Low pH Fermentation to Succinic Acid, the Basis for Efficient Recovery

Royal DSM N.V., the global Life Sciences and Materials Sciences company headquartered in the Netherlands, and the French starch and starch-derivatives company ROQUETTE have joined forces to implement and commercialize the fermentative production of bio-renewable succinic acid (joint venture REVERDIA), which opens the possibility to produce bio-based performance materials. Succinic acid is a chemical currently produced as a derivative from crude oil and natural gas. It is commonly used directly in a variety of industry applications, such as pharmaceuticals, food and automotive and also as an intermediate for the production of several (high-performance) polymers.

For future economic success of its major applications it is important to realize the lowest possible cost price for succinic acid. We deliberately chose for a fermentation process at low pH, thereby directly producing the acid. In this way salt production in the recovery process is minimized and at the same time its carbon footprint will be lowered. In this paper we would like to stress the importance of certain key performance indicators (KPI’s) and illustrate their effect on cost price.  

To realize our ambitions we have engineered yeasts to produce succinic acid with high titer and yield. This was accomplished by introducing heterologous genes that were optimized for expression in the host. Strain performance was further improved in controlled fermentations towards a low pH. Currently, the process has been successfully scaled up to >100 m³ in our first commercial plant in Cassano, Italy. In parallel, implementation for future bigger scale operation is in progress.