Industrial applications of lignin-transforming enzymes

Lignin-degrading and modifying enzymes are produced under specific culture conditions by white-rot fungi. Most of these enzymes are excreted into the extracellular environment and can be purified from culture supernatant. At RepliGen we have characterized many of the extracellular proteins from the white-rot fungus Phanerochaete chrysosporium . Industrial application potentials for these enzymes are predicted to be in the chemical industry, pulp and paper industry, and perhaps in pollution control. The isolation and characterization of enzymes that catalyse specific reactions on kraft lignins and lignosulphonates will be discussed. These reactions include (1) a polymerizing—depolymerizing activity that changes the size of the lignin substrate and (2) a decolorizing reaction that reduces chromophoric groups in lignin. Kraft lignin and lignosulphonates have many diverse commercial applications because of their dual properties of hydrophobicity and hydrophilicity. They could have broad use if modified, as in the above reactions, in an efficient manner. The development of enzyme systems may provide just such efficient reactions.

2018 ◽  
Vol 14 (4) ◽  
pp. 721-726
Author(s):  
Nguyen Thi Hong Lien ◽  
Nguyen Van Hieu ◽  
Luong Thi Hong ◽  
Hy Tuan Anh ◽  
Phan Thi Hong Thao

Wood-rotting fungi represent an important component of forest ecosystems. Among them, white-rot fungi are the most efficient lignin degraders. Biopulping using white-rot fungi in pretreatment of the materials, is one of the solutions to overcome disadvantages of traditional production methods. Today, the isolation and screening of lignin degrading fungi capable for application in biopulping are of keen interest in Vietnam. The use of non–wood, plant fibres in pulp and paper industry, special, agricultural residuces such as rice and wheat straw, sugarcane baggase, cornstalks etc is the new production toward, potential, serving sustainable development. The fungus CP9, which possessed high ligninolytic activity, was identified and studied in pretreatment of rice straw for biopulping. The fruiting bodies of strain CP9 were effuse on trunk. The hymenium was porous and brown white with short tubes, the white mycelia penetrated wood block. The colony was off-white, blossom, irregularly circular. The mycelia were thick and closely bound together. Beside lignin, this fungus could degrade other substrates such as casein, carboxymethyl cellulose and starch. Biological and morphological characteristics of the fungus CP9 suggested its placement in subdivision Basidiomycota. Combined with the results of phylogenetic analysis, which showed 99% similarity of the fungus with species Leiotrametes lactinea, our strain was named as Leiotrametes lactinea CP9. This fungus could grow well on rice straw under solid state fermentation. Pretreatment of rice straw using L. lactinea CP9 was based on the activity of fungal lignin peroxidase and laccase. After 20 days, the residual enzyme activity was of 21.6 and 18.4 nkat/g material for lignin peroxidase and laccase, respectively. Pretreatment significantly improved the quality of straw, as lignin loss of 38% while cellulosic fibers were comparatively well preserved.


BioResources ◽  
2020 ◽  
Vol 15 (4) ◽  
pp. 9166-9179
Author(s):  
Qi An ◽  
Jie Qiao ◽  
Lu-Sen Bian ◽  
Mei-Ling Han ◽  
Xun-You Yan ◽  
...  

Different Pleurotus ostreatus and Flammulina velutipes species were compared relative to their ability to produce laccase in submerged fermentation of various lignocellulosic wastes. Fungi cultivation in identical culture conditions revealed wide differences among both species and strains of the same species. The laccase secretion ability of P. ostreatus strains was superior to F. velutipes strains. Maximum laccase production on cottonseed hull, corncob, and poplar wood was secreted by P. ostreatus CY 568, P. ostreatus CCEF 89, and P. ostreatus CY 568, respectively. The nature of lignocellulosic materials played an important role in determining the expression of laccase potential of fungi. The presence of cottonseed hull improved laccase activity and accelerated the rate of enzyme production. Maximum laccase production on cottonseed hull was nearly 1.29-fold and 1.53-fold higher than that on corncob and poplar wood, respectively. Laccase activity was detected in almost all tested strains on cottonseed hull on the first day, while only a few strains on poplar wood and corncob were detected on the first day. These findings will be helpful for selecting the appropriate strain in industrial applications and for optimization of integrated industrial laccase production.


1991 ◽  
Vol 24 (3-4) ◽  
pp. 189-198 ◽  
Author(s):  
V. P. Lankinen ◽  
M. M. Inkeröinen ◽  
J. Pellinen ◽  
A. I. Hatakka

Decrease of adsorbable organic chlorine (AOX) is becoming the most important criterion for the efficiency of pulp mill effluent treatment in the 1990s. Two methods, designated MYCOR and MYCOPOR which utilize the white-rot fungus Phanerochaete chrysosporium have earlier been developed for the color removal of pulp mill effluents, but the processes have also a capacity to decrease the amount of chlorinated organic compounds. Lignin peroxidases (ligninases) produced by P. chrvsosporium may dechlorinate chlorinated phenols. In this work possibilities to use selected white-rot fungi in the treatment of E1-stage bleach plant effluent were studied. Phlebia radiata. Phanerochaete chrvsosporium and Merulius (Phlebia) tremellosus were compared in shake flasks for their ability to produce laccase, lignin peroxidase(s) and manganese-dependent peroxidase(s) and to remove color from a medium containing effluent. Softwood bleaching effluents were treated by carrier-immobilized P. radiata in 2 1 bioreactors and a 10 1 BiostatR -fermentor. Dechlorination was followed using Cl ion and AOX determinations. All fungi removed the color of the effluent. In P. radiata cultivations AOX decrease was ca. 4 mg l−1 in one day. Apparent lignin peroxidase activities as determined by veratryl alcohol oxidation method were negligible or zero in a medium with AOX content of ca. 60 mg l−1, prepared using about 20 % (v/v) of softwood effluent. However, the purification of extracellular enzymes implied that large amounts of lignin peroxidases were present in the medium and, after the purification, in active form. Enzyme proteins were separated using anion exchange chromatography, and they were further characterized by electrophoresis (SDS-PAGE) to reveal the kind of enzymes that were present during AOX decrease and color removal. The most characteristic lignin peroxidase isoenzymes in effluent media were LiP2 and LiP3.


2021 ◽  
Vol 12 ◽  
Author(s):  
Jing Si ◽  
Hongfei Ma ◽  
Yongjia Cao ◽  
Baokai Cui ◽  
Yucheng Dai

This study introduces a valuable laccase, designated ThLacc-S, purified from white rot fungus Trametes hirsuta. ThLacc-S is a monomeric protein in nature with a molecular weight of 57.0 kDa and can efficiently metabolize endocrine disrupting chemicals. The enzyme was successfully purified to homogeneity via three consecutive steps consisting of salt precipitation and column chromatography, resulting in a 20.76-fold increase in purity and 46.79% yield, with specific activity of 22.111 U/mg protein. ThLacc-S was deciphered as a novel member of the laccase family and is a rare metalloenzyme that contains cysteine, serine, histidine, and tyrosine residues in its catalytic site, and follows Michaelis-Menten kinetic behavior with a Km and a kcat/Km of 87.466 μM and 1.479 s–1μM–1, respectively. ThLacc-S exerted excellent thermo-alkali stability, since it was markedly active after a 2-h incubation at temperatures ranging from 20 to 70°C and retained more than 50% of its activity after incubation for 72 h in a broad pH range of 5.0–10.0. Enzymatic activities of ThLacc-S were enhanced and preserved when exposed to metallic ions, surfactants, and organic solvents, rendering this novel enzyme of interest as a green catalyst for versatile biotechnological and industrial applications that require these singularities of laccases, particularly biodegradation and bioremediation of environmental pollutants.


BioResources ◽  
2021 ◽  
Vol 16 (2) ◽  
pp. 3797-3807
Author(s):  
Magdah Ganash ◽  
Tarek M. Abdel Ghany ◽  
Mohamed A. Al Abboud ◽  
Mohamed M. Alawlaqi ◽  
Husam Qanash ◽  
...  

Lignocellulolytic white-rot fungi allow the bioconversion of agricultural wastes into value-added products that are used in a myriad of applications. The aim of this work was to use corn residues (Zea mays L.) to produce valuable products under solid-state fermentation (SSF) with Pleurotus ostreatus. White-rot fungus P. ostreatus was isolated from maize silage (MS) and thereafter it was inoculated on MS as substrate and compared with maize stover (MSt) and maize cobs (MC) to determine the best lignocellulosic substrate for the production of lignocellulolytic enzymes and extracellular protein. The MS gave the highest productivity of CMCase (368.2 U/mL), FPase (170.5 U/mL), laccase (11.4 U/mL), and MnPase (6.6 U/mL). This is compared to productivity on MSt of 222 U/mL, 50.2 U/mL, 4.55 U/mL, and 2.57 U/mL, respectively; and productivity on MC at the same incubation period as 150.5 U/mL, 48.2 U/mL, 3.58 U/mL, and 2.5 U/mL, respectively. The levels of enzyme production declined with increasing incubation period after 15 and 20 days using MS and MC, respectively, as substrates. Maximum liberated extracellular protein content (754 to 878 µg/mL) was recorded using MS, while a low amount (343 to 408 µg/mL) was liberated with using MSt and MC.


2002 ◽  
pp. 287-297
Author(s):  
G. Ruiz-Aguilar ◽  
J. Fernández-Sánchez ◽  
R. Rodríguez-Vázquez ◽  
H. M. Poggi-Varaldo ◽  
F. Esparza-García ◽  
...  

Forests ◽  
2019 ◽  
Vol 10 (10) ◽  
pp. 885 ◽  
Author(s):  
Casado-Sanz ◽  
Silva-Castro ◽  
Ponce-Herrero ◽  
Martín-Ramos ◽  
Martín-Gil ◽  
...  

There is growing interest in the development of non-toxic, natural wood preservation agents to replace conventional chemicals. In this paper, the antifungal activities of silver nanoparticles, chitosan oligomers, and propolis ethanolic extract were evaluated against white-rot fungus Trametes versicolor (L.) Lloyd, with a view to protecting Populus spp. wood. In order to create a more realistic in-service type environment, the biocidal products were assessed according to EN:113 European standard, instead of using routine in vitro antimicrobial susceptibility testing methods. Wood blocks were impregnated with the aforementioned antifungal agents by the vacuum-pressure method in an autoclave, and their biodeterioration was monitored over 16 weeks. The results showed that treatments based on silver nanoparticles, at concentrations ranging from 5 to 20 ppm, presented high antifungal activity, protecting the wood from fungal attack over time, with weight losses in the range of 8.49% to 8.94% after 16 weeks, versus 24.79% weight loss in the control (untreated) samples. This was confirmed by SEM and optical microscopy images, which showed a noticeably higher cell wall degradation in control samples than in samples treated with silver nanoparticles. On the other hand, the efficacy of the treatments based on chitosan oligomers and propolis gradually decreased over time, which would be a limiting factor for their application as wood preservatives. The nanometal-based approach is thus posed as the preferred choice for the industrial treatment of poplar wood aimed at wood-based engineering products (plywood, laminated veneer lumber, cross-laminated timber, etc.).


Holzforschung ◽  
1999 ◽  
Vol 53 (3) ◽  
pp. 247-252 ◽  
Author(s):  
M.J. Martínez-Inigo ◽  
P. Immerzeel ◽  
A. Gutierrez ◽  
J.C. del Río ◽  
R. Sierra-Alvarez

SummaryThe fungal degradation of lipophilic extractives in sapwood and heartwood from Scots pine (Pinus sylvestris) was studied. In sapwood, the white rot fungi,Bjerkanderasp. andFunalia trogii, removed higher amounts of extractives than the sapstain strains,Ophiostoma ainoaeandCeratocystis allantospora. Triglycerides, long chain fatty acids, steryl esters and waxes in pine sapwood were almost completely degraded by all the fungi. Sterols and resin acids were also extensively degraded by the white rot strains; however, these components were not or only poorly removed by the sapstain fungi. The removal of total extractives by all the fungal strains was higher in sapwood as compared to heartwood. The highly concentrated extractive fraction in pine heartwood mainly consists of resin acids. As observed in sapwood, sapstain were also poorly effective in the degradation of the resin acids present in heartwood. The fungal degradation of heartwood extractives was not only limited by the degradative ability of the various test microorganisms, but also by the inhibitory effect exerted by the extractive fraction. The white rot fungusF. trogiiwas particularly inhibited on heartwood.Bjerkanderasp. showed a higher tolerance to toxic extractives and was the most efficient fungus in degrading extractive constituents in both Scots pine heartwood and sapwood. Therefore,Bjerkanderasp. strain BOS55 should be considered as a potential agent for pitch control in pulp and paper manufacture.


2018 ◽  
Vol 19 (8) ◽  
pp. 2379 ◽  
Author(s):  
Young-Jin Park ◽  
Yong-Un Jeong ◽  
Won-Sik Kong

Next-generation sequencing (NGS) of the Flammulina elastica (wood-rotting basidiomycete) genome was performed to identify carbohydrate-active enzymes (CAZymes). The resulting assembly (31 kmer) revealed a total length of 35,045,521 bp (49.7% GC content). Using the AUGUSTUS tool, 12,536 total gene structures were predicted by ab initio gene prediction. An analysis of orthologs revealed that 6806 groups contained at least one F. elastica protein. Among the 12,536 predicted genes, F. elastica contained 24 species-specific genes, of which 17 genes were paralogous. CAZymes are divided into five classes: glycoside hydrolases (GHs), carbohydrate esterases (CEs), polysaccharide lyases (PLs), glycosyltransferases (GTs), and auxiliary activities (AA). In the present study, annotation of the predicted amino acid sequences from F. elastica genes using the dbCAN CAZyme database revealed 508 CAZymes, including 82 AAs, 218 GHs, 89 GTs, 18 PLs, 59 CEs, and 42 carbohydrate binding modules in the F. elastica genome. Although the CAZyme repertoire of F. elastica was similar to those of other fungal species, the total number of GTs in F. elastica was larger than those of other basidiomycetes. This genome information elucidates newly identified wood-degrading machinery in F. elastica, offers opportunities to better understand this fungus, and presents possibilities for more detailed studies on lignocellulosic biomass degradation that may lead to future biotechnological and industrial applications.


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