CAZymes from the thermophilic fungus Thermoascus aurantiacus are induced by C5 and C6 sugars

Background Filamentous fungi are excellent lignocellulose degraders, which they achieve through producing carbohydrate active enzymes (CAZymes). CAZyme production is highly orchestrated and gene expression analysis has greatly expanded understanding of this important biotechnological process. The thermophilic fungus Thermoascus aurantiacus secretes highly active thermostable enzymes that enable saccharifications at higher temperatures; however, the genome-wide measurements of gene expression in response to CAZyme induction are not understood. Results A fed-batch system with plant biomass-derived sugars d-xylose, l-arabinose and cellobiose established that these sugars induce CAZyme expression in T. aurantiacus. The C5 sugars induced both cellulases and hemicellulases, while cellobiose specifically induced cellulases. A minimal medium formulation was developed to enable gene expression studies of T. aurantiacus with these inducers. It was found that d-xylose and l-arabinose strongly induced a wide variety of CAZymes, auxiliary activity (AA) enzymes and carbohydrate esterases (CEs), while cellobiose facilitated lower expression of mostly cellulase genes. Furthermore, putative orthologues of different unfolded protein response genes were up-regulated during the C5 sugar feeding together with genes in the C5 sugar assimilation pathways. Conclusion This work has identified two additional CAZyme inducers for T. aurantiacus, l-arabinose and cellobiose, along with d-xylose. A combination of biochemical assays and RNA-seq measurements established that C5 sugars induce a suite of cellulases and hemicellulases, providing paths to produce broad spectrum thermotolerant enzymatic mixtures.ISSN:1754-683

CAZymes from the thermophilic fungus Thermoascus aurantiacus are induced by C5 and C6 sugars

Background: Filamentous fungi are excellent lignocellulose degraders, which they achieve through producing carbohydrate active enzymes (CAZymes). CAZyme production is highly orchestrated and gene expression analysis has greatly expanded understanding of this important biotechnological process. The thermophilic fungus Thermoascus aurantiacus secretes highly active thermostable enzymes that enable saccharifications at higher temperatures; however, the genome-wide measurements of gene expression in response to CAZyme induction are not understood. Results: A fed-batch system with plant biomass-derived sugars D-xylose, L-arabinose and cellobiose established that these sugars induce CAZyme expression in T. aurantiacus. The C5 sugars induced both cellulases and hemicellulases, while cellobiose specifically induced cellulases. A minimal medium formulation was developed to enable gene expression studies of T. aurantiacus with these inducers. It was found that d-xylose and L-arabinose strongly induced a wide variety of CAZymes, auxiliary activity (AA) enzymes and carbohydrate esterases (CEs), while cellobiose facilitated lower expression of mostly cellulase genes. Furthermore, putative orthologues of different unfolded protein response genes were up-regulated during the C5 sugar feeding together with genes in the C5 sugar assimilation pathways. Conclusion: This work has identified two additional CAZyme inducers for T. aurantiacus, L-arabinose and cellobiose, along with D-xylose. A combination of biochemical assays and RNA-seq measurements established that C5 sugars induce a suite of cellulases and hemicellulases, providing paths to produce broad spectrum thermotolerant enzymatic mixtures

CAZymes from the thermophilic fungus Thermoascus aurantiacus are induced by C5 and C6 sugars.

BackgroundFilamentous fungi are excellent lignocellulose degraders, which they achieve through producing carbohydrate active enzymes (CAZymes). CAZyme production is highly orchestrated and gene expression analysis has greatly expanded understanding of this important biotechnological process. The thermophilic fungus Thermoascus aurantiacus secretes highly active thermostable enzymes that enable saccharifications at higher temperatures; however, the genome-wide measurements of gene expression in response to CAZyme induction are not understood.ResultsA fed-batch system with plant biomass-derived sugars D-xylose, L-arabinose and cellobiose established that these sugars induce CAZyme expression in T. aurantiacus. The C5 sugars induced both cellulases and hemicellulases, while cellobiose specifically induced cellulases. A minimal medium formulation was developed to enable gene expression studies of T. aurantiacus with these inducers. It was found that d-xylose and L-arabinose strongly induced a wide variety of CAZymes, auxiliary activity (AA) enzymes and carbohydrate esterases (CEs), while cellobiose facilitated lower expression of mostly cellulase genes. Furthermore, putative orthologues of different unfolded protein response genes were up-regulated during the C5 sugar feeding together with genes in the C5 sugar assimilation pathways.ConclusionThis work has identified two additional CAZyme inducers for T. aurantiacus, L-arabinose and cellobiose, along with D-xylose. A combination of biochemical assays and RNA-seq measurements established that C5 sugars induce a suite of cellulases and hemicellulases, providing paths to produce broad spectrum thermotolerant enzymatic mixtures

Development of genetic tools for the thermophilic filamentous fungus Thermoascus aurantiacus.

BackgroundFungal enzymes are vital for industrial biotechnology, including the conversion of plant biomass to biofuels and bio-based chemicals. In recent years, there is increasing interest in using enzymes from thermophilic fungi, which often have higher reaction rates and thermal tolerance compared to currently used fungal enzymes. The thermophilic filamentous fungus Thermoascus aurantiacus produces large amounts of highly thermostable plant cell wall-degrading enzymes. However, no genetic tools have yet been developed for this fungus, which prevents strain engineering efforts. The goal of this study was to develop strain engineering tools such as a transformation system, a CRISPR/Cas9 gene editing system and a sexual crossing protocol to improve the enzyme production.ResultsHere, we report Agrobacterium tumefaciens-mediated transformation (ATMT) of T. aurantiacus using the hph marker gene, conferring resistance to hygromycin B. The newly developed transformation protocol was optimized and used to integrate an expression cassette of the transcriptional xylanase regulator xlnR, which led to up to 500% increased xylanase activity. Furthermore, a CRISPR/Cas9 gene editing system was established in this fungus, and two different gRNAs were tested to delete the pyrG orthologue with 10% and 35% deletion efficiency, respectively. Lastly, a sexual crossing protocol was established using a hygromycin B- and a 5-fluoroorotic acid-resistant parent strain. Crossing and isolation of progeny on selective media were completed in a week.ConclusionThe genetic tools developed for T. aurantiacus can now be used individually or in combination to further improve thermostable enzyme production by this fungus

Development of genetic tools for the thermophilic filamentous fungus Thermoascus aurantiacus.

BackgroundFungal enzymes are vital for industrial biotechnology, including the conversion of plant biomass to biofuels and bio-based chemicals. In recent years, there is increasing interest in using enzymes from thermophilic fungi, which often have higher reaction rates and thermal tolerance compared to currently used fungal enzymes. The thermophilic filamentous fungus Thermoascus aurantiacus produces large amounts of highly thermostable plant cell wall-degrading enzymes. However, no genetic tools have yet been developed for this fungus, which prevents strain engineering efforts. The goal of this study was to develop strain engineering tools such as a transformation system, a CRISPR/Cas9 gene editing system and a sexual crossing protocol to improve the enzyme production.ResultsHere, we report Agrobacterium tumefaciens-mediated transformation (ATMT) of T. aurantiacus using the hph marker gene, conferring resistance to hygromycin B. The newly developed transformation protocol was optimized and used to integrate an expression cassette of the transcriptional xylanase regulator xlnR, which led to up to 500% increased xylanase activity. Furthermore, a CRISPR/Cas9 gene editing system was established in this fungus, and two different gRNAs were tested to delete the pyrG orthologue with 10% and 35% deletion efficiency, respectively. Lastly, a sexual crossing protocol was established using a hygromycin B- and a 5-fluoroorotic acid-resistant parent strain. Crossing and isolation of progeny on selective media were completed in a week.ConclusionThe genetic tools developed for T. aurantiacus can now be used individually or in combination to further improve thermostable enzyme production by this fungus

Invasive pulmonary aspergillosis treatment duration in haematology patients in Europe: An EFISG, IDWP-EBMT, EORTC-IDG and SEIFEM survey

Invasive pulmonary aspergillosis (IPA) optimal duration of antifungal treatment is not known. In a joint effort, four international scientific societies/groups performed a survey to capture current practices in European haematology centres regarding management of IPA. We conducted a cross-sectional internet-based questionnaire survey in 2017 to assess practices in sixteen European countries concerning IPA management in haematology patients including tools to evaluate treatment response, duration and discontinuation. The following four groups/societies were involved in the project: European Society of Clinical Microbiology and Infectious Diseases (ESCMID) Fungal Infection Study Group (EFISG), Infectious Diseases Working Party-European Society for Blood and Bone Marrow Transplantation (IDWP-EBMT), European Organisation for Research and Treatment-Infectious Disease group (EORTC-IDG) and Sorveglianza Epidemiologica Infezioni nelle Emopatie (SEIFEM). A total of 112 physicians from 14/16 countries answered the survey. Galactomannan antigen was available in serum and bronchoalveolar lavage in most centres (106/112 [95%] and 97/112 [87%], respectively), quantitative Aspergillus PCR in 27/112 (24%) centres, beta-D-glucan in 24/112 (21%) and positron emission tomography in 50/112 (45%). Treatment duration differed between haematological malignancies, with a median duration of 6 weeks [IQR 3-12] for patients with AML, 11 [4-12] for patients with allogenic stem cell transplantation and GvHD and 6 [3-12] for patients with lymphoproliferative disease. Treatment duration significantly differed according to country. Essential IPA biomarkers are not available in all European countries, and treatment duration is highly variable according to country. It will be important to provide guidelines to help with IPA treatment cessation with algorithms according to biomarker availability

ECMM CandiReg-A ready to use platform for outbreaks and epidemiological studies

BACKGROUND: Recent outbreaks of Candida auris further exemplify that invasive Candida infections are a substantial threat to patients and healthcare systems. Even short treatment delays are associated with higher mortality rates. Epidemiological shifts towards more resistant Candida spp. require careful surveillance. OBJECTIVES: Triggered by the emergence of C auris and by increasing antifungal resistance rates the European Confederation of Medical Mycology developed an international Candida Registry (FungiScope™ CandiReg) to allow contemporary multinational surveillance. METHODS: CandiReg serves as platform for international cooperation to enhance research regarding invasive Candida infections. CandiReg uses the General Data Protection Regulation compliant data platform ClinicalSurveys.net that holds the electronic case report forms (eCRF). Data entry is supported via an interactive macro created by the software that can be accessed via any Internet browser. RESULTS: CandiReg provides an eCRF for invasive Candida infections that can be used for a variety of studies from cohort studies on attributable mortality to evaluations of guideline adherence, offering to the investigators of the 28 ECMM member countries the opportunity to document their cases of invasive Candida infection. CandiReg allows the monitoring of epidemiology of invasive Candida infections, including monitoring of multinational outbreaks. Here, we describe the structure and management of the CandiReg platform. CONCLUSION: CandiReg supports the collection of clinical information and isolates to improve the knowledge on epidemiology and eventually to improve management of invasive Candida infections. CandiReg promotes international collaboration, improving the availability and quality of evidence on invasive Candida infection and contributes to improved patient management.status: publishe