Biodegradation of monocrotophos by Stenotrophomonas maltophilia and its potential in vitro plant growth promoting activities

Abstract

Extensive field application of monocrotophos (MCP), an organophosphate pesticide to protect agricultural crops and yields, imposes severe environmental issues due to its long-term persistence in soil and water. Indigenous bacterial strain CAB5 was isolated from a severely monocrotophos-contaminated agricultural field in Mysuru, Karnataka. The strain was assessed for its ability to biodegrade monocrotophos and plant-growth promoting factors. CAB5, identified as Stenotrophomonas maltophilia (OQ861256). It exhibited monocrotophos tolerance up to 1000 ppm by utilizing it as sole carbon source for metabolism and growth. S. maltophilia can produce several plant growth-promoting (PGP) traits, including ammonia, cellulase, IAA, catalase, and phosphate solubilization. The optimal condition for CAB5 growth observed as pH 8, 37 ℃ temperature, and 96 h of incubation time, respectively. Biodegradation was analyzed by combining hyphenated techniques like UV spectroscopy and TLC, and the intermediate metabolites were analyzed by FT-IR and LC-MS. Dimethyl-phosphate, Trimethyl phosphate, and Cyclohexanone, 2-cyclohexylidene were the intermediate metabolites formed from biodegradation. It is concluded that S. maltophilia CAB5 could be an advantageous with the consortium-based formulated prototype for the refinement of polluted sites for toxic pollutants along with plant growth promotion.

Keywords

• Organophosphate
• Monocrotophos
• Biodegradation
• Stenotrophomonas maltophilia
• Plant growth promotion