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The effect of inoculum density and conditioned medium on the production of ajmalicine and catharanthine from immobilized Catharanthus roseus cells
Author(s) -
Lee Carolyn W.T.,
Shuler Michael L.
Publication year - 2000
Publication title -
biotechnology and bioengineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.136
H-Index - 189
eISSN - 1097-0290
pISSN - 0006-3592
DOI - 10.1002/(sici)1097-0290(20000105)67:1<61::aid-bit7>3.0.co;2-j
Subject(s) - catharanthus roseus , sucrose , food science , alkaloid , ammonium , chemistry , botany , biology , biochemistry , organic chemistry
Abstract The effect of the cell‐inoculum size and the addition of conditioned medium on ajmalicine and catharanthine production were studied using immobilized Catharanthus roseus cells. Higher specific‐uptake rates of ammonium, nitrate, and sugars were observed in the low‐inoculum‐density cultures (50 g FW/L) compared to the high‐inoculum‐density cultures (100 g FW/L). Alkaloid production was not correlated with the exhaustion of a particular nutrient from the medium. The high‐inoculum‐density cultures produced higher ajmalicine concentrations throughout the experiment. Catharanthine production was similar between the two inoculum‐density cultures. The addition of conditioned medium to MS‐production medium dramatically improved the production of ajmalicine and catharanthine. The addition of conditioned medium enhanced ajmalicine production from immobilized Catharanthus roseus cultures on day 15 by at least two‐ to fourfold compared to media without the conditioning factors. Catharanthine production was increased by nearly fivefold in cultures with conditioned medium compared to those without conditioned medium. The enhancing effects of conditioned medium on alkaloid production were attributed to an unidentified factor produced and secreted by suspension cultures of C. roseus . The presence of conditioned medium also decreased the sucrose hydrolysis rate. The ajmalicine concentration in these immobilized cell cultures was found to be a function of the fresh‐weight concentration, irrespective of the inoculum density or the culture medium. The medium choice and the inoculum density determined how rapidly fresh weight was accumulated and thus, how quickly ajmalicine was produced. Ajmalicine production correlated positively with fresh‐weight concentration, but catharanthine production was not correlated with fresh‐weight concentration. © 2000 John Wiley & Sons, Inc. Biotechnol Bioeng 67: 61–71, 2000.