Synthesis of fluorescent citric acid carbon dots composites derived from empty fruit bunches of palm oil tree and its anti-bacterial property

Abstract

Green luminescent water-soluble citric acid-carbon dots composite were synthesized from empty fruit bunches (EFB) biochar. The hydrothermal method solves the weakness of the difficult size to control and the large energy. The hydrothermal method has the advantages of being easy, environmentally friendly, not requiring large energy, and the particle size is easy to control. The average size of the composites was 4 nm. The resulting belongs to the n-π* transition of carbonyl groups and C–N bonds. Maximum emission peak was observed at 450 nm excitation wavelength with a gradual decrease in intensity from 350 nm to 310 nm. Purple-blue to the blue region when the excitation wavelength is increased from 300 nm to 350 nm due to the presence of citrazinic acid. The addition of carbon dots with citric acid is effective as an antibacterial. The growth rate of any bacteria co-cultured with citric acid derived carbon dots (CDs-CA) dropped significantly as the concentration of CDs-CA increased, meaning that as the concentration increases, there are more chances for CDs-CA to stick to bacterial cell walls and have an effect on them. It can effectively stop bacteria from growing. The %antimicrobial up to 100% and the minimum inhibitory concentration (MIC) is the lowest antibacterial agent concentration that shows the value for E. coli and S. aureus is 60 μg/mL.

Keywords

• Anti-bacterial activity
• Carbon dots
• Empty fruit bunch
• Escherichia coli
• Staphylococcus aureus