Fusel Alcohols in Fuel Ethanol Fermentation Matt Hawkins Lallemand Biofuels & Distilled Spirits Overview Fusel Alcohols Structures and Formation Fusels in Corn Mash Fermentation Fusels Produced in Fermentation Factors Influencing Fusel Formation Fusels in Liquefaction Measurement and Impact Dealing with Fusel Alcohols Title Area Fusel Alcohol Structures Tert-amyl Alcohol Isopropanol Tert-Butyl Alcohol
Iso-amyl Alcohol 1-Propanol 3, 2, or 1 -Pentanol Isobutanol Title Area General Fermentation Title Area Fusel Formation Hazelwood et al, 2008 Appl. Envir. Title Area Micro. Measurement of Fusels - HPLC Isopropanol 1-Propanol Tert-amyl
Tert-Butyl Title Area Isobutanol 2-Pentanol 3-Pentanol 1-Pentanol Isoamyl Fusels in Corn Fermentation Title Area Hirose et al. 1962 Agr. Biol. Chem. Fusels Produced in Fermentation (plant) Isopropanol tert-butyl 1-propanol Isobutanol
tert-amyl 3-pentanol 2-pentanol Isoamyl 1-pentanol Total Title Area Average 0 0 36.78 49.13 0 0 0 402.23 0 488.14 Min 0 0 30.73 39.07 0
0 0 300.80 0 388.53 Max 0 0 43.15 54.33 0 0 0 479.95 0 570.95 Fusel Production in Fermentation (plant) Fusel Production During Fermentation Fusel Concentration (ppm) 250 200 150
100 50 0 Liq 10Hr 18Hr 25Hr 32Hr 39Hr 45Hr 50Hr Drop BW Title Area Tert-Butyl 1-propanol Isobutanol Isoamyl Fusels Produced in Fermentation (lab) Isopropanol tert-butyl1-propanol Isobutanol tert-amyl3-pentanol 2-pentanol Isoamyl 1-pentanol Total Title Area Mash A 0 0
183.28 122.43 0 0 0 362.86 0 668.57 Mash B 0 0 61.20 76.61 0 0 0 341.54 0 479.35 Mash C 0 0 43.90 82.00
0 0 0 307.40 0 433.30 Impact of Urea Dose Fusel Concentration (ppm) Affect of Urea Dose on Fusel Oil Production 500 400 Total Fusels Linear (Total Fusels) 300 200 100 0 Title Area
Insufficient Minimal Urea Dose Excess Impact of Protease Dose Fusel Concentration (ppm) Affect of Protease Usage on Fusel Oil Production 500 Total Fusels Linear (Total Fusels) 1-propanol Linear (1-propanol) Isobutanol Linear (Isobutanol) Isoamyl Linear (Isoamyl) 400 300 200
100 0 None 10ppm 30ppm Protease Dose Title Area 100pp m Impact of Fermentation Temperature Affect of Increasing Temperature on Fusel Oil Production Fusel Cocentration (ppm) 500 Total Fusels Linear (Total Fusels) 1-propanol Linear (1-propanol) isobutanol Linear (isobutanol)
isoamyl Linear (isoamyl) 400 300 200 100 0 31 32 33 34 35 Temperature (C) Title Area 36 37 Impact of Mash Solids
Affect of Increasing Mash Solids on Fusel Oil Production Fusel Concentration (ppm) 600 500 400 300 Total Fusels 200 100 0 30.5% 31.0% 31.5% 32.0% 32.5% 33.0% 33.5% 34.0% Percent Solids of Mash Title Area Removal of Fusel Oils Tert-amyl Alcohol BP:214F (101C) Isopropanol
BP:181F (82C) Iso-amyl Alcohol BP:268F (131C) 1-Propanol BP: 206F (97C) Isobutanol BP: 226F (108C) Title Area Tert-Butyl Alcohol BP: 180F (82C) Ethanol BP:173F (78C) Removing Fusel Oils Lower Temperatures Higher Temperatures Title
Area Source: Ethanol Producer Magazine Fusels in Liq Mash Isopropanol tert-butyl-alcohol 1-propanol Isobutanol tert-amyl-alcohol Avg 5.18 Min 5.18 Max 5.18 Count 1 30.26 52.86 73.60
3.38 22.83 73.60 122.58 130.05 73.60 8 8 1 84.30 11.92 184.76 16 0 0 192.58 34.72
932.64 27 0 3-pentanol 2-pentanol Isoamyl alcohol 1-pentanol Title Area Testing Fusels in the Lab Fusel Species Isoamyl Alcohol Tert-amyl Alcohol 1-Propanol Tert-Butyl Alcohol Isobutanol Title Area Concentrations tested (ppm) 35 85 135 235 435 835 1235 0 50 100 200 400 800 1200
0 50 100 200 400 800 1200 69 119 169 269 469 869 1269 0 50 100 200 400 800 1200 Observed Observed Max Min 933 34 185 12 130 23 123 3 74 74 Dextrose R elative to Control Impact of Fusel Oils on Fermentation Effect of Fusel Addition on Dextrose Concentration (48hr) 120% 80%
Isoamyl Tert-amyl 1-Propanol Tert-Butyl Isobutanol 40% 0% 0ppm 50ppm 100ppm 200ppm 400ppm 800ppm 1200ppm -40% Fusel Addition Title Area Impact of Fusel Oils of Fermentation Ethanol Relative to Control Effect of Fusel Addition on Ethanol Production (48hr) 5% 0%
0ppm -5% 50ppm 100ppm 200ppm 400ppm 800ppm 1200ppm -10% -15% Fusel Addition Title Area Isoamyl Tert-amyl 1-Propanol Tert-Butyl Isobutanol Impact of Fermentation Conditions on Fusel Inhibition Effect of Temperature and Isoamyl Alcohol on Ethanol Production (48hr) 13.8 Ethanol (%w/v) 13.2 32.2
33.3 34.4 12.6 12.0 11.4 0 50 200 Isoamyl Alcohol Dose (ppm) Title Area 400 800 Impact of Fermentation Conditions on Fusel Inhibition Effect of Temperature and Isoamyl Alcohol on Ethanol Production (48hr) 1.00%
0.00% 0 50 200 400 800 Relative Ethanol -1.00% 32.2 33.3 34.4 -2.00% -3.00% -4.00% -5.00% -6.00% Isoamyl Alcohol Dose (ppm)
Title Area Impact of Fermentation Conditions on Fusel Inhibition Effect of Mash Solids and Isoamyl Alcohol on Ethanol Production (48hr) 13.6 13.4 Relative Ethanol 13.2 32.47% Solids 33.70% Solids 34.57% Solids 13.0 12.8 12.6 12.4 12.2 0 Title Area 50
200 400 Isoamyl Alcohol Dose (ppm) 800 Impact of Fermentation Conditions on Fusel Inhibition Effect of Mash Solids and Isoamyl Alcohol on Ethanol Production (48hr) 0.0% 0 -1.0% 50 200 400 800 Relative Ethanol -2.0% 32.47% Solids 33.70% Solids
34.57% Solids -3.0% -4.0% -5.0% -6.0% -7.0% Isoamyl Alcohol Dose (ppm) Title Area Impact of Fermentation Conditions on Fusel Inhibition Effect of Urea Dose and Isoamyl Contamination on Dextrose Consumption 2.5 Dextrose (%w/v) 2.0 1.5 450ppm Urea 650ppm urea 850ppm Urea 1.0
0.5 0.0 0 50 200 400 800 Isoamyl Dose (ppm) Title Area 800 + P 800 + P Impact of Fermentation Conditions on Fusel Inhibition Effect of Protease Use on Ethanol Production in Isoamyl Contaminated Corn Mash 13.6
0ppm 50ppm 200ppm 400ppm 800ppm 800ppm +P 800ppm +P Ethanol (%w/v) 13.5 13.4 13.3 13.2 Title Area Drop Ethanol Production Impact of Fermentation Conditions on Fusel Inhibition Effect of Propagation Nutrient Addition on Ethanol Production in Fusel Contaminated Fermentations 14
+2.7% Ethanol (% w /v) 12 10 +3.8% 8 6 Title Area Control Nutrient 24 Time (h) 48
Summary Fusel oils produced during normal fermentation Predominately Isoamyl alcohol, Isobutanol, and 1 propanol Others can be observed as well High variance in concentration Providing insufficient nitrogen increases isoamyl alcohol formation Protease addition marginally reduced fusel production Fusels are observed in liquefaction samples Isoamyl was observed as the most inhibitory to yeast Others can be problematic in combination with isoamyl Addition of supplemental nutrition can help with fusel issues; as can reduced fermentation temperatures and mash solids Title Area
