Hydrogen-producing conditions and mutation mechanisms of a highly efficient mutant strain Ethanoligenens harbinense YR-3

Abstract

In this study, the optimal hydrogen (H₂) production conditions of the high-efficiency H₂-producing mutant strain Ethanoligenens harbinense YR-3 (carbon-nitrogen ratio 5.5, phosphate buffer 80 mM, initial pH 6.0, biotin 1.4 mg/L) are obtained by intermittent experiments. The maximum specific H₂ production rate of YR-3 (2.85 mol H₂/mol glucose) was 1.4 times that of the wild strain ZGX4 (2.04 mol H₂/mol glucose). The liquid-phase products are mainly ethanol and acetic acid, indicating that the metabolic pathway has not changed. Two-dimensional electrophoresis and mass spectrometry were used to compare and analyze the protein map differences between YR-3 and ZGX4. The results show that 1,6-fructose diphosphate aldolase and the flavoprotein in hydrogenase are highly expressed. This study will provide a theoretical basis for the genetic modification of high-efficiency H₂-producing strains and the improvement of H₂ production capacity.