scholarly journals Trichoderma reesei: A Fungal Enzyme Producer for Cellulosic Biofuels

Author(s):  
Bernhard Seiboth ◽  
Christa Ivanova ◽  
Verena Seidl-Seiboth
2018 ◽  
Vol 63 (2) ◽  
pp. 115-129
Author(s):  
Rahela Carpa ◽  
◽  
Alin Cândea ◽  
Alexei Remizovschi ◽  
Lucian Barbu-Tudoran ◽  
...  

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Shannon M. Hoffman ◽  
Maria Alvarez ◽  
Gilad Alfassi ◽  
Dmitry M. Rein ◽  
Sergio Garcia-Echauri ◽  
...  

Abstract Background Future expansion of corn-derived ethanol raises concerns of sustainability and competition with the food industry. Therefore, cellulosic biofuels derived from agricultural waste and dedicated energy crops are necessary. To date, slow and incomplete saccharification as well as high enzyme costs have hindered the economic viability of cellulosic biofuels, and while approaches like simultaneous saccharification and fermentation (SSF) and the use of thermotolerant microorganisms can enhance production, further improvements are needed. Cellulosic emulsions have been shown to enhance saccharification by increasing enzyme contact with cellulose fibers. In this study, we use these emulsions to develop an emulsified SSF (eSSF) process for rapid and efficient cellulosic biofuel production and make a direct three-way comparison of ethanol production between S. cerevisiae, O. polymorpha, and K. marxianus in glucose and cellulosic media at different temperatures. Results In this work, we show that cellulosic emulsions hydrolyze rapidly at temperatures tolerable to yeast, reaching up to 40-fold higher conversion in the first hour compared to microcrystalline cellulose (MCC). To evaluate suitable conditions for the eSSF process, we explored the upper temperature limits for the thermotolerant yeasts Kluyveromyces marxianus and Ogataea polymorpha, as well as Saccharomyces cerevisiae, and observed robust fermentation at up to 46, 50, and 42 °C for each yeast, respectively. We show that the eSSF process reaches high ethanol titers in short processing times, and produces close to theoretical yields at temperatures as low as 30 °C. Finally, we demonstrate the transferability of the eSSF technology to other products by producing the advanced biofuel isobutanol in a light-controlled eSSF using optogenetic regulators, resulting in up to fourfold higher titers relative to MCC SSF. Conclusions The eSSF process addresses the main challenges of cellulosic biofuel production by increasing saccharification rate at temperatures tolerable to yeast. The rapid hydrolysis of these emulsions at low temperatures permits fermentation using non-thermotolerant yeasts, short processing times, low enzyme loads, and makes it possible to extend the process to chemicals other than ethanol, such as isobutanol. This transferability establishes the eSSF process as a platform for the sustainable production of biofuels and chemicals as a whole.


2021 ◽  
Vol 7 (3) ◽  
pp. 207
Author(s):  
Lene Lange ◽  
Kristian Barrett ◽  
Anne S. Meyer

Fungal genome sequencing data represent an enormous pool of information for enzyme discovery. Here, we report a new approach to identify and quantitatively compare biomass-degrading capacity and diversity of fungal genomes via integrated function-family annotation of carbohydrate-active enzymes (CAZymes) encoded by the genomes. Based on analyses of 1932 fungal genomes the most potent hotspots of fungal biomass processing CAZymes are identified and ranked according to substrate degradation capacity. The analysis is achieved by a new bioinformatics approach, Conserved Unique Peptide Patterns (CUPP), providing for CAZyme-family annotation and robust prediction of molecular function followed by conversion of the CUPP output to lists of integrated “Function;Family” (e.g., EC 3.2.1.4;GH5) enzyme observations. An EC-function found in several protein families counts as different observations. Summing up such observations allows for ranking of all analyzed genome sequenced fungal species according to richness in CAZyme function diversity and degrading capacity. Identifying fungal CAZyme hotspots provides for identification of fungal species richest in cellulolytic, xylanolytic, pectinolytic, and lignin modifying enzymes. The fungal enzyme hotspots are found in fungi having very different lifestyle, ecology, physiology and substrate/host affinity. Surprisingly, most CAZyme hotspots are found in enzymatically understudied and unexploited species. In contrast, the most well-known fungal enzyme producers, from where many industrially exploited enzymes are derived, are ranking unexpectedly low. The results contribute to elucidating the evolution of fungal substrate-digestive CAZyme profiles, ecophysiology, and habitat adaptations, and expand the knowledge base for novel and improved biomass resource utilization.


2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Yumeng Chen ◽  
Xingjia Fan ◽  
Xinqing Zhao ◽  
Yaling Shen ◽  
Xiangyang Xu ◽  
...  

Abstract Background The filamentous fungus Trichoderma reesei is one of the best producers of cellulase and has been widely studied for the production of cellulosic ethanol and bio-based products. We previously reported that Mn2+ and N,N-dimethylformamide (DMF) can stimulate cellulase overexpression via Ca2+ bursts and calcium signalling in T. reesei under cellulase-inducing conditions. To further understand the regulatory networks involved in cellulase overexpression in T. reesei, we characterised the Mn2+/DMF-induced calcium signalling pathway involved in the stimulation of cellulase overexpression. Results We found that Mn2+/DMF stimulation significantly increased the intracellular levels of cAMP in an adenylate cyclase (ACY1)-dependent manner. Deletion of acy1 confirmed that cAMP is crucial for the Mn2+/DMF-stimulated cellulase overexpression in T. reesei. We further revealed that cAMP elevation induces a cytosolic Ca2+ burst, thereby initiating the Ca2+ signal transduction pathway in T. reesei, and that cAMP signalling causes the Ca2+ signalling pathway to regulate cellulase production in T. reesei. Furthermore, using a phospholipase C encoding gene plc-e deletion strain, we showed that the plc-e gene is vital for cellulase overexpression in response to stimulation by both Mn2+ and DMF, and that cAMP induces a Ca2+ burst through PLC-E. Conclusions The findings of this study reveal the presence of a signal transduction pathway in which Mn2+/DMF stimulation produces cAMP. Increase in the levels of cAMP activates the calcium signalling pathway via phospholipase C to regulate cellulase overexpression under cellulase-inducing conditions. These findings provide insights into the molecular mechanism of the cAMP–PLC–calcium signalling pathway underlying cellulase expression in T. reesei and highlight the potential applications of signal transduction in the regulation of gene expression in fungi.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Sami Havukainen ◽  
Jonai Pujol-Giménez ◽  
Mari Valkonen ◽  
Ann Westerholm-Parvinen ◽  
Matthias A. Hediger ◽  
...  

AbstractTrichoderma reesei is an ascomycete fungus known for its capability to secrete high amounts of extracellular cellulose- and hemicellulose-degrading enzymes. These enzymes are utilized in the production of second-generation biofuels and T. reesei is a well-established host for their production. Although this species has gained considerable interest in the scientific literature, the sugar transportome of T. reesei remains poorly characterized. Better understanding of the proteins involved in the transport of different sugars could be utilized for engineering better enzyme production strains. In this study we aimed to shed light on this matter by characterizing multiple T. reesei transporters capable of transporting various types of sugars. We used phylogenetics to select transporters for expression in Xenopus laevis oocytes to screen for transport activities. Of the 18 tested transporters, 8 were found to be functional in oocytes. 10 transporters in total were investigated in oocytes and in yeast, and for 3 of them no transport function had been described in literature. This comprehensive analysis provides a large body of new knowledge about T. reesei sugar transporters, and further establishes X. laevis oocytes as a valuable tool for studying fungal sugar transporters.


Author(s):  
Hamed A. A. Omer ◽  
Sawsan M. Ahmed ◽  
Roshdy I. El-Kady ◽  
Aly A. El-Shahat ◽  
Mahmoud Y. El-Ayek ◽  
...  

Abstract Background Agriculture by-products are considered a great potential value for utilization by ruminants as well as rabbits. They usually can be the maintenance and part of the production requirements. However, in developing countries, as well as in Egypt, animals suffer from shortage of feeds that are continuously increasing in costs. In general, biological treatments were shown to be the most effective and improved chemical composition of rice straw or corn stalks. Method This work aimed to investigate the possible ways of utilizing rice straws or corn stalks in rabbit feeding. The field work is designed to study the effect of biological treatment of Pleurotus ostreatus cultivated on rice straws and Trichoderma reesei cultivated on corn stalks and replacing clover hay by rice straws and corn stalks at levels of 0, 33, 66, and 100% either without or with microbes adding. Seventy-eight New Zealand White (NZW) rabbits aged 4–5 weeks (565 ± 13.57 g) were randomly divided into thirteen equal experimental groups. Results Untreated rice straws or biologically treated with Pleurotus ostreatus increased their contents of crude protein (CP) by 178.75 and 224.5% and nitrogen-free extract (NFE) by 6.30 and 24.53, respectively. Meanwhile, crude fiber (CF) content was reduced by 31.32 and 56.75%, and organic matter content was decreased by 2.81 and 5.51%, respectively, in comparison with the raw rice straws. Also, biological treatment of rice straws caused a decrease in values of neutral detergent fiber (NDF), acid detergent fiber (ADF), acid detergent lignin (ADL), and hemicellulose contents in comparison with either raw or treated rice straws. Furthermore, biological treatment with Trichoderma reesei realized a decrease in organic matter (OM), CF, NDF, and ADF and increased CP and ash contents in corn stalks. NFE content of corn stalks was decreased as a result of treatment without or with Trichoderma reesei experimental rations by 11.95% and 3.82% compared to raw corn stalks (CS). Biological treatments with fungi significantly (P < 0.05) improved average daily gain (ADG) and feed conversion. ADG and feed conversion were significantly (P < 0.05) improved when rabbits were fed diets containing rice straw (RS) compared to that fed CS. Rabbits fed diets replaced clover hay (CH) with 33% or 66% of RS or CS significantly increased ADG compared to control and that replaced 100% of both RS and CS containing rations. Levels of replacing had no significant effect on their dry matter intake (DMI) values. The highest improvement in feed conversion was recorded with rabbits that received diets replaced 33% of berseem hay (BH) by RS or CS, followed by that replaced 66% of BH by RS or CS. There were significantly interactions between biological treatments (T), roughage source (S), and replacement levels (L) (T × S × L) only on ADG. The best fed conversion was realized by rabbits fed diet replaced BH with 33% of RS that are treated by Pleurotus ostreatus (4.05 g DMI/g gain). Rabbits fed 33% biologically treated rice straw with Pleurotus ostreatus showed the highest economic efficiency (179%) followed by rabbits that received 33% of both rice straws treated without Pleurotus ostreatus and rabbits that received corn stalks biologically treated with Trichoderma reesei (161%). Conclusion Biological treatments of rice straws by Pleurotus ostreatus or corn stalks by Trichoderma reesei were safe, and it improves their chemical analysis and improved both daily gain and feed conversion, decreasing the costing of diet formulation which consequently decreased the price of 1-kg live body weight.


2001 ◽  
Vol 16 (1) ◽  
pp. 7-15 ◽  
Author(s):  
Marı́a Gómez ◽  
Pablo Isorna ◽  
Marta Rojo ◽  
Pilar Estrada

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