Calotropis a laticiferous xerophyte, is a potential source of biogas with the following features: a perennial shrub, distributed in the tropical and subtropical areas in all types of soils and environmental conditions, requiring no cultivation practices and not grazed by animals. Inspite of all these advantages, the toxic secondary metabolites were feared to be the hindrance for utilizing the biogas residue as manure. Hence,the reduction of toxicity during biomethanation was assessed in this study. For the assessment, the qty of biogas generated, phytochemical changes and macronutrients...