Isolation and Selection of Potential Chitinolytic Bacteria from River Sediments Based on *In Vitro* Inhibition of Meloidogyne spp. Egg Hatching

Abstract

Root-knot nematodes are significant pathogens of cultivated crops capable of causing substantial losses. Chemical pesticide control poses potential environmental risks, necessitating more sustainable alternatives; one such approach involves the use of chitinolytic bacteria capable of degrading the chitin found in nematode eggs. This study aimed to identify chitinolytic bacterial isolates from river sediments that could potentially inhibit the hatching of root-knot nematode (Meloidogyne spp.) eggs in vitro. The study employed a Completely Randomized Design (CRD) with a single factor comprising five treatments and one control (untreated), with three replicates for each. Bacteria were isolated from river sediments in Aluh-Aluh District, Banjar Regency, South Kalimantan. Seventeen isolates were successfully obtained, and five were selected based on a chitinolytic index (CI) value of ≥ 2. Nematicidal activity assays revealed that isolate BKS5a, at a concentration of 0.2 ml, yielded the highest egg-hatching inhibition rate at 46%. These findings confirm the potential of chitinolytic bacteria to be developed as eco-friendly biological control agents for suppressing root-knot disease in cultivated crops.