Evaluation of a laboratory scale conventional shake flask and a bioreactor on cell growth and regeneration of banana cell suspension cultures

• First report on comparison between banana cell growth in shake flask and bioreactor.
• Cell suspension in bioreactor achieved higher growth rate compared to shake flask.
• Bioreactors with controlled pH conditions significantly supported high specific cell growth rate.
• Stress level of cells in bioreactor did not affect plantlet regeneration.
• Normal regenerants were obtained from shake flasks, pH and non pH controlled bioreactors.

It is important to develop a system to enhance the growth and regeneration of cells with limited totipotency into healthy plantlets. In this study, a semi automated cell suspension culture protocol for Musa acuminata cv. Berangan using bioreactor has been established. After eight months of culture, embryogenic calli generated from male inflorescences were transferred to liquid medium. Cell suspension cultures showed better cell growth when cultured in the M2 modified liquid medium containing 2% (w/v) sucrose with an initial inoculum density of 1:50 (cells:medium). The yield of cell suspension cultures was increased to 165% and 210%, respectively, when inoculated in 5 l balloon type bubble column bioreactors (BTBCBs) without pH control and with pH maintained at 5.7, over 14 days of culture. It was also shown that the growth yield was 3-fold higher when cultured in pH-controlled BTBCB, followed by 2.5-fold in uncontrolled-pH BTBCB and 2.2-fold in shake flask culture in comparison to initial culture (day 1). In all growth vessels tested, catalase (CAT) activity was found to be correlated with hydrogen peroxide (H2O2) concentration, suggesting its effective scavenging activity, whereas no significant difference was observed for superoxide dismutase (SOD). More than 60% of the embryos started to form shoots after 2 weeks of culture on M4 medium for all growth vessels tested. Potentially, this protocol may help in mass producing disease-free and high yielding banana as it provides a comparable cell growth rate producing normal regenerants in comparison to the conventional shake flask cultures.