Evaluating the Methanogenic Potential of Fresh and Dry Stinging Nettle (Urtica dioica) as a Co-Substrate in Anaerobic Digestion: Experimental Insights and Kinetic Modelling

This study investigates the impact of incorporating fresh and dry stinging nettle (Urtica dioica) as a co-substrate (20% by mass) into anaerobic fermentation processes utilizing cattle manure inoculum. Over a 60-day period, biogas and methane production were monitored, and the results were interpreted through two-component Gompertz modelling. While the addition of dry nettle signiFicantly inhibited biogas and methane yields, fresh nettle enhanced the overall biogas output by 68% and methane content by 113% compared to the cattle manure control. The kinetic modelling revealed accelerated methane production in the fresh nettle mixture, highlighting its potential to enhance the efFiciency of anaerobic digestion. These Findings underscore the importance of substrate state and composition in optimizing biogas generation from agricultural residues and invasive plant species.