Table 5.

Downstream index for scale-up in advanced FBSSF program

Type	External substrate	Evaluation parameter for industrial applications
		Biodegradability d	Fermentability e
			Fermentation for 48 h	Fermentation for 144 h
FBSSF	33.8 g RSc	≤9.3% (3.0 ± 0.1 g glucose/L)	≤57.2% (9.3 ± 0.2 g ethanol/L)	≤72.3% (11.7 ± 0.2 g ethanol/L)
SSFa	33.8 g RSc	≤8.3% (2.7 ± 0.1 g glucose/L)	≤47.2% (7.7 ± 0.2 g ethanol/L)	≤59.8% (9.7 ± 0.2 g ethanol/L)
Untreatedb	34.5 g RS	≤7.1% (2.3 ± 0.1 g glucose/L)	≤22.7% (3.7 ± 0.1 g ethanol/L)	≤25.8% (4.2 ± 0.1 g ethanol/L)
Untreatedb	12.4 g Avicel	≤11.0% (3.5 ± 0.1 g glucose/L)	≤74.4% (12.0 ± 0.2 g ethanol/L)	≤82.4% (13.3 ± 0.2 g ethanol/L)

^aSSF by S. cerevisiae D5A (ATCC 200062); Bak 2014d.

^bFBSSF without the EBI.

^closs (approximately 2%) of RS substrate by the EBI.

^dthe maximum yield of soluble monomeric sugar after 24 h of fermentation.

^ethe yield of theoretical maximum ethanol.