Feedstock

Feedstock availability

Starch content, % w/w

Liquefaction and Saccharification

Fermentation organism/conditions

Ethanol formed

Reference

Corn HSG and PFC varieties

7.2 tonnes∙ha⁻¹

HSG: Starch 67.3%, total sugar 7.4% and PFC: starch 73.6%, total sugar 1.2%

SSF; Saccharification using STARGEN 002 at 2 kg∙tonne⁻¹ of corn with 300 g∙L⁻¹ initial solid concentration

S. cerevisiae ATCC 96581; fermentation at 30˚C, pH 4.2, 96 h and inoculum 2 mL per 100 mL

media

From HSG: 0.4 g∙ethanolg⁻¹ dry corn, 141.5 g∙L⁻¹ From PFC: 0.4 g∙ethanolg⁻¹ dry corn, 130.5 g∙L⁻¹

[26]

Corn meal

Starch 70.8%

Two-step enzymatic treatment using commercially available α-amylase and glucoamylase

S. cerevisiae; fermentation at 32˚C, pH 5.0, 48 h and inoculum 1.3% w/w

80% of the theoretical ethanol yield

[4]

Wheat

3.6 tonnes∙ha⁻¹ annum⁻¹

Total carbohydrates 69.7% and crude fiber 1%

S. cerevisiae; fermentation conditions not available

423 L∙tonne⁻¹; 1560 L∙ha⁻¹∙annum⁻¹

[29]

Wheat

Mash obtained under VHG conditions at 38% w/v solid concentration

Active dry yeast; fermentation at 20˚C and inoculums 10⁶ cells per 1 g wheat mash

23.80% v/v after 200 h at 20˚C

[27]

Wheat

Starch 53% - 57%

Liquefaction at 95˚C for 2 h and 45 min using α-amylase and saccharification at 55˚C for 2 h using glucoamylase at grain/flour to water weight ratio of 1:2.7

S. cerevisiae; fermentation 30˚C, 72 h and inoculum 1.6^*10⁷ cells∙mL⁻¹

From grain: 10% - 11% w/v, 12.7% - 13.8% v/v, 377 - 399 L∙tonne⁻¹; from flour: 12% - 12.7% w/v, 15.0% - 15.9% v/v and 344 - 367 L∙tonne⁻¹

[12]

Cassava

36.3 tonnes∙ha⁻¹ annum⁻¹ [29]

Starch 76% - 81%

Liquefaction using Spezyme enzyme for 30 min at 90˚C followed by SSF using Stargen enzyme at 1:100 w/w ratio of Stargen to starch and 10% w/v solid concentration

Dry bake’s Yeast; fermentation at 30˚C, 48 h, pH 5.5, and inoculum 10 mL yeast suspension having O.D 3.8 - 4.0 at 450 nm

558 g ethanol∙kg⁻¹ cassava starch, fermentation efficiency 98.4%

[30]

Cassava flour

Liquefaction at 80˚C for 90 min using Spezyme followed by SSF using alpha amylase, beta glucanase and two glucoamylases

S. cerevisiae; fermentation at 30˚C, pH 5.5, 72 h and inoculum 1.5^*10⁷ cells∙mL⁻¹

At lab scale: 17.2% v/v, 86.1% of the theoretical ethanol yield; At pilot scale: 16.5% v/v, 83.6% of the theoretical ethanol yield

[31]

Wild cassava

Liquefaction and saccharification using α-amylase and β-glucanase

Caloramator boliviensis (Thermoanaerobe); fermentation at 60˚C, pH 7, 48 h and inoculum 50 mL overnight culture per 240 mL media

33.0 g∙L⁻¹, 1.7 mol∙mol⁻¹, 85% of the theoretical ethanol yield

[33]