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Potential use of vetiver grass for cellulolytic enzyme production and bioethanol production

Subsamran, Khajeewan, Mahakhan, Polson, Vichitphan, Kanit, Vichitphan, Sukanda, Sawaengkaew, Jutaporn
Biocatalysis and agricultural biotechnology 2019 v.17 pp. 261-268
Aspergillus tubingensis, Chrysopogon zizanioides, beta-glucosidase, cellulose, endo-1,4-beta-glucanase, enzymatic hydrolysis, enzyme activity, ethanol production, fungal growth, hydrolysis, lignocellulose, pH, reducing sugars, response surface methodology, sodium hydroxide, solid state fermentation, sulfuric acid, water content
Vetiver grass (VG) high cellulose is an abundant lignocellulosic material used in both cellulolytic enzyme and bioethanol production. Appropriate VG size for fungal growth and enzymes production was 500 µm, while the optimum cellulolytic enzyme production by Aspergillus tubingensis HS1–5 under solid state fermentation using response surface methodology (RSM) was the substrate volume of 12.36 g, moisture content of 56.45% and pH at 4.4. Filter Paperase (FPase), Carboxymethylcellulase (CMCase) and β-glucosidase activities of 156.84, 2096.67 and 63.11 U/g substrate, respectively were investigated under these conditions. The highest yield of reducing sugar was found with pretreatment of VG with 1% (w/v) NaOH followed by 0.5% (v/v) H2SO4 at 121 °C for 60 min. Maximum fermentable sugar from enzymatic hydrolysis (90 FPU/mL) and bioethanol production were obtained with 21.10 and 5.85 g/L, respectively. The crude cellulase enzyme was suitable for VG hydrolysis and the sugar released can be further utilized for bioethanol production.