CARDILLO Alejandra Beatriz
congresos y reuniones científicas
Combination of strategies for anthraquinone production in hairy root cultures of Rubia tinctorum
Simposio; International PSE Symposium; 2016
Anthraquinones (AQs) are anthracene derivatives produced by Rubia tinctorum (Rubiaceae) traditionally used as dyes in the textile industry. These secondary metabolites also exhibit interesting properties, such as antioxidant, antimicrobial and anticancer in vitro activities. Although they are produced by chemical synthesis, there is a growing interest of developing processes in agreement with green chemistry concepts. Plant in vitro culture emerge as an attractive alternative for producing secondary metabolites since it combines safety, possibility to meet GMP requirements and less production of toxic wastes, and it avoids both the exploitation of the natural source and the use of land that can be destined for food production. Moreover, in vitro cultures allow the application of strategies for enhancing secondary metabolite production, such as permeabilization, in situ removal or elicitation. The aim of this work was to develop a process for AQ production in hairy roots of R. tinctorum by the combination of medium selection, elicitation and in situ removal. Growth and AQ production of hairy roots were evaluated in 100 ml erlenmeyer flasks in Gamborg B5 (half-saline strength; B51/2) and Lloyd and McCown?s Woody Plant Medium (WPM). Although biomass production was higher in WPM than in B51/2, intracellular specific AQ content (ICAQ) was enhanced in B51/2 (11.9 μmol/gFW at 35 days) when compared to WPM (6.4 μmol/gFW). Elicitation was performed in B51/2, since extracellular AQ accumulation (ECAQ) was observed. Addition of 100 μM MeJ to 14-day-old hairy roots resulted in significant increases in the ICAQ (50, 73 and 110% at 2, 4 and 7 days of elicitation, respectively) and the ECAQ (between 27 and 17% of total AQs). Growth and MeJ elicitation of hairy roots was successfully achieved in a 1.2 L stirred-tank bioreactor adapted with a plastic net for root anchoring. Compared to erlenmeyers, similar biomass and ICAQ were found in the bioreactor, but the recovered ECAQ was 42% less, due to adhesion of AQs to plastic and steel parts of the bioreactor. Treatment with both MeJ and Mygliol 814 (for in situ removal) in 100 ml erlenmeyer flasks showed similar total AQ levels than those of MeJ alone, although a higher proportion of ECAQ. Our results represent new evidence of the reported advantages of the combination of strategies for enhancing secondary metabolite production and show the feasibility of adapting a stirred-tank bioreactor for hairy root culture.