Optimization of cultural conditions affecting improved bioactive metabolite production by endophytic fungus Trichoderma harzianum

Abstract

The present study aimed to optimize cultural conditions for optimum bioactive metabolite production by endophytic fungus Trichoderma harzianum, isolated by surface sterilization method from the leaf of the eucalyptus plant. The fungus was identified based on morphological characterization. Fungal metabolites were carried out by ethyl acetate solvent. The antibacterial activity was tested against Escherichia coli (ATCC 25922) and Staphylococcus aureus (NCTC 6571). Various carbon, nitrogen sources, pH, temperature, incubation period, and NaCl on the antibacterial metabolite production were studied. Bioactive metabolite production of T. harzianum exhibits a broad spectrum of in vitro antibacterial activity against two strains of bacteria. For the optimum production of bioactive metabolites, Dextrose and Glucose were found to be the best sources of carbon and the best sources of Nitrogen Yeast extract (YE) and (NH4)2SO. The maximum production of bioactive metabolites occurs at pH 7 and 25°C.; the NaCl showed a positive influence on bioactive metabolites.

Optimization of culture conditions for the production, antifungal activity and characterization of secondary metabolites of <i>Trichoderma longibrachiatum</i>

“…The pH, precursors, and incubation time are a few more variables that can affect the formation of bioactive molecules. A large number of microorganisms can produce pH-based secondary metabolites in the range of 5.5 and 8.5 (Thongwai & Kunopakarn, 2007;Hateet et al, 2021). Our study results showed that media supplemented with optimized pH, carbon and nitrogen sources with sodium nitrate showed the maximum antifungal activity by producing secondary metabolites.…”

“…Simple carbohydrates like glucose and dextrose alter metabolic pathways that produce intermediates that produce primary and secondary metabolites in addition to CO 2 , water, and energy. (Hateet et al, 2021). However, initiatives have begun to manipulate dietary components to encourage the microorganism's production of secondary metabolites.…”

“…The medium was then inoculated and cultured for 7 days at 28±2°C. Following incubation, the biomass was recorded as mg/100ml and studied antifungal activity of the culture filtrate containing secondary metabolites (Hateet et al, 2021;Shuwu et al, 2020).…”

“…The optimum concentration of the screened carbon (Glucose and Sucrose) and nitrogen sources (Beef extract and Peptone) was studied in the basal medium as Minimal Davis broth with concentrations of 0.5%, 1.0%, 1.5% and 2.0% respectively. Following incubation, the biomass was recorded as mg/100ml and studied antifungal activity of the culture filtrate containing secondary metabolites (Hateet et al, 2021).…”

“…The optimum incubation duration was also determined with the screened concentrations of C and N sources incorporated in the basal medium as Minimal Davis broth with optimized pH for different days i.e., 3, 5, 7, 9, 12, 15 and 18 days, respectively. Following incubation, studied antifungal activity of the culture filtrate containing secondary metabolites (Hateet et al, 2021;Shuwu et al, 2020;Choez-Guaranda et al, 2023)…”