Biological and biochemical studies on cell surface functions in microorganisms used in brewing and fermentation...

When brewing microorganisms, which include bacteria and fungi, act on solid cereal substrates, the microbial cell surface interacts with the substrate. When microorganisms use sugars and amino acids released by hydrolysis of the substrate, this occurs on the cell surface. Throughout my career, I have focused on functional studies of cell surface molecules such as solute transporters, cell wall components, and bio-surfactants and applied the knowledge obtained to the development of fermentation technologies. In this review, I describe (i) catabolite control by sugar transporters and energy generation coupled with amino acid decarboxylation in lactic acid bacteria; (ii) recruitment of a polyesterase by the fungal bio-surfactant proteins to polyesters and subsequent promotion of polyester hydrolysis; and (iii) hyphal aggregation via cell wall α-1,3-glucan and galactosaminogalactan in aspergilli and the development of a novel liquid culture method with hyphal dispersed mutants lacking these two polysaccharides.