The 55th Hiroshima University Biomass Evening Seminar(The 16th Hiroshima University ACE Seminar)

The 55th Hiroshima University Biomass Evening Seminar

(The 16th Hiroshima University ACE Seminar)was held.


Date & Time: Wed .19  Jul., 2017   16:20-17:50

Place: Engineering 110 Lecture Room, Higashi-Hiroshima Campus, Hiroshima University




Commentary: Yukihiko MATSUMURA

        Professor, Institute of Engineering, Hiroshima University



M2 Student, Graduate School of Engineering, Hiroshima University

“Novel hydrothermal treatment of xylose with acetic acid addition”                      


The hydrothermal gasification of xylose, as a model substance of hemicellulose, was carried out at high temperatures and pressures (350, 400, 450 °C, 25 MPa) in the presence of acetic acid by using continuous-flow reactor. As acetic acid is one kind of organic compound, environmental friendly, low corrosiveness, and also byproduct of hemicellulose gasification, it was chosen to be the catalyst to understand more about the behavior of each reaction in supercritical gasification of xylose. This study aimed to compare the reaction rate constant of xylose decomposition with and without acetic acid addition. The experiments were investigated to determine the influence of residence time varied from 0.5 to 5 s. The concentration of xylose was 1.5 wt% mixed with 1.5 wt% of acetic acid. When acetic acid was added in supercritical gasification of xylose, it gave radical scavenger effect and provided H+, so the retro-aldol reaction and carbon gasification production, which are radical reactions, were be suppressed. Meanwhile, the dehydration of xylose and xylulose to furfural was be promoted significantly. The different between sub- and supercritical conditions is that xylulose yield decreased with increasing acetic acid at subcritical, but at supercritical xylulose increase with increasing acetic acid. At subcritical, dehydration of xylulose to furfural was faster than that of xylose to furfural. In contrast, at supercritical, furfural was produced from xylose more than xylulose.



Lecture: Mattana TUNCHAI             

D3 Student, Graduate School of Advanced Sciences of Matter, Hiroshima University

“ Novel method to control bacterial wilt by disturbing its ability to locate host root ”


Ralstonia solanacearum causes bacterial wilt disease in many economically important crops worldwide. Directed-movement, called chemotaxis, is essential for R. solanacearum to locate the plant root which is considered as a critical early step for host invasion. Therefore, disturbing its chemotaxis system may be able to delay or even suppress the host infection. After having gained knowledge of its attractants and repellants, we tested suppression effect of these compounds on tomato infection. Consequently, we found that malate, identified as one of signal compounds attracting the pathogen to host root, is a promising bacterial wilt control agent.



Lecture: Luo GONGLINFENG               

    M2 Student, Graduate School of Advanced Sciences of Matter, Hiroshima University

“Carboxylic acid production by psychrophlie-based simple catalyst”


Production of valuable chemicals from biomass has been regarded as a hopeful approach to reduce the reliance on petroleum chemicals. Organic acids, especially carboxylic acids contained in TCA cycle(tricarboxylic cycle) have a very board application in chemical industry[1] due to their founctioal groups. There are only several carboxylic acids which are produced commercially by fermentation or biotransformation. Since a lot of carboxylic acids are intermediates or precursors for metabolisms, the diffculties on over accumulation in cells and transportation through cell membranes hampered the development of efficient production process. In our research, we conducted a biocatalyst based on psychrophile which is unable to grow and reproduce over 30°C due to inactivited enzymes and membrane damage. when the reaction was carried at over 30°C, the permeability change caused by membrane damge gave the mesophilic enzymes that we introduced into the host a better access to the substance which leaded to a faster production of carboxylic acid.



Lecture: Paksung NATTACHA

 D3 Student, Graduate School of Engineering, Hiroshima University

“Effect of Phenol on the Glucose Decomposition in Supercritical Water”


Supercritical water (SCW) is a promising medium for biomass conversion into chemicals and fuel gases. It has specific properties that make it possible to dissolve biomass homogeneously. Lignocellulosic biomass is a candidate as feedstock because of its abundant availability. Glucose is often used to represent cellulose in the lignocellulosic biomass. It produces tarry material and char at low temperature, but the production is demoted in SCW. Phenol is a derivative of lignin and is believed to provide radicals in SCW. When biomass is treated in SCW, interaction between cellulose and lignin takes place, which should be modeled by interaction between glucose and phenol. However, this interaction has not been studied in detail. The purpose of this study is to determine the interaction. Mixture of glucose and phenol was fed to continuous reactor. Interaction resulted in large increase in tarry material.



Chair: Obie FAROBIE

     Visiting Reseacher, Institute of Engineering, Hiroshima University