Simultaneous Saccharification and Fermentation of Sugar Beet Pulp for Efficient Bioethanol Production

Table 3

Ethanol yield (kg absolute ethanol) from 100 kg of wet (ca. 23% d.m.) sugar beet pulp.

Fermentation trial	Pretreatment
	Without pretreatment, pulp suspended in water	Pressure-thermal pretreatment				Ultrasound pretreatment
		30 min		60 min		50% amplitude, 20 min		100% amplitude, 20 min
		Pulp suspended in water	Pulp suspended in 2% w/w sulfuric acid solution	Pulp suspended in water	Pulp suspended in 2% w/w sulfuric acid solution	Pulp suspended in water	Pulp suspended in 2% w/w sulfuric acid solution	Pulp suspended in water	Pulp suspended in 2% w/w sulfuric acid solution
Without enzymatic activation	3.6 ± 0.2	5.0 ± 0.2	5.6 ± 0.3	5.1 ± 0.2	5.7 ± 0.2	3.9 ± 0.1	4.1 ± 0.2	4.1 ± 0.1	4.4 ± 0.2
Enzymatic activation, Variant I	4.2 ± 0.1	5.6 ± 0.2	6.7 ± 0.3	5.9 ± 0.2	6.8 ± 0.3	4.4 ± 0.2	4.6 ± 0.2	4.5 ± 0.2	4.7 ± 0.2
Enzymatic activation, Variant II	4.2 ± 0.1	5.5 ± 0.2	6.7 ± 0.4	5.7 ± 0.2	6.7 ± 0.4	4.5 ± 0.2	4.7 ± 0.2	4.8 ± 0.2	4.9 ± 0.2
Enzymatic activation, Variant I & aeration	4.3 ± 0.1	5.7 ± 0.2	6.6 ± 0.3	5.6 ± 0.2	6.6 ± 0.3	4.7 ± 0.1	4.9 ± 0.2	4.9 ± 0.2	5.0 ± 0.2

Results expressed as mean values ± SE (); mean values with different letters are significantly different ( < 0.05, two-way ANOVA).