The critical roles of exposed surface residues for the thermostability and halotolerance of a novel GH11 xylanase from the metagenomic library of a saline-alkaline soil

Characterization of a new bifunctional endo-1,4-β-xylanase/esterase found in the rumen metagenome

“…11 ) indicates an important characteristic of this enzyme, thus demonstrating its feasibility for use in the biotechnological sector. Halotolerant xylanases have been previously reported 40 , 46 , 47 as feed additives for broilers 48 and other farm animals because the diets of these animals are routinely formulated with the inclusion of NaCl; moreover, they are included in pretreatments containing high concentrations of NaCl, such as for cellulose solubilization and depolymerization 49 , because they increase the efficiency and synergy between these pretreatments. Additionally, the tolerance of XylR to organic solvents (Fig.…”

Xylanolytic Extremozymes Retrieved From Environmental Metagenomes: Characteristics, Genetic Engineering, and Applications

“…Soil ( Li et al, 2019 ), compost ( Jeong et al, 2012 ), and gut ( Shi et al, 2011 ) are the three most highly explored habitats for harvesting xylan-degrading enzyme-encoding genes in metagenomics. Compost soil grabbed attention due to the high load of microbial biomass and unique biochemical properties.…”

“…Halophilic/halotolerant xylanases show immense applications in the processing of seafood and clarification of juices and wine ( Wang et al, 2016 ; Alokika et al, 2018 ). Metagenomics has dug out numerous halotolerant xylanolytic enzymes from different environmental sources ( Al-Darkazali et al, 2017 ; Fredriksen et al, 2019 ; Ghadikolaei et al, 2019 ; Li et al, 2019 ; Alves et al, 2020 ). Metagenomic xylanase from alkaline-saline soil has shown the ability to retain 80% of its activity at 3M NaCl.…”

“…Metagenomic xylanase from alkaline-saline soil has shown the ability to retain 80% of its activity at 3M NaCl. On further characterization, this thermostable xylanase reveals that the surface glutamates (E137 and E139) play a key role in its halotolerance and halostability ( Li et al, 2019 ). Chicken cecum metagenome is also shown to be the source of highly halotolerant xylanase that retains 96% activity at 4M NaCl ( Al-Darkazali et al, 2017 ).…”

“…Other environmental samples, such as soil, sediment, water, and effluent, from extreme as well as normal habitats have also been explored for xylan-depolymerizing enzymes ( Lee et al, 2006 ; Hu et al, 2008 ; Wang et al, 2010 ; Li et al, 2019 ; Alves et al, 2020 ). Several cold-active GH-10 and GH-11 xylanase-encoding genes have been retrieved from tundra soil; xylanases displayed cold adaptation ( Wang et al, 2010 ).…”