Department of Molecular Biosciences and Bioengineering, University of Hawaii at Manoa, Honolulu, HI 96822, USA.
Bioresour Technol. 2010 Apr;101(8):2741-7. doi: 10.1016/j.biortech.2009.10.075. Epub 2009 Nov 24.
The effects of ultrasound and heat pretreatments on ethanol yields from cassava chips were investigated. Cassava slurries were sonicated for 10 and 30 s at the amplitudes of 80, 160, and 320 microm(pp) (peak to peak amplitude in microm) corresponding to low, medium, and high power levels, respectively. The sonicated and non-sonicated (control) samples were then subjected to simultaneous liquefaction-saccharification and ethanol fermentation. Cassava starch-to-ethanol conversion efficiencies showed that higher ethanol yields were directly related to sonication times, but not to power levels. Significantly higher ethanol yields were observed only for sonicated samples at the high power level. The ethanol yield from the sonicated sample was 2.7-fold higher than yield from the control sample. Starch-to-ethanol conversion rates from sonicated cassava chips were also significantly higher; the fermentation time could be reduced by nearly 24 h for sonicated samples to achieve the same ethanol yield as control samples. Thus, ultrasound pretreatment enhanced both the overall ethanol yield and fermentation rate. When compared to heat-treated samples, the sonicated samples produced nearly 29% more ethanol yield. Combined heat and ultrasound treatment had no significant effect on overall ethanol yields from cassava chips. Ultrasound is also preferable to heat pretreatment because of lower energy requirements, as indicated by energy balances. Integration of ultrasound application in cassava-based ethanol plants can significantly improve ethanol yields and reduce the overall production costs.
研究了超声和热预处理对木薯渣乙醇产量的影响。木薯浆分别在低、中、高强度下（分别对应 80、160 和 320 μm（峰到峰振幅））进行超声处理 10 和 30 s。然后对超声和未超声（对照）样品进行同时液化-糖化和乙醇发酵。木薯淀粉到乙醇的转化率表明，更高的乙醇产量直接与超声时间有关，而与功率水平无关。仅在高强度下对超声处理的样品观察到明显更高的乙醇产量。超声处理样品的乙醇产量比对照样品高 2.7 倍。超声处理木薯渣的淀粉到乙醇的转化率也显著提高；对于超声处理的样品，发酵时间可以缩短近 24 h，即可达到与对照样品相同的乙醇产量。因此，超声预处理提高了乙醇的整体产率和发酵速度。与热处理样品相比，超声处理的样品产生的乙醇产量高出近 29%。与对照样品相比，联合热和超声处理对木薯渣的总乙醇产率没有显著影响。由于能量平衡表明超声预处理的能量需求较低，因此与热预处理相比，超声处理更具优势。在基于木薯的乙醇工厂中应用超声技术可以显著提高乙醇产量并降低整体生产成本。
