Economizing the lignocellulosic hydrolysis process using heterologously expressed auxiliary enzymes feruloyl esterase D (CE1) and β-xylosidase (GH43) derived from thermophilic fungi Scytalidium thermophilum

• Published in: Bioresource technology 2021-11, Vol.339, p.125603-125603, Article 125603
• Main Authors: Agrawal, Dhruv, Tsang, Adrian, Chadha, Bhupinder Singh
• Format: Article
• Language: English
• Subjects: Cloning; Feruloyl esterase; Hydrolysis; Scytalidium thermophilum; β-xylosidase
• ISSN: 0960-8524; 1873-2976
• DOI: 10.1016/j.biortech.2021.125603

[Display omitted] •Cloning of CE1 and GH43 accessory enzymes from S. thermophilum.•FAE (FAED_SCYTH) sub-classified as SF5 esterase.•β-xylosidase (XYL43B_SCYTH) was found to be highly xylose tolerant.•The accessory enzymes enhanced the hydrolytic efficiency of Cellic CTec2.•Priming of acid treated rice straw slurry with CE1 and GH43 improved hydrolysis. Two lignocellulolytic accessory enzymes, feruloyl esterase D (FAED_SCYTH) and β-xylosidase (XYL43B_SCYTH) were cloned and produced in the Pichia pastoris X33 as host. The molecular weight of recombinant enzymes FAED_SCYTH and XYL43B_SCYTH were ~ 31 and 40 kDa, respectively. FAED_SCYTH showed optimal activity at pH 6.0, 60 °C; and XYL43B_SCYTH at pH 7.0, 50 °C. FAED_SCYTH and XYL43B_SCYTH exhibited t1/2: 4 and 0.5 h, respectively (50 °C, pH 5.0). The β-xylosidase was bi-functional with pronounced activity against pNP-α-arabinofuranoside besides being highly xylose tolerant (retaining ~ 97% activity in the presence of 700 mM xylose). Cocktails prepared using these enzymes along with AA9 protein (PMO9D_SCYTH) and commercial cellulase CellicCTec2, showed improved hydrolysis of the pre-treated lignocellulosic biomass. Priming of pre-treated lignocellulosic biomass with these accessory enzymes was found to further enhance the hydrolytic potential of CellicCTec2 promising to reduce the enzyme load and cost required for obtaining sugars from biorefinery relevant pre-treated substrates.