Satake Multimix Corporation, Tohoku University and Godo Shusei Co. as part of NEDO’s “Development of Bio-based Product Production Technology to Accelerate the Realization of Carbon Recycling” project have established a stirring system that can efficiently stir the culture medium with lower power and ensure aeration volume. By establishing a stirring system that can efficiently agitate the culture medium and secure an airflow rate with lower power consumption. The system can be used for highly viscous filamentous fungi. This enables microbial cultivation at a lower installation cost than conventional systems, while reducing power consumption. Compared to conventional reusable bioreactors, the market supply price of this newly developed reactor has been reduced by approximately 40% in terms of installation costs, including environmental maintenance. The running cost has also been reduced to less than one-third of the general cost level in the market.
The three parties will further evaluate the culture and durability of the product, with the aim of commercializing and marketing it by the end of FY2023. A small-scale model (4 liters) of this reactor, the result of this project, will be exhibited in the NEDO booth at BioJapan 2023, a biotechnology exhibition to be held at Pacifico Yokohama from October 11 to 13.
The Rushton turbine (6FT) used in conventional bioreactors has a problem with power efficiency in microorganism cultivation because the dispersion of air bubbles and the fluidity of the culture medium are reduced by aeration agitation. Therefore, we have applied an agitation system that combines a high-efficiency turbine (HS100 turbine) with improved bubble dispersion during aeration agitation and an axial-flow impeller (HR100 impeller) with powerful agitation action in the culture tank to the cultivation of filamentous fungi, thereby achieving a bioreactor that can efficiently agitate culture medium with lower power consumption. The agitation system is also used to produce numerical values using this agitation system.
In addition, using this agitation system, we conducted Computational Fluid Dynamics (CFD) simulations and actual culture verification and scale-up studies, and confirmed the suppression of power consumption and improvement of liquid flow action and gas dispersion action compared to the conventional 6FT. A viscosity-reduced mycelial dispersion strain developed by Tohoku University was used in this simulation.
By using the agitation system established above, microbial production can be carried out with lower power than before, enabling single-use bioreactors. Although sterilization of the inside of the culture tank (bag) is still required for single-use bioreactors, the application of a new sterilization system based on Satake Multimix’s proprietary technology to this reactor has eliminated the need for expensive sterilization equipment. At the same time, in order to maintain the robustness to handle filamentous fungi cultivation with a high operational load, the reactor was completed as a complete system with only the culture tank and piping for single use.
The market supply price of this newly developed reactor is approximately 40% lower than that of a reused bioreactor, including environmental maintenance. The running cost can also be reduced to less than one-third of the cost level generally accepted in the market, which is expected to reduce the barriers to entry for new businesses.