Department of Microbiology and Cell Science, University of Florida, Gainesville, FL 32611, USA.
Bioresour Technol. 2011 Feb;102(3):2702-11. doi: 10.1016/j.biortech.2010.10.143. Epub 2010 Nov 4.
Hexose and pentose sugars from phosphoric acid pretreated sugarcane bagasse were co-fermented to ethanol in a single vessel (SScF), eliminating process steps for solid-liquid separation and sugar cleanup. An initial liquefaction step (L) with cellulase was included to improve mixing and saccharification (L+SScF), analogous to a corn ethanol process. Fermentation was enabled by the development of a hydrolysate-resistant mutant of Escherichia coli LY180, designated MM160. Strain MM160 was more resistant than the parent to inhibitors (furfural, 5-hydroxymethylfurfural, and acetate) formed during pretreatment. Bagasse slurries containing 10% and 14% dry weight (fiber plus solubles) were tested using pretreatment temperatures of 160-190°C (1% phosphoric acid, 10 min). Enzymatic saccharification and inhibitor production both increased with pretreatment temperature. The highest titer (30 g/L ethanol) and yield (0.21 g ethanol/g bagasse dry weight) were obtained after incubation for 122 h using 14% dry weight slurries of pretreated bagasse (180°C).
己糖和戊糖从磷酸预处理甘蔗渣中共同发酵为乙醇在一个单一的容器（SScF），消除了固液分离和糖清洗的步骤。包括最初的液化步骤（L）用纤维素酶来提高混合和糖化（L + SScF），类似于玉米乙醇工艺。通过开发一种耐水解物的大肠杆菌突变体 LY180，命名为 MM160，实现了发酵。与亲本相比，MM160 菌株对预处理过程中形成的抑制剂（糠醛、5-羟甲基糠醛和乙酸盐）的抗性更强。使用预处理温度为 160-190°C（1%磷酸，10 min），测试了含有 10%和 14%干重（纤维加可溶物）的甘蔗渣浆。酶解和抑制剂的产生都随着预处理温度的升高而增加。用预处理甘蔗渣（180°C）14%干重浆在 122 h 孵育后，获得了最高的浓度（30 g/L 乙醇）和产率（0.21 g 乙醇/甘蔗渣干重）。
