Molecular Microbiology and Biotechnology Group
Group Leader / Chief Researcher
Masayuki Inui

In recent years, the concept of "bioeconomy" attracts growing attention as a comprehensive bio-based strategy to tackle major environmental challenges mainly in Europe and the United States. Bioeconomy refers to a set of economic activities focused on biotechnology that promotes production of renewable biological resources and their conversion into bio-based products and bioenergy, and thus development of biorefining technologies are considered to be the key for its success. Over the years, our group has been working on establishment of biorefining processes to produce green chemicals and biofuels from renewable biomass.

Regarding biofuels, 120 million kL of bioethanol was produced worldwide in 2017, and the United States accounted for about half of the production. Bioethanol, which is produced from corn and sugarcane in the United States and Brazil, respectively, is mixed with gasoline by 10 to 25% and supplied as fuel for automobiles. Production of biodiesel that is derived mainly from rapeseeds in Europe and soybeans in the United States is estimated at 3.7 million kL in 2017. Compared to electric cars, it is much more challenging to electrify aircraft systems and large vessels. These transportation systems remain dependent on liquid fuels at least for a while, and replacing petroleum-based fuels with biofuel is a major strategy to reduce CO₂ emissions. Use of biojet fuels has been expanding year by year. For example, several foreign airlines operate commercial flights using the biojet fuel derived from used cooking oil.

Green chemicals are expected to make a major contribution to establishment of a sustainable society. Production of green chemicals such as biomaterials and biopolymers promotes transition from fossil resources to renewable biomass and reduction of CO₂ emissions. According to the European Bioplastics Association, the global production of bioplastics in 2017 is estimated to be 4.4 million tons and predicted to be 6.1 million tons in 2021. When it comes to the domestic situation, consumption of biodegradable poly-lactic acid and drop-in type biopolyethylene terephthalate (Bio-PET) has been increasing. We expect that development of the smart cell technology, on which we have been working from FY 2016, enables to produce bio-based polymers from various types of monomers with high productivity levels and further promote use of green chemicals.

In 1990s, we started a research project to develop biorefinery technologies and established our core system "Growth-arrested bioprocess (RITE Bioprocess)". Based on this unique system, we have achieved efficient bio-production of ethanol, organic acids, and amino acids. We are currently working on commercialization of our technologies. Our workforce Corynebacterium glutamicum has a unique property, which is the key for "Growth-arrested bioprocess". Under a certain condition, the bacterium stops growing while its major metabolic pathways remain active. "Growth-arrested bioprocess" takes advantage of this feature, achieving higher yields and rates compared to the conventional fermentation processes, in which formation of products and biomass inevitably occurs in parallel. "Simultaneous utilization of C6 and C5 mixed sugars" and "tolerance to fermentation inhibitors" are the two major challenges for processing of non-food biomass to bio-products and biofuels. To the best of our knowledge, our "Growth-arrested bioprocess" is the only bioprocess that overcome both of these challenges.

In recent years, long-chain alkanes and aromatic compounds draw increasing attention as materials for jet fuels, polymers, pharmaceuticals, cosmetics, dyes and so on. Due to the intrinsic toxicities of these compounds, however, their commercial-scale production by conventional growth-associated fermentation has been hampered. We found that C. glutamicum is much more tolerant to the toxicities of long-chain alkanes and aromatic compounds compared to other industrial microorganisms such as Escherichia coli and a solvent-tolerant bacterium Pseudomonas putida. Indeed, we have achieved higher productivities of toxic compounds like phenol compared to the published data, using our "Growth-arrested bioprocess".

Aiming at commercialization of our technologies, we, RITE, launched collaboration with Sumitomo Bakelite Co., Ltd., and developed a "two step bioprocess for phenol production". The invention opened the door to commercial-scale production of phenol from C5 and C6 mixed sugars derived from non-food cellulosic biomass. In 2014, we established "Green Phenol Development Co., Ltd."（GPD） in order to speed up the commercialization process. In 2016, GPD, RITE and Sumitomo Bakelite Co., Ltd., received the "15th Green Sustainable Chemistry (GSC) Encouragement Award" for our achievements in development of plant-derived phenol manufacturing technology from the Japan Chemical Industry Promotion Association (JACI) Green Sustainable Chemistry Network Conference. We expand the scope of our business and apply the technology we established to production of various aromatic compounds in addition to phenol. Accordingly, we changed our company name from GPD to "Green Chemicals Co., Ltd." (GCC) on April 1, 2018.

A current goal of our group is to further improve our "Growth-arrested bioprocess" and enable bio-production of diverse fuels and chemicals regardless of their toxicities. Through our research activities, we would like to contribute to establishing a carbon-free, energy-efficient society. I would appreciate your continued support.