Modeling of permeabilization process in Pseudomonas putida G7 for enhanced limonin bioconversion

Abstract

A facile process of enhanced whole cell biotransformation to debitter the triterpenoid limonin in citrus juices was optimized in this work. To maximize bioconversion, permeabilization conditions were modeled using response surface methodology. A central composite rotatable design with four significant variables (concentration, temperature, pH, and treatment time) was employed. The second order polynomial equations with R² values above 0.9 showed good correspondence between experimental and predicted values. The concentration, temperature, pH, and treatment time as well as their interactions had significant effects (p < 0.001) on limonin bioconversion. The optimum operating conditions for permeabilization were observed at a Na₂EDTA concentration of 1.5 μM, treatment time of 15 min, temperature of 28 °C, and pH 8. A maximum reduction of 76.71% in the limonin content was achieved within 150 min under selected conditions. The results are promising for refining permeabilization technique for whole cell biocatalysts thereby improving the debittering of citrus juices significantly.

Whole cell bioconversion of (+)‐valencene to (+)‐nootkatone by Yarrowia lipolytica using a three phase partitioning bioreactor

“…Two types of experiments were considered to enhance bioconversion and bioselectivity of the desired product. On one hand, experiments of cell membrane permeabilization using Triton X‐100 (0.05–1.0% v/v), cetyl trimethylammonium bromide (CTAB) (0.1–0.4% w/v), and by sonication (0.25–1.5 h) were conducted in 250 mL Erlenmeyer flasks. On the other hand, experiments for cofactor NADPH regeneration adding glycerol (0.05–1.0% v/v) and vitamin B 3 niacin (0.5–10 mmol L −1 ) were conducted in Erlenmeyer flasks.…”

Solubilization capacity of nonionic surfactant micelles exhibiting strong influence on export of intracellular pigments in Monascus fermentation

“…Even cell surface display is developed to direct synthesis of microbial product on the outside of cell membrane (Sun et al ., ). Chemical treatments of microbial cells, such as incubation in organic solvent (Kondo et al ., ), nonionic surfactant micelle aqueous solution (Malik et al ., ) etc., have also been applied to release intracellular product.…”

Improving the catalytic performance of Pichia pastoris whole-cell biocatalysts by fermentation process

“… 20 One of the main limiting factors is transport-limited caused by cell walls and cytomembranes. 21 Generally, there are three main strategies to improve the permeability of whole-cell biocatalysts reliving the limitation of transport: (i) adding permeabilizing reagent, such as surfactant, 22,23 organic solvent, 24 chelating agent, 25 and other similar agents. 26,27 (ii) Physical processing, such as ultrasonic treatment, 28 osmotic pressure, 29 etc .…”