Development of highly efficient, low-cost lignocellulolytic enzyme systems in the post-genomic era

Liu, Guodong; Qin, Yuqi; Li, Zhonghai; Qu, Yinbo

doi:10.1016/j.biotechadv.2013.03.001

Cited by 89 publications

(49 citation statements)

References 169 publications

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“…Upon enzymatic hydrolysis, these biopolymers that can be degraded to fermentable saccharide for producing biofuel or chemical intermediates. Currently, production of low cost and high efficiency lignocellulolytic enzymes is still a major barrier in utilizing cellulose through the saccharification process (Liu et al, 2013). The Sordariomycete Trichoderma reesei (T. reesei, teleomorph Hypocrea jecorina) is a filamentous fungi that is industrially applicable for cellulase and heterologous protein production (Nevalainen et al, 2005).…”

Section: Introductionmentioning

confidence: 99%

Mitochondria thioredoxin's backup role in oxidative stress resistance in Trichoderma reesei

Wang

Xiong

et al. 2015

Microbiological Research

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Microorganisms often suffer from oxidative stress created from nutrient starvation and environmental changes. Thioredoxin (Trx) and glutathione (GSH) pathways are believed critical in related protective functions. The roles of Trx in improving abiotic stress resistance in Trichoderma reesei are still unclear. In this study, we identified a Trx-encoding gene, Trtrx1. The protein expressed located specifically in the mitochondria as verified by the fluorescence signals of TrTRX1-EGFP. TrTRX1 can catalyze the reduction of insulin disulfides by dithiothreitol (DTT). Loss of Trtrx1 however, did not lead to either significant morphology abnormality under normal and oxidative stress condition, or detectable difference in reactive oxygen species (ROS) resistance. The unchanged GSH amount in Trtrx1 deletion strain under normal condition and slight increase under oxidative stress condition, as well as the interplay between Trx and GSH systems suggested that GSH system was dominant and sufficient to maintain the mitochondrial redox state in T. reesei, where TrTRX1 played a role as the backup oxidative stress resistance.

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Section: Introductionmentioning

confidence: 99%

Mitochondria thioredoxin's backup role in oxidative stress resistance in Trichoderma reesei

Wang

Xiong

et al. 2015

Microbiological Research

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“…Wheat straw, as the source of lignocellulose, can potentially serve to provide building blocks for production of plastics or energy in biofuels [4]. The conversion of lignocellulosic polymers into monomers that can be further processed involves the synergistic action of a range of secreted enzymes, that is, peroxidases, xylanases and endo/exoglucanases [5,6]. In spite of the fact that intricate knowledge on the decomposition process is lacking, many bacteria are known to be capable of producing such enzymes.…”

Section: Introductionmentioning

confidence: 99%

Metataxonomic profiling and prediction of functional behaviour of wheat straw degrading microbial consortia

Jiménez

Dini‐Andreote

Elsas

2014

Biotechnol Biofuels

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BackgroundMixed microbial cultures, in which bacteria and fungi interact, have been proposed as an efficient way to deconstruct plant waste. The characterization of specific microbial consortia could be the starting point for novel biotechnological applications related to the efficient conversion of lignocellulose to cello-oligosaccharides, plastics and/or biofuels. Here, the diversity, composition and predicted functional profiles of novel bacterial-fungal consortia are reported, on the basis of replicated aerobic wheat straw enrichment cultures.ResultsIn order to set up biodegradative microcosms, microbial communities were retrieved from a forest soil and introduced into a mineral salt medium containing 1% of (un)treated wheat straw. Following each incubation step, sequential transfers were carried out using 1 to 1,000 dilutions. The microbial source next to three sequential batch cultures (transfers 1, 3 and 10) were analyzed by bacterial 16S rRNA gene and fungal ITS1 pyrosequencing. Faith’s phylogenetic diversity values became progressively smaller from the inoculum to the sequential batch cultures. Moreover, increases in the relative abundances of Enterobacteriales, Pseudomonadales, Flavobacteriales and Sphingobacteriales were noted along the enrichment process. Operational taxonomic units affiliated with Acinetobacter johnsonii, Pseudomonas putida and Sphingobacterium faecium were abundant and the underlying strains were successfully isolated. Interestingly, Klebsiella variicola (OTU1062) was found to dominate in both consortia, whereas K. variicola-affiliated strains retrieved from untreated wheat straw consortia showed endoglucanase/xylanase activities. Among the fungal players with high biotechnological relevance, we recovered members of the genera Penicillium, Acremonium, Coniochaeta and Trichosporon. Remarkably, the presence of peroxidases, alpha-L-fucosidases, beta-xylosidases, beta-mannases and beta-glucosidases, involved in lignocellulose degradation, was indicated by predictive bacterial metagenome reconstruction. Reassuringly, tests for specific (hemi)cellulolytic enzymatic activities, performed on the consortial secretomes, confirmed the presence of such gene functions.ConclusionIn an in-depth characterization of two wheat straw degrading microbial consortia, we revealed the enrichment and selection of specific bacterial and fungal taxa that were presumably involved in (hemi) cellulose degradation. Interestingly, the microbial community composition was strongly influenced by the wheat straw pretreatment. Finally, the functional bacterial-metagenome prediction and the evaluation of enzymatic activities (at the consortial secretomes) revealed the presence and enrichment of proteins involved in the deconstruction of plant biomass.

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“…This in turn allows us to consider the stability and/or performance of target enzymes, enabling the design of new enzyme cocktails and engineering microbial mixed cultures for an optimized lignocellulose bioconversion. Technologies for the rapid screening of GH’s activities are currently in development for high throughput analysis [6, 11, 38, 65]. Functional metagenomic has been proven to be useful tool to achieve this screening of GH’s activities (see review [27, 58]).…”

Section: Discussionmentioning

confidence: 99%

CAZyChip: dynamic assessment of exploration of glycoside hydrolases in microbial ecosystems

et al. 2016

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BackgroundMicroorganisms constitute a reservoir of enzymes involved in environmental carbon cycling and degradation of plant polysaccharides through their production of a vast variety of Glycoside Hydrolases (GH). The CAZyChip was developed to allow a rapid characterization at transcriptomic level of these GHs and to identify enzymes acting on hydrolysis of polysaccharides or glycans.ResultsThis DNA biochip contains the signature of 55,220 bacterial GHs available in the CAZy database. Probes were designed using two softwares, and microarrays were directly synthesized using the in situ ink-jet technology. CAZyChip specificity and reproducibility was validated by hybridization of known GHs RNA extracted from recombinant E. coli strains, which were previously identified by a functional metagenomic approach. The GHs arsenal was also studied in bioprocess conditions using rumen derived microbiota.ConclusionsThe CAZyChip appears to be a user friendly tool for profiling the expression of a large variety of GHs. It can be used to study temporal variations of functional diversity, thereby facilitating the identification of new efficient candidates for enzymatic conversions from various ecosystems.Electronic supplementary materialThe online version of this article (doi:10.1186/s12864-016-2988-4) contains supplementary material, which is available to authorized users.

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Development of highly efficient, low-cost lignocellulolytic enzyme systems in the post-genomic era

Cited by 89 publications

References 169 publications

Mitochondria thioredoxin's backup role in oxidative stress resistance in Trichoderma reesei

Mitochondria thioredoxin's backup role in oxidative stress resistance in Trichoderma reesei

Metataxonomic profiling and prediction of functional behaviour of wheat straw degrading microbial consortia

CAZyChip: dynamic assessment of exploration of glycoside hydrolases in microbial ecosystems

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