EcoLodge - Efficient production of Butyl-Butyrate from Lignocellulose derived Sugars

The production of bio-fuel from green plant waste is the first step towards better integration of humans into the earth's biotope. It is an alternative to the use of mined carbon for transport though with the option of producing other chemicals at the same time. The ultimate objective is to expand towards replacing a large portion of the current coal, petroleum and gas derived chemistry by a production chain that builds on resources that regenerate in nature quickly, in a time scale that fits the consumption. In this way, one avoids the accumulation of climate gases and other waste products, which cause undesired long-term effects on the earth's developments. This project aims at producing substitutes for diesel and jet engine fuel. The thereby produced chemicals can potentially also be utilised for the production of more complex chemicals; thus, the developed process aims at providing an alternative to the current production of a family of commercial chemicals. The project is a collaboration of SINTEF together with Chemical Engineering at NTNU and Jadavpur University in India.

The main result of the project is that we gained more insight into the fermentation process. While the first period focused on the mechanisms explored in a diluted system, the last and most valuable model is in a concentration range, we expect a potential future plant would operate. The design sub-project gave insight into the dependency of the product concentration range one can feasibly achieve. The project's result forms a solid basis for further research aiming at the design of a commercial plant.

The fatty acid ester butyl butyrate is regarded as a promising substitute for diesel and jet engine fuel, thus being of relevance in energy supply for both land-based and aviation transport. The building blocks of the ester, n-butanol and butyric acid, are important platform chemicals themselves and can be produced in biotechnological processes based on renewable sources such as lignocellulosic biomass, thereby addressing the transition from a petroleum-based to a sustainable energy supply. A previous approach to produce butyl butyrate in a single bioreactor with the goal to circumvent common challenges associated with biofuel production such as product inhibition and high downstream processing costs yielded only 0.5 % enrichment of kerosine with the ester. In the proposed research project we propose to pursue an alternative, less integrated approach to produce BuB in which the individual components can and will be optimized individually prior to a subsequent integration in a continuous process for BuB production with improved productivity. The overall objective is to considerably improve continuous Clostridium fermentations by efficient separation of butanol and butyric acid from the fermentation broths. The final product will be obtained by enzymatic esterification, preferably in an ionic liquid, followed by product recovery. Process design and process development will be employed to integrate all steps into a continuous process with minimal side streams and waste. The project aims at an experimental verification of the process at laboratory scale, in line with a techno-economical evaluation for exploring the possibility for future industrial applications. Success of this interdisciplinary project will be ensured by a tight collaboration between the Norwegian (NTNU, SINTEF) and Indian collaboration partners (Jadavpur University) with support from European experts from the partner's scientific networks with additional expertise in bio- and process technology.