Deconstruction of Lignin: From Enzymes to Microorganisms

Silva, Jéssica P; Ticona, Alonso R. P.; Hamann, Pedro Ricardo Vieira; Quirino, Betânia Ferraz; Noronha, Eliane Ferreira

doi:10.3390/molecules26082299

Cited by 45 publications

(20 citation statements)

References 119 publications

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“…Although these methods produce a wide range of products of importance such as pyro char, bio-oil, ethylene benzene and others [ 6 ], they have several drawbacks such as high-energy demands, complicated process control and complex product formation due to the general inertness of lignin [ 6 , 32 ]. Moreover, the poorly established methods may lead to other modifications to lignin resulting in increased recalcitrance and subsequent difficulty in the separation of the desired products from the repolymerised lignin [ 21 , 33 , 34 , 35 ]. In a world of a fast-growing population, dwindling resources and climate change, such unsustainable methods of lignin depolymerisation are being challenged by a much more attractive biological valorisation approach.…”

Section: Lignin Waste Stream Backgroundmentioning

confidence: 99%

Looking into the world’s largest elephant population in search of ligninolytic microorganisms for biorefineries: a mini-review

Rammala

Zhou

2022

Biotechnol Biofuels

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Gastrointestinal tracts (GIT) of herbivores are lignin-rich environments with the potential to find ligninolytic microorganisms. The occurrence of the microorganisms in herbivore GIT is a well-documented mutualistic relationship where the former benefits from the provision of nutrients and the latter benefits from the microorganism-assisted digestion of their recalcitrant lignin diets. Elephants are one of the largest herbivores that rely on the microbial anaerobic fermentation of their bulky recalcitrant low-quality forage lignocellulosic diet given their inability to break down major components of plant cells. Tapping the potential of these mutualistic associations in the biggest population of elephants in the whole world found in Botswana is attractive in the valorisation of the bulky recalcitrant lignin waste stream generated from the pulp and paper, biofuel, and agro-industries. Despite the massive potential as a feedstock for industrial fermentations, few microorganisms have been commercialised. This review focuses on the potential of microbiota from the gastrointestinal tract and excreta of the worlds’ largest population of elephants of Botswana as a potential source of extremophilic ligninolytic microorganisms. The review further discusses the recalcitrance of lignin, achievements, limitations, and challenges with its biological depolymerisation. Methods of isolation of microorganisms from elephant dung and their improvement as industrial strains are further highlighted.

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Section: Lignin Waste Stream Backgroundmentioning

confidence: 99%

Looking into the world’s largest elephant population in search of ligninolytic microorganisms for biorefineries: a mini-review

Rammala

Zhou

2022

Biotechnol Biofuels

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“…Lignocellulose is mainly composed of lignin, cellulose, and hemicellulose, forming a highly complex and varying polymeric structure that is highly recalcitrant to degradation and thus requires a consortium of carbohydrate-active enzymes (CAZymes) that act in synergism to provide its complete decomposition [ 11 ]. Lignin degradation is an enzymatic oxidation catalyzed by two main groups of enzymes, namely, lignin-modifying enzymes (LMEs) and lignin-degrading auxiliary (LDA) enzymes [ 12 ]. In contrast to lignin degradation, enzymatic degradation of cellulose and hemicellulose is mainly mediated by a process of hydrolysis through the action of glycoside hydrolases.…”

Section: Introductionmentioning

confidence: 99%

“…In addition, recent studies have indicated that the efficiency of lignocellulose degradation can be remarkably improved by the cooperative action of lytic polysaccharide monooxygenases (LPMOs), which are able to directly oxidize and depolymerize insoluble crystalline substrate surfaces or soluble hemicellulosic substrates such as xyloglucan, xylan, and β-glucans [ 14 – 16 ]. In natural ecosystems, the degradation of lignocellulosic biomass is mainly dependent on a repertoire of enzymes produced by bacteria and fungi [ 11 , 12 ]. However, more efficient degradation can be achieved by host eukaryotes working together with their gut microorganisms (often referred to as a “holobiont”) [ 17 – 19 ].…”

Section: Introductionmentioning

confidence: 99%

Lignocellulose degradation in Protaetia brevitarsis larvae digestive tract: refining on a tightly designed microbial fermentation production line

Wang

Gao

et al. 2022

Microbiome

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Background The Scarabaeidae insect Protaetia brevitarsis (PB) has recently gained increasing research interest as a resource insect because its larvae can effectively convert decaying organic matter to plant growth-promoting frass with a high humic acid content and produce healthy, nutritional insect protein sources. Lignocellulose is the main component of PB larvae (PBL) feed, but PB genome annotation shows that PBL carbohydrate-active enzymes are not able to complete the lignocellulose degradation process. Thus, the mechanism by which PBL efficiently degrade lignocellulose is worthy of further study. Results Herein, we used combined host genomic and gut metagenomic datasets to investigate the lignocellulose degradation activity of PBL, and a comprehensive reference catalog of gut microbial genes and host gut transcriptomic genes was first established. We characterized a gene repertoire comprising highly abundant and diversified lignocellulose-degrading enzymes and demonstrated that there was unique teamwork between PBL and their gut bacterial microbiota for efficient lignocellulose degradation. PBL selectively enriched lignocellulose-degrading microbial species, mainly from Firmicutes and Bacteroidetes, which are capable of producing a broad array of cellulases and hemicellulases, thus playing a major role in lignocellulosic biomass degradation. In addition, most of the lignocellulose degradation-related module sequences in the PBL microbiome were novel. PBL provide organic functional complementarity for lignocellulose degradation via their evolved strong mouthparts, alkaline midgut, and mild stable hindgut microenvironment to facilitate lignocellulosic biomass grinding, dissolving, and symbiotic microbial fermentation, respectively. Conclusions This work shows that PBL are a promising model to study lignocellulose degradation, which can provide highly abundant novel enzymes and relevant lignocellulose-degrading bacterial strains for biotechnological biomass conversion industries. The unique teamwork between PBL and their gut symbiotic bacterial microbiota for efficient lignocellulose degradation will expand the knowledge of holobionts and open a new beginning in the theory of holobionts.

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“…In the CAZy database, hemicelluloses were classified in the GH families 2,5,6,7,8,9,10,11,12,16,26,30,31,36,43,44,45,48,51,61,74,95, and 124 [37,39]. Ligninolytic enzymes (e.g., laccase, EC 1.10.3.2; lignin peroxidase, EC 1.11.1.7; and manganese peroxidase, EC 1.11.1.13) are involved in the breakdown of lignin and primarily belong to the CAZy auxiliary activities (AA) families AA1 to AA7 [37,40]. The ability of Celeribacter spp.…”

Section: Introductionmentioning

confidence: 99%

Genome Analysis of Celeribacter sp. PS-C1 Isolated from Sekinchan Beach in Selangor, Malaysia, Reveals Its β-Glucosidase and Licheninase Activities

et al. 2022

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A halophilic marine bacterial strain, PS-C1, was isolated from Sekinchan beach in Selangor, Malaysia. The 16S rRNA gene sequence analysis indicated that strain PS-C1 was associated with the genus Celeribacter. To date, there have been no reports on enzymes from the genus Celeribacter. The present study reports on the cellular features of Celeribacter sp. PS-C1, its annotated genome sequence, and comparative genome analyses of Celeribacter glycoside hydrolase (GH) enzymes. The genome of strain PS-C1 has a size of 3.87 Mbp and a G+C content of 59.10%, and contains 3739 protein-coding genes. Detailed analysis using the Carbohydrate-Active enZYmes (CAZy) database revealed that Celeribacter genomes harboured at least 12 putative genes encoding industrially important GHs that are grouped as cellulases, β-glucanases, hemicellulases, and starch-degrading enzymes. Herein, the potential applications of these enzymes are discussed. Furthermore, the activities of two types of GHs (β-glucosidase and licheninase) in strain PS-C1 were demonstrated. These findings suggest that strain PS-C1 could be a reservoir of novel GH enzymes for lignocellulosic biomass degradation.

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Deconstruction of Lignin: From Enzymes to Microorganisms

Cited by 45 publications

References 119 publications

Looking into the world’s largest elephant population in search of ligninolytic microorganisms for biorefineries: a mini-review

Looking into the world’s largest elephant population in search of ligninolytic microorganisms for biorefineries: a mini-review

Lignocellulose degradation in Protaetia brevitarsis larvae digestive tract: refining on a tightly designed microbial fermentation production line

Genome Analysis of Celeribacter sp. PS-C1 Isolated from Sekinchan Beach in Selangor, Malaysia, Reveals Its β-Glucosidase and Licheninase Activities

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