We have developed a new self-sufficient bioethanol producing system that suppresses the inhibition of fermentation by thermally processed residual lignin in a separate hydrolysis and fermentation (SHF) and one-pot simultaneous saccharification and cofermentation (SSCF). The new fermentation process incorporates detoxification with the lignin-derived adsorbent; thus, needs no purchased adsorbent, produces no waste adsorbent and relieves wastewater treatment load. Eucalyptus globulus wood was pretreated by microwave (MW)-assisted hydrothermolysis in aqueous maleic acid and separated into soluble and insoluble fractions. The insoluble fraction was hydrolyzed with cellulolytic enzymes, and the residual lignin was separated. We found that thermal processing of the lignin under a normoxic atmosphere efficiently adsorbed fermentation inhibitors without affecting monosaccharide concentration by enzymatic saccharification. The processing was achieved at 250–350 °C, which are much lower temperatures for wood charcoal production and resulted in higher yields of the adsorbent. The residual lignin formed after SSCF was also converted to the selective adsorbent. Using the lignin-derived adsorbent and genetically engineered Zymomonas mobiliz, bioethanol was produced at 54 g/L from the pretreated biomass mash by one-pot SSCF processes coupled with prehydrolysis. The lignin-derived adsorbent is recyclable and potentially applicable to a wide range of fermentation processes of lignocellulosics.

A simple, low reflection, and highly-efficient pilot-plant scale microwave irradiation reactor for woody biomass pretreatment was fabricated. Pretreatment is an essential process for effective bioethanol production. The fabricated reactor consists of 8 microwave irradiators which are attached to a metal pipe. The woody biomass mixture which contains water and organic acid flows through the metal pipe and is heated by microwaves at a total power of 12 kW. To design the microwave irradiators, we used a 3D Finite Element Method (FEM) simulator, which was based on the measured complex permittivity data of the woody biomass mixture. The simulation results showed that the reflection coefficient |S 11 | from the reactor was less than −30 dB when the woody biomass mixture temperature was between 30 • C and 90 • C. Finally, we experimentally confirmed that the fabricated irradiation reactor yielded a microwave absorption efficiency of 79%. key words: Microwave heating, permittivity measurement, finite element method, magnetron neers (IEICE) and the Institute of Electrical Engineers of Japan (IEEJ) Masakazu Daidaireceived the B.E., M.E., and Ph.D. degree in chemical engineering from