Articles
Effect of oxygen transfer rate in stirred tank and air-lift bioreactors for Theobroma cacao cell culture
Article number
1359_34
Pages
261 – 268
Language
English
Abstract
Plant cell cultures for metabolite production have been performed in stirred tank bioreactor (STB) and air-lift bioreactor (AB). However, to optimize plant cell cultures and evaluate their perspectives for scale-up it is necessary to study the effect of the oxygen transfer rate (OTR) as a function of the volumetric oxygen transfer coefficient (kLa). The aim of this work was to evaluate the effect of the kLa in 7.5L STB and AB of Theobroma cacao cell cultures for polyphenol production.
For this purpose, four empirical models of kLa for different impeller-gas sparger configurations were obtained in STB. The results evidenced that pitched-blademicrobubbles (PB-Mi) configuration reached kLa values from 17.92 to 53.89 h‑1. On the other hand, pitched blade perforated ring (PB-PR) configuration reached kLa values from 2.41 to 32.18 h‑1. In the AB, two empirical models of kLa for two types of gas spargers were obtained.
The results showed that the stainless-steel mesh reached kLa values between 7.16 to 31.36 h‑1. An optimal kLa value of 27.13±0.25 h‑1 in STB for T. cacao cell culture a volumetric productivity of 0.835±0.034 g L‑1 day‑1 and a cell viability of 79.2±3.0% after 14 days of culture.
Additionally, the total polyphenol content (TPC) was 34.193±2.739 mg GAE g‑1, in which the content of (+)-catechin and (-)-epicatechin was 0.55±0.07 and 3.23±0.44 mg g‑1, respectively.
For AB the optimal kLa value was 28.38±1.15 h‑1 with a low volumetric productivity of 0.351±0.007 g L‑1 day‑1, a cell viability of 55.0±4.2% after 14 days of culture, and a low TPC.
For this purpose, four empirical models of kLa for different impeller-gas sparger configurations were obtained in STB. The results evidenced that pitched-blademicrobubbles (PB-Mi) configuration reached kLa values from 17.92 to 53.89 h‑1. On the other hand, pitched blade perforated ring (PB-PR) configuration reached kLa values from 2.41 to 32.18 h‑1. In the AB, two empirical models of kLa for two types of gas spargers were obtained.
The results showed that the stainless-steel mesh reached kLa values between 7.16 to 31.36 h‑1. An optimal kLa value of 27.13±0.25 h‑1 in STB for T. cacao cell culture a volumetric productivity of 0.835±0.034 g L‑1 day‑1 and a cell viability of 79.2±3.0% after 14 days of culture.
Additionally, the total polyphenol content (TPC) was 34.193±2.739 mg GAE g‑1, in which the content of (+)-catechin and (-)-epicatechin was 0.55±0.07 and 3.23±0.44 mg g‑1, respectively.
For AB the optimal kLa value was 28.38±1.15 h‑1 with a low volumetric productivity of 0.351±0.007 g L‑1 day‑1, a cell viability of 55.0±4.2% after 14 days of culture, and a low TPC.
Authors
L.F. Rojas, M.I. Restrepo, E. Acosta, L. Atehortúa
Keywords
cell suspension cultures, pitched blade, kLa, microbubble gas sparger, Theobroma cacao
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