BIOFILM INHIBITORY EFFECT OF CHLORELLA EXTRACTS ON PSEUDOMONAS AERUGINOSAAbstract
Background: Biofilm is a layer like aggregates of bacterial cells which are formed on biotic and abiotic surfaces. Pseudomonas aeruginosa plays an essential role in the aggregation of bacteria on biofilm formation. Quorum sensing and extracellular polysaccharide play a vital role in the biofilm formation in P. aeruginosa. The present study was aimed to investigate the anti-biofilm effect of lyophilized extracts of Chlorella. Materials and Methods: The lyophilized aqueous and ethanolic extracts of Chlorella were screened for anti-biofilm activity by MTT assay; microdilution and antibacterial activity were assessed by disc diffusion assay. GC-MS were used to determine the bioactive compound. Results: The lyophilized ethanolic extract of Chlorella showed concentration-dependent inhibition of up to 85% in biofilm, from a concentration of 2 mg/ml to 500 µg/ml by MTT assay. The antibiofilm activity of the significant ethanolic extract of chlorella was ascertained through a scanning electron microscope. The anti-bacterial activity showed a moderate to low inhibition around the disc showing no anti-bacterial activity. GC-MS analyses revealed the presence of 8 major compounds in the ethanolic extract of Chlorella. Cytotoxic results revealed that the ethanolic extract was non-toxic from 1000 µg/ml proving Chlorella extracts to be non-toxic at all concentrations. Conclusion: Current study proves that micro-algae like Chlorella have the potential to inhibit the pathogenic activity of P. aeruginosa in biofilm formation by providing a novel alternative to the conventional anti-microbial agents.
K. V. Gayatri, C. Soundhari * and B. P. Pavithra
Department of Microbiology, Valliammal College for Women, Chennai, Tamil Nadu, India.
08 August 2018
09 October 2018
10 October 2018
01 April 2019