Cellulase production by Penicillium funiculosum and its application in the hydrolysis of sugar cane bagasse for second generation ethanol production by fed batch operation
Cellulase production by Penicillium funiculosum and its application in the hydrolysis of sugar cane bagasse for second generation ethanol production by fed batch operation
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DOI：
10.1016/j.jbiotec.2012.10.014
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发表时间：
2013-01-10
影响因子：
4.1
通讯作者：
Pereira, Nei, Jr.
中科院分区：
文献类型：
--
作者：
Maeda, Roberto Nobuyuki;Barcelos, Carolina Araujo;Pereira, Nei, Jr.
本研究旨在生产一种纤维素酶混合物，并评估其在蔗渣同步糖化发酵（SSF）工艺中用于第二代乙醇生产的应用。对甘蔗渣进行预处理（稀释酸和碱性），以使纤维素复合物分解，并使纤维素组分更易于酶解。将剩余固体部分命名为蔗渣部分脱木质素纤维素蛋白（PDC），用于制酶和乙醇发酵。酶的生产在两种接种浓度（5%和10% v/v）的生物反应器中进行。接种较高接种量的发酵使产酶时间由72缩短至48。将酶提取物在中空纤维膜上进行切向超滤浓缩，并在37℃（同时SSF工艺操作温度）和50℃（纤维素酶混合酶活性的最佳温度）下评价所制纤维素酶混合物的稳定性。在37℃和50℃的条件下，纤维素水解产物至少稳定300 h。乙醇生产采用PDC进料间歇SSF工艺，使用现场混合纤维素酶。进料策略通过减少任何时候高固液比的存在，避免了扩散限制的经典问题，从而在过程结束时产生高乙醇浓度（100 g/L），这相当于理论上可获得的最大发酵效率的78%。实验结果表明，每吨甘蔗渣PDC的乙醇用量为380 L。(C) 2012 Elsevier B.V.版权所有
This study aimed to produce a cellulase blend and to evaluate its application in a simultaneous saccharification and fermentation (SSF) process for second generation ethanol production from sugar cane bagasse. The sugar cane bagasse was subjected to pretreatments (diluted acid and alkaline), as for disorganizing the ligocellulosic complex, and making the cellulose component more amenable to enzymatic hydrolysis. The residual solid fraction was named sugar cane bagasse partially delignified cellulignin (PDC), and was used for enzyme production and ethanol fermentation. The enzyme production was performed in a bioreactor with two inoculum concentrations (5 and 10% v/v). The fermentation inoculated with higher inoculum size reduced the time for maximum enzyme production (from 72 to 48). The enzyme extract was concentrated using tangential ultrafiltration in hollow fiber membranes, and the produced cellulase blend was evaluated for its stability at 37 degrees C, operation temperature of the simultaneous SSF process, and at 50 degrees C, optimum temperature of cellulase blend activity. The cellulolytic preparation was stable for at least 300 h at both 37 degrees C and 50 degrees C. The ethanol production was carried out by PDC fed-batch SSF process, using the onsite cellulase blend. The feeding strategy circumvented the classic problems of diffusion limitations by diminishing the presence of a high solid: liquid ratio at any time, resulting in high ethanol concentration at the end of the process (100 g/L), which corresponded to a fermentation efficiency of 78% of the maximum obtainable theoretically. The experimental results led to the ratio of 380 L of ethanol per ton of sugar cane bagasse PDC. (C) 2012 Elsevier B.V. All rights reserved.