Isolation and Characterisation of Actinomycetes in the Rhizosfer Pandanus ammaryllifolius Plants in Gorontalo

Actinomycetes are a group of gram-positive bacteria known to have high bioactivity, including the potential to produce antibiotics and other bioactive compounds. These microorganisms have cosmopolitan nature and adaptability in various soil habitats indicating that they can be found and adapt well in various types of soil. This study aims to isolate and characterise Actinomycetes bacteria from the rhizosphere of Pandanus ammaryllifolius plants in Gorontalo. The rhizosphere, which is the soil segment around plant roots, is rich in microorganisms that play an important role in nutrient cycling and ecosystem health. Sampling was conducted in two locations, namely the plantations of Pahu Village, Asparaga District, and Bone Bolango, Tilongkabila District. Isolation results using the spread plate method on Starch Casein Agar (SCA) media, showed the presence of Actinomycetes obtained 9 isolates of Actinomycetes. The highest number of isolates was found in the Bone Bolango plantation location, which was 6 isolates. Meanwhile, 3 other isolates were found in Pahu Village. Environmental conditions at the Pahu Village site had a pH of 4.4 and humidity of 5.7%, while the soil at the Bone Bolango plantation site had a pH of 7.9 and humidity of 6.8%. Morphological characterisation results showed variations in colony shape, size and colour. Actinomycetes isolates obtained were small with irregular and circular colony shapes. The colour of the colony substrate mycelium was dominated by yellow, orange, white, blackish yellow, and greyish white. The Morphological characteristics found in this isolate indicated three potential groups of Actinomycetes: Streptomyces, Micromonospora, and Micrococcus. All isolates were found to be Gram positive.