Immobilization Parameters Statistically Optimized for Whole Cells of Pseudomonas putida G7 to Enhance Limonin Biotransformation

This study was aimed for optimizing the immobilization parameters for Pseudomonas putida G7 in Ca-alginate beads, in order to establish a debittering strategy for citrus juices, by biotransforming the bitter principle - Limonin. Response Surface Methodology (RSM) with Central Composite Design (CCD) was employed to model the significant parameters for an enhanced response. An enhanced limonin bioconversion and immobilized bead stability was obtained with alginate concentration (2%), cell load (47.2g/l), and a bead diameter (2.1mm); which had significant effects (p <0.001) on limonin biotransformation. The R2 values of 0.9 showed good agreement between experimental and predicted response. Validation experiments under optimized parameters showed good association between experimental (limonin biotransformation and stability response of 65.8% and 0.97 OD respectively) and predicted responses (limonin biotransformation and stability of 65.1% and 0.094 respectively). Thus, the approach is promising to develop a strategy for debittering citrus juices by biotransforming limonin at a faster rate.