Neste Oil has applied for patents to cover technology developed to produce microbial oil from waste and residues with the help of various yeasts and molds for use as a feedstock for its NExBTL renewable diesel. (Earlier post.)
Research work started with the Aalto University School of Science and Technology at the end of 2007 has resolved the process technology-related challenges involved, according to the company. Microbial oil produced in this way has already been successfully refined into NExBTL renewable diesel.
NExBTL technology is based on the high-pressure hydrogenation of fatty acids. The product is a synthetic diesel fuel, free of oxygen and aromatic compounds; side products include propane and gasoline. The process can use a flexible input of any vegetable oil or animal fat to produce a product with characteristics similar to Fischer-Tropsch output.
Our research is currently concentrating on ways of extending the range of raw materials we can use for producing NExBTL, and we’re particularly focusing on nonfood materials capable of making a significant contribution to reducing greenhouse gas emissions. Our work has shown that waste-based microbial oil represents an excellent opportunity, and we believe it’s a very promising future raw material.—Neste Oil’s Biotechnology Manager, Markku Patajoki
Following the success of the lab work, the emphasis will now shift to evaluating microbial oil’s potential for pilot-scale production. Commercial production is likely to be possible by 2015 at the earliest.
Research has shown that agricultural residues, together with waste and sidestreams from industry, represent an excellent source of energy and carbon for yeasts and molds, which feed off organic compounds.
Sugars from cereals and sugar cane can also be used, but agricultural and industrial waste and residues are even more interesting materials from a sustainable point of view. We’re currently in the process of evaluating a number of alternative raw materials for processing using yeasts and moulds. Agricultural residues such as straw or an industrial by-product such as glycerol from traditional biodiesel process, for example, are suitable for producing microbial oil using yeasts or molds.—Neste Oil Researcher Perttu Koskinen
The Aalto University School of Science and Technology concentrated on the initial phase of identifying which yeast and mold strains are the most suitable for industrial use and developing the systems technology needed to ensure that microbes generate sufficient levels of oil. Neste Oil, for its part, focused on leveraging its expertise to extract the microbial oil produced from the biomass.
NExBTL technology can be used to produce renewable diesel from different types of raw materials, such as vegetable oil and waste fat from food industry. NExBTL renewable diesel is currently produced from palm oil and rapeseed oil and waste fat sourced from the food industry.
Neste Oil’s NExBTL renewable diesel is compatible with all diesel engines and can be used as such or blended with fossil diesel. It has an identical chemical composition to that of fossil diesel and offers equally good or superior product properties. NExBTL renewable diesel has been tested extensively and successfully in trucks, buses, and cars around the world. Neste Oil supplies the Finnish market with Neste Green diesel, which contains a minimum of 10% renewable content.