The Enhancement of Biomass Accumulation, Caffeoylquinic Acid Derivative Production, and Antioxidant Activity of Rhaponticum carthamoides Transformed Roots Cultured in a Nutrient Sprinkle Bioreactor

TL;DR

This study shows that using a nutrient sprinkle bioreactor improves biomass and valuable compound production in a rare plant species.

Contribution

The study introduces a new bioreactor system for enhanced production of caffeoylquinic acids in R. carthamoides.

Findings

The NSB bioreactor achieved the highest dry biomass production (20.4-22.2 g/L).

The NSB bioreactor produced the highest CQA levels (544.5 mg/L) and 5-CQA concentration (7.38 mg/g DW).

The NSB bioreactor is a promising alternative to reduce overharvesting of wild R. carthamoides.

Abstract

Rhaponticum carthamoides (Willd.) Iljin. is an endemic plant species found in Siberia, Mongolia, and Kazakhstan. Its roots and rhizomes are used to treat physical fatigue and weakness following illness. The present study examines the scaling up of caffeoylquinic acid (CQA) derivative and flavonoid production in R. carthamoides transformed roots. The transformed roots were grown in shaken Erlenmeyer flasks of varying volumes (0.5–2 L), a temporary immersion system (TIS) (Rita® and PlantForm bioreactors), and a nutrient sprinkle bioreactor (NSB) in Woody Plant medium for 35 days. The highest dry biomass production was achieved in the 0.5 L and 1 L flasks and in the NSB bioreactor, yielding 22.2 to 20.4 g/L—approximately 14 to 23 times the weight of the inoculum. The accumulation of individual specialized metabolites varied depending on the culture system used. The peak amount of CQAs (544.5 mg/L), in terms of the increase in dry weight and metabolite levels, was obtained in the NSB bioreactor. The primary CQAs were chlorogenic acid (5-CQA) and a tri-CQA 1. The highest concentration of 5-CQA (7.38 mg/g DW) was found in the roots cultivated in the NSB bioreactor. In contrast, the tri-CQA 1 dominated in the roots from 2 L shaken Erlenmeyer flasks (8.44 mg/g DW). Our findings demonstrate that transformed roots growing in an NSB bioreactor are an effective system for increasing CQA production, potentially serving as an alternative source. This biotechnological approach could help reduce the overexploitation of field-grown R. carthamoides, a currently threatened species.

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