A high-rate perfusion bioreactor for plant cells

✍ Scribed by C. De Dobbeleer; M. Cloutier; M. Fouilland; R. Legros; M. Jolicoeur

• Publisher: John Wiley and Sons
• Year: 2006
• Tongue: English
• Weight: 328 KB
• Volume: 95
• Category: Article
• ISSN: 0006-3592
• DOI: 10.1002/bit.21077

✦ Synopsis

A perfusion bioreactor allowing continuous extraction of secondary metabolites was designed and challenged for Eschscholtzia californica plant cell suspensions. Four sedimentation columns mounted inside a 2.5-L bioreactor separated single cells and cell aggregates from the culture medium. Cells were elicited with chitin at day 4 and the liquid medium free of cells and debris was then continuously pumped to the extraction columns containing fluidized XAD-7 resins, and then recirculated back to the cell suspension. A medium upward velocity corresponding to cell sedimentation velocity maintained a stable cell/medium separation front in the columns for sedimented cell volume (SCV) of 90% (70% packed cell volume, PCV). Two perfusion bioreactor cultures of 10 and 14 days were performed. A maximum dilution rate of 20.4/ day was reached from day 4 to day 6, and was then reduced to 5/day at day 9 for 55% SCV. Control cultures were performed without and with free extraction resins into the cell suspension. Perfusion cultures showed similar specific growth rates of 0.24 AE 0.04/day before and after elicitation. However, production level in the perfusion cultures was similar to that from the culture without resins with a maximum of 2.06 mmole/gDW total alkaloids, with 1.54 mmole/gDW in the resins. Cultures with free resins resulted in 30.94 mmole/gDW with 28.4 AE 8.8 mmole/gDW in the resins. Difference in the cells nutritional state from elicitation was identified as a major cause in the production reduction. However, pathway to chelilutine was favored in the continuous extraction culture.