Agricultural wastes as substrates for β-glucosidase production by Talaromyces thermophilus: Role of these enzymes in enhancing waste paper saccharification.
In the present study, we investigated a potent extracellular β-glucosidases secreted by the thermophilic fungal strain AX4 of Talaromyces thermophilus, isolated from Tunisian soil samples. This strain was selected referring to the highest thermostability of its β-glucosidases compared to the other fungal isolates. The β-glucosidase production was investigated by submerged fermentation. The optimal temperature and initial pH for maximum β-glucosidase production were 50°C and 7.0, respectively. Several carbon sources were assayed for their effects on β-glucosidase production, significant yields were obtained in media containing lactose 1% (3.0 ± 0.36 U/ml) and wheat bran 2% (4.0 ± 0.4 U/ml). The combination of wheat bran at 2% and lactose at 0.8% as carbon source enhanced β-glucosidase production, which reached 8.5 ± 0.28 U/ml. Furthermore, the β-glucosidase-rich enzymatic juice of T. thermophilus exhibited significant synergism with Trichoderma reesei (Rut C30) cellulases for pretreated waste paper (PWP) hydrolysis. Interestingly, the use of this optimal enzymatic cocktail increased 4.23 fold the glucose yield after saccharification of waste paper. A maximum sugar yield (94%) was reached when using low substrate (2%) and enzyme loading (EC1).
a Laboratory of Eukaryotes Molecular Biotechnology, Center of Biotechnology of Sfax , University of Sfax , Sfax , Tunisia.
Hanen
H
Mallek-Fakhfakh
b Laboratory of Chemistry of Natural Substances, Faculty of Sciences of Sfax , University of Sfax , Sfax , Tunisia.
Jawhar
J
Fakhfakh
a Laboratory of Eukaryotes Molecular Biotechnology, Center of Biotechnology of Sfax , University of Sfax , Sfax , Tunisia.
Najla
N
Masmoudi
a Laboratory of Eukaryotes Molecular Biotechnology, Center of Biotechnology of Sfax , University of Sfax , Sfax , Tunisia.
Fatma
F
Rezgui
a Laboratory of Eukaryotes Molecular Biotechnology, Center of Biotechnology of Sfax , University of Sfax , Sfax , Tunisia.
Ali
A
Gargouri
a Laboratory of Eukaryotes Molecular Biotechnology, Center of Biotechnology of Sfax , University of Sfax , Sfax , Tunisia.
Hafedh
H
Belghith
D004043:Dietary Fiber / Q000378:metabolism; D004795:Enzyme Stability; D005285:Fermentation; D006863:Hydrogen-Ion Concentration; D006868:Hydrolysis; D007218:Industrial Microbiology / Q000379:methods*; D007785:Lactose / Q000378:metabolism; D010209:Paper; D012037:Refuse Disposal / Q000379:methods*; D012988:Soil Microbiology; D032901:Talaromyces / Q000201:enzymology* / Q000378:metabolism; D013696:Temperature; D001617:beta-Glucosidase / Q000378:metabolism*
D004043:Dietary Fiber; D001617:beta-Glucosidase; D007785:Lactose
Talaromyces thermophilus; lactose; waste paper saccharification; wheat bran; β-glucosidase