Natural biowaste of banana peel-derived porous carbon for in-vitro antibacterial activity toward Escherichia coli

Abstract

Banana peel-derived porous carbon from natural biowaste had been prepared with different annealing temperatures at 300, 400, 500, 600, and 700 °C. The as-prepared carbon powders were carefully characterized with XRD, SEM, TEM, EIS, and XPS measurements and their antibacterial activities were tested toward Escherichia coli (E. coli - ATCC 25922). It was found that 600 °C as-prepared porous carbon exhibited the most significant inhibitor against E. coli colonies’ growth. It was found that the natural potassium chloride in the banana peel-derived porous carbon played an essential role in preventing the bacterial growth. Furthermore, the as-prepared nanosized porous carbon also directly contacted the bacterial cell wall, which seriously affected the cellular activities, including the metabolic processes and transfer of substances in the cell interfaces. Therefore, the synergistic effect between natural potassium chloride and porous carbon gave rise to antimicrobial activity. The generated electron and hole from low thermal-induced excitation in porous carbon and released electron from potassium significantly deactivated the bacteria activity. The bactericides of banana peel-derived porous carbon were investigated at 37 °C without light illumination and the mechanism of antibacterial growth was elucidated and proposed in this work.

Keywords

• Banana peel
• Porous carbon
• E. coli
• ATCC 25922
• Potassium chloride