Production of ethanol from alkali-pretreated sugarcane bagasse under the influence of different process parameters

Figures & data

Table 1. Comparison of the main contents of untreated and treated sugarcane bagasse.

Substrate	Cellulose (%)	Lignin (%)	Total phenol (mg/ml)
Untreated sugarcane bagasse	35 ± 2.0	25 ± 1.5	0.000
Treated sugarcane bagasse	74 ± 3.0	9.0 ± 1.0	0.012 ± 0.002

Table 2. Effect of various incubation temperatures on fermentation efficiency and ethanol production by Saccharomyces cerevisiae G1 in the simultaneous saccharification and fermentation process.

Temperature (°C)	Sugar (mg/ml)	Ethanol (%)	Ethanol yield (g/g)	Fermentation efficiency (%)
25	28.321 ± 0.134	2.54	0.0843	16.52
30	20.471 ± 0.069	5.231	0.1377	27
35	20.102 ± 0.099	5.201	0.1356	26.58
40	34.431 ± 0.064	2.231	0.0928	18.19
45	56.912 ± 0.402	0.0421	0.0274	5.37

Note: initial pH = 5; incubation period = 96 h; inoculum size = 2% (v/v).

Table 3. Effect of various incubation periods on fermentation efficiency and ethanol production by Saccharomyces cerevisiae G1 in the simultaneous saccharification and fermentation process.

Incubation period (h)	Sugar (mg/ml)	Ethanol (%)	Ethanol yield (g/g)	Fermentation efficiency (%)
24	38.213 ± 0.125	1.541	0.0761	14.92
48	29.423 ± 0.210	4.951	0.17055	33.44
72	25.912 ± 0.160	5.212	0.1602	31.41
96	21.451 ± 0.152	5.851	0.1581	31.0
120	19.321 ± 0.123	5.751	0.1469	28.80
144	19.212 ± 0.144	5.701	0.1453	28.49

Note: initial pH = 5; incubation temperature = 30°C; inoculum size = 2% (v/v).

Table 4. Effect of various inoculum sizes on fermentation efficiency and ethanol production by Saccharomyces cerevisiae G1 in the simultaneous saccharification and fermentation process.

Inoculum size (%)	Sugar (mg/ml)	Ethanol (%)	Ethanol yield (g/g)	Fermentation efficiency (%)
1	26.401 ± 0.356	4.852	0.1514	29.68
2	20.451 ± 0.344	5.350	0.1407	27.58
3	18.213 ± 0.222	5.989	0.1523	29.86
4	19.145 ± 0.240	5.752	0.1465	28.72
5	19.231 ± 0.218	5.452	0.1391	27.27

Note: initial pH = 5; incubation temperature = 30°C; incubation period = 96 h.

Table 5. Effect of various initial pH values of the growth medium on fermentation efficiency and ethanol production by Saccharomyces cerevisiae G1 in the simultaneous saccharification and fermentation process.

Initial pH	Sugar (mg/ml)	Ethanol (%)	Ethanol yield (g/g)	Fermentation efficiency (%)
4.0	35.351 ± 0.275	3.521	0.1524	29.88
4.5	30.415 ± 0.301	4.452	0.1588	31.14
5.0	24.910 ± 0.255	5.531	0.1649	32.33
5.5	20.122 ± 0.214	5.992	0.1563	30.65
6.0	29.311 ± 0.331	4.982	0.1710	33.53
6.5	36.391 ± 0.291	3.303	0.1497	29.35
7.0	38.912 ± 0.370	2.521	0.1290	25.29

Note: incubation temperature = 30°C; incubation period = 96 h; inoculum size = 3% (v/v).

Table 6. Effect of various nitrogen sources on fermentation efficiency and ethanol production by Saccharomyces cerevisiae G1 in the simultaneous saccharification and fermentation process.

Nitrogen source		Sugar (mg/ml)	Ethanol (%)	Ethanol yield (g/g)	Fermentation efficiency (%)
Organic	Yeast extract	21.245 ± 0.266	5.821	0.1564	30.67
	Peptone	29.958 ± 0.187	4.921	0.1727	33.86
	Tryptone	30.391 ± 0.127	4.921	0.1754	34.39
	Urea	29.41 ± 0.049	4.281	0.1474	28.90
Inorganic	Ammonium sulphate	20.912 ± 0.188	5.891	0.1569	30.77
	Ammonium nitrate	31.910 ± 0.141	3.981	0.1499	29.39
	Ammonium chloride	30.121 ± 0.473	3.121	0.110	21.57

Note: initial pH = 5.5; incubation temperature = 30°C; incubation period = 96 h; inoculum size = 3% (v/v).