Process demonstration isobutene

Isobutene is an important petrochemical feedstock. At the Fraunhofer Center for Chemical-Biotechnological Processes CBP in Leuna, the Global Bioenergies S.A. company had built a demonstration plant that for the first time produced isobutene from renewable raw materials instead of petroleum.

Novel fermentative production process

In contrast to petroleum-based production, the novel process uses fermentative production. Various first- and second-generation sugars currently serve as starting materials and are converted into the small but multipotent molecule isobutene by genetically modified microorganisms.

The metabolic pathway from sugars to isobutene was developed by Global Bioenergies S.A. using molecular biology methods. Fermentatively produced isobutene serves as a feedstock for biobased fuel additives, and for various components of cosmetics.

The demonstration plant with with a nominal capacity of 100 tons per year and a fermentation volume of 5,000 liters was built for the purpose of scaling up and optimizing the process previously developed by Global Bioenergies in the laboratory.

Fraunhofer CBP supported the construction and commissioning of the plant and has been operating the demonstration plant on behalf of the company from 2017 to 2021.  The scientific evaluation and validation of the process campaigns were carried out in close cooperation between Fraunhofer CBP and Global Bioenergies. In this way, the process was continuously further optimized in terms of process technology.

Directly connected product purification

Unique in Europe was the directly connected product purification for liquefaction of the pure isobutene. Due to the aerobic fermentation process in combination with the highly flammable isobutene, special focus was placed on safety engineering.

In the years of research, sufficient quantities of isobutene have been generated to validate further processing and use in biobased fuels as well as cosmetics, and to advance their market readiness.