Aspergillus niger TC1 as multi-functional bioinoculant for biodegradation of chlorpyrifos, plant growth promotion and biocontrol of phytopathogens.

Chlorpyrifos is an organophosphorus pesticide which is most widely used in agricultural farmlands to control insect pests. Besides protecting crops from pests, chlorpyrifos enters into soil and water bodies, and pose serious health hazards to living organisms. Biodegradation involves the use of microorganisms to degrade pesticides into non-toxic substances. In the present study Aspergillus niger TC1 showed maximum degradation of chlorpyrifos. The isolate was able to tolerate 500 ppm concentration of chlorpyrifos and substantially degraded 400 ppm concentration of chlorpyrifos. Based on GC-MS analysis, Aspergillus niger TC1 degraded chlorpyrifos into 2,4 Bis (1,1 dimethyl ethyl) phenol, a fuel additive compound. Based on HPLC analysis, the percentage of chlorpyrifos degradation was calculated to be 95.2%. A temperature of 27 ℃ and pH 7 were identified as optimum conditions for maximum degradation of chlorpyrifos. The isolate showed positive results for Indole-3-Acetic Acid and ammonia production, along with phosphate and zinc solubilizing plant growth-promoting assays. Also, the isolate showed increased seed germination along with increased shoot and root length in the seed germination and pot assay. Further, Aspergillus niger TC1 showed significant biocontrol potential against Rhizoctonia solani and Fusarium oxysporum. The isolate showed significant degradation of chlorpyrifos along with plant growth promotion and biocontrol potential. While chlorpyrifos degradation by Aspergillus niger has been previously reported, this study is the first to comprehensively assess a single strain for its combined abilities in chlorpyrifos degradation, plant growth promotion, and biocontrol potential. The study shows that Aspergillus niger TC1 can be efficiently used for sustainable agriculture.