Isolation of Soil Fungi from Laem Phak Bia Salt Pans and Evaluation of Their Antimicrobial and Enzymatic Activities

Abstract

Laem Phak Bia is located at the coastal estuary where the salt pans are considered as an extreme environment. Fungi that thrive in extreme environments could produce extremolytes and extremozymes due to the harsh conditions. Research on soil fungi needs to be updated regularly, as soil fungal communities may be vulnerable to global changes. This study aims to isolate and identify the diversity of Laem Phak Bia salt pans soil fungi and assess their antagonistic properties against phytopathogenic fungi, as well as their antibacterial and enzymatic activities. Nine fungal isolates were collected from Laem Phak Bia salt pan soil, classified into 5 genera such as Aspergillus, Aureobasidium, Stachybotrys, Curvularia, and Acremonium. All isolates were tested for antagonistic properties against three plant pathogens such as Phytophthora palmivora, Colletotrichum sp., and Curvularia sp. Isolate 1A, belonging to the genus Aspergillus, exhibited the best growth inhibitory activity. Additionally, the culture broth supernatant of all isolates underwent preliminary antibacterial testing against several bacteria, including Staphylococcus aureus, S. epidermidis, Escherichia coli, and Bacillus subtilis, with isolate 1A showing the broader inhibition. The isolates were also screened for enzymatic activity, showing some are positive on producing amylase and lignin peroxidase.

Laem Phak Bia terletak di muara pesisir yang mana tambak garamnya dianggap sebagai lingkungan ekstrem. Cendawan yang tumbuh di lingkungan ekstrem dapat menghasilkan extremolyte dan ekstremozim karena kondisinya yang keras. Penelitian tentang cendawan tanah perlu diperbarui secara berkala, karena komunitas cendawan tanah mungkin rentan terhadap perubahan global. Studi ini bertujuan untuk mengisolasi dan mengidentifikasi keragaman cendawan tanah pada tambak garam di Laem Phak Bia serta melihat sifat antagonisnya terhadap cendawan patogen tumbuhan, serta aktivitas antibakteri dan enzimatiknya. Sembilan isolat cendawan dikumpulkan dari tanah yang berasa, dari tambak garam Laem Phak Bia, diklasifikasikan ke dalam 5 genus yakni Aspergillus, Aureobasidium, Stachybotrys, Curvularia, dan Acremonium. Semua isolat diuji untuk sifat antagonisnya terhadap tiga cendawan patogen tanaman seperti Phytophthora palmivora, Colletotrichum sp., dan Curvularia sp. Isolat 1A, yang termasuk ke dalam genus Aspergillus, menunjukkan aktivitas inhibisi pertumbuhan terbaik. Selain itu, supernatan kultur cair dari semua isolat dipakai untuk uji awal sifat antibakterinya terhadap beberapa bakteri, termasuk Staphylococcus aureus, S. epidermidis, Escherichia coli, dan Bacillus subtilis, dengan isolat 1A menunjukkan penghambatan terbaik. Pengujian aktivitas enzimatik pada semua isolat juga dilakukan, dan beberapa di antaranya menunjukkan hasil positif dalam produksi amilase serta lignin peroksidase.