Lo Enlin, Brabo-Catala Luiza, Dogaris Ioannis, Ammar Ehab M, Philippidis George P
Department of Chemical and Biomedical Engineering, University of South Florida, 4202 E. Fowler Avenue, Tampa, FL 33620, USA.
Patel College of Global Sustainability, University of South Florida, 4202 E. Fowler Avenue, Tampa, FL 33620, USA.
J Biosci Bioeng. 2020 Jan;129(1):104-109. doi: 10.1016/j.jbiosc.2019.07.003. Epub 2019 Aug 8.
Succinic acid, an important intermediate in the manufacture of plastics and other commodity and specialty chemicals, is currently made primarily from petroleum. We attempted to biosynthesize succinic acid through microbial fermentation of cellulosic sugars derived from the bagasse of sweet sorghum, a renewable feedstock that can grow in a wide range of climates around the world. We investigated pretreating sweet sorghum bagasse (SSB) with concentrated phosphoric acid at mild conditions (40-85°C) at various residence times and biomass concentrations. We then subjected the pretreated SSB to enzymatic hydrolysis with a commercial cellulase to release glucose. The highest glucose yield was obtained when SSB was pretreated at 50°C for 43 min at 130 g/L biomass concentration on dry basis. Fermentation was carried out with Actinobacillus succinogenes 130Z, which readily converted 29.2 g/L of cellulosic glucose to 17.8 g/L of succinic acid in a 3.5-L bioreactor sparged with CO at a rate of 0.5 vvm, thus reducing the carbon footprint of the process. Overall, we demonstrated, for the first time, the use of SSB for production of succinic acid using practices that lower energy use, future equipment cost, waste generation, and carbon footprint.
琥珀酸是制造塑料及其他通用化学品和特种化学品的重要中间体，目前主要由石油制成。我们尝试通过对甜高粱蔗渣中衍生的纤维素糖进行微生物发酵来生物合成琥珀酸，甜高粱是一种可再生原料，能在全球广泛的气候条件下生长。我们研究了在温和条件（40 - 85°C）下，在不同停留时间和生物质浓度下用浓磷酸预处理甜高粱蔗渣（SSB）。然后将预处理后的SSB用商业纤维素酶进行酶水解以释放葡萄糖。当以干基计生物质浓度为130 g/L时，在50°C下对SSB预处理43分钟，可获得最高的葡萄糖产率。发酵使用产琥珀酸放线杆菌130Z进行，在一个3.5升的生物反应器中，以0.5 vvm的速率通入CO，该菌能轻松地将29.2 g/L的纤维素葡萄糖转化为17.8 g/L的琥珀酸，从而减少了该过程的碳足迹。总体而言，我们首次展示了使用SSB生产琥珀酸的方法，该方法降低了能源消耗、未来设备成本、废物产生以及碳足迹。
