The cost of saccharifying enzymes is one of the factors hindering the practical use of cellulosic bioethanol. In an attempt to address this issue, research has been conducted to create a novel saccharifying enzyme, in parallel with efforts to reduce the quantity of the enzyme used and the cost of production of the enzyme.Reduction of the quantity of the enzyme used involved the creation of an original saccharifying enzyme mixture that did not include any unnecessary enzymes. In addition, genetic engineering techniques were applied in order to substitute an amino acid sequence in the enzyme that formed the main constituent, increasing enzyme activity.Reduction of the cost of production of the enzyme involved utilizing the biomass employed in the ethanol production process as a carbon source, and employing an onsite enzyme production process exploiting solid-state fermentation, a high-efficiency production method. An original enzyme-producing strain of Aspergillus oryzae was created in order to realize this process.The two outcomes discussed above represent new findings with the potential to reduce the cost of saccharifying enzymes for bioethanol production.
Article of Honda R&D Technical Review Vol.28 No.2 (117 - 122)