Table 2.

Comparison of several ethanol productions using Tween as an additive found in the literature and in the current study

Raw material	Pretreated method	Tween additives	Adding method of Tween	Fermentation method	Particle size of raw material	Washed or unwashed with water	Prehydrolysis time (hours) + fermentation time (hours)	Enzyme loadings	Ethanol concentration(g/L)	Ethanol yield (%)	Reference
Reed straw	LHW	Tween 40	Prior to fermentation	Fed-batch S-SSF	3 to 5 cm	Unwashed	18 + 72	25 FPU cellulase/g oven-dried WIS	56.28	69.1	This study
Corn stover	LHW	Tween 40	Prior to fermentation	Fed-batch S-SSF	4 to 7 cm	Unwashed	18 + 72	25 FPU cellulase/g oven-dried WIS	52.26	71.1	This study
Reed straw	LHW	-	-	Fed-batch S-SSF	20 to 80 mesh	Washed	18 + 72	40 FPU cellulase/g oven-dried WIS	39.40	75.1	[27]
Corn stover	LHW	-	-	Fed-batch S-SSF	20 to 80 mesh	Washed	18 + 72	40 FPU cellulase/g oven-dried WIS	39.40	74.4	In press
Wheat straw	Sulfuric acid	Tween 20	In the fermentation stage	SSF	40 mesh	Washed	72	20 FPU cellulase and 40 CBU β-glucosidase/g glucan	12.4	73.9	[24]
Spruce	Steam pretreatment	Tween 20	In the fermentation stage	SSF	2 to 10 mm	Washed	48	44 FPU/g cellulose	20 to 25	92	[15]
Sugarcane bagasse	Dilute ammonia	Tween 80	In the pretreatment stage	SSF	0.05 to 1.5 cm	Washed	72	30 FPU Spezyme CP and 30 CBU Novozyme 188/g glucan	18 g/100 g of dry biomass	69	[23]
Sugarcane bagasse	Dilute ammonia	Tween 20	In the pretreatment stage	SSF	0.05 to 1.5 cm	Washed	72	30 FPU Spezyme CP and 30 CBU Novozyme 188/g glucan	15 g/100 g of dry biomass	59	[23]

CBU, cellobiase unit; LHW, liquid hot water; SSF, simultaneous saccharification and fermentation; S-SSF, semi-simultaneous saccharification and fermentation; WIS, water-insoluble solids.