RESULTS: Here, we firstly report that a soluble soy protein (SP) extracted from inexpensive defatted soy powder (DSP) showed excellent performance in promoting the EC of glucan in LHW-pretreated lignocellulosic substrates. The addition of the SP (80 mg/g glucan) could readily reduce the cellulase (Celluclast 1.5 L®) loading by 8 times from 96.7 to 12.1 mg protein/g glucan and achieve a glucan EC of 80% at a hydrolysis time of 72 h. With the same cellulase (Celluclast 1.5 L®) loading (24.2 mg protein/g glucan), the ECs of glucan in LHW-pretreated bamboo, eucalyptus, and Masson pine substrates increased from 57%, 54% and 45% (without SP) to 87%, 94% and 86% (with 80 mg SP/g glucan), respectively. Similar effects were also observed when Cellic CTec2, a newer-generation cellulase preparation, was used. Mechanistic studies indicated that the adsorption of soluble SP onto the surface of lignin residues could reduce the nonproductive binding of cellulolytic enzymes to lignin. The cost of the SP required for effective promotion would be equivalent to the cost of 2.9 mg cellulase (Celluclast 1.5 L®) protein (or 1.2 FPU/g glucan), if a proposed semi-simultaneous saccharification and fermentation (semi-SSF) model was used.
CONCLUSIONS: Near-complete saccharification of glucan in LHW-pretreated lignocellulosic substrates could be achieved with the addition of the inexpensive and biocompatible SP additive extracted from DSP. This simple but remarkably effective technique could readily contribute to improving the economics of the cellulosic biorefinery industry.
结果:这里,我们首次报道了从廉价的脱脂大豆粉(DSP)中提取的可溶性大豆蛋白(SP)在LHW预处理的木质纤维素底物中显示出优异的促进葡聚糖EC的性能。添加SP(80mg/g葡聚糖)可以很容易地将纤维素酶(Celluclast1.5L®)负荷从96.7降低8倍至12.1mg蛋白质/g葡聚糖,并在水解时间为72小时时达到80%的葡聚糖EC。使用相同的纤维素酶(Celluclast1.5L®)负荷(24.2mg蛋白质/g葡聚糖),LHW预处理竹子中葡聚糖的ECs,桉树,马尾松基质从57%增加,54%和45%(无SP)到87%,94%和86%(含80mgSP/g葡聚糖),分别。当新一代纤维素酶制备物CellicCTec2时,也观察到类似的效果,被使用。机理研究表明,可溶性SP在木质素残留物表面的吸附可以减少纤维素分解酶与木质素的非生产性结合。有效推广所需的SP成本相当于2.9mg纤维素酶(Celluclast1.5L®)蛋白(或1.2FPU/g葡聚糖)的成本,如果使用拟议的半同时糖化和发酵(半SSF)模型。
结论:通过添加从DSP提取的廉价且生物相容的SP添加剂,可以实现LHW预处理的木质纤维素底物中葡聚糖的接近完全糖化。这种简单但非常有效的技术可以很容易地有助于改善纤维素生物炼制工业的经济性。