From second generation feed-stocks to innovative fermentation and downstream techniques for succinic acid production

Succinic acid (SA) is one of the most important biobuilding blocks in biorefinery. Its production from fermentation of renewable biomass sources is becoming a consolidated alternative that is more sustainable and potentially more economic than the traditional petroleum-based path for SA production. Fermentative production of SA has been successfully commercialized and a large and increasing number of SA-derivatives are promoting the economic stability of this production. However, the companies producing SA from fermentation are targeting specialized markets and the production is far from large-scale bulk chemical synthesis. In order to develop optimized and economic processes, the best candidates in every step of the SA production process must be identified. In this paper, the most promising biomass sources, pretreatment methods, fermentation conditions (i.e. host microorganism, fermenter design and operative mode) and separation techniques for industrial SA production are critically reviewed. Selection of the host microorganism is a key factor for SA production. However, the availability, potential and sustainability of feedstocks, fermentation and separation process must also be carefully evaluated for a cost-effective and environmentally sustainable SA production.