ASPEX- an advanced Schizosaccharomyces expression system
Since around 2000, the Japanese government, through its Ministry of Economics, Trade and Industry (METI) and its project organization NEDO, supports applied research on microbial genomes. Within private public partnerships, called “research associations”, an alliance of companies and academic institutions has teamed up on the topic of “minimum genome factories”, with a focus on 3 microorganisms:
- Escherichia coli (industrial partner: Kyowa Hakko)
- Bacillus subtilis (industrial partner: Kao Corporation), and
- Schizosaccharomyces pombe (industrial partner: Asahi Glass Company (AGC))
AGC is a major international company based in Japan, with about 48.000 employees and a turnover of 1.150 billion Yen in 2009 (~85 billion €). Major business fields are glass (construction, automobiles etc.), displays, e. g., glass substrates for LCD TVs, glass-based electronic materials and glass-related chemicals, originally caustic soda, potash, hydrochloric and hypochloric acid. The chemical portfolio was further developed over the years and by now includes, e. g., vinylchloride, epichlorohydrine, trichloroethylene, propylene glycol and other polyols.
AGC’s Research Center is based in Yokohama, Kanagawa Prefecture. It is home to to more than 500 researchers focused on the key areas of AGC’s business. In addition, a biotechnology laboratory and fermentation laboratory has been established there already 15 years ago.
As a result, AGC offers “The ASPEX System”, a full-scale contract manufacturing service for recombinant proteins, up to the 3000 L scale. It is based on S. pombe, an endotoxin-free fission yeast isolated from east African beer. The dedicated production facility, located close to the Research Center, is organized under cGMP rules and thus enables supply of biopharmaceuticals. Its down-stream processing unit contains a clean-room. Examples for gene expressions are manifold, and some are indicated below.
Based on the functional genome analysis of S. pombe, more than 50 proteases were identified and knock-out mutants for a large number of combinations of these proteases were studied in view of enhanced protein expression. As a result, many of the expressed genes could be produced within the cells at an amount of 30–50% of total soluble protein, or also secreted into the medium at amounts of several hundred mg/L up to several g/L, in batch cultures or fed-batch formats.
AGC offers a choice of expression vectors leading to either constitutive or inducible production or else secretion of a foreign protein. Both episomal vectors based on antibiotic control or integrative vector systems with multi-copy integration are available.
Thus, AGC has established a promising protein production system which has been used already for biopharmaceuticals, diagnostics and industrial enzymes.
AGC’s business model includes the custom production of proteins, but also strain and process development and transfer of both to a licensed customer. An up to 3000 l – scale GMP-plant is now available in-house which can be operated under high-cell density conditions.
The ASPEX technologies and business are presently managed by AGC Japan, and the contact person is
Mr. Soichiro Ikeda
1-12-1, Yurakucho,Chiyoda-ku, Tokyo 100-8405, Japan