George Oluoch

Pan African University, Nigeria

Title: Nanoencapsulation of Thymol with Chitosan Nanoparticles and the Effect against Ralstonia solanacearum

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Biography

George Oluoch is a Molecular Biologist at Pan African University based in Nairobi, Kenya.  He holds a PhD in Molecular Biology and Biotechnology from Pan African University, Institute for Basic Sciences, Technology and Innovation (PAUSTI), and a master’s degree from the Graduate School of Chinese Academy of Agricultural Science based in Beijing, China. His current research focus is on the application of nanotechnology in agricultural biotechnology. 

Abstract

Essential oils (EOs) are natural bioactive compounds with antibacterial activity against a variety of microorganisms including phytopathogens. The use of EOs and their components as viable therapeutic antibacterials is however greatly compromised by their volatile nature, hydrophobicity, and instability when exposed to environmental and physiological factors. Encapsulation of these compounds in an appropriate carrier system can alleviate these challenges. This study therefore aimed at developing, characterizing, and evaluating the efficacy of the antibacterial potential of thymol-loaded chitosan nanoparticles (TCNPs) against Ralstonia solanacearum, the bacterial wilt-causing pathogen in potatoes. Synthesis of TCNP was achieved via the ionic gelation method and the prepared nanoparticles were characterized by their particle size distributions, encapsulation efficiency, loading capacity (LC), and in-vitro release characteristics.

Antibacterial activities of the nanoparticles were investigated using agar dilution and colony counting methods and their minimum inhibitory concentration (MIC) was determined by the 96-well broth micro-dilution method. Scanning electron microscope images of TCNPs showed that the nanoparticles were spherical in shape and were well separated with an average particle size of 590 nm. The encapsulation efficiency was 72.9% with an LC of 48.3%. The growth inhibition of R. solanacearum was 92% and 94% for TCNP and ECNPs respectively. The MIC of thymol before encapsulation was 175 µg/ml, but this reduced significantly to 22.5 µg/ml after encapsulation. Thus, encapsulation of thymol in chitosan nanoparticles has shown promising potential as a bactericide alternative for R. solanacearum and could be useful in managing the soil-borne phytopathogen.