Enhancing ethanol yields in corn dry grind process by reducing glycerol production

2020 ◽  
Vol 97 (5) ◽  
pp. 1026-1036
Author(s):  
Deepak Kumar ◽  
Mickel Jansen ◽  
Rahul Basu ◽  
Vijay Singh
Keyword(s):  
Glycerol Production ◽  
Dry Grind ◽  
Ethanol Yields

scholarly journals Impact of Fractionation Process on the Technical and Economic Viability of Corn Dry Grind Ethanol Process

Processes ◽  
2019 ◽  
Vol 7 (9) ◽  
pp. 578 ◽  
Author(s):  
Kurambhatti ◽  
Kumar ◽  
Singh
Keyword(s):  
Ethanol Production ◽  
Simulation Models ◽  
Economic Feasibility ◽  
Production Costs ◽  
Internal Rate Of Return ◽  
Dry Fractionation ◽  
Fractionation Process ◽  
Dry Grind ◽  
Capital Costs ◽  
Ethanol Yields

Use of corn fractionation techniques in dry grind process increases the number of coproducts, enhances their quality and value, generates feedstock for cellulosic ethanol production and potentially increases profitability of the dry grind process. The aim of this study is to develop process simulation models for eight different wet and dry corn fractionation techniques recovering germ, pericarp fiber and/or endosperm fiber, and evaluate their techno-economic feasibility at the commercial scale. Ethanol yields for plants processing 1113.11 MT corn/day were 37.2 to 40 million gal for wet fractionation and 37.3 to 31.3 million gal for dry fractionation, compared to 40.2 million gal for conventional dry grind process. Capital costs were higher for wet fractionation processes ($92.85 to $97.38 million) in comparison to conventional ($83.95 million) and dry fractionation ($83.35 to $84.91 million) processes. Due to high value of coproducts, ethanol production costs in most fractionation processes ($1.29 to $1.35/gal) were lower than conventional ($1.36/gal) process. Internal rate of return for most of the wet (6.88 to 8.58%) and dry fractionation (6.45 to 7.04%) processes was higher than the conventional (6.39%) process. Wet fractionation process designed for germ and pericarp fiber recovery was most profitable among the processes.

scholarly journals Ethanol Production from Corn Fiber Separated after Liquefaction in the Dry Grind Process

Energies ◽  
2018 ◽  
Vol 11 (11) ◽  
pp. 2921 ◽  
Author(s):  
Chinmay Kurambhatti ◽  
Deepak Kumar ◽  
Kent Rausch ◽  
Mike Tumbleson ◽  
Vijay Singh
Keyword(s):  
Hot Water ◽  
Corn Fiber ◽  
Dry Grind ◽  
Untreated Fiber ◽  
Water Pretreatment ◽  
Ethanol Yields ◽  
Chemical Pretreatments ◽  
Enzyme Dosage ◽  
Hot Water Pretreatment ◽  
Conversion Efficiencies

Conversion of corn fiber to ethanol in the dry grind process can increase ethanol yields, improve coproduct quality and contribute to process sustainability. This work investigates the use of two physio-chemical pretreatments on corn fiber and effect of cellulase enzyme dosage to improve ethanol yields. Fiber separated after liquefaction of corn was pretreated using (I) hot water pretreatment (160 °C for 5, 10 or 20 min) and (II) wet disk milling and converted to ethanol. The conversion efficiencies of hot water pretreated fiber were higher than untreated fiber, with highest increase in conversion (10.4%) achieved for 5 min residence time at 160 °C. Disk milling was not effective in increasing conversion compared to other treatments. Hydrolysis and fermentation of untreated fiber with excess cellulase enzymes resulted in 33.3% higher conversion compared to untreated fiber.

scholarly journals Elimination of Glycerol Production in Anaerobic Cultures of a Saccharomyces cerevisiae Strain Engineered To Use Acetic Acid as an Electron Acceptor

2009 ◽  
Vol 76 (1) ◽  
pp. 190-195 ◽  
Author(s):  
Víctor Guadalupe Medina ◽  
Marinka J. H. Almering ◽  
Antonius J. A. van Maris ◽  
Jack T. Pronk
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Acetic Acid ◽  
Coenzyme A ◽  
Anaerobic Growth ◽  
Industrial Biotechnology ◽  
Glycerol Production ◽  
Complete Replacement ◽  
Lignocellulosic Hydrolysates ◽  
Ethanol Yields ◽  
Acetate Reduction

ABSTRACT In anaerobic cultures of wild-type Saccharomyces cerevisiae, glycerol production is essential to reoxidize NADH produced in biosynthetic processes. Consequently, glycerol is a major by-product during anaerobic production of ethanol by S. cerevisiae, the single largest fermentation process in industrial biotechnology. The present study investigates the possibility of completely eliminating glycerol production by engineering S. cerevisiae such that it can reoxidize NADH by the reduction of acetic acid to ethanol via NADH-dependent reactions. Acetic acid is available at significant amounts in lignocellulosic hydrolysates of agricultural residues. Consistent with earlier studies, deletion of the two genes encoding NAD-dependent glycerol-3-phosphate dehydrogenase (GPD1 and GPD2) led to elimination of glycerol production and an inability to grow anaerobically. However, when the E. coli mhpF gene, encoding the acetylating NAD-dependent acetaldehyde dehydrogenase (EC 1.2.1.10; acetaldehyde + NAD+ + coenzyme A ↔ acetyl coenzyme A + NADH + H+), was expressed in the gpd1Δ gpd2Δ strain, anaerobic growth was restored by supplementation with 2.0 g liter−1 acetic acid. The stoichiometry of acetate consumption and growth was consistent with the complete replacement of glycerol formation by acetate reduction to ethanol as the mechanism for NADH reoxidation. This study provides a proof of principle for the potential of this metabolic engineering strategy to improve ethanol yields, eliminate glycerol production, and partially convert acetate, which is a well-known inhibitor of yeast performance in lignocellulosic hydrolysates, to ethanol. Further research should address the kinetic aspects of acetate reduction and the effect of the elimination of glycerol production on cellular robustness (e.g., osmotolerance).

scholarly journals Metabolome and proteome analyses reveal transcriptional misregulation in glycolysis of engineered E. coli

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Chun-Ying Wang ◽  
Martin Lempp ◽  
Niklas Farke ◽  
Stefano Donati ◽  
Timo Glatter ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Binding Site ◽  
Metabolic Pathways ◽  
Glycerol Production ◽  
Inducible Promoters ◽  
E Coli ◽  
Inhibition Of Glycolysis ◽  
Underlying Mechanisms ◽  
Rate Limiting ◽  
Engineered Bacteria

AbstractSynthetic metabolic pathways are a burden for engineered bacteria, but the underlying mechanisms often remain elusive. Here we show that the misregulated activity of the transcription factor Cra is responsible for the growth burden of glycerol overproducing E. coli. Glycerol production decreases the concentration of fructose-1,6-bisphoshate (FBP), which then activates Cra resulting in the downregulation of glycolytic enzymes and upregulation of gluconeogenesis enzymes. Because cells grow on glucose, the improper activation of gluconeogenesis and the concomitant inhibition of glycolysis likely impairs growth at higher induction of the glycerol pathway. We solve this misregulation by engineering a Cra-binding site in the promoter controlling the expression of the rate limiting enzyme of the glycerol pathway to maintain FBP levels sufficiently high. We show the broad applicability of this approach by engineering Cra-dependent regulation into a set of constitutive and inducible promoters, and use one of them to overproduce carotenoids in E. coli.

Effect of Hybrid Variability on Modified E-Mill Dry Grind Corn Process

2006 ◽  
Author(s):  
Vivek Sharma ◽  
James V. Graeber ◽  
Vijay Singh
Keyword(s):  
Dry Grind

scholarly journals Kinetics and Metabolism of Bifidobacterium adolescentis MB 239 Growing on Glucose, Galactose, Lactose, and Galactooligosaccharides

2007 ◽  
Vol 73 (11) ◽  
pp. 3637-3644 ◽  
Author(s):  
Alberto Amaretti ◽  
Tatiana Bernardi ◽  
Elena Tamburini ◽  
Simona Zanoni ◽  
Mariella Lomma ◽  
...  
Keyword(s):  
Growth Rate ◽  
Recursive Algorithm ◽  
Carbon Fluxes ◽  
Degree Of Polymerization ◽  
Substrate Selectivity ◽  
Carbon Distribution ◽  
Bifidobacterium Adolescentis ◽  
Fermentation Products ◽  
Batch Cultures ◽  
Ethanol Yields

ABSTRACT The kinetics and the metabolism of Bifidobacterium adolescentis MB 239 growing on galactooligosaccharides (GOS), lactose, galactose, and glucose were investigated. An unstructured unsegregated model for growth in batch cultures was developed, and kinetic parameters were calculated with a recursive algorithm. The growth rate and cellular yield were highest on galactose, followed by lactose and GOS, and were lowest on glucose. Lactate, acetate, and ethanol yields allowed the calculation of carbon fluxes toward fermentation products. Distributions between two- and three-carbon products were similar on all the carbohydrates (55 and 45%, respectively), but ethanol yields were different on glucose, GOS, lactose, and galactose, in decreasing order of production. Based on the stoichiometry of the fructose-6-phosphate shunt and on the carbon distribution among the products, the ATP yield was calculated. The highest yield was obtained on galactose, while the yields were 5, 8, and 25% lower on lactose, GOS, and glucose, respectively. Therefore, a correspondence among ethanol production, low ATP yields, and low biomass production was established, demonstrating that carbohydrate preferences may result from different distributions of carbon fluxes through the fermentative pathway. During the fermentation of a GOS mixture, substrate selectivity based on the degree of polymerization was exhibited, since lactose and the trisaccharide were the first to be consumed, while a delay was observed until longer oligosaccharides were utilized. Throughout the growth on both lactose and GOS, galactose accumulated in the cultural broth, suggesting that β(1-4) galactosides can be hydrolyzed before they are taken up.

Preparation and Structure of Tetraphenylarsonium Bis[1,2-Dicyanoethenedithiolato]oxotechnetate(V)

1988 ◽  
Vol 41 (1) ◽  
pp. 151 ◽  
Author(s):  
SF Colmanet ◽  
MF Mackay
Keyword(s):  
Bond Distance ◽  
Apical Position ◽  
Space Group ◽  
Ethanol Yields ◽  
Oxo Ligand

The reaction of sodium 1,2-dicyanoethenedithiolate with [AsPh4][TcOCl4] in ethanol yields crystals of [AsPh4][ TcO ( mnt )2] (1). Crystals of (1) are monoclinic and belong to the space group P21/c with a 12.636(1), b 13.749(1), c 18.484(1)Ǻ, β 93.49(1)� with Z 4. Refinement on 3669 data measured with Cu Kα radiation converged at R 0.063. The structure consists of [ TcO ( mnt )2]- anions and [AsPh4]+ cations. The technetium(V) atom is five-coordinate with the four sulfur atoms in the basal positions and the oxo ligand in the apical position, to give a distorted square-pyramidal environment about the technetium. The Tc =O bond distance is 1.655(6)Ǻ.

Comparison of chemical composition and calculated ethanol yields of sugarcane varieties harvested for two growing seasons

2014 ◽  
Vol 58 ◽  
pp. 133-141 ◽  
Author(s):  
Y. Benjamin ◽  
J.F. Görgens ◽  
S.V. Joshi
Keyword(s):  
Chemical Composition ◽  
Sugarcane Varieties ◽  
Growing Seasons ◽  
Ethanol Yields

scholarly journals Sustainable Second-Generation Bioethanol Production from Enzymatically Hydrolyzed Domestic Food Waste Using Pichia anomala as Biocatalyst

2020 ◽  
Vol 13 (1) ◽  
pp. 259
Author(s):  
Ioanna Ntaikou ◽  
Georgia Antonopoulou ◽  
Gerasimos Lyberatos
Keyword(s):  
Food Waste ◽  
Second Generation ◽  
Scale Up ◽  
Pichia Anomala ◽  
Small Scale ◽  
Amylolytic Enzymes ◽  
Second Generation Bioethanol ◽  
Saccharification Efficiency ◽  
Ethanol Yields ◽  
Domestic Food

In the current study, a domestic food waste containing more than 50% of carbohydrates was assessed as feedstock to produce second-generation bioethanol. Aiming to the maximum exploitation of the carbohydrate fraction of the waste, its hydrolysis via cellulolytic and amylolytic enzymatic blends was investigated and the saccharification efficiency was assessed in each case. Fermentation experiments were performed using the non-conventional yeast Pichia anomala (Wickerhamomyces anomalus) under both separate hydrolysis and fermentation (SHF) and simultaneous saccharification and fermentation (SSF) modes to evaluate the conversion efficiencies and ethanol yields for different enzymatic loadings. It was shown that the fermentation efficiency of the yeast was not affected by the fermentation mode and was high for all handlings, reaching 83%, whereas the enzymatic blend containing the highest amount of both cellulolytic and amylolytic enzymes led to almost complete liquefaction of the waste, resulting also in ethanol yields reaching 141.06 ± 6.81 g ethanol/kg waste (0.40 ± 0.03 g ethanol/g consumed carbohydrates). In the sequel, a scale-up fermentation experiment was performed with the highest loading of enzymes in SHF mode, from which the maximum specific growth rate, μmax, and the biomass yield, Yx/s, of the yeast from the hydrolyzed waste were estimated. The ethanol yields that were achieved were similar to those of the respective small scale experiments reaching 138.67 ± 5.69 g ethanol/kg waste (0.40 ± 0.01 g ethanol/g consumed carbohydrates).

Enzymatic Dry Grind Corn Process Using a New Enzyme

2005 ◽  
Author(s):  
Ping Wang ◽  
Li Xu ◽  
David B. Johnston ◽  
Kent D. Rausch ◽  
M. E. Tumbleson ◽  
...  
Keyword(s):  
Dry Grind
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