Modeling of biohydrogen production using generalized multi-scale kinetic model: Impacts of fermentation conditions

This paper presents a new multi-scale kinetic model built upon the multi-stage growth Hypothesis for predicting biohydrogen production. The proposed model represents the significant factors affecting biohydrogen production using a sum of first-order kinetic terms with varying dynamics from slow to fast one. The current work investigates 52 case studies of biohydrogen production that show the double first-order kinetic model provides the best modeling fitness (R-2 > 0.99). This result suggests two prevalent pathways or microbial groups with distinct dynamics (i.e., fast and slow modes) in biohydrogen production. An increase in temperature (30 degrees C-43 degrees C) or substrate concentration (10 g/L to 40 g/L) and the use of simple substrates or mixed cultures can increase the fast-mode dominance up to 100% contribution. Model analysis suggests that the fast mode corresponds to the butyrate production pathway, the growth-associated hydrogen-producing activity, the easily-biodegradable substrates, or the quick hydrogen-producing groups. (c) 2022 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.

Automated summary

This paper presents a new multi-scale kinetic model for predicting biohydrogen production. The study reveals the existence of two prevalent pathways or microbial groups with distinct dynamics in biohydrogen production. Modulating temperature, substrate concentration, and using different types of substrates can control the contribution of different modes in biohydrogen production.