Bioethanol from Lignocellulosic Biomass: Current Findings Determine Research Priorities

Table 6

Assessment of selected pretreatment processes [15, 88–96].

Pretreatment process	Yield of fermentable sugars	Wastes	Investment
Physical or physicochemical
(i) Mechanical	Low	Very low	Low
(ii) Steam explosion	High	Low	High
(iii) Ammonia fiber explosion (AFEX)	Moderate	Very low	High
(iv) Carbonic acid	Very high	Very low	Low
Chemical
(i) Dilute acid	Very high	High	Moderate
(ii) Concentrated acid	Very high	High	High
(iii) Alkaline extraction	Very high	High	Low
(iv) Wet oxidation	High	Low	Low
(v) Organosolv	Very high	Low	Very high