Worldwide attention is currently focused on bioethanol production from viewpoints of global warming prevention and energy security enforcement. However, feedstock for current bioethanol production processes comprises food crops, which will be in limited supplies in the near future. Therefore, there is a pressing need to use abundant lignocellulosic biomass, some obtained from inedible parts of food crops, as demand for bioethanol proliferates.
We developed the "RITE-bioprocess" to produce ethanol from soft-biomass in collaboration with Honda R&D. The RITE-bioprocess utilizes Corynebacterium glutamicum, which is widely used in industrial production of amino acids. The process is based on a new concept that fundamentally resolved the technological problems of the existing bioprocesses. Using genetically modified C. glutamicum cells, various substances have been produced at high volumetric productivity with cells packed in a reactor to high density under growth-arrested conditions which are implemented by oxygen deprivation. We constructed ethanologenic C. glutamicum strains to demonstrate ethanol production, and have improved the ethanol production process from mixed sugars containing hexose and pentose sugars derived from lignocellulosic biomass. In this presentation, our current research into bioethanol production for industrialization will be discussed.