TABLE 4.
Production of value-added products from BSG hydrolysates.
| Pretreatment methods a | Intermediate product(s) obtained after pretreatment | Fermentation type/medium/conditions | Microorganism(s) | Product | Yield level | Literature |
|---|---|---|---|---|---|---|
| P1: Acid hydrolysis (1.25% H2SO4; T = 120°C; t = 17 min) | BSG hydrolysate (50 g/L glucose) | SmF/BSG hydrolysate +5 M NaOH +1 g/L cell concentration/V = 25 ml; T = 37°C; t = 48 h | Lactobacillus delbrueckii UFV H2B20 | Lactic acid | 0.73 g lactic acid/g glucose consumed | Mussatto et al. (2007b) |
| P2: Alkali hydrolysis (2% NaOH; T = 120°C; t = 90 min) | ||||||
| P3: Enzymatic hydrolysis (Cellulast complex; 45 FPU/g; 100 rpm; t = 96 h) | ||||||
| P1: Acid hydrolysis (1.25% H2SO4; T = 120°C; t = 17 min) | BSG hydrolysate (75 g/L glucose) | SmF/BSG hydrolysate +5 M NaOH +10% cell suspension + yeast extract (or without)/V = 250 ml; T = 37°C; t = 96 h; 60 g | Lactobacillus acidophilus ATCC 43121 | Lactic acid | 0.48 g lactic acid/g glucose consumed from BSG hydrolysate (without add. of yeast extract) | Liguori et al. (2015) |
| P2: Alkali hydrolysis (2% NaOH; T = 120°C; t = 90 min) | ||||||
| P3: Enzymatic hydrolysis (2.24% cellulase and 1% β-glucosidase; T = 45°C, 120 rpm; t = 72 h) | 0.60 g lactic acid/g glucose consumed from BSG hydrolysate (with add. of yeast extract) | |||||
| Acid hydrolysis (1.5 M H2SO4; T = 130°C; t = 30 min) | BSG hydrolysate (39.85% glucose) | SmF/Culture media and BSG hydrolysate (1:10)/T = 35°C; t = 72 h; 200 rpm | Lactobacillus plantarum ATCC 8014 | Lactic acid | 27.78% | Assefa and Jabasingh (2020) |
| P1: Acid hydrolysis (72% H2SO4; T = 120°C; t = 17 min) | Lignin (solubilized 60 and 90%) | - | - | Ferulic acid, p-coumaric acid | 9.65 mg ferulic acid/g of solubilized lignin and 9.22 mg p-coumaric acid/g of solubilized lignin | Mussatto et al. (2007a) |
| P2: Alkali hydrolysis (2% NaOH; T = 120°C; t = 90 min) | ||||||
| Acid hydrolysis (H2SO4, T = 120°C; t = 17 min) | BSG hydrolysate (21.88 g/L xylose) | SmF/BSG hydrolysate +1 g/L cell concentration/V = 250 ml; T = 30°C; t = 24 h | Candida guilliermondii FTI 20 037 | Xylitol | 0.70 g xylitol/g xylose consumed | Mussatto and Roberto (2005) |
| Hydrothermal pretreatment (BSG + distilled water; T = 160°C; t = 20 min) | Hemicellulose liquor (20 g/L xylose) | SmF/BSG liquor + cell suspension/V = 2 ml; T = 30°C; 100 rpm; t = 24 h intervals | Pachysolen tannophilus | Xylitol | 0.47 g xylitol/g xylose consumed | da Silva et al. (2019) |
| Enzymatic hydrolysis (dried BSG + enzymatic extract obtained after the SSF with A. niger + enzymatic cocktail Viscozyme L (1%); t = 48 h) | BSG hydrolysate (0.56 g of reducing sugar/gDM) | SmF/BSG hydrolysate +5% cell/V = 100 ml; T = 30°C; 120 rpm; t = 48 h (C. necator); t = 72 h; (B. cepacia) | Burkholderia cepacia | Poly-3-hidroxybutyrate (PHB) | 7 mg PHB/gDM | Llimós et al. (2020) |
| Cupriavidus necator | 9 mg PHB/gDM | |||||
| P1: Acid hydrolysis (1–6% H2SO4, T = 120°C, t = 15 min) | Glucose, arabinose, xylose + added monosodium glutamate (8 g/L) | SmF/BSG hydrolysate +2% of spore solution + MSG, KH2PO4, K2HPO4, MgSO4·7H2O, CaCl2, and ZnSO4·7H2O/V = 50 ml; T = 30°C; t = 7 days; 350 rpm | Monascus purpureus CMU001 | Natural red pigment | 22.25 UA500 | Silbir and Göksungur (2019) |
| P2: Detoxification (Ca(OH)2, T = 55°C, t = 1 h) | ||||||
| P: Acid hydrolysis (1.5% H2SO4, T = 121°C, t = 20 min) | Glucose, xylose and arabinose (0.44 g/g total solids) | Acidogenic fermentation/BSG + anaerobic granular sludge/V = 1.75 L; T = 37°C; t = 72 h; 1,500 rpm | - | Volatile fatty acids | 16.89 g COD/L | Castilla-Archilla et al. (2020) |
| P1: Microwave-assisted alkali hydrolysis (0.5% NaOH; microwave radiation 400 W; t = 60 s) | BSG hydrolysate (0.25 g glucose/g biomass) | SmF/BSG hydrolysate +2% of inoculum + (NH4)2HPO4, (NH4)2SO4, KOH, EDTA, MgSO4·7H2O, FeSO4⋅7H2O, CaCl2⋅6H2O, MnSO4⋅H2O and ZnSO4·7H2O/V = 100 ml; T = 30°C; 180 rpm | Enterobacter ludwigii | 2,3-Butanediol | 0.43 g 2,3-Butanediol/g glucose consumed from BSG hydrolysate | Amraoui et al. (2022) |
| P2: Enzymatic hydrolysis (cellulase 100 U/mL; T = 50°C, 150 rpm; t = 96 h) | ||||||
| NP | Protein and carbon sources | SSF/BSG + inoculum + glucose, FeSO4⋅7H2O, MgSO4, MnSO4⋅H2O and ZnSO4·7H2O/V = 500 ml; T = 28°C, t = 96 h | Fusarium fujikuroi | Gibberellic acid (GA3) | 0.82 g GA3/kg BSG | da Silva et al. (2021) |
| NP | Carbon source (sugars, CO2, biomass) | SmF/BSG + peptone, yeast extracts, KH2PO4, (NH4)2SO4, MgSO4·H2O+ methanol +0.1% of spore suspension/conival flask; T = 30°C; t = 14 days | Aspergilus niger | Citric acid | 0.512% mass per volume of citric acid | Femi-Ola and Atere (2012) |
| Saccharomyces cerevisiae | 0.312% mass per volume of citric acid | |||||
| NP | Carbon source (sugars) | SSF/BSG + peptone, yeast extract, KH2PO4, (NH4)2SO4, MgSO4·H2O/V = 150 ml | Aspergilus niger strain | Citric acid | 0.23% mass per volume of citric acid | Pathania et al. (2018) |
| NP | Sugars (D-glucose) | SmF/BSG + D-glucose, l-galactose, yeast extract, peptone, monosodium glutamate/T = 40°C; t = 96 h; 100 rpm | Aspergillus flavus | Ascorbic acid | 7.25 g/L | Banjo et al. (2018) |
| Aspergillus tamarii | 6.25 g/L | |||||
| NP | Ergosterol | SSF/50% BSG + rye, 5 ml liquid inoculum/V = 720 ml; t = 24 h; under cool white fluorescent light | Cordyceps militaris | Cordycepin | 10.42 mg cordycepin/g substrate | Gregori (2014) |
a
P, pretreatment; P1, 1st step of pretreatment; P2, 2nd step of pretreatment; P3, 3rd step of pretreatment; NP, no pretreatmet.