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Enzymatic Process for Corn Dry‐Grind High‐Solids Fermentation
Author(s) -
Kaur Prabhjot,
Rausch Kent D.,
Tumbleson M. E.,
Singh Vijay
Publication year - 2011
Publication title -
cereal chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.558
H-Index - 100
eISSN - 1943-3638
pISSN - 0009-0352
DOI - 10.1094/cchem-09-10-0130
Subject(s) - chemistry , fermentation , slurry , total dissolved solids , starch , food science , hydrolysis , chromatography , amylase , biochemistry , enzyme , materials science , environmental engineering , engineering , composite material
A modified dry‐grind process that combined the use of conventional amylases (glucoamylase [GA]), phytase, and granular starch hydrolyzing enzymes (GSHE) to achieve low liquefaction viscosities and low glucose concentrations during simultaneous saccharification and fermentation (SSF) with a high slurry solids content (>33% w/w) was developed. Doses of GSHE and GA were optimized for the modified process. At 35% solids content, the modified process had 80% lower slurry viscosity, 24% lower peak glucose concentration, 7.5% higher final ethanol concentration, and 51% higher fermentation rate compared with the conventional dry‐grind process. At 40% solids content, the modified process had lower viscosities, lower peak and residual glucose concentrations, and higher ethanol concentrations than the conventional process; however, the results were in contrast to those for 35% solids content. At 40% solids content, SSF did not run to completion for conventional or modified processes, and more than 2.5% w/v of residual glucose was left in the fermentation broth. Final ethanol concentration achieved with the modified process at 40% solids content was 19.5% v/v, similar to the ethanol concentration achieved with the modified process at 35% solids content. At 35% slurry solids content, a GSHE level of 1.25 μL/g db of corn and a GA level of 0.25 μL/g db of corn were selected as optimum enzyme doses for the modified process.