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Ultrasonic pretreatment for enhanced...

Iowa State University., Agricultural and Biosystems Engineering.

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Ultrasonic pretreatment for enhanced saccharification and fermentation of ethanol production from corn.

Record Type:	Electronic resources : Monograph/item
Title/Author:	Ultrasonic pretreatment for enhanced saccharification and fermentation of ethanol production from corn./
Author:	Montalbo-Lomboy, Melissa T.
Description:	205 p.
Notes:	Advisers: David Grewell; J. (Hans) van Leeuwen.
Contained By:	Dissertation Abstracts International70-01B.
Subject:	Energy. -
Online resource:	http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=3342275
ISBN:	9780549997504

Ultrasonic pretreatment for enhanced saccharification and fermentation of ethanol production from corn.
Montalbo-Lomboy, Melissa T.

Ultrasonic pretreatment for enhanced saccharification and fermentation of ethanol production from corn. - 205 p.

Advisers: David Grewell; J. (Hans) van Leeuwen.

Thesis (Ph.D.)--Iowa State University, 2008.

Based on these results, ultrasonication is a promising pretreatment method in corn ethanol production, as an alternative to jet cooking.

ISBN: 9780549997504Subjects--Topical Terms:

876794
Energy.

Ultrasonic pretreatment for enhanced saccharification and fermentation of ethanol production from corn.
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020 $a 9780549997504
035 $a (UMI)AAI3342275
035 $a AAI3342275
040 $a UMI $c UMI
100 1 $a Montalbo-Lomboy, Melissa T. $3 1057411
245 1 0 $a Ultrasonic pretreatment for enhanced saccharification and fermentation of ethanol production from corn.
300 $a 205 p.
500 $a Advisers: David Grewell; J. (Hans) van Leeuwen.
500 $a Source: Dissertation Abstracts International, Volume: 70-01, Section: B, page: 0595.
502 $a Thesis (Ph.D.)--Iowa State University, 2008.
520 $a Based on these results, ultrasonication is a promising pretreatment method in corn ethanol production, as an alternative to jet cooking.
520 $a The 21st Century human lifestyle has become heavily dependent on hydrocarbon inputs. Energy demand and the global warming effects due to the burning of fossil fuels have continued to increase. Rising awareness of the negative environmental and economic impacts of hydrocarbon dependence has led to a resurgence of interest in renewable energy sources such as ethanol. Fuel ethanol is known to be a cleaner and renewable source of energy relative to gasoline. Many studies have agreed that fuel ethanol has reduced greenhouse gas (GHG) emissions and has larger overall energy benefits compared to gasoline. Currently, the majority of the fuel ethanol in the United States is produced from corn using dry-grind milling process. The typical dry-grind ethanol plant incorporates jet cooking using steam to cook the corn slurry as pretreatment for saccharification; an energy intensive step. In aiming to reduce energy usage, this study evaluated the use of ultrasonics as an alternative to jet cooking.
520 $a Ultrasonic batch experiments were conducted using a Branson 2000 Series bench-scale ultrasonic unit operating at a frequency of 20 kHz and a maximum output of 2.2 kW. Corn slurry was sonicated at varying amplitudes from 192 to 320 mumpeak-to-peak(p-p) for 0-40 seconds. Enzyme stability was investigated by adding enzyme (STARGEN(TM)001) before and after sonication. Scanning electron micrograph (SEM) images and particle size distribution analysis showed a nearly 20-fold size reduction by disintegration of corn particles due to ultrasonication. The results also showed a 30% improvement in sugar release of sonicated samples relative to the control group (untreated). The efficiency exceeded 100% in terms of relative energy gain from the additional sugar released due to ultrasonication compared to the ultrasonic energy applied. Interestingly, enzymatic activity was enhanced when sonicated at low and medium power. This result suggested that ultrasonic energy did not denature the enzymes during pretreatment.
520 $a Ultrasonication of sugary-2 corn was also investigated in the study. Results similar to those for commodity corn (dent corn) were found, in terms of glucose yield and starch conversion. SEM and polarized-light microscope pictures showed the partial gelatinization of corn slurry due to ultrasound. In the 96-h saccharification time, a model was formulated to fit the sugar release curve. The results have shown 17-21% increase in the extent of sugar production from sonicated samples relative to the control group. Additionally, the reaction rates of the sonicated samples were 2- to 10-fold higher than the reaction rates for the control group. In comparing sugary-2 corn with commodity corn, it was found that sonicated sugary-2 corn saccharified faster than sonicated commodity corn. It is important to note, without ultrasonic treatment, sugary-2 corn released more reducing sugar than commodity corn during saccharification.
520 $a To further investigate the potential of ultrasonics for scale-up, a continuous flow system was studied. An ultrasonic continuous flow system was tested using Branson's flow-through "donut" horn. The donut horn, which vibrates radially, was placed inside a 5.5 L stainless steel reactor. The amplitude was maintained at 12 mumpp and the feed flow rate was varied from 8-27 L/min (2-7 gal/min) with reactor retention times varying from 12-40 seconds. Samples sonicated in continuous flow system showed lower reducing sugar yield than batch ultrasonication. However, considering the ultrasonic energy density of batch and continuous systems, the continuous systems proved to be more energy efficient in terms of glucose production compared with the batch system. It was also seen that particle size disintegration was proportional to energy density regardless of the type of ultrasonic system used.
520 $a To compare ultrasonics with jet cooking, fermentation experiments were conducted. There were only marginal differences between jet cooked samples and the sonicated samples in terms of ethanol conversion based on theoretical yield. Furthermore, statistical analysis confirmed that there was no significant difference (p<0.05) in the ethanol yields of the two pretreatment methods. Economic analysis indicated that the capital cost of installing ultrasonics was higher compared to jet cooker equipment. However, due to the energy needs of jet cooking, a typical 189 million liters (50 million gallon) per year ethanol plant ethanol plant would save about 16% in pretreatment cost by using ultrasonics.
590 $a School code: 0097.
650 4 $a Energy. $3 876794
650 4 $a Engineering, Agricultural. $3 1019504
650 4 $a Engineering, Environmental. $3 783782
650 4 $a Engineering, Mechanical. $3 783786
690 $a 0539
690 $a 0548
690 $a 0775
690 $a 0791
710 2 0 $a Iowa State University. $b Agricultural and Biosystems Engineering. $3 1026283
773 0 $t Dissertation Abstracts International $g 70-01B.
790 $a 0097
790 1 0 $a Dunn, Larson, Jr. $e committee member
790 1 0 $a Grewell, David, $e advisor
790 1 0 $a Khanal, Samir Kumar $e committee member
790 1 0 $a Raman, D. Raj $e committee member
790 1 0 $a van Leeuwen, J. (Hans), $e advisor
791 $a Ph.D.
792 $a 2008
856 4 0 $u http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=3342275