Open AccessCharacterization of two thermophilic cellulases from Talaromyces leycettanus JCM12802 and their synergistic action on cellulose hydrolysis
Author(s) -
Yuan Gu,
Fei Zheng,
Yuan Wang,
Xiaoyun Su,
Yingguo Bai,
Bin Yao,
Huoqing Huang,
Huiying Luo
Publication year - 2019
Publication title -
plos one
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.99
H-Index - 332
ISSN - 1932-6203
DOI - 10.1371/journal.pone.0224803
Subject(s) - cellulase , thermophile , cellulose , hydrolysis , chemistry , straw , food science , pichia pastoris , enzymatic hydrolysis , substrate (aquarium) , biomass (ecology) , phosphoric acid , biochemistry , enzyme , nuclear chemistry , biology , organic chemistry , agronomy , inorganic chemistry , ecology , gene , recombinant dna
Talaromyces leycettanus JCM12802 is a great producer of thermophilic glycoside hydrolases (GHs). In this study, two cellulases ( Tl Cel5A and Tl Cel6A) belonging to GH5 and GH6 respectively were expressed in Pichia pastoris and functionally characterized. The enzymes had acidic and thermophilic properties, showing optimal activities at pH 3.5–4.5 and 75–80°C, and retained stable at temperatures up to 60°C and over a broad pH range of 2.0−8.0. Tl Cel5A and Tl Cel6A acted against several cellulose substrates with varied activities (3,101.1 vs. 92.9 U/mg to barley β-glucan, 3,905.6 U/mg vs. 109.0 U/mg to lichenan, and 840.3 and 0.09 U/mg to CMC-Na). When using Avicel, phosphoric acid swollen cellulose (PASC) or steam-exploded corn straw (SECS) as the substrate, combination of Tl Cel5A and Tl Cel6A showed significant synergistic action, releasing more reduced sugars (1.08–2.87 mM) than the individual enzymes. These two cellulases may represent potential enzyme additives for the efficient biomass conversion and bioethanol production.