Novel multidomain, multifunctional glycoside hydrolases from highly lignocellulolytic Caldicellulosiruptor species

Abstract

Biological hydrolysis of microcrystalline cellulose is an uncommon feature in the microbial world, especially among bacteria and archaea growing optimally above 70°C (the so‐called extreme thermophiles). In fact, among this group only certain species in the genus Caldicellulosiruptor are capable of rapid and extensive cellulose degradation. Four novel multidomain glycoside hydrolases (GHs) from Caldicellulosiruptor morganii and Caldicellulosiruptor danielii were produced recombinantly in Caldicellulosiruptor bescii and characterized. These GHs are structurally organized with two or three catalytic domains flanking carbohydrate binding modules from Family 3. Collectively, these enzymes represent GH families 5, 9, 10, 12, 44, 48, and 74, and hydrolyze crystalline cellulose, glucan, xylan, and mannan, the primary carbohydrates in plant biomass. Degradation of microcrystalline cellulose by cocktails of GHs from three Caldicellulosiruptor species demonstrated that synergistic interactions enable mixtures of multiple enzymes to outperform single enzymes, suggesting a community mode of action for lignocellulose utilization in thermal environments. © 2018 American Institute of Chemical Engineers AIChE J, 64: 4218–4228, 2018

Insights into Thermophilic Plant Biomass Hydrolysis from Caldicellulosiruptor Systems Biology

“…Four additional combinations of catalytic domains in the GDL were identified from the genome sequencing of C. danielii, C. morganii, and C. naganoensis, including two enzymes that include three catalytic domains (GH12-Gh5-CBM3 × 3-GH48 and GH10-CBM3-GH12-GH48) [23]. Homologous production of full length, glycosylated versions of these enzymes noted that these enzymes, like others encoded by the C. bescii GDL, hydrolyze microcrystalline cellulose synergistically [94] and are candidates for engineering a superior C. bescii biocatalyst.…”

The GH10 and GH48 dual-functional catalytic domains from a multimodular glycoside hydrolase synergize in hydrolyzing both cellulose and xylan

“…Among the six multimodular GHs in C. bescii , Cb Xyn10C/Cel48B [17] (or CelC [18]) is intriguing in that it has a nearly identical domain organization pattern, as well as amino acid sequence, to that of CelA [19]. The most prominent difference is that the N-terminal GH9-CBM3c domains in CelA are replaced by a GH10 catalytic domain in Cb Xyn10C/Cel48B.…”

“…The most prominent difference is that the N-terminal GH9-CBM3c domains in CelA are replaced by a GH10 catalytic domain in Cb Xyn10C/Cel48B. Strong intermolecular synergy in hydrolyzing crystalline cellulose has been observed when combining some of these multimodular enzymes (such as CelA and Cb Xyn10C/Cel48B), which is believed to be important for cellulose utilization by C. bescii [18]. However, until now the underlying mechanism about such a synergy has not been fully elucidated.…”

Genomic and physiological analyses reveal that extremely thermophilicCaldicellulosiruptor changbaiensisdeploys unique cellulose attachment mechanisms

“…Here, we have analyzed the genome sequence of Caldicellulosiruptor changbaiensis , isolated from a hot spring in the Changbai Mountains [3], representing the 14 th and most recent addition to the Caldicellulosiruptor pangenome. Past Caldicellulosiruptor pangenomes were comprised of multiple species from most countries of origin, which allowed for prior analysis on the basis of biogeography [5], with the exception of China and Japan [20]. Now with the addition of the C. changbaiensis genome sequence, insights into the biogeography of isolates from China and how they compare to the global Caldicellulosiruptor pangenome is possible.…”

“…Now with the addition of the C. changbaiensis genome sequence, insights into the biogeography of isolates from China and how they compare to the global Caldicellulosiruptor pangenome is possible. Furthermore, on the basis of the open Caldicellulosiruptor pangenome [20,5], we hypothesize that the C. changbaiensis genome may encode for novel substrate-binding proteins and/ or plant biomass degrading enzymes. In addition to updating the Caldicellulosiruptor pangenome, we also present differences in the growth physiology of C. changbaiensis versus Caldicellulosiruptor bescii , currently the benchmark species against which most Caldicellulosiruptor are compared for their plant biomass degrading capabilities.…”