Transport phenomena of carbazole biodegradation by immobilized Thalasosspira profundimaris cell and mechanical properties

Carbazole is a heterocyclic aromatic compound that imposes threat to the environment when contaminates water source. A marine-isolated bacterium, Thalassospira profundimaris shows ability to degrade carbazole. The use of free-cell for bioremediation is inefficient as the cells are exposed to harsh environmental condition. In this study, immobilizations of T. profundimaris in gellan gum were investigated to develop robust systems for bioremediation. The mechanical strength and its relationship with transport of carbazole was investigated. The findings proved that concentration of immobilization media affects diffusivity and mechanical strength. Higher media concentration formed a stronger bead with lower diffusivity where lower concentration formed soft bead with higher diffusivity. The optimum concentration of gellan gum was 0.7% (w/v) with 61% carbazole degradation recorded and an optimum diffusivity of 36.8 × 10⁻⁷ cm²/s. It has the highest Young’s modulus (0.041810 N/mm²) among other concentrations. The findings of the optimum carbazole degradation, strength and diffusivity were profound to increase the performance of the bacteria entrapped inside the immobilization media for bioremediation and withstand harsh environment.