Compound   Structure   Hydrolysates   Concentrations in hydrolysates   Concentrations showed effects on S.cerevisiae   biomass preparation method mg/l ref mg/l ref formic acid Corn stover Acid/temperature 130-310 [12] 4000 [16] Spruce/ bagasse Acid/temperature 600-800 [14] 2700 [32] Hardwood chips Autohydrolysis/ temperature 4000-4600 [33]     Corn stover Steam explosion 6800 [16]     acetic acid Bagasse Bagasse Wheat straw Wheat straw Corn stover Willow wood Acid hydrolysis Enzymehydrolysis Acid hydrolysis Enzymehydrolysis Acid hydrolysis Acid hydrolysis 2400 2100 1300 900 2300 2200 [34] [34] [34] [34] [34] [34] 5000 6000 7500 >10000 [34] [16] [32] [35] Yellow polar wood Organosolv 900-4900 [36]     Spruce/ bagasse Acid/temperature 3100-5200 [14]     Corn stover Acid/temperature 2270-3740 [12]     Hardwood chips Autohydrolysis/ temperature 4500-5800 [33]     Corn stover Steam explosion 7800 [16]     levulinic acid Spruce/ bagasse Acid/temperature 200-300 [14]     Corn stover Acid/temperature 130-410 [12]     furfural Yellow polar wood Organosolv 0.2-35.2 [36] 1000 [34] Wheat straw Alkaline/oxidation 0-146* [5] >800 [35] Bagasse Wheat straw Corn stover Willow wood Acid hydrolysis Acid hydrolysis Acid hydrolysis Acid hydrolysis 410 270 510 500 [34] [34] [34] [34] >4000 [16] Hardwood chips Autohydrolysis/ temperature 510-780 [33]     Corn stover Acid/temperature 570 [12]     Corn stover Steam explosion 710 [16]     Wheat straw Spruce Barley straw Acid steam explosion Acid steam Acid steam 480-680 1100 2880 [15] [15] [15]     Spruce/ bagasse Acid/temperature 600-1200 [14]     furfuryl alcohol N.A. 2-furan methanol acetate N.A. HMF Wheat straw Alkaline/oxidation 0-16* [5] 1000 [34] Yellow polar wood Organosolv 0-56.5 [36] >3000 [35] Hardwood chips Autohydrolysis/ temperature 80-130 [33] >4000 [16] Bagasse Wheat straw Corn stover Willow wood Acid hydrolysis Acid hydrolysis Acid hydrolysis Acid hydrolysis 70 60 100 140 [34] [34] [34] [34]     Corn stover Acid/temperature 50-140 [12]     Wheat straw Spruce Barley straw Acid steam explosion Acid steam Acid steam 177-277 2140 996 [15] [15] [15]     Corn stover Steam explosion 560 [16]     Spruce/ bagasse Acid/temperature 1600-3400 [14]     vanillin Wheat straw Alkaline/oxidation 8-96* [5] 4000 [16] Wheat straw Spruce Barley straw Acid steam explosion Acid steam Acid steam 91-122 152 106 [15] [15] [15]     Willow Corn stover Dilute acid Steam explosion 430 4000 [1] [16]     syringic acid Wheat straw Wet oxidation 22 [1]   Wheat straw Alkaline/oxidation 6-52* [5]   Wheat straw Willow Wheat straw Wet oxidation Dilute acid Alkaline/oxidation 21 10 12-59* [1] [1] [5]   benzoic acid Corn stover Steam explosion 900 [16] 2000 [16] *: these values are expressed as g/100g straw N.A.: Not Available

Table 4: A summary of the selected compounds: their concentrations detected in various hydrolysates, and the concentrations at which inhibitory effects were shown on S.cerevisiae.