{Reference Type}: Journal Article {Title}: Comment on "Humic acid-dependent respiratory growth of Methanosarcina acetivorans involves pyrroloquinoline quinone" by Yuanxu Song et al. {Author}: Lovley DR;Holmes DE; {Journal}: ISME J {Volume}: 18 {Issue}: 1 {Year}: 2024 Jan 8 {Factor}: 11.217 {DOI}: 10.1093/ismejo/wrae020