The remarkable properties of humic acids have generated a broad spectrum of applications in pharmaceutical, cosmetic and agricultural fields, and encouraged fermentation studies focusing on humic acids production. This work compares the humic acids production of Trichoderma (viride and reesei) species using empty fruit bunch as the substrate during submerged fermentation. The performance of each species was compared by examining spore production in oat medium, and the significant medium components and fermentation conditions were identified using Plackett and Burman statistical design. For both Trichoderma species, the results indicate that humic acids production can be enhanced by increasing the temperature, empty fruit bunch and peptone concentrations and by decreasing the (NH4)2SO4 concentration. T. reesei performed better than T. viride, generating 3-fold more of humic acids.
Key words: Humic acids, Trichoderma reesei, Trichoderm aviride, submerged fermentation, empty fruit bunch.