Polyscias filicifolia cell suspension culture enriched in triterpene glycosides: Growth parameters and target metabolite profile comparison of long-term in flasks batch culture and in a semi-continuous mode in bioreactor.

The modern pharma, food and other industries related to serving human needs are constantly demanding for biologically active substances (BAS) of plant origin. Plant cell suspension cultures (CSCs) have long been considered a replacement for depleting traditional BAS sources-wild, cultivated, and agricultural plants-and hold great promise for biotechnological applications. In particular, Polyscias filicifolia plants, which are valuable sources of oleanane-type glycosides with a promising spectrum of pharmacological activity, should be considered as starting material for the establishment of CSCs. There are limited data on long-term cultivation of Polyscias spp. cell cultures and no data on long-term cultivation of P. filicifolia cell cultures with high productivity of oleanane glycosides. This study presents the research of unique seven-year-old CSC of P. filicifolia, namely the Pf-SH strain. The Pf-SH strain was capable of synthesizing a wide range of oleanane glycosides, and their maximum total content (21.4mg/g DW) was higher than that in whole plant leaves (13.5mg/g DW). The oleanane glycoside profiles in P. filicifolia leaves and Pf-SH cells were radically different, with a significant predominance of more glycosylated forms (e.g., polyscioside E) in Pf-SH cells. During five years of Pf-SH cells cultivation in flasks, they retained the ability to synthesize eleven oleanane glycosides, and their ratio remained fairly stable. Changes in the content of glycosides and growth parameters of Pf-SH cells were detected during a 372-day semi-continuous cultivation in a bubble-type bioreactor. The optimal strategy for bioreactor cultivation for maximum accumulation of cellular biomass and target BAS is discussed.