Lateral root bridging as a strategy to enhance <scp>L</scp>‐DOPA production in <i>Stizolobium hassjoo</i> hairy root cultures by using a mesh hindrance mist trickling bioreactor

Abstract

Abstract Stizolobium hassjoo hairy roots exhibited a lateral root bridging behavior, enabling not only root dry weight but enhancement of intracellular L ‐DOPA content. When a single root tip was exerted a proper hindrance, the primary root growth was inhibited while lateral roots were profusely induced. The hindrance‐induced lateral roots from individual primary root could bridge together under appropriate inoculation densities, leading to high density hairy root cultures producing secondary metabolites. In the present paper, a novel bioreactor was proposed based on a strategy of lateral root bridging by utilizing mesh as a hindrance, called “mesh hindrance mist trickling bioreactor (MHMTB)”. Significant improvements of dry weight and L ‐DOPA production by using MHMTB were 1.8 and 2.2‐folds, respectively, higher than those in the control run without the mesh hindrance within the root bed. © 2005 Wiley Periodicals, Inc.