Extraction and Characterization of Chitin and Chitosan from Aspergillus niger, Synthesis of Silver-Chitosan Nanocomposites and Evaluation of their Antimicrobial Potential

Abstract

The fungal species such as Aspergillus niger are the rich source of antimicrobial compounds. The chitin which is the cell wall component are being isolated and used as potential source of antimicrobial along with its derivates. In the present study, the chitin and chitosan were purified from the mycelial mat of the A. niger. By using the chitosan isolated from the fungi, the chitosan-silver nanocomposite was synthesized under lab conditions. The comparative antibacterial potential of chitin, chitosan and nanocomposites were screened against Bacillus subtilis and Bacillus cereus, which are infecting mulberry silkworm (Bombyx mori) and humans respectively. The in vitro inhibition study results revealed that, Nanocomposites showed more inhibition of pathogens in comparison with other treatments along with positive control.  Further, the highest antibacterial activity of chitosan-silver nanocomposites may be due to presence of two potential antimicrobial compounds in combination. Based on the results of the present study, chitosan based nanocomposites can be used for the management of the bacterial diseases of silkworm. The nanocomposite derived in the present work can be used for management of medically important pathogens infecting humans.