Respon Komunitas Mikroba Terimobilisasi terhadap Stres Termal pada Peruraian Anaerob Palm Oil Mill Effluent

Abstract

This study investigates the response of immobilized microbial communities to thermal stress during anaerobic digestion of palm oil mill effluent (POME). Thermophilic reactors (55 °C) were operated with different immobilization media, namely natural zeolite and synthetic mesh. On day 30, the systems were subjected to thermal shock (100 °C) to assess microbial resilience. 16S rRNA gene sequencing revealed that before treatment, microbial communities across reactors remained stable, dominated by acetogenic and methanogenic groups. After thermal stress, both control and mesh-based reactors exhibited a significant decline in functional microbes alongside an increase in opportunistic pathogens (Salmonella, Escherichia-Shigella). In contrast, zeolite-based reactors were able to recover and maintain functional microbial dominance while suppressing the proliferation of pathogens. These findings demonstrate that natural zeolite serves as an effective immobilization medium to enhance microbial community resilience against thermal stress in POME anaerobic digestion.