(768f) Flocculation and Vacuum Filtration of Algal-Slurry Intermediates to Enable Parallel-Algal Processing
While immobilized-culture fermentation offers high specific productivities, it necessitates clarified sugar feedstocks. This presentation will focus on the development and use of a flocculation-enable solid-liquid separation of the pretreated algal slurries. Guided by zeta-potential measurements, trial-and-error testing of several variants of a commercial polyacrylamide flocculent (KemSep-brand, Kemira Chemicals, Helsinki, Finland) identified a suitable flocculent for pretreated algal slurries at the desired pH for fermentation. Additional dosing and mixing studies were performed, enabling vacuum filtration with acceptable permeate flux. The clarified liquor was subsequently used in a 756-hour continuous fermentation, achieving a maximum productivity of 1.2 g/L/h and a process conversion yield of 0.7 g succinic acid/g sugar.