Investigation of Nutrient Feeding Strategies in a Countercurrent Mixed-Acid Multi-Staged Fermentation: Experimental Data

Abstract

Nutrients are essential for microbial growth and metabolism in mixed-culture acid fermentations. Understanding the influence of nutrient feeding strategies on fermentation performance is necessary for optimization. For a four-bottle fermentation train, five nutrient contacting patterns (single-point nutrient addition to fermentors F1, F2, F3, and F4 and multi-point parallel addition) were investigated. Compared to the traditional nutrient contacting method (all nutrients fed to F1), the near-optimal feeding strategies improved exit yield, culture yield, process yield, exit acetate-equivalent yield, conversion, and total acid productivity by approximately 31%, 39%, 46%, 31%, 100%, and 19%, respectively. There was no statistical improvement in total acid concentration. The traditional nutrient feeding strategy had the highest selectivity and acetate-equivalent selectivity. Total acid productivity depends on carbon-nitrogen ratio.

Sustainable Aviation Fuel from High-Strength Wastewater via Membrane-Assisted Volatile Fatty Acid Production: Experimental Evaluation, Techno-economic, and Life-Cycle Analyses

“…The results from sensitivity analyses underline the importance for future researchers and practitioners to focus on enhancing VFA yield in the overall process (e.g., increase AM efficiency, reduce VFA loss from down- stream processes) and minimizing the cost related with VFA acidification (e.g., WBA cost reduction, WBA capacity increase). Enhancing VFA yield in AM can be achieved through several strategies: (1) employing tailored microbial consortia with higher VFA productivity and tolerance, 4 (2) increasing feedstock COD concentration or volatile solid loading rate, 15 (3) implementing multistage countercurrent operation strategy for high-solid content feedstocks, 35 (4) utilizing a codigestion approach with nutrient-rich feedstocks (e.g., food waste, manure) to maintain an optimal carbon and nitrogen ratio in the digester environment, 38 and ( 5) implementing pretreatment processes to increase digestibility of feedstocks. Additionally, ISPR presents a promising approach for further enhancing the VFA yield, but minimizing the associated OPEX and CAPEX is crucial for its expanded applications.…”