Isolation, screening, and characterization of Carbaryl-degrading bacteria from rice soil

• Main Author: Mallorca, Marion A.
• Format: text
• Language: English
• Published: Animo Repository 1998
• Subjects: Carbaryl; Carbamates; Insecticides > Physiological effect; Soil microbiology; Soils > Testing; Agricultural Economics; Agricultural Science; Agronomy and Crop Sciences; Biotechnology; Microbial Physiology; Organismal Biological Physiology
• Online Access: https://animorepository.dlsu.edu.ph/etd_masteral/1989
• Institution: De La Salle University

A carbaryl-hydrolyzing bacterium was isolated from flooded rice soil with a history of carbaryl application. The characteristics of the isolate closely resembled those of Pseudomonas aeruginosa. However, it exhibited negative gelatinase reaction and was nonmotile, hence, it was tentatively identified as Pseudomonas sp. The isolate completely degraded carbaryl 32h after incubation based on a micro thin layer chromatography test of carbaryl. The development of brown-colored spots was observed on filter paper strips indicative of a negative reaction to phenols, the hydrolytic product of carbaryl degradation. The occurrence of a brown-colored product on the inoculated minimal medium broths which progressed in color intensity with time further affirmed carbaryl transformation to non-phenolic metabolites. Control set-up showed a consistent positive reaction to carbaryl/phenols throughout the entire 40h incubation period. If the brown colored products proved to be less toxic or non-toxic than the toxic phenols, the isolate could be used to detoxify industrial wastes containing carbaryl and phenols.