Diversity of Organic Acid-Producing Filamentous Fungi Isolated From Agricultural Soils of North Gondar, Ethiopia.

Introduction: Filamentous fungi are crucial for the production of commercial enzymes, organic acids, antibiotics, and many other organic compounds. Citric, acetic, and gluconic acids are among the organic acids that are produced from fungi and have many functions. They are mostly used as a chemical reagent, fungicide, herbicide, microbicide, pH adjuster, counterirritant, and solvent in a variety of industries, including food, agriculture, cleaning, and cosmetics. Objectives: This study aimed to study the diversity of selected organic acids (citric, acetic, and gluconic acids) produced by filamentous fungi isolated from the agricultural soils of North Gondar, Ethiopia. Methods: In this study, a total of 36 soil samples were randomly collected from agricultural fields at different locations in North Gondar, Ethiopia. The isolates were identified to the genus and species level based on morphological study and sequencing methods (ITS1-5·8S-ITS2 region). Their distribution was evaluated with respect to different agroecologies (climate conditions). The organic acid production capacity of the isolates was evaluated. Results: Based on the results of morphological characteristics and ITS1-5·8S-ITS2 region gene sequencing, 12 filamentous fungi were obtained. All 12 filamentous fungal isolates had one common ancestor and belonged to Aspergillus terreus (KIA, KIC, KID, and KIG), Aspergillus nidulans (KIB), Aspergillus niger (KIF), Penicillium chrysogenum (KIH), Penicillium brevicompactum (KII), Talaromyces pinophilus (KIJ), Penicillium kongii (KIK), Penicillium paraherquei (KIL), and Talaromyces sp. (KIM). Among these, three of them, namely, KIA, KIH, and KIF, were found to be the best producers of acetic acid, citric acid, and gluconic acid, respectively. Conclusion: Organic acid-producing filamentous fungi could be isolated from varied agroecologies.