Metabolic engineering of the thermophilic fungus Myceliophthora thermophila for L-glutamate production from lignocellulosic biomass

The thermophilic ascomycete fungus Myceliophthora thermophila has been developed as a platform for producing value-added chemicals from lignocellulosic biomass. In this study, we explored the feasibility of engineering M. thermophila for l-glutamate production from biomass-derived carbon sources.

Genome-scale metabolic modeling indicated that M. thermophila has the stoichiometric capacity to synthesize l-glutamate from glucose and ammonium. Experimental fermentation confirmed extracellular l-glutamate accumulation, and medium optimization revealed that nitrogen source selection and extracellular pH homeostasis strongly affected l-glutamate accumulation. Overexpression of the native NADPH-dependent glutamate dehydrogenase gene gdh1 markedly increased glutamate production.