Serratia liquefaciens from IMO: Antibacterial and Chitinolytic Potentials

Abstract

Indigenous microorganisms (IMOs) and effective microorganisms (EMs) have long been used in natural farming as substitutes for conventional fertilizers and pesticides. While the microbial composition of EMs is well-documented, the identity of microbes in IMOs are obscure and may vary depending on the source. In this study, bacteria in IMOs collected from a local community in Bukidnon were identified and screened for antimicrobial and chitinolytic potential. Serratia liquefaciens exhibited antimicrobial potential against the tomato bacterial wilt pathogen Ralstonia solanacearum (Smith). Serratia liquefaciens-impregnated discs inhibited the growth of R. solanacearum with an average annular zone of inhibition radii 5.3 mm, indicating considerable antimicrobial activity. S. liquefaciens was also evaluated for chitinolytic potential using shrimp exoskeletons. Results showed that the chitin mass exposed to S. liquefaciens was significantly reduced compared to the control (n=30, T= -3.04, p-value=0.0043). The results of this study infer that the presence of S. liquefaciens in IMOs may contribute to the inherent potentials of indigenous microorganisms to inhibit microbial pathogens and possible biodegradation activity.