scholarly journals Transcriptomic Analysis of the White-rot Basidiomycete Lentinus Squarrosulus to Provide Insights Into Its Lignocellulose Biodegradation Ability

Author(s):  
Aarthi Ravichandran ◽  
Atul Kolte ◽  
Arindam Dhali ◽  
S Gopinath ◽  
Manpal Srid

Abstract BackgroundBasidiomycetes are of special interest in biotechnological research for their versatile potential in the degradation of lignocellulosic biomass, chiefly attributed to ligninolytic enzymes along with exo, endo β-glucanases, xylanases, esterases, pectinases, mannanases, cellobiohydrolases, polysaccharide monooxygenases. Relatively little is known about the metabolic process and the subsequent polysaccharide degradation. Transcriptomic analysis of lignicolous fungi grown on different substrates, although attempted by researchers, has focused on a fairly small group of species reporting the expression of fungal genes in response to lignocellulosic biomass as a substrate. This study accordingly reports analysis of transcriptome of a white-rot Basidiomycete L.squarrosulus grown in simple potato dextrose broth supplemented with aromatic compound, reactive black dye to gain an insight into the degradation ability of the fungus. RNA was sequenced using Illumina NextSeq 500 to obtain 6,679,162 high-quality paired-end reads that were assembled de novo using CLC assembly cells to generate 25,244 contigs. Putative functions were assigned for the 10,494 transcripts based on sequence similarities through BLAST2GO 5.2 and Function annotator.ResultsFunctional assignments revealed enhanced oxidoreductase activity through the expression of diverse biomass-degrading enzymes and their corresponding coregulators. CAZyme analysis through dbCAN and CUPP revealed the presence of 6 families of polysaccharide lyases, 51 families of glycoside hydrolases, 23 families of glycoside transferases, 7 families of carbohydrate esterases and 10 families of auxiliary activities. Genes encoding ligninolytic enzymes and auxiliary activities among the transcript sequences were identified through gene prediction by AUGUSTUS and FGENESH. Biochemical analysis of several biomass-degrading enzymes substantiated the functional predictions.ConclusionIn essence, L. squarrosulus grown in a simple medium devoid of lignocellulosic substrate demonstrated the presence of a repertoire of lignocellulose-degrading enzymes, simplying that a source of lignocellulose is not required for the expression of these biomass-degrading enzymes. This study on the transcriptome analysis of L. squarrosulus revealed significant facts on this front and will definitely enhance the knowledge about the biodegradative ability of this fungus, potentially paving the way for efficient biotechnological applications utilizing its potency in biomass degradation and its future functional exploitation in biomass conversion applications.

2020 ◽  
Author(s):  
Aarthi Ravichandran ◽  
Atul P Kolte ◽  
Arindham Dhali ◽  
S. Maheswarappa Gopinath ◽  
Manpal Sridhar

AbstractBasidiomycetes are of special interest in biotechnological research for their versatile potential in degradation of lignocellulosic biomass. This study accordingly reports analysis of transcriptome of a white-rot Basidiomycete L.squarrosulus grown in simple potato dextrose broth supplemented with aromatic compound, reactive black dye to gain an insight into the degradation ability of the fungus. RNA was sequenced using Illumina NextSeq 500 to obtain 6,679,162 high quality paired end reads that were assembled de novo using CLC assembly cell to generate 25,244 contigs.Putative functions were assigned for the 10,494 transcripts based on sequence similarities through BLAST2GO 5.2 and Function annotator. Functional assignments revealed enhanced oxidoreductase activity through the expression of diverse biomass degrading enzymes and their corresponding co-regulators. CAZyme analysis through dbCAN and CUPP revealed the presence of 6 families of polysaccharide lyases, 51 families of glycoside hydrolases, 23 families of glycoside transferases, 7 families of carbohydrate esterases and 10 families of Auxiliary activities.Genes encoding the ligninolytic enzymes and auxiliary activities among the transcript sequences were identified through gene prediction by AUGUSTUS and FGENESH. Biochemical analysis of a couple of biomass degrading enzymes substantiated the functional predictions. In essence, L.squarrosulus grown in a simple medium devoid of lignocellulosic substrate demonstrated presence of a repertoire of lignocellulose degrading enzymesimplying that source of lignocellulose is not required for expression of these biomass degrading enzymes. The study hereby underlines the significance of L.squarrosulus in biomass degradation and its future functional exploitation in biomass conversion applications.


Fermentation ◽  
2021 ◽  
Vol 7 (1) ◽  
pp. 19
Author(s):  
Anastasia Zerva ◽  
Nikolaos Tsafantakis ◽  
Evangelos Topakas

White-rot basidiomycetes are the only microorganisms with the ability to produce both hydrolytic (cellulases and hemicellulases) and oxidative (ligninolytic) enzymes for degrading cellulose/hemicellulose and lignin. In addition, they produce biologically active natural products with important application in cosmetic formulations, either as pure compounds or as standardized extracts. In the present work, three wild strains of Basidiomycetes fungi (Pleurotus citrinopileatus, Abortiporus biennis and Ganoderma resinaceum) from Greek habitats were grown in agro-industrial residues (oil mill wastewater, and corn cob) and evaluated for their anti-tyrosinase and antioxidant activity and for the production of biotechnologically relevant enzymes. P. citrinopileatus showed the most interesting tyrosinase inhibitory activity, while A. biennis showed the highest DPPH(2,2-diphenyl-1-picryl-hydrazyl) scavenging potential. Corn cobs were the most appropriate carbon source for maximizing the inhibitory effect of fungal biomasses on both activities, while the use of oil mill wastewater selectively increased the anti-tyrosinase potential of P. citrinopileatus culture filtrate. All strains were found to be preferential lignin degraders, similarly to most white-rot fungi. Bioinformatic analyses were performed on the proteome of the strains P. citrinopileatus and A. biennis, focusing on CAZymes with biotechnological relevance, and the results were compared with the enzyme activities of culture supernatants. Overall, all three strains showed strong production of oxidative enzymes for biomass conversion applications.


1996 ◽  
Vol 41 (3) ◽  
pp. 264-266 ◽  
Author(s):  
F. Nerud ◽  
Z. Mišurcová

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Xiao Fu ◽  
Jialong Zhang ◽  
Xiangyu Gu ◽  
Hongbo Yu ◽  
Shulin Chen

Abstract Background The efficiency of biological systems as an option for pretreating lignocellulosic biomass has to be improved to make the process practical. Fungal treatment with manganese (Mn) addition for improving lignocellulosic biomass fractionation and enzyme accessibility were investigated in this study. The broad-spectrum effect was tested on two different types of feedstocks with three fungal species. Since the physicochemical and structural properties of biomass were the main changes caused by fungal degradation, detailed characterization of biomass structural features was conducted to understand the mechanism of Mn-enhanced biomass saccharification. Results The glucose yields of fungal-treated poplar and wheat straw increased by 2.97- and 5.71-fold, respectively, after Mn addition. Particularly, over 90% of glucose yield was achieved in Mn-assisted Pleurotus ostreatus-treated wheat straw. A comparison study using pyrolysis gas chromatography mass spectrometry (Py-GC/MS) and two-dimensional 1H–13C heteronuclear single quantum coherence (2D HSQC) nuclear magnetic resonance (NMR) spectroscopy was conducted to elucidate the role of Mn addition on fungal disruption of the cross-linked structure of whole plant cell wall. The increased Cα-oxidized products was consistent with the enhanced cleavage of the major β-O-4 ether linkages in poplar and wheat straw lignin or in the wheat straw lignin–carbohydrate complexes (LCCs), which led to the reduced condensation degree in lignin and decreased lignin content in Mn-assisted fungal-treated biomass. The correlation analysis and principal component analysis (PCA) further demonstrated that Mn addition to fungal treatment enhanced bond cleavage in lignin, especially the β-O-4 ether linkage cleavage played the dominant role in removing the biomass recalcitrance and contributing to the glucose yield enhancement. Meanwhile, enhanced deconstruction of LCCs was important in reducing wheat straw recalcitrance. The findings provided not only mechanistic insights into the Mn-enhanced biomass digestibility by fungus, but also a strategy for improving biological pretreatment efficiency of lignocellulose. Conclusion The mechanism of enhanced saccharification of biomass by Mn-assisted fungal treatment mainly through Cα-oxidative cleavage of β-O-4 ether linkages further led to the decreased condensation degree in lignin, as a result, biomass recalcitrance was significantly reduced by Mn addition. Graphic abstract


Hoehnea ◽  
2016 ◽  
Vol 43 (4) ◽  
pp. 575-581 ◽  
Author(s):  
Thiara Siqueira Bento ◽  
Luce Maria Brandão Torres ◽  
Mauricio Batista Fialho ◽  
Vera Lúcia Ramos Bononi

ABSTRACT White-rot basidiomycetes are able to deteriorate wood products and be pathogenic to living trees, requiring, thus requiring control. The tropical flora is an important source of eco-friendly antifungal compounds; however, the knowledge on how leaf extracts affect the fungal physiology is limited. Therefore, in the present work we investigated the influence of ethanolic leaf extracts of Casearia sylvestris and C. decandra at 0.1 mg mL-1 on the production of ligninolytic enzymes by Trametes villosa, Ganoderma australe and Pycnoporus sanguineus. Overall, the extracts inhibited the mycelial growth and the production of biomass. Additionally, C. sylvestris extract reduced the production of manganese peroxidase and laccase; however, the exposure to C. decandra extract resulted in variable responses. Therefore, enzymes related to lignin degradation are potential targets to control wood decay fungi by plant bioactive compounds, as their ability to colonize the substrate may be impaired.


2018 ◽  
Vol 15 (1) ◽  
pp. 87-100 ◽  
Author(s):  
Puja Chandrayan

Pectin is an integral part of plant cell wall and since centuries pectin extracted from plants is widely used in food and fruit juice processing. Moreover, in last half century, the applications have also invaded into many bio-processing applications such as pharmaceutical, bioenergy, textile, paper and tea processing. In these growing industries, the use of pectinases has grown with a significant amount i.e. approximately 10 % of total global enzyme market comes from pectinases. Herein comprehensive analyses of information related to structure and function of pectin in plant cell wall as well as structural classes of pectins have been discussed. The major function of pectin is in cementing the cellulose and hemicelluloses network, cell-cell adhesion and plant defence. Keeping the wide use of pectin in food industry and growing need of environment friendly technology for pectin extraction has accelerated the demand of pectin degrading enzymes (PDEs). PDEs are from three enzyme classes: carbohydrate esterases from CE8 and CE12 family, glycoside hydrolases from GH28 family and lyases from PL1, 2, 3, 9 and 10. We have reviewed the literature related to abundance and structure-function of these abovementioned enzymes from bacteria. From the current available literature, we found very limited information is present about thermostable PDEs. Hence, in future it could be a topic of study to gain the insight about structure-function of enzymes together with the expanded role of thermostable enzymes in development of bioprocesses based on these enzymes.


Biotechnology ◽  
2019 ◽  
pp. 1086-1108
Author(s):  
Saritha Vara

The most abundant aromatic biopolymer on earth Lignin is extremely recalcitrant to degradation. It creates a barrier to solutions or enzymes by linking to both hemicellulose and cellulose preventing the penetration of lignocellulolytic enzymes into the interior lignocellulosic structure. Global attention has been gained by fungi owing to the potential use of their versatile enzymes for agriculture, medicines, industries and bioremediation. The combination of extracellular ligninolytic enzymes, mediators, organic acids and accessory enzymes make some of the basidiomycete white-rot fungi to be able to degrade lignin efficiently. This review describes remediation of lignocelluloses by fungi, properties of fungi, their spatial distribution and the mechanisms of action which render them attractive candidates in biotechnological applications like biopulping, animal feed, genetic engineering and space exploration.


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