Table 2.
Effects of alkaline treatment on monosaccharides and ethanol production
| System studied | Detoxification conditions | Improvement in fermentability | Effect on inhibitors and sugar | Reference | |
|---|---|---|---|---|---|
| Spruce hydrolysate. S. cerevisiae |
Ca(OH)2 pH 10, 1 h |
BEYa= 98% |
Furan aldehydes, decrease: ~21% |
[33] |
|
| |
|
BEYa (untreatedb)= 71% |
Phenols, decrease: ~19% |
|
|
| |
|
BEYa (referencec)= 100% |
Sugar, decrease: ~4%d |
|
|
| |
NaOH pH 10, 1 h |
BEYa= 94% |
Furan aldehydes, decrease: ~18% |
|
|
| |
|
BEYa (untreatedb)= 71% |
Phenols, decrease: ~18% |
|
|
| |
|
BEYa (referencec)= 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 |
BEYa= 92% |
Furan aldehydes, decrease: >25% |
[43] |
|
| |
|
BEYa (untreatedb)= 68% |
Phenols, decrease: ~17% |
|
|
| |
|
BEYa (referencec)= 100% |
Sugar, decrease: ~1%f |
|
|
| Spruce hydrolysate. S. cerevisiae |
Ca(OH)2 pH 11, 30°C, 3 h |
BEYa= 120% |
Furan aldehydes, decrease: ~59% |
[49] |
|
| |
|
BEYa (untreatedb)= 5% |
Phenols, decrease: ~22% |
|
|
| |
|
BEYa (referencec)= 100% |
Sugar, decrease: ~14%h |
|
|
| Spruce hydrolysate. S. cerevisiae |
NH4OH pH 10, 22°C, 3 h |
BEYa =110% |
Not determined |
[76] |
|
| |
|
BEYa (untreatedb)= 10% |
|
|
|
| |
|
BEYa (referencec)= 100% |
|
|
|
| Spruce hydrolysate. S. cerevisiae |
NaOH pH 9, 55°C, 3 h |
BEYa = 111% |
Furan aldehydes, decrease: ~33% |
[77] |
|
| |
|
BEYa (untreatedb) = 6% |
Phenols, decrease: ~12% |
|
|
| |
|
BEYa (referencec) = 100% |
Sugar, decrease: ~9%d |
|
|
| |
NH4OH pH 9, 55°C, 3 h |
BEYa =120% |
Furan aldehydes, decrease: ~33% |
|
|
| |
|
BEYa (untreatedb) = 7% |
Phenols, decrease: ~13% |
|
|
| |
|
BEYa (referencec) = 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 |
a Balanced ethanol yield given in percent of a reference fermentation of a sugar solution. b Untreated hydrolysate. c Reference sugar solution. d Glucose, xylose, arabinose, galactose mannose, and cellobiose. e Ethanol productivity. f Glucose, xylose, arabinose, galactose, and mannose. g Glucose, xylose, galactose, and mannose. h Glucose and mannose. i Overall ethanol yield, yield calculated on sugars present prior to detoxification, given in percent of the theoretical yield. j Glucose, xylose, and arabinose.