Table 2 Effects of alkaline treatment on monosaccharides and ethanol production

Spruce hydrolysate. S. cerevisiae

Ca(OH)₂ pH 10, 1 h

BEY^a= 98%

Furan aldehydes, decrease: ~21%

[33]

BEY^a (untreated^b)= 71%

Phenols, decrease: ~19%

BEY^a (reference^c)= 100%

Sugar, decrease: ~4%^d

NaOH pH 10, 1 h

BEY^a= 94%

Furan aldehydes, decrease: ~18%

BEY^a (untreated^b)= 71%

Phenols, decrease: ~18%

BEY^a (reference^c)= 100%

Sugar, decrease: ~4%^d

Bagasse hydrolysate. E. coli

Ca(OH)₂ pH 9, 60°C, 0.5 h

Q _{(24 h)}^e: ~1.3 g/Lh

Furan aldehydes, decrease: ~69%

[97]

No reference fermentation

Phenols, decrease: ~35%

Sugar, decrease: ~15%^f

Ca(OH)₂ pH 10, 60°C, 0.5 h

Q_{(24 h)}^e: ~ 1.0 g/Lh

Sugar, decrease: ~33%^f

No reference fermentation

Spruce hydrolysate. S. cerevisiae

Ca(OH)₂ pH 12, 60°C, 170 h

Q_{(24 h)}^e: ~ 0.3 g/Lh

Furan aldehydes, decrease: ~100%

[100]

No reference fermentation

Phenols, increase: ~150%

Sugar, decrease: ~68%^g

Ca(OH)₂ pH 11, 25°C, 20 h

Q_{(24 h)}^e: ~ 0 g/Lh

Furan aldehydes, decrease: ~77%

Q_{(48 h)}^e: ~ 0.3 g/Lh

Phenols, decrease: ~8%

No reference fermentation

Sugar, decrease: <5%^g

Bagasse hydrolysate. S. cerevisiae

Ca(OH)₂ pH 10, 1 h

BEY^a= 92%

Furan aldehydes, decrease: >25%

[43]

BEY^a (untreated^b)= 68%

Phenols, decrease: ~17%

BEY^a (reference^c)= 100%

Sugar, decrease: ~1%^f

Spruce hydrolysate. S. cerevisiae

Ca(OH)₂ pH 11, 30°C, 3 h

BEY^a= 120%

Furan aldehydes, decrease: ~59%

[49]

BEY^a (untreated^b)= 5%

Phenols, decrease: ~22%

BEY^a (reference^c)= 100%

Sugar, decrease: ~14%^h

Spruce hydrolysate. S. cerevisiae

NH₄OH pH 10, 22°C, 3 h

BEY^a =110%

Not determined

[76]

BEY^a (untreated^b)= 10%

BEY^a (reference^c)= 100%

Spruce hydrolysate. S. cerevisiae

NaOH pH 9, 55°C, 3 h

BEY^a = 111%

Furan aldehydes, decrease: ~33%

[77]

BEY^a (untreated^b) = 6%

Phenols, decrease: ~12%

BEY^a (reference^c) = 100%

Sugar, decrease: ~9%^d

NH₄OH pH 9, 55°C, 3 h

BEY^a =120%

Furan aldehydes, decrease: ~33%

BEY^a (untreated^b) = 7%

Phenols, decrease: ~13%

BEY^a (reference^c) = 100%

Sugar, decrease: ~7%^d

Corn stover hydrolysate. Z. mobilis

Ca(OH)₂ pH 9, 50°C, 0.5 h

No reference fermentation. OEYⁱ = 62%

Sugar, decrease: ~7%^j

[101]

Ca(OH)₂ pH 10, 50°C, 0.5 h

No reference fermentation. OEYⁱ = 70%.

Sugar, decrease: ~13%^j

Ca(OH)₂ pH 11, 50°C, 0.5 h

No reference fermentation. OEYⁱ = 59%

Sugar, decrease: ~29%^j