[3S05Ae] 12. Environmental Microbiology and Technology - Part 4

4:45 PM - 5:00 PM JST(7:45 AM - 8:00 AM UTC)

[3EMT-03] Multiple Bio-plastic Degradation and Plant Growth-Promoting Traits of Streptomyces sp. JJY08 for Plastic-Contaminated Soil Remediation

○Geeta Chhetri¹, Jong-Min Jeon¹, Jeong-Jun Yoon¹ (1. Korea Institute of Industrial Technology (Korea))

Keywords:

Biodegradation,Bio-plastics,Biofertilizer,Melanin,Novel

The widespread use of biodegradable plastics has resulted in increasing environmental accumulation of partially degraded residues, emphasizing the need for efficient microbial strategies to treat mixed polymer waste. In this study, a novel actinobacterial strain, Streptomyces sp. JJY08, isolated from eggplant field soil, demonstrated the ability to degrade multiple biodegradable polyesters under ambient conditions. Clear halo zone formation on emulsified agar plates indicated extracellular hydrolytic activity. Furthermore, in flask shake cultures, strain JJY08 showed rapid degradation of polycaprolactone (PCL) and polyhydroxybutyrate (PHB), achieving 99.4% degradation within 8 days and 98.0% within 15 days, respectively. Moderate degradation was observed for polybutylene succinate (PBS) and polylactic acid (PLA), with 55.5% degradation after 21 days and 65.2% after 35 days of incubation. Structural and chemical analyses using scanning electron microscopy (SEM) and Fourier-transform infrared (FT-IR) spectroscopy confirmed surface erosion and ester bond cleavage during polymer breakdown. In addition to its degradative capacity, the strain exhibited plant growth associated traits, including indole-3-acetic acid (IAA) synthesis, siderophore secretion, phosphate solubilization, hydrogen cyanide (HCN) formation, and melanin biosynthesis, suggesting strong ecological adaptability. Genomic analysis revealed genes associated with polyester hydrolysis, environmental stress adaptation, and secondary metabolism. Genome mining further identified diverse biosynthetic gene clusters, including those related to nonribosomal peptide synthetases, polyketide synthases, siderophores, terpenes, and hydrogen cyanide, suggesting metabolic versatility and ecological competitiveness. These findings highlight the potential of strain JJY08 as a versatile microbial candidate for sustainable management of mixed biodegradable plastic residues and for application in plastic-contaminated soil remediation. This work was supported by the Technology Innovation Program [grant number: RS-2025-02310257] funded by the Ministry of Trade, Industry & Resources (MOTIR, Korea), and the National Research Foundation of Korea (NRF) grant funded by the Korea government (MSIT) [RS-2026-25474153].