Chiang Mai Journal of Science

        Trichoderma harzianum is an important fungi that well known for their ability to produce a wide range of secondary metabolite, antibiotic substance and cell-wall degrading enzyme (CWDE) against phytopathogenic fungi. However, information on the antimicrobial agent in T. harzianum isolate T9 has not been reported. Hence, this research is the first report about antibiotic activity of Trichoderma metabolites against human pathogenic bacteria and enterobacteria. Data for antimicrobial activity were measured at 3 (TS3), 6 (TS6), 9 (TS9), 12 (TS12) and 15 (TS15) days after culture. All culture supernatants from each culture day showed broad-spectrum activity in inhibiting growth of human pathogens and enterobacteria. Especially, inhibiting the growth of Salmonella typhi ATCC5784, this is a human-specific pathogen. Moreover, it was stable to thermal and pronase digestion. Therefore, these culture supernatants were further characterized by thin layer chromatography (TLC), high-performance liquid chromatography (HPLC) and proteomics analysis. The TLC fractions activity shows that their activity was loss when compared with the crude compound. Due to the higher antimicrobial activity of TS3 and TS12, their fractions were chosen for further purification by C₁₈ Reversed-phase HPLC. The results showed that antibacterial activity against Staphylococcus aureus  ATCC25923 of these samples was found only one peak of TS3 (F1) and two peaks of TS12 (F1 and F2). Additionally, proteomics analysis shows that the secreted proteins in log and early late log phase appeared to be a proteases enzyme. From our results, it is likely that T. harzianum isolate T9 against human pathogenic bacteria and enterobacteria with multiple mechanisms including release of antimicrobial agent and CWDE.