Potential biocontrol agent of indigenous Bacillus sp. EG6.4: Molecular identification, larvicidal toxicity, and mechanism of actions

Salamun, Rizky Danang Susetyo, Farah Aisyah Nafidiastri, Rizki Amaliah Zain, Rossy Permata Sari, Almando Geraldi, Fatimah, Ni’matuzahroh

Research output: Contribution to journalArticlepeer-review

2 Citations (Scopus)

Abstract

This research was carried out for molecular identification, as well as the determination and mechanism of action of larvicidal toxicity of Bacillus sp. EG6.4 isolated from breeding sites of Aedes aegypti from Gresik, East Java, Indonesia. Bacillus sp. EG6.4 was a Gram-positive endospore-forming bacteria. Molecular species identification using 16S rRNA gene sequencing showed that isolate had 97.89% similarity with Bacillus mojavensis. The isolate showed larvicidal toxicity against A. aegypti larvae. The lethal concentration 50% (LC50) values at 24 and 48hours exposure were 8.99±1.01 ×107 cells/mL and 8.43±1.01 ×107 cells/mL, respectively, while lethal time 50% (LT50) value was 11.9±1.1 hours. Production of chitinolytic enzymes or biosurfactants, chitinolytic and hemolytic assays were conducted to determine the larvicidal mechanism. As a result, Bacillus sp. EG6.4 showed hemolytic, but not chitinolytic activity, indicating its potency to produce biosurfactants. Transmission Electron Microscopy (TEM) result showed that isolate had oval-shaped endospores located subterminal with massive-shape parasporal inclusions. The detection of srfA-D gene showed that isolate produced surfactin biosynthesis thioesterase. Thus, Bacillus sp. EG6.4 produced biosurfactant that potentially to be developed as a biocontrol agent for disease vectors and plant pathogens.

Original languageEnglish
Pages (from-to)5431-5438
Number of pages8
JournalBiodiversitas
Volume23
Issue number10
DOIs
Publication statusPublished - Oct 2022

Keywords

  • Aedes aegypti
  • Bacillus mojavensis
  • biosurfactants
  • larvicidal toxicity
  • parasporal inclusion
  • srfA-D gene

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