Biodegradation of tetradecane using Acinetobacter venetianus immobilized on bagasse

• Bagasse was used as a carrier to immobilize cells for n-alkane degradation.
• In contrast to free cells, immobilized cells increased tetradecane degradation.
• Bagasse was able to protect the cells from pollution stress.

Immobilized cells present advantages for degrading organic pollutants compared to free suspended cells. However, the immobilization of cells with reference to agricultural waste is still limited. This study investigated using bagasse as a carrier to immobilize Acinetobacter venetianus (A. venetianus) for the degradation of n-alkane. The degradation of alkane based on both adsorption and biodegradation by immobilized A. venetianus was observed, where 93.3%, 77.7% and 24.0% of tetradecane (400 mg L−1) were removed by the immobilized cells, free cells and bagasse after 36 h incubation, respectively. Additionally, alkane (C10–C25) in diesel was effectively degraded by the immobilized cells, of which 800 mg L−1 of alkane was completely degraded after 60 h. Furthermore, results showed: (1) tetradecane served as the optimal carbon source at the concentration of 100 mg L−1; and (2) cells immobilization reached its peak efficiency with the cells-to-bagasse ratio of 0.5 mgcell g−1bagasse. Cells strongly immobilized on bagasse retained a high degradation rate of 77.6% after shaking at 1500 rpm. Bagasse protected the cells from pollution stress including cadmium (Cd(II)) and phenanthrene. After 8 reuse cycles, immobilized cells became more stable and efficient. Bagasse-A. venetianus has potential for future application in remediating diesel contaminants.