November 30, 2017

Industrial way to make sugars from plant biomass
Research highlights
First report of a continuous slurry process for the conversion of cellulosic biomass to sugars using asolid catalyst. Cellulose, the main component of plant biomass, is hydrolyzed to β-1,4-glucans andglucose in the process using a solid carbon catalyst. Carbon captures cellulose and efficiently converts itto sugars in a slurry reactor. The new process gives 28 times higher productivity compared to aconventional batch system. We hope that our process is easily adopted by chemical industry for biomassconversion.
OutlineCellulose present in plant biomass is a useful source for synthesis of useful chemicals. The
industrial conversion of cellulose is difficult due to its low reactivity and high processing costs. In theirrecent study, the group of Prof. Fukuoka and Dr. Shrotri report the design of a process for hydrolysis ofcellulose in a slurry reactor with high yield and productivity. Using an inexpensive carbon material,
they prepared an active catalyst by oxidizing it with air. The cellulose was adsorbed on carbon surface
by ball milling to increase its reactivity. Using a continuous slurry reactor designed in their lab they
produce β-1,4-glucans and glucose with high yield. More importantly, due to low reaction time they
can achieve 28 times higher productivity compared with conventional batch processes in their lab.
This process is expected to reduce the cost of cellulose conversion to produce valuable chemicals.
This study was supported by Advanced Low Carbon Technology Research and Development
Program (JST ALCA).

Publication
Title: Cellulose hydrolysis using oxidized carbon catalyst in a plug flow slurry process
Author: Abhijit Shrotri, Hirokazu Kobayashi, Hiroyuki Kaiki, Mizuho Yabushita and Atsushi Fukuoka*(Institute for Catalysis, Hokkaido University)
Journal name: Industrial & Engineering Chemistry Research (a chemistry and chemical engineering
journal, American Chemical Society)
Publication date: Nov. 21, 2017 (USA time)

Brief summary of the research(Background)
Plant biomass is abundantly available as waste and it has great potential to be an alternative to fossil
fuels for chemical synthesis. Cellulose in plant biomass is converted to glucose, which is a potential
feedstock for many chemicals. Solid acid catalysts are promising for this reaction as they can be easily
separated and have low environmental impact. However, the interaction between solid catalyst and solid

cellulose is poor, resulting in low yield and productivity. Yield of glucose can be improved by using a batch
reactor to enhance catalyst-cellulose contact. Nevertheless, it is not possible to achieve an economic
process for cellulose conversion with high productivity in a batch process. Therefore, it is necessary todevelop a continuous process that can provide high productivity for cellulose conversion using solid acidcatalysts.
(Method to overcome the issue)A plug flow continuous slurry reactor was designed to achieve high productivity for cellulose
conversion. Acidic carbon catalyst and cellulose were milled together before reaction to overcome thelimited interaction between them. Carbon materials show high affinity to attach with cellulose
molecules caused by strong interaction between them. The carbon catalyst was prepared by oxidationof an inexpensive activated carbon in the presence of air.
(Results)
Hydrolysis of cellulose in slurry flow process was successful without clogging in the reactor system.
High yield of glucose or β-1,4-glucans were obtained by simply altering the reaction conditions.
Glucose is a potential feedstock for chemical industry and β-1,4-glucans are high value products
useful as health food. The productivity of glucose synthesis in this process was 28 times higher thanthe batch process. Therefore, the cost of cellulose conversion using this process can be reduced andmultiple value added products can be obtained. Notably this process can also convert raw biomass tomonomeric sugars with high yield.
(Perspective)
Cellulose conversion at industrial scale is severely hampered by lack of an efficient process. This
research demonstrates a strategy to overcome the challenges in designing a continues slurry process
for cellulose conversion. Once the cellulose is adsorbed on carbon surface, high productivity can beachieved. This report opens the way for cellulose conversion at industrial scale using carbon catalyst.

Contact information
Prof. Dr. Atsushi Fukuoka, Institute for Catalysis, Hokkaido University
TEL: +81-11-706-9140 FAX: +81-11-706-9139 E-mail: fukuoka@cat.hokudai.ac.jp
Web site: http://www.cat.hokudai.ac.jp/fukuoka/

Graphical summary