Lignin Syngas Bioconversion by Butyribacterium methylotrophicum: Advancing towards an Integrated Biorefinery

Hybrid bio-thermochemical based technologies have the potential to ensure greater feedstock flexibility for production of bioenergy and bioproducts. This study focused on bioconversion syngas produced from low grade technical lignin C2-/C4-carboxylic acids by Butyribacterium methylotrophicum. The effects pH, medium supplementation use crude were analyzed. At pH 6.0, B. methylotrophicum consumed CO, CO2 H2 simultaneously up 87 mol% carbon fixation, with acetate increased butyrate 6.3 times. In long-term bioreactor experiments, 38.3 51.1 mM acetic acid 0.7 2.0 butyric synthetic syngas, respectively. Carbon fixation reached 83 88 mol%, conversion rate decreased 13.3 0.9 NmL/h throughout assay. appearance a grayish pellet cell aggregates after approximately 220 h was indicative tar deposition. Nevertheless, stressed cells remained metabolically active maintained syngas. challenge that impurities represent in has direct impact cleaning requirements operation costs, supporting pursuit more robust versatile acetogens.