Philippine Journal of Science
152 (5): 1641-1652, October 2023
ISSN 0031 – 7683
Date Received: 13 Feb 2023

In Vitro Assessment of the Inhibitory Effect of Sludge against
Fusarium oxysporum f. sp. cubense (Smith) Synder et Hansen

Jessica R. Francisco1*, Maria Aileen Leah G. Guzman1,
Neil H. Tan Gana2, Jewel Racquel S. Unson1, Emilyn Q. Espiritu1,
Pia Clarisse R. Gulpeo1, and Aurea Marie M. Sandoval3

1Department of Environmental Science, Ateneo de Manila University,
Loyola Heights 1108 Quezon City, Philippines
2Department of Biochemistry and Molecular Biology
University of the Philippines Manila, Ermita 1000 Metro Manila
3Office of the Quality Assurance and Accreditation Office, Benguet State University,
La Trinidad, Benguet 2601 Philippines

*Corresponding author: jessica.francisco@obf.ateneo.edu

[Download]
Francisco J et al. 2023. In Vitro Assessment of the Inhibitory Effect of Sludge against
Fusarium oxysporum f. sp. cubense (Smith) Synder et Hansen. Philipp J Sci 152(5): 1641–1652.
https://doi.org/10.56899/152.05.10

 

ABSTRACT

Sludge production is a major challenge for wastewater treatment plants and is expected to exceed 10,000 tons per day worldwide. Inadequate management of sludge can result in treatment and disposal issues, necessitating the need for effective sludge disposal strategies. Recent studies have shown that sludge may be effective in controlling soil-borne pathogens, but the underlying mechanisms and potential applications of this property in local environments remain unclear. To address this knowledge gap, this study investigated the physico-chemical properties of sludge from a sewage treatment plant and its inhibitory activity against the fungal pathogen Fusarium oxysporum. Sludge samples produced at various drying rates were tested, and the percent relative inhibition zone diameter (% RIZD) was measured. Potential bacterial species with inhibitory properties were isolated from the sludge and identified, and correlational analysis was carried out. The results show that sludge extract, after two months of drying, had the highest % RIZD (78.29 ± 5.7%, p < 0.05) – which correlated positively with the total bacterial count, total nitrogen, potassium, and microbial respiration. These results indicate that the biotic components may have a positive effect on the sludge’s inhibitory potential against F. oxysporum. Although sludge has been found to have the potential to inhibit fungal pathogens, further treatment is necessary to meet regulatory standards (PNS/BAFS 40:2016) and avoid environmental contamination. This study provides a baseline for future research on sludge reuse and management policies.