Formate-limited growth of Methanobacterium formicium in steady-state cultures

Abstract

Growth of Methanobacterium formicicum strain MF was studied in pH-stat batch cultures and formatelimited chemostat cultures. The maxium rate of methanogenesis from formate occurred at pH 7.6 and 43°C and the maximum specific growth rate constant (μm) was 0.08 h-1. The Ks and maximum growth yield (Ysmax) were 3.5 mM formate and 1.4 (g dry wt) mol01 formate respectively, and the maintenance coefficient (m) was calculated as 6.8 mmol formate (g dry wt)-1 h-1. The efficiency of electron transport phosphorylation during formate metabolism assuming YATP of 10.5 g mol-1 was about 20%. The specific activities of hydrogenase and formate dehydrogenase increased slightly with dilution rate.