Applications of alpha-amylase corn in the dry grind process for fuel ethanol production

Dry grind processing for fuel ethanol production from corn faces obstacles that limit profitability and sustainability. High temperatures required for liquefaction demand large thermal energy inputs and produce slurries with high final viscosities. These viscosity values increase power consumed by pumping systems and limit slurry solids contents to 32% w/w. Furthermore, enzymes needed for converting starch into glucose account for a considerable fraction of total production costs. To address these issues, inclusion of amylase corn was evaluated. This corn contains alpha-amylase enzyme and therefore obviates the need for addition of exogenous alpha-amylase. We analyzed the effects of low liquefaction temperatures (65 and 75˚C) on final ethanol concentrations. Corn feedstock included 15% amylase corn and had 32% (w/w) solid loading. Samples with amylase corn (15%) liquefied at 75˚C resulted in ethanol yields similar to those from only yellow dent corn liquefied at 85˚C. Viscosity profiles were evaluated at 36% (w/w) solids loading during liquefaction. The profiles of mixtures with 15% amylase corn were compared against two treatments of only yellow dent corn, each liquefied with an exogenous commercial alpha-amylase. Initial and peak viscosities of 15% amylase corn samples were higher than those observed in the yellow dent corn treatments. However, final viscosity of alpha-amylase corn treatment was lower than in one of the yellow dent corn treatments and similar to the remaining one. Corn mixtures with 32 and 36% (w/w) solids loadings and 15% amylase corn were combined with five commercial glucoamylases for evaluating maximum ethanol yields. Ethanol concentrations ranged from 17 to 19% v/v. Ethanol levels obtained in samples with amylase corn and certain glucoamylases were not different from those observed in samples with only yellow dent corn and conventional enzymes. Due to high residual glucose levels, some treatments with 32% (w/w) solid loading were tested reducing the liquefaction times from 150 to 90 min. Reduced liquefaction temperatures resulted in lower concentrations of residual saccharides. Inclusion of amylase corn (15%) reduced the liquefaction temperature by 10˚C, resulted in low post liquefaction viscosities and eliminated the need for exogenous alpha-amylases. Addition of alpha-amylase corn in the dry grind process can result in energy savings and may reduce overall processing costs.

Name thesis:degree_name

M.S.

Level thesis:degree_level

Thesis

Discipline thesis:degree_discipline

Agricultural & Biological Engr

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2016

Author dc:creator

• Guagliano, Bruno Javier

Contributors dc:contributor

• Singh, Vijay
• Rausch, Kent
• Tumbleson, Mike

• Amylase Corn, Dry Grind

Statement dc:rights

• Copyright 2016 Bruno Guagliano

Language dc:language

en

Handle dc:identifier

http://hdl.handle.net/2142/92754

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/92754