Growth and pigment production by hairy root cultures of Beta vulgaris L. in a bubble column reactor

Beet hairy root cultures established from red and yellow varieties were grown in a 2 L bubble column reactor. The yellow clone showed profuse root hairs and a predominance of betaxanthin pigment while the red clone showed fewer root hairs and both betaxanthin and betacyanin pigments. The cultures displayed different ionic and sugar yields: 2.1 mg dry wt / mS.mL and 0.361 g dry wt / g sugar for the yellow clone and 2.3 mg dry wt / mS.mL and 0.375 g dry wt / g sugar for the red one. Both cultures grew at the same specific growth rate of 0.22 d(-1) in the bubble column, as compared to 0.32 d(-1) in shake flasks, indicating mass transfer limitations for growth in reactors.