Enhanced anthocyanin production by repeated-batch culture of strawberry cells with medium shift

Abstract

Repeated-batch cultures of strawberry cells (Fragaria ananassa cv. Shikinari) subjected to four medium-shift procedures (constant LS medium, constant B5 medium, alternation between LS and B5 starting from LS and alternation between LS and B5 starting from B5) were investigated for the enhanced anthocyanin productivity. To determine the optimum period for repeated batch cultures, two medium-shift periods of 9 and 14 days were studied, which represent the end of the exponential growth phase and the stationary phase. By comparison with the corresponding batch cultures, higher anthocyanin productivity was achieved for all the repeated-batch cultures at a 9-day medium-shift period. The average anthocyanin productivity was enhanced 1.7-and 1.76-fold by repeated-batch cultures in constant LS and constant B5 medium at a 9-day shift period for 45 days, respectively. No further improvement was observed when the medium was alternated between LS (the growth medium) and B5 (the production medium). Anthocyanin production was unstable at a 14-day shift period regardless of the medium-shift procedures. The results show that it is feasible to improve anthocyanin production by a repeated-batch culture of strawberry cells. IntroductionA large number of research reports and patent applications have been published to consider plant cell cultures of various species as potential commercial sources of anthocyanins (Cormier et al. 1996). However, to date, no patent application has dealt with a true commercial process. The major hindrances to commercialization are slow growth, low product concentration, and low productivity in plant cell cultures. To circumvent these problems, several methods have been proposed, e.g., genetic manipulation and clonal selection (Nozue et al. 1987;Payne et al. 1991), optimization of culture conditions (Drapeau et al. 1986;Mori and Sakurai 1994;Pepin et al. 1995;Sato et al. 1996;Zhang et al. 1997), and process system (Zhang et al. 1999). The optimization of process system is easy to manipulate, and sometimes a significant improvement can be expected. Unfortunately, the insights regarding this issue have not yet been demonstrated properly for anthocyanin production by plant cell cultures.Plant cells have been grown in batch, fed-batch and continuous cultures and have been maintained in a viable state for extended periods of time in a variety of suspension and immobilized systems (Tal and Goldberg 1982; Dougall et al. 1983;Alfermann et al. 1985;Reinhard et al. 1989). Strawberry cell suspension culture has become established for the production of anthocyanin and batch mode was adopted for all these cultures (Hong et al. 1989;Mori et al. 1993;Sato et al. 1996;Zhang et al. 1997Zhang et al. , 1998Zhang et al. , 1999. It seems a favorable and necessary undertaking to explore process optimization to enhance anthocyanin productivity in strawberry cell culture.The present study investigated the feasibility of carrying out a repeated-batch culture mode with medium shift to avoid the downtime required for the ...

Investigation of vinegar production using a novel shaken repeated batch culture system

“…In previous studies of repeated batch fermentations other than vinegar production, medium exchange was often scheduled in a time‐dependent manner, disregarding the state of the individual microbial culture, and sometimes even lacking an online control . In such cases, it is not certain if the best time point for the medium exchange is met.…”

“…If the exchange took place too late, the productivity would be underestimated and microbial activity might already have begun to decline. Zhang et al demonstrated this problem for the anthocyanin production by strawberry cells. If the medium exchange takes place too early, maximum productivity or product concentration may not be achieved.…”

“…If this point is missed and ethanol is exhausted, the acetic acid bacteria would die In previous studies of repeated batch fermentations other than vinegar production, medium exchange was often scheduled in a time-dependent manner, disregarding the state of the individual microbial culture, and sometimes even lacking an online control. [27][28][29][30][31][32] In such cases, it is not certain if the best time point for the medium exchange is met. If the exchange took place too late, the productivity would be underestimated and microbial activity might already have begun to decline.…”