Enhancing emerging pollutant removal mediated by root iron plaques: Integrated abiotic and biotic effects.

As a contact interface among plants, microbes, and the liquid phase, root iron plaque (IP) occupies a crucial ecological niche on the root surface in constructed wetlands. However, research on the integrated work mechanisms of the various processes mediated by root IP in removing emerging pollutants is limited. This study analyzed four IP-mediated pathways in plant hydroponic systems, categorizing them into abiotic (adsorption and ·OH oxidation) and biotic (plant uptake and microbial degradation) effects.

Effective synthesis of high-content fructooligosaccharides in engineered Aspergillus niger.

Background: Aspergillus niger ATCC 20611 is an industrially important fructooligosaccharides (FOS) producer since it produces the β-fructofuranosidase with superior transglycosylation activity, which is responsible for the conversion of sucrose to FOS accompanied by the by-product (glucose) generation. This study aims to consume glucose to enhance the content of FOS by heterologously expressing glucose oxidase and peroxidase in engineered A. niger.

An efficient CRISPR/Cas9 genome editing system based on a multiple sgRNA processing platform in Trichoderma reesei for strain improvement and enzyme production.

Background: The CRISPR/Cas9 technology is being employed as a convenient tool for genetic engineering of the industrially important filamentous fungus Trichoderma reesei. However, multiplex gene editing is still constrained by the sgRNA processing capability, hindering strain improvement of T. reesei for the production of lignocellulose-degrading enzymes and recombinant proteins.

A novel sucrose-inducible expression system and its application for production of biomass-degrading enzymes in Aspergillus niger.

Background: Filamentous fungi are extensively exploited as important enzyme producers due to the superior secretory capability. However, the complexity of their secretomes greatly impairs the titer and purity of heterologous enzymes. Meanwhile, high-efficient evaluation and production of bulk enzymes, such as biomass-degrading enzymes, necessitate constructing powerful expression systems for bio-refinery applications.

Enhancing the production of a heterologous Trametes laccase (LacA) by replacement of the major cellulase CBH1 in Trichoderma reesei.

Unlabelled: The laccases from white-rot fungi exhibit high redox potential in treating phenolic compounds. However, their application in commercial purposes has been limited because of the relatively low productivity of the native hosts. Here, the laccase A-encoding gene lacA of Trametes sp.

The ERAD Pathway Participates in Fungal Growth and Cellulase Secretion in .

is a powerful fungal cell factory for the production of cellulolytic enzymes due to its outstanding protein secretion capacity. Endoplasmic reticulum-associated degradation (ERAD) plays an integral role in protein secretion that responds to secretion pressure and removes misfolded proteins. However, the role of ERAD in fungal growth and endogenous protein secretion, particularly cellulase secretion, remains poorly understood in .

Tailoring the expression of Xyr1 leads to efficient production of lignocellulolytic enzymes in Trichoderma reesei for improved saccharification of corncob residues.

Background: The filamentous fungus Trichoderma reesei is extensively used for the industrial-scale cellulase production. It has been well known that the transcription factor Xyr1 plays an important role in the regulatory network controlling cellulase gene expression. However, the role of Xyr1 in the regulation of cellulase expression has not been comprehensively elucidated, which hinders further improvement of lignocellulolytic enzyme production.

Constitutive overexpression of cellobiohydrolase 2 in reveals its ability to initiate cellulose degradation.

Cellulose degradation results from the synergistic effect of different enzymes, but which enzyme is involved in the initial stage of cellulose degradation is still not well understood. Cellobiohydrolase 2 (CBH2) attached to the conidial surface is possibly associated with the initial stage. However, its specific mechanism is still incompletely known.

The complex Tup1-Cyc8 bridges transcription factor ClrB and putative histone methyltransferase LaeA to activate the expression of cellulolytic genes.

The degradation of lignocellulosic biomass by cellulolytic enzymes is involved in the global carbon cycle. The hydrolysis of lignocellulosic biomass into fermentable sugars is potential as an excellent industrial resource to produce a variety of chemical products. The production of cellulolytic enzymes is regulated mainly at the transcriptional level in filamentous fungi.

Development of a novel expression platform for heterologous protein production via deleting the p53-like regulator Vib1 in Trichoderma reesei.

Trichoderma reesei is widely used as a protein production host due to its high natural capacity to secrete enzymes. Nonetheless, the complexity and abundance of secretome limit its extensive application in heterologous protein production. Here, a novel heterologous protein expression system with remarkable reduction of undesired background proteins was developed by deletion of the p53-like transcriptional factor Vib1.

Engineering the endoplasmic reticulum secretory pathway in Trichoderma reesei for improved cellulase production.

The filamentous fungus Trichoderma reesei is an extraordinarily efficient cell factory of industrial cellulase for production of biofuels and other bio-based products because of its excellent potential to secrete cellulolytic enzymes. Engineering the protein secretory pathway may be a powerful means for efficient protein production. However, it is uncertain whether this engineering approach could improve cellulase production in T.

Disruption of the Trichoderma reesei gul1 gene stimulates hyphal branching and reduces broth viscosity in cellulase production.

Hyphal morphology is considered to have a close relationship with the production level of secreted proteins by filamentous fungi. In this study, the gul1 gene, which encodes a putative mRNA-binding protein, was disrupted in cellulase-producing fungus Trichoderma reesei. The hyphae of Δgul1 strain produced more lateral branches than the parent strain.

Continuous production of fructooligosaccharides by recycling of the thermal-stable β-fructofuranosidase produced by Aspergillus niger.

Objective: To achieve continuous production of fructooligosaccharides (FOS) by recycling of the mycelial cells containing the thermal-stable β-fructofuranosidase in Aspergillus niger without immobilization.

Results: The thermal-stable β-fructofuranosidase FopA-V1 was successfully expressed in A. niger ATCC 20611 under the control of the constitutive promoter PgpdA.

Extracellular protease production regulated by nitrogen and carbon sources in Trichoderma reesei.

The filamentous fungus Trichoderma reesei is an important producer of industrial enzymes, and possesses abundant extracellular protease genes based on the genome sequence data. However, the production of extracellular proteases remains poorly understood. Here, protease production was extensively investigated on different carbon (glucose and lactose) and nitrogen sources ((NH ) SO , NaNO , peptone, and corn steep liquor).

Engineering for Hyperproduction of Cellulases on Glucose to Efficiently Saccharify Pretreated Corncobs.

The filamentous fungus (teleomorph ) is widely used as a cellulase producer in the industry. Herein, we describe the rational engineering of the publicly available QM9414 strain to achieve a remarkable high-level production of cellulase on glucose. Overexpression of the key cellulase regulator XYR1 by the copper-repressible promoter P was first implemented to achieve a full cellulase production in the context of catabolite repression (CCR) while eliminating the requirement of inducing sugars for enzyme production.

CRISPR/Cas9-mediated genome editing in Penicillium oxalicum and Trichoderma reesei using 5S rRNA promoter-driven guide RNAs.

Objective: To construct convenient CRISPR/Cas9-mediated genome editing systems in industrial enzyme-producing fungi Penicillium oxalicum and Trichoderma reesei.

Results: Employing the 5S rRNA promoter from Aspergillus niger for guide RNA expression, the β-glucosidase gene bgl2 in P. oxalicum was deleted using a donor DNA carrying 40-bp homology arms or a donor containing no selectable marker gene.

The effects of deletion of cellobiohydrolase genes on carbon source-dependent growth and enzymatic lignocellulose hydrolysis in Trichoderma reesei.

The saprophytic fungus Trichoderma reesei has long been used as a model to study microbial degradation of lignocellulosic biomass. The major cellulolytic enzymes of T. reesei are the cellobiohydrolases CBH1 and CBH2, which constitute more than 70% of total proteins secreted by the fungus.

Enhancement of Cellulase Production in via Disruption of Multiple Protease Genes Identified by Comparative Secretomics.

The filamentous fungus is one of the most studied cellulolytic organisms and the major producer of cellulases for industrial applications. However, undesired degradation of cellulases often happens in culture filtrates and commercial enzyme preparations. Even studies have been reported about describing proteolytic degradation of heterologous proteins in , there are few systematic explorations concerning the extracellular proteases responsible for degradation of cellulases.

Establishment of a rapid and effective plate chromogenic assay for screening of Aspergillus species with high β-fructofuranosidase activity for fructooligosaccharides production.

Fructooligosaccharides (FOS) are commonly regarded as prebiotics and used as components of functional foods. Currently, the industrial sucrose-to-FOS biotransformation is mainly carried out using the microbial-derived β-fructofuranosidases with transglycosylation activity as catalysts. Evaluation of the ability of a microorganism to produce β-fructofuranosidase is commonly conducted by measuring enzyme activity.

CLP1, a Novel Plant Homeo Domain Protein, Participates in Regulating Cellulase Gene Expression in the Filamentous Fungus .

The stringent regulatory network of cellulase gene expression in the filamentous fungus involves multiple transcriptional regulators. However, identification and mechanistic investigation of these regulators are still insufficient. Here, we identified a novel transcriptional regulator, CLP1, a plant homeo domain (PHD) Protein that participates in regulating cellulase gene expression.

The GATA-Type Transcriptional Factor Are1 Modulates the Expression of Extracellular Proteases and Cellulases in .

is a biotechnologically important filamentous fungus with the remarkable ability to secrete large amounts of enzymes, whose production is strongly affected by both the carbon and nitrogen sources. While the carbon metabolism regulators are extensively studied, the regulation of enzyme production by the nitrogen metabolism regulators is still poorly understood. In this study, the GATA transcription factor Are1, which is an orthologue of the global nitrogen regulator AREA, was identified and characterized for its functions in regulation of both protease and cellulase production in .

Heterologous expression of Talaromyces emersonii cellobiohydrolase Cel7A in Trichoderma reesei increases the efficiency of corncob residues saccharification.

Objective: Improve the hydrolysis efficiency of the Trichoderma reesei cellulase system by heterologously expressing cellobiohydrolase Cel7A (Te-Cel7A) from the thermophilic fungus Talaromyces emersonii.

Results: Te-Cel7A was expressed in T. reesei under control of the cdna1 promoter and the generated transformant QTC14 could successfully secrete Te-Cel7A into the supernatant using glucose as carbon source.

A copper-controlled RNA interference system for reversible silencing of target genes in .

Background: is a primary lignocellulosic enzyme producer in industry. However, the mechanisms underlying cellulase synthesis as well as other physiological processes are insufficiently understood partly due to the sophisticated process for its genetic manipulation. Target gene knockdown by RNA interference (RNAi) is a powerful tool for genetic research and biotechnology in eukaryotes including filamentous fungi.

Production of the versatile cellulase for cellulose bioconversion and cellulase inducer synthesis by genetic improvement of .

Background: The enzymes for efficient hydrolysis of lignocellulosic biomass are a major factor in the development of an economically feasible cellulose bioconversion process. Up to now, low hydrolysis efficiency and high production cost of cellulases remain the significant hurdles in this process. The aim of the present study was to develop a versatile cellulase system with the enhanced hydrolytic efficiency and the ability to synthesize powerful inducers by genetically engineering .