Mersedeh Mirrezvani Test your strain on other media and test your PDA plates with other fungi.

PDA is one of diagnostic media for T. ressei (Colonies on potato dextrose agar (PDA) grow rapidly and produce a bright yellow, water-soluble pigment in the medium. They tend to form concentric rings of fluffy mycelium, one in the center and one along the edge of the plate. Conidia are yellow-green and are more abundant in the center of the colony. The odor of the colonies is barely noticeable.)

Hello,

Trichoderma reesei (formerly known as Trichoderma viride) is a filamentous fungus that is widely used in industrial processes, especially for the production of cellulase enzymes. While Trichoderma species like T. reesei are known for their robust growth on various media, including potato dextrose agar (PDA), there could be several reasons why it may not grow well or at all on a particular medium like PDA:

To address issues related to Trichoderma growth on PDA or other media, it's essential to optimize the culture conditions, including adjusting the pH, supplementing the medium with appropriate nutrients, maintaining aseptic techniques to prevent contamination, and using specific strains known for their robust growth in laboratory settings. Additionally, alternative media formulations or selective media specific for Trichoderma species can be used to promote their growth and isolate pure cultures for research or industrial applications.

PDA is a general media for fungi and ideally, Trichoderma ressei ought to grow on it.

However, some factors can hinder the growth of T.ressei on PDA. They include; Temperature (in respect to sporulation) , chemical composition of the media and contamination.

Additionally, I’ll recommend you try growing the organisms you have on a Trichoderma selective media to confirm if it’s actually a strain of Trichoderma then proceed to confirm it genetically.