開發離子導體材料回收生物質發酵液中琥珀酸

Abstract

在生物精煉概念下，將生物質作為原料，透過微生物發酵轉化為高價化學品或化學原料的生產途徑，因相較於化學合成生產途徑，可減少對於石化原料依賴，實現循環經濟目標，引起研究單位和產業的關注。琥珀酸便是一種能透過微生物發酵生產之高價化學品，但發酵液複雜成分具其他副產物（例如：醋酸、甲酸），需要透過下游分離純化技術來獲得高純度之琥珀酸產品。目前傳統分離純化處理技術成本高，因此相較於化學合成途徑，發酵過程生產出的琥珀酸的較不具經濟優勢。本研究開發離子導體材料應用於電去離子（Electrodeionization，簡稱EDI）技術，以高效率且低能耗的分離純化程序來回收琥珀酸。本研究首先進行由離子聚合物與離子交換樹脂組成的離子導體材料（Ionically Conductive Material，簡稱ICM）開發與製作，並對其物化特性進行探討。相較於傳統的樹脂晶圓（Resin wafer，簡稱RW），ICM表現出更高的樹脂填充量，及更優異之導電特性，使系統在分離稀薄琥珀酸溶液時系統導電度可提升兩個數量級，且展現出較高的極限電流密度；將ICM材料導入雙極膜電去離子模組中，來研析ICM材料對於合成的發酵液之琥珀酸關鍵分離指標（例如：回收效率、能耗、產率及電流效率）。根據本研究結果顯示，相較於傳統RW材料，本研究開發之ICM能在25 V時提升1.4倍之產率（至0.55 kg/m2/h），程序能耗約為2.53 kWh/kg，且電流效率維持在90%以上。最後，本研究為了解離子導體材料應用於雙極膜電去離子模組回收琥珀酸之可行性，進行初步成本效益分析，在25 V之施加電壓情況下，益本比約為4.49，顯示出此技術結合ICM材料於回收琥珀酸上具有經濟效益。綜合以上，本研究成功開發離子導電材料並應用於電去離子技術中，提升從生物質發酵液中回收琥珀酸之效率，並降低分離程序能耗，促進生物精煉和永續化學品生產加速落實。

Under the concept of biorefinery, the utilization of biomass as a raw material and its conversion into high-value chemicals or chemical feedstocks through microbial fermentation has gained significant attention from research institutions and industries. This approach offers several advantages, including reduced reliance on petrochemicals and contributions to achieving a circular economy. One such high-value chemical is succinic acid, which can be produced through microbial fermentation. However, the fermentation broth contains complex components and by-products like acetic acid and formic acid, necessitating downstream separation and purification processes to obtain high-purity succinic acid products. Currently, traditional separation and purification techniques are costly, making the production of succinic acid through the fermentation process less economically advantageous compared to chemical synthesis routes. To address this challenge, this study aims to develop an ionically conductive material (ICM) for use in electrodeionization (EDI) technology, enabling efficient and low-energy consumption separation and purification processes for succinic acid recovery. Initially, the ICM, composed of ionomer and ion exchange resins, is developed and manufactured, and its physicochemical properties are thoroughly investigated. Compared to the traditional resin wafer (RW), the ICM exhibits higher resin loading and superior electric conductivity performance, resulting in a two-order of magnitude increase in system conductivity when separating low concentration succinic acid solutions. Additionally, the ICM demonstrates higher limiting current density. These characteristics make it a promising candidate for succinic acid recovery. The ICM material is then integrated into a bipolar membrane electrodeionization (BMEDI) module to evaluate its key performance indicators, including recovery efficiency, energy consumption, productivity, and current efficiency, in the separation of simulated succinate fermentation broth. The research results demonstrate that, when compared to RW, the ICM achieves a remarkable 1.4-fold increase in productivity, reaching 0.55 kg/m2/h at 25 V, with an energy consumption of 2.53 kWh/kg, while maintaining a current efficiency above 90%. Finally, a preliminary cost-benefit analysis is conducted to assess the feasibility of applying the ICM in succinic acid recovery through BMEDI. The analysis reveals a benefit-cost ratio (BCR) of 4.49 under a voltage of 25 V, indicating that this technology holds significant economic benefits for the recovery of succinic acid. In conclusion, the development and application of the ionically conductive material in electrodeionization technology present a promising and economically viable approach to enhance the efficiency of succinic acid recovery from fermentation broth, thereby advancing the prospects of biorefinery concepts and sustainable chemical production.