Alabama Center for Paper and Bioresource Engineering, Department of Chemical Engineering, Auburn University, Auburn, AL 36849, United States.
Department of Biosystems Engineering, Auburn University, Auburn, AL 36849, United States.
Waste Manag. 2021 Jun 15;129:35-46. doi: 10.1016/j.wasman.2021.05.008. Epub 2021 May 21.
Paper mill sludge (PMS) raises critical environmental issues due to its disposal problem, but its high sugar content and well-dispersed structure make it a great feedstock for biochemical production. The technical feasibility of integrating cellulase enzyme production into lactic acid (LA) fermentation from PMS was investigated in this study. The low ash content of PMS suggests a great potential for cellulase production. The enzyme produced using PMS without any treatment gave an activity of 7.8 FPU/ml, a performance comparable to the commercial enzyme, Cellic CTec 2. The LA yield from PMS with in-house enzyme was 64.7% and 73.7% at the enzyme loading of 10 and 15 FPU/g-glucan, respectively. The LA obtained was optically pure L- isomer with over 99% purity. The optimal condition of LA production by Bacillus coagulans was found to be 50 °C and pH 5.3 (with 50 g/L CaCO). The nutrient effect of yeast extract (YE) and corn steep liquor (CSL) was substrate dependent, and CSL could substitute YE as an inexpensive nutrient when using PMS as a substrate.
造纸厂污泥 (PMS) 因其处置问题引发了重大的环境问题，但由于其高糖含量和良好的分散结构，使其成为生物化学生产的极好原料。本研究探讨了将纤维素酶生产整合到从 PMS 发酵乳酸 (LA) 中的技术可行性。PMS 的低灰分含量表明其具有很大的纤维素酶生产潜力。未经任何处理使用 PMS 生产的酶的活性为 7.8 FPU/ml，与商业酶 Cellic CTec 2 的性能相当。在 10 和 15 FPU/g-葡聚糖的酶负荷下，来自 PMS 的 LA 产率分别为 64.7%和 73.7%。获得的 LA 为光学纯 L-异构体，纯度超过 99%。发现凝结芽孢杆菌生产 LA 的最佳条件为 50°C 和 pH 5.3（使用 50 g/L CaCO）。酵母提取物 (YE) 和玉米浆 (CSL) 的营养效应取决于底物，并且当使用 PMS 作为底物时，CSL 可以替代 YE 作为廉价的营养物。
