Degradation of Mannan I and II Crystals by Fungalendo-β-1,4-Mannanases and a β-1,4-Mannosidase Studied with Transmission Electron Microscopy

Abstract

We have used the endo-beta-1,4-mannanase from Trichoderma reesei (Tr Man5A), the endo-beta-1,4-mannanase from Aspergillus niger (An Man5A) and the exo-beta-1,4-mannosidase from A. niger (An Mnd2A) to follow the enzymatic degradation of mannan I and II crystals. The degradation process was studied by transmission electron microscopy and also followed by analysis of the released soluble reducing sugars. The mannan crystals were degraded by the endo-beta-1,4-mannanases and to a lesser extent by the exo-beta-1,4-mannosidase. The observed hydrolysis pattern on mannan I crystals is fully consistent with the current view of the molecular structure of these crystals. The molecular organization of the mannan chains in mannan II crystals is less clear and the digestion results give some further information about the ultrastructure of mannan II. In addition, insight is provided into the mode of the enzymatic attack on the crystals of mannan I and mannan II.

Bottom-up Construction of Xylan Nanocrystals in Dimethyl Sulfoxide

“…35 To prepare the nanocrystals, xylan was dispersed in DMSO by using magnetic stirring at 60 ˚C (Figure S1B). After suspending xylan in DMSO at 60 ˚C for 10 days, an elongated flake-like structure was observed under AFM imaging (Figure 2A), similar to precipitates of low molecular weight cellulose 37,38 or mannan 29,30 . The anisotropic shape of the nanostructure is due to a faster growth along one direction.…”

“…22,23 However, hemicellulose, a major part of lignocellulosic biomass, 24 has not been investigated from the point of view of nanocrystals andalthough they do existeven the reports on its crystallization are scarce. 25,26,27,28,29,30 Hemicellulose is generally considered to be amorphous due to the side groups 31 and therefore, its proposed applications have been mainly in bulk applications, for example, films for packaging and coating. 32,33,34 The difficulty to construct controlled, nano-sized crystalline structures, such as rods or fibrils, from hemicellulose has largely impeded its use in more sophisticated materials applications so far.…”

Introduction of theAspergillus fumigatusα-1,2-mannosidase MsdS intoTrichoderma reeseileads to abnormal polarity and improves the ligno-cellulose degradation

“…For example, in Talaromyces cellulolyticus the approximately 80% mannose yield was increased with high β-mannanase and β-mannosidase activities when supplemented with A. niger derived commercial enzyme (Inoue et al, 2015). It has been shown that the crystal of mannan can be degraded when endo-α-1,4-mannanase from T. reesei , endo-α-1,4-mannanase from A. niger and exo-α-1,4-mannosidase from A. niger are used (Hagglund et al, 2001). To evaluate the effects of N-glycan processing on protein secretion, in this study we further analyzed cellulase and β-mannanase activities in Tr-MsdS strain.…”

Introduction of the Aspergillus fumigatus α-1,2-mannosidase MsdS into Trichoderma reesei improves the ligno-cellulose degradation

“…For example, in Talaromyces cellulolyticus the approximately 80% mannose yield was increased with high β-mannanase and β-mannosidase activities when supplemented with A. niger derived commercial enzyme [42]. It has been shown that the crystal of mannan can be degraded when endo-α-1,4-mannanase from T. reesei, endo-α-1,4-mannanase from A. niger and exo-α-1,4-mannosidase from A. niger are used [43]. To evaluate the effects of N-glycan processing on protein secretion, in this study we further analyzed cellulase and β-mannanase activities in Tr-MsdS strain.…”