Studies on the potential use of sugarcane bagasse as carrier matrix for immobilization of Candida tropicalis PHB5 for phenol biodegradation

•Candida tropicalis was immobilized into sugarcane bagasse used as carrier matrix.•Effect of physical parameters on phenol removal by immobilized cells was evaluated.•Effect of matrix particle size on phenol removal was evaluated.•Comparative study of phenol removal kinetics by alginate and SCB immobilized cells.•Repeated batch phenol degradation by SCB immobilized cells was possible.

Sugarcane bagasse (SCB) as cheap, abundant, alternative cell immobilization matrix for phenol biodegradation was investigated in the present study. Scanning electron microscopy revealed that yeast Candida tropicalis PHB5 attached to the cavum of stalk cells of SCB efficiently through adsorption and maximum value of immobilization efficiency and cell retention were 87.74% ± 2.42 and 368384 ± 10195.96 cfu g−1 SCB, respectively. In order to assess the degradation efficacy of SCB immobilized cells, kinetics of phenol degradation was compared for free as well as alginate and SCB immobilized cells. The maximum specific degradation rates were 9.599, 1.665, and 2.481 g g−1 h−1 for free cells, alginate and SCB immobilized cells, respectively. The effective diffusivity and diffusion effectiveness factor of phenol in immobilization matrices were calculated for different sizes of matrix particles. The results showed that intraparticle diffusion resistance was comparatively less for SCB particle. Studies revealed that 23.45% of SCB immobilized cells can be effectively retained during storage at 4 °C up to 30 days and can be reused for 4–5 repeated batch degradation, giving almost similar results found with alginate immobilized cells. The foregoing results justify the applicability of SCB as carrier matrix for immobilization of microorganisms in removal of phenolic compounds from industrial wastewaters.