 1.0 mol m ^–3 were found toreduce respiratory activity, this could be restored by the sequentialchemical treatment of the cells, using precursor-free medium.The ability of immobilized pepper cells to produce capsaicinunder such conditions was examined. Evidence is presented whichsuggests that the immobilization in polyurethane acts to stabilizecells (in terms of the retention of esterase, respiratory andsecondary metabolic activity) when subjected to storage at 3°C. Key words: Immobilization, Viability, Secondary metabolism