Aktivitas Biosurfaktan Isolat Bacillus sp. galur LP04 dan Potensinya sebagai Anticendawan terhadap Ganoderma boninense

Abstract

Biosurfaktan adalah salah satu kelas dari molekul amfipatik yang dapat diproduksi oleh berbagai mikroorganisme. Biosurfaktan dimanfaatkan sebagai biopestisida dan agens biokontrol, karena memiliki aktivitas antimikrob khususnya sebagai agens anticendawan pada beberapa spesies cendawan patogen seperti Ganoderma boninense yang menyerang tanaman kelapa sawit. Penelitian ini bertujuan mendeteksi aktivitas biosurfaktan dari isolat Bacillus sp. galur LP04 dan potensinya sebagai agens anticendawan terhadap cendawan Ganoderma boninense. Biosurfaktan diproduksi pada media mineral salt medium (MSM) dengan cara memanen supernatan bebas sel. Penapisan isolat penghasil biosurfaktan dilakukan dengan uji oil spreading assay, hemolysis assay, dan indeks emulsifikasi. Aktivitas anticendawan isolat kemudian diuji dengan metode agar diffusion. Isolat Bacillus sp. galur LP04 merupakan bakteri Gram positif yang berpotensi memiliki aktivitas biosurfaktan yang dicirikan dengan hasil positif pada uji oil spreading assay, dan memiliki indeks emulsifikasi 48.33 ± 2.87%. Isolat bakteri ini dapat menghambat pertumbuhan cendawan Ganoderma boninense dengan persentase penghambatan sebesar 51.11%.

Biosurfactants are a class of amphipathic molecules that can be produced by various microorganisms. Biosurfactants are used as biopesticides and biocontrol agents, because they have antimicrobial activity, especially as antifungal agents in several species of fungal pathogens such as Ganoderma boninense that attack the palm oil trees. This study aims to detect the biosurfactant activity of Bacillus sp. strain LP04 and its potential as antifungal agent against the fungi Ganoderma boninense. Biosurfactants were produced in mineral salt medium (MSM) by harvesting cell-free supernatants. Screening of biosurfactant-producing isolates was carried out by oil spreading assay, hemolysis assay, and emulsification index. The antifungal activity of the isolates was then tested by the agar diffusion method. Bacillus sp. strain LP04 is a Gram-positive bacterium that has the potential to have biosurfactant activity which is characterized by a positive result on the oil spreading assay test, and has an emulsification index of 48.33 ± 2.87%. This bacterial isolate was able to inhibit the growth of Ganoderma boninense with the growth inhibition rate of 51.11%.