Bioreactor for cultivation of red beet hairy roots and in situ recovery of primary and secondary metabolites

Abstract

To arrive at an appropriate bioreactor design and in situ recovery of the products, red beet hairy roots were used as a model system where the levels of betalain pigments (betacyanins and betaxanthins) were followed as secondary metabolite and the peroxidase enzyme as primary metabolite. Medium volume and other kinetic parameters were found to play significant roles by way of directly affecting the biomass yield rather than a specific metabolite. The hydrodynamic stress created on the roots by large culture volume could be minimized by pulse‐feeding of medium in shake‐flasks; and by separating the biomass chamber from the aerated medium reservoir in circulatory fed‐batch bioreactor. Accordingly the bioreactor was modified to provide anchorage and air‐enrichment chamber which resulted in higher formation of both the metabolites than in shake‐flasks. Various down‐stream processing aspects such as in situ release of pigments by non‐destructive methods, followed by adsorption through a column and recovery by desorption were optimized for betalains. A strategy for simultaneous recovery of pigment and peroxidase was worked out using aqueous two phase extraction (ATPE).

Betalains in Some Species of the Amaranthaceae Family: A Review

“…However, the yield production is generally low and almost always needing bioreactor systems for improving large scale production [ 35 ]. Some examples include the production of betalains by hairy root cultures, cell suspension and callus culture of beetroot [ 39 , 40 , 41 , 42 , 43 , 44 , 45 , 46 ]. Generally, in these works, the authors used methods and studied factors that could improve the production or recovery of betalains by cell cultures of Beta vulgaris (radiation, light, utilization of adsorbents, changes in the composition of the culture medium, alterations of the bioreactors, among other factors).…”

“…Several factors have been evaluated (some constituents of culture media, light, pH, type and inoculum cultures, utilization of adsorbents) in order to enhance the production of betalains by Beta tissue cultures [ 40 , 44 ], particularly hairy roots [ 39 , 41 , 42 , 43 , 45 , 139 , 140 , 141 , 142 ].…”

Antioxidant Activity and Phenolic Content of Betalain Extracts from Intact Plants and Hairy Root Cultures of the Red Beetroot Beta vulgaris cv. Detroit Dark Red

“…Detroit Dark Red have considerable potential for producing betalain pigments with high antioxidant activities [15,16]. The successful cultivation of hairy roots in shake flasks and several types of bioreactors demonstrated the potential for developing suitable large-scale biotechnological systems for betalain production [17][18][19][20]. However, the in vitro cultivation of plant cells could significantly change their metabolic profiles as a result of stresses that they are exposed to under in vitro conditions.…”

Techno-commercial Aspects of Relevance to Red Beet

“…Ever since hairy roots were reported, red beet was again the material of choice for research (Taya et al 1992(Taya et al , 1994Thimmaraju et al 2003aThimmaraju et al , b, 2004 . Later Pavlov et al ( 2005aPavlov et al ( , b , 2007, Neelwarne and Thimmaraju ( 2009 ) and Suresh et al 2004 ) made substantial contributions towards product formation and down-stream recovery of the betalains, substantiating the commercial feasibility of such processes. As an inherent regulatory mechanism, biosynthesis and accumulation of different secondary metabolites are strictly regulated in plant cells, where, after reaching a speci fi c level, no further synthesis and accumulation of the metabolite occurs.…”