Showing papers on "Trichoderma reesei published in 2011"

Comparative genome sequence analysis underscores mycoparasitism as the ancestral life style of Trichoderma

Abstract: Mycoparasitism, a lifestyle where one fungus is parasitic on another fungus, has special relevance when the prey is a plant pathogen, providing a strategy for biological control of pests for plant protection. Probably, the most studied biocontrol agents are species of the genus Hypocrea/Trichoderma. Here we report an analysis of the genome sequences of the two biocontrol species Trichoderma atroviride (teleomorph Hypocrea atroviridis) and Trichoderma virens (formerly Gliocladium virens, teleomorph Hypocrea virens), and a comparison with Trichoderma reesei (teleomorph Hypocrea jecorina). These three Trichoderma species display a remarkable conservation of gene order (78 to 96%), and a lack of active mobile elements probably due to repeat-induced point mutation. Several gene families are expanded in the two mycoparasitic species relative to T. reesei or other ascomycetes, and are overrepresented in non-syntenic genome regions. A phylogenetic analysis shows that T. reesei and T. virens are derived relative to T. atroviride. The mycoparasitism-specific genes thus arose in a common Trichoderma ancestor but were subsequently lost in T. reesei. The data offer a better understanding of mycoparasitism, and thus enforce the development of improved biocontrol strains for efficient and environmentally friendly protection of plants.

Traffic Jams Reduce Hydrolytic Efficiency of Cellulase on Cellulose Surface

Abstract: A deeper mechanistic understanding of the saccharification of cellulosic biomass could enhance the efficiency of biofuels development We report here the real-time visualization of crystalline cellulose degradation by individual cellulase enzymes through use of an advanced version of high-speed atomic force microscopy Trichoderma reesei cellobiohydrolase I (TrCel7A) molecules were observed to slide unidirectionally along the crystalline cellulose surface but at one point exhibited collective halting analogous to a traffic jam Changing the crystalline polymorphic form of cellulose by means of an ammonia treatment increased the apparent number of accessible lanes on the crystalline surface and consequently the number of moving cellulase molecules Treatment of this bulky crystalline cellulose simultaneously or separately with T reesei cellobiohydrolase II (TrCel6A) resulted in a remarkable increase in the proportion of mobile enzyme molecules on the surface Cellulose was completely degraded by the synergistic action between the two enzymes

Biotechnological strategies to overcome inhibitors in lignocellulose hydrolysates for ethanol production: review.

Abstract: One of the major challenges faced in commercial production of lignocellulosic bioethanol is the inhibitory compounds generated during the thermo-chemical pre-treatment step of biomass. These inhibitory compounds are toxic to fermenting micro-organisms. The ethanol yield and productivity obtained during fermentation of lignocellulosic hydrolysates is decreased due to the presence of inhibiting compounds, such as weak acids, furans and phenolic compounds formed or released during thermo-chemical pre-treatment step such as acid and steam explosion. This review describes the application and/or effect of biological detoxification (removal of inhibitors before fermentation) or use of bioreduction capability of fermenting yeasts on the fermentability of the hydrolysates. Inhibition of yeast fermentation by the inhibitor compounds in the lignocellulosic hydrolysates can be reduced by treatment with enzymes such as the lignolytic enzymes, for example, laccase and micro-organisms such as Trichoderma reesei, Coniochaeta ligniaria NRRL30616, Trametes versicolor, Pseudomonas putida Fu1, Candida guilliermondii, and Ureibacillus thermosphaericus. Microbial and enzymatic detoxifications of lignocellulosic hydrolysate are mild and more specific in their action. The efficiency of enzymatic process is quite comparable to other physical and chemical methods. Adaptation of the fermentation yeasts to the lignocellulosic hydrolysate prior to fermentation is suggested as an alternative approach to detoxification. Increases in fermentation rate and ethanol yield by adapted micro-organisms to acid pre-treated lignocellulosic hydrolysates have been reported in some studies. Another approach to alleviate the inhibition problem is to use genetic engineering to introduce increased tolerance by Saccharomyces cerevisiae, for example, by overexpressing genes encoding enzymes for resistance against specific inhibitors and altering co-factor balance. Cloning of the laccase gene followed by heterologous expression in yeasts was shown to provide higher enzyme yields and permit production of laccases with desired properties for detoxification of lignocellulose hydrolysates. A combination of more inhibitor-tolerant yeast strains with efficient feed strategies such as fed-batch will likely improve lignocellulose-to-ethanol process robustness.

Biosynthesis of Silver Nanoparticles by Fungus Trichoderma Reesei (A Route for LargeScale Production of AgNPs)

Abstract: One of the requirements for advancement of nanotechnology are the development of reliable experimental protocols for the synthesis of nanomaterials over a range of biological compositions, sizes and high monodispersity. An attractive possibility of green nanotechnology is to use microorganisms in the syn thesis of nanoparticles. Recently, the utilization of biological systems, especially fungi, has emerged as a novel method for the synthesis of nanoparticles. Nanoparticles are considered as fundamental molecular building blocks for nanotechnology. They are the starting points for preparing many nanostructured materials and devices. In this paper we report the extracellular biosynthesis of silver nanoparticles (AgNPs) by using a fungus named Trichoderma Reesei (also known as Hypocrea jecorina ). In the biosynthesis of AgNPs by this fungus, the fungus mycelium is exposed to the silver nitrate solution. That prompts the fungus to produce enzymes and metabolites for its own survival. In this process the toxic Ag + ions are reduced to the none� toxic metallic AgNPs through the catalytic effect of the extracellular enzyme and metabolites of the fungus. Absorption UVVisible li ght spectroscopy is used to follow up with the reaction process. Fluorescence emission spectroscopy is used to produce detailed information on the progress of reduction of silver nitrate (formation of silver nanoparticles) on the nanosecond timescale. Fourier transform infrared spectroscopy is used for quantitative analyses of the reaction products. Our measurements indicate that extracellular biosynthesis of AgNPs by Trichoderma reesei produces AgNPs with the diameters in the range of 5�50 nm . Trichoderma Reesei is an environmentally friendly fungus, and it is well known for its formation of extracellular enzyme and metabolites in very large amounts, much higher than other fungi. The present process is an excellent candidate for industrial scale production of silver nanoparticles.

Inhibition of enzymatic hydrolysis by residual lignins from softwood--study of enzyme binding and inactivation on lignin-rich surface.

Abstract: Lignin-derived inhibition is a major obstacle restricting the enzymatic hydrolysis of cell wall polysaccharides especially with softwood lignocellulosics. Enzyme adsorption on lignin is suggested to contribute to the inhibitory effect of lignin. The interaction of cellulases with softwood lignin was studied in the present work with commercial Trichoderma reesei cellulases (Celluclast) and lignin-rich residues isolated from steam pretreated softwood (SPS) by enzymatic and acid hydrolysis. Both lignin preparations inhibited the hydrolysis of microcrystalline cellulose (Avicel) and adsorbed the major cellulases present in the commercial cellulase mixture. The adsorption phenomenon was studied at low temperature (4°C) and at the typical hydrolysis temperature (45°C) by following activities of free and lignin-bound enzymes. Severe inactivation of the lignin-bound enzymes was observed at 45°C, however at 4°C the enzymes retained well their activity. Furthermore, SDS-PAGE analysis of the lignin-bound enzymes indicated that very strong interactions form between the residue and the enzymes at 45°C, because the enzymes were not released from the residue in the electrophoresis. These results suggest that heat-induced denaturation may take place on the surface of softwood lignin at the hydrolysis temperature.

Arsenal of plant cell wall degrading enzymes reflects host preference among plant pathogenic fungi

Abstract: Background The discovery and development of novel plant cell wall degrading enzymes is a key step towards more efficient depolymerization of polysaccharides to fermentable sugars for the production of liquid transportation biofuels and other bioproducts. The industrial fungus Trichoderma reesei is known to be highly cellulolytic and is a major industrial microbial source for commercial cellulases, xylanases and other cell wall degrading enzymes. However, enzyme-prospecting research continues to identify opportunities to enhance the activity of T. reesei enzyme preparations by supplementing with enzymatic diversity from other microbes. The goal of this study was to evaluate the enzymatic potential of a broad range of plant pathogenic and non-pathogenic fungi for their ability to degrade plant biomass and isolated polysaccharides.

The CRE1 carbon catabolite repressor of the fungus Trichoderma reesei: a master regulator of carbon assimilation

Abstract: The identification and characterization of the transcriptional regulatory networks governing the physiology and adaptation of microbial cells is a key step in understanding their behaviour. One such wide-domain regulatory circuit, essential to all cells, is carbon catabolite repression (CCR): it allows the cell to prefer some carbon sources, whose assimilation is of high nutritional value, over less profitable ones. In lower multicellular fungi, the C2H2 zinc finger CreA/CRE1 protein has been shown to act as the transcriptional repressor in this process. However, the complete list of its gene targets is not known. Here, we deciphered the CRE1 regulatory range in the model cellulose and hemicellulose-degrading fungus Trichoderma reesei (anamorph of Hypocrea jecorina) by profiling transcription in a wild-type and a delta-cre1 mutant strain on glucose at constant growth rates known to repress and de-repress CCR-affected genes. Analysis of genome-wide microarrays reveals 2.8% of transcripts whose expression was regulated in at least one of the four experimental conditions: 47.3% of which were repressed by CRE1, whereas 29.0% were actually induced by CRE1, and 17.2% only affected by the growth rate but CRE1 independent. Among CRE1 repressed transcripts, genes encoding unknown proteins and transport proteins were overrepresented. In addition, we found CRE1-repression of nitrogenous substances uptake, components of chromatin remodeling and the transcriptional mediator complex, as well as developmental processes. Our study provides the first global insight into the molecular physiological response of a multicellular fungus to carbon catabolite regulation and identifies several not yet known targets in a growth-controlled environment.

The role of acetyl xylan esterase in the solubilization of xylan and enzymatic hydrolysis of wheat straw and giant reed

Abstract: Background Due to the complexity of lignocellulosic materials, a complete enzymatic hydrolysis into fermentable sugars requires a variety of cellulolytic and xylanolytic enzymes. Addition of xylanases has been shown to significantly improve the performance of cellulases and to increase cellulose hydrolysis by solubilizing xylans in lignocellulosic materials. The goal of this work was to investigate the effect of acetyl xylan esterase (AXE) originating from Trichoderma reesei on xylan solubilization and enzymatic hydrolysis of cellulose.

Differential regulation of the cellulase transcription factors XYR1, ACE2, and ACE1 in Trichoderma reesei strains producing high and low levels of cellulase.

Abstract: Due to its capacity to produce large amounts of cellulases, Trichoderma reesei is increasingly being investigated for second-generation biofuel production from lignocellulosic biomass. The induction mechanisms of T. reesei cellulases have been described recently, but the regulation of the genes involved in their transcription has not been studied thoroughly. Here we report the regulation of expression of the two activator genes xyr1 and ace2, and the corepressor gene ace1, during the induction of cellulase biosynthesis by the inducer lactose in T. reesei QM 9414, a strain producing low levels of cellulase (low producer). We show that all three genes are induced by lactose. xyr1 was also induced by D-galactose, but this induction was independent of D-galactose metabolism. Moreover, ace1 was carbon catabolite repressed, whereas full induction of xyr1 and ace2 in fact required CRE1. Significant differences in these regulatory patterns were observed in the high-producer strain RUT C30 and the hyperproducer strain T. reesei CL847. These observations suggest that a strongly elevated basal transcription level of xyr1 and reduced upregulation of ace1 by lactose may have been important for generating the hyperproducer strain and that thus, these genes are major control elements of cellulase production.

Transformation System for Hypocrea jecorina (Trichoderma reesei) That Favors Homologous Integration and Employs Reusable Bidirectionally Selectable Markers

Abstract: Hypocrea jecorina is an industrially important filamentous fungus due to its effective production of hydrolytic enzymes. It has received increasing interest because of its ability to convert lignocellulosic biomass to monomeric sugars, which can be converted into biofuels or platform chemicals. Genetic engineering of strains is a highly important means of meeting the requirements of tailor-made applications. Therefore, we report the development of a transformation system that allows highly efficient gene targeting by using a tmus53 (human LIG4 homolog) deletion strain. Moreover, it permits the unlimited reuse of the same marker by employing a Cre/loxP-based excision system. Both marker insertion and marker excision can be positively selected for by combining resistance to hygromycin B and loss of sensitivity to fluoroacetamide. Finally, the marker pyr4, also positively selectable for insertion and loss, can be used to remove the cre gene.

Fungal arabinan and l-arabinose metabolism

Abstract: l-Arabinose is the second most abundant pentose beside d-xylose and is found in the plant polysaccharides, hemicellulose and pectin. The need to find renewable carbon and energy sources has accelerated research to investigate the potential of l-arabinose for the development and production of biofuels and other bioproducts. Fungi produce a number of extracellular arabinanases, including α-l-arabinofuranosidases and endo-arabinanases, to specifically release l-arabinose from the plant polymers. Following uptake of l-arabinose, its intracellular catabolism follows a four-step alternating reduction and oxidation path, which is concluded by a phosphorylation, resulting in d-xylulose 5-phosphate, an intermediate of the pentose phosphate pathway. The genes and encoding enzymes l-arabinose reductase, l-arabinitol dehydrogenase, l-xylulose reductase, xylitol dehydrogenase, and xylulokinase of this pathway were mainly characterized in the two biotechnological important fungi Aspergillus niger and Trichoderma reesei. Analysis of the components of the l-arabinose pathway revealed a number of specific adaptations in the enzymatic and regulatory machinery towards the utilization of l-arabinose. Further genetic and biochemical analysis provided evidence that l-arabinose and the interconnected d-xylose pathway are also involved in the oxidoreductive degradation of the hexose d-galactose.

Compatible Ionic liquid‐cellulases system for hydrolysis of lignocellulosic biomass

Abstract: Ionic liquids (ILs) have been increasingly recognized as novel solvents for dissolution and pretreatment of cellulose. However, cellulases are inactivated in the presence of ILs, even when present at low concentrations. To more fully exploit the benefits of ILs it is critical to develop a compatible IL-cellulases system in which the IL is able to effectively solubilize and activate the lignocellulosic biomass, and the cellulases possess high stability and activity. In this study, we investigated the stability and activity of a commercially available cellulases mixture in the presence of different concentrations of 1-ethyl-3-methylimidazolium acetate ([Emim][OAc]). A mixture of cellulases and β-glucosidase (Celluclast1.5L, from Trichoderma reesei, and Novozyme188, from Aspergillus niger, respectively) retained 77% and 65% of its original activity after being pre-incubated in 15% and 20% (w/v) IL solutions, respectively, at 50°C for 3 h. The cellulases mixture also retained high activity in 15% [Emim][OAc] to hydrolyze Avicel, a model substrate for cellulose analysis, with conversion efficiency of approximately 91%. Notably, the presence of different amounts of yellow poplar lignin did not interfere significantly with the enzymatic hydrolysis of Avicel. Using this IL-cellulase system (15% [Emim][OAc]), the saccharification of yellow poplar biomass was also significantly improved (33%) compared to the untreated control (3%) during the first hour of enzymatic hydrolysis. Together, these findings provide compelling evidence that [Emim][OAc] was compatible with the cellulase mixture, and this compatible IL-cellulases system is promising for efficient activation and hydrolysis of native biomass to produce biofuels and co-products from the individual biomass components.

Enzyme production by filamentous fungi: analysis of the secretome of Trichoderma reesei grown on unconventional carbon source

Abstract: Background Spent hydrolysates from bioethanolic fermentation processes based on agricultural residues have potential as an abundant and inexpensive source of pentose sugars and acids that could serve as nutrients for industrial enzyme-producing microorganisms, especially filamentous fungi. However, the enzyme mixtures produced in such media are poorly defined. In this study, the secretome of Trichoderma reesei Rut C-30 grown either on a spent hydrolysate model medium (SHMM) or on a lactose-based standard medium (LBSM) was explored using proteomics.

Podospora anserina Hemicellulases Potentiate the Trichoderma reesei Secretome for Saccharification of Lignocellulosic Biomass

Abstract: To improve the enzymatic hydrolysis (saccharification) of lignocellulosic biomass by Trichoderma reesei, a set of genes encoding putative polysaccharide-degrading enzymes were selected from the coprophilic fungus Podospora anserina using comparative genomics. Five hemicellulase-encoding genes were successfully cloned and expressed as secreted functional proteins in the yeast Pichia pastoris. These novel fungal CAZymes belonging to different glycoside hydrolase families (PaMan5A and PaMan26A mannanases, PaXyn11A xylanase, and PaAbf51A and PaAbf62A arabinofuranosidases) were able to break down their predicted cognate substrates. Although PaMan5A and PaMan26A displayed similar specificities toward a range of mannan substrates, they differed in their end products, suggesting differences in substrate binding. The N-terminal CBM35 module of PaMan26A displayed dual binding specificity toward xylan and mannan. PaXyn11A harboring a C-terminal CBM1 module efficiently degraded wheat arabinoxylan, releasing mainly xylobiose as end product. PaAbf51A and PaAbf62A arabinose-debranching enzymes exhibited differences in activity toward arabinose-containing substrates. Further investigation of the contribution made by each P. anserina auxiliary enzyme to the saccharification of wheat straw and spruce demonstrated that the endo-acting hemicellulases (PaXyn11A, PaMan5A, and PaMan26A) individually supplemented the secretome of the industrial T. reesei CL847 strain. The most striking effect was obtained with PaMan5A that improved the release of total sugars by 28% and of glucose by 18%, using spruce as lignocellulosic substrate.

How recombinant swollenin from Kluyveromyces lactis affects cellulosic substrates and accelerates their hydrolysis

Abstract: In order to generate biofuels, insoluble cellulosic substrates are pretreated andsubsequently hydrolyzed with cellulases. One way to pretreat cellulose in a safeand environmentally friendly manner is to apply, under mild conditions,non-hydrolyzing proteins such as swollenin - naturally produced in low yields bythe fungus Trichoderma reesei. To yield sufficient swollenin forindustrial applications, the first aim of this study is to present a new way ofproducing recombinant swollenin. The main objective is to show how swolleninquantitatively affects relevant physical properties of cellulosic substrates andhow it affects subsequent hydrolysis. After expression in the yeast Kluyveromyces lactis, the resultingswollenin was purified. The adsorption parameters of the recombinant swolleninonto cellulose were quantified for the first time and were comparable to those ofindividual cellulases from T. reesei. Four different insoluble cellulosicsubstrates were then pretreated with swollenin. At first, it could bequalitatively shown by macroscopic evaluation and microscopy that swollenin causeddeagglomeration of bigger cellulose agglomerates as well as dispersion ofcellulose microfibrils (amorphogenesis). Afterwards, the effects of swollenin oncellulose particle size, maximum cellulase adsorption and cellulose crystallinitywere quantified. The pretreatment with swollenin resulted in a significantdecrease in particle size of the cellulosic substrates as well as in theircrystallinity, thereby substantially increasing maximum cellulase adsorption ontothese substrates. Subsequently, the pretreated cellulosic substrates werehydrolyzed with cellulases. Here, pretreatment of cellulosic substrates withswollenin, even in non-saturating concentrations, significantly accelerated thehydrolysis. By correlating particle size and crystallinity of the cellulosicsubstrates with initial hydrolysis rates, it could be shown that theswollenin-induced reduction in particle size and crystallinity resulted in highcellulose hydrolysis rates. Recombinant swollenin can be easily produced with the robust yeast K.lactis. Moreover, swollenin induces deagglomeration of celluloseagglomerates as well as amorphogenesis (decrystallization). For the first time,this study quantifies and elucidates in detail how swollenin affects differentcellulosic substrates and their hydrolysis.

Proteomics-based Compositional Analysis of Complex Cellulase–Hemicellulase Mixtures

Abstract: Efficient deconstruction of cellulosic biomass to fermentable sugars for fuel and chemical production is accomplished by a complex mixture of cellulases, hemicellulases, and accessory enzymes (e.g., >50 extracellular proteins). Cellulolytic enzyme mixtures, produced industrially mostly using fungi like Trichoderma reesei, are poorly characterized in terms of their protein composition and its correlation to hydrolytic activity on cellulosic biomass. The secretomes of commercial glycosyl hydrolase-producing microbes was explored using a proteomics approach with high-throughput quantification using liquid chromatography-tandem mass spectrometry (LC-MS/MS). Here, we show that proteomics-based spectral counting approach is a reasonably accurate and rapid analytical technique that can be used to determine protein composition of complex glycosyl hydrolase mixtures that also correlates with the specific activity of individual enzymes present within the mixture. For example, a strong linear correlation was seen between Avicelase activity and total cellobiohydrolase content. Reliable, quantitative and cheaper analytical methods that provide insight into the cellulosic biomass degrading fungal and bacterial secretomes would lead to further improvements toward commercialization of plant biomass-derived fuels and chemicals.

Trichoderma reesei: A Fungal Enzyme Producer for Cellulosic Biofuels

Abstract: Enzymes are proteins that catalyse chemical reactions by lowering the activation energy needed and thus speed up the reaction itself. The advantage of enzymes is that they can be applied under mild reaction conditions and that they exhibit high substrate specificity, stereoselectivity and less side product formation than conventional chemical reactions, making biotechnological processes often more cost-effective than chemical approaches. Microorganisms, such as bacteria and fungi are widely exploited for the industrial production of numerous enzymes. Filamentous fungi (moulds) can grow on a wide range of substrates and efficiently degrade biopolymers and are thus an attractive resource for new enzymes. The decomposition of cellulosic plant biomass to glucose monomers for biofuel production is a typical example for an application that requires an enzyme-based approach in order to specifically cleave the glycosidic bonds between the glucose monomers of the cellulose chain and release single glucose molecules. The main enzymes necessary to degrade cellulosic plant material are cellulases and hemicellulases. The filamentous fungus Trichoderma reesei is today a paradigm for commercial scale production of different cellulases and hemicellulases and is well adapted to fermenter cultivations. Beside well established applications of these enzymes in pulp, paper, food, feed or textile processing industries, these plant cell wall degrading enzymes are nowadays also employed for the saccharification of cellulosic plant biomass to simple sugars for biofuel production (Bouws et al., 2008; Harman and Kubicek, 1998; Kumar et al., 2008). The cellulolytic potential of this pantropical fungus was already recognized during WWII through the deterioration of cotton fabrics of the US Army. Strain QM6a (originally named T. viride) was isolated from the cotton canvas of an army tent from Bougainville Island (Solomon Islands). After identification of the fungus as the cause for the massive destruction, it was put under quarantine in the eponymous Quartermaster collection of the US army at Natick. Strain QM6a was later recognized as an own species and named after its principal investigator in those years Elwyn T. Reese (Reese, 1976). It is an important peculiarity that this T. reesei strain QM6a is the ancestor of all enzyme producing T. reesei strains in commercial use. Later it was found, that, based on DNA-based phylogenetic markers, the asexual fungus T. reesei was indistinguishable from the sexually propagating fungus Hypocrea jecorina, thus indicating that they belong to the same species (Kuhls et al., 1996). More recent investigations demonstrated that even the original isolate T. reesei QM6a, which was for a long time considered to be an asexual clonal line, can be sexually crossed with H. jecorina

Cellulolytic Enzymes Production via Solid-State Fermentation: Effect of Pretreatment Methods on Physicochemical Characteristics of Substrate

Abstract: We investigated the effect of pretreatment on the physicochemical characteristics—crystallinity, bed porosity, and volumetric specific surface of soybean hulls and production of cellulolytic enzymes in solid-state fermentation of Trichoderma reesei and Aspergillus oryzae cultures. Mild acid and alkali and steam pretreatments significantly increased crystallinity and bed porosity without significant change inholocellulosic composition of substrate. Crystalline and porous steam-pretreated soybean hulls inoculated with T. reesei culture had 4 filter paper units (FPU)/g-ds, 0.6 IU/g-ds β-glucosidase, and 45 IU/g-ds endocellulase, whereas untreated hulls had 0.75 FPU/g-ds, 0.06 IU/g-ds β-glucosidase, and 7.29 IU/g-ds endocellulase enzyme activities. In A. oryzae steam-pretreated soybean hulls had 47.10 IU/g-ds endocellulase compared to 30.82 IU/g-ds in untreated soybean hulls. Generalized linear statistical model fitted to enzyme activity data showed that effects of physicochemical characteristics on enzymes production were both culture and enzyme specific. The paper shows a correlation between substrate physicochemical properties and enzyme production.

Production and Optimization of Cellulase Enzyme Using Aspergillus niger USM AI 1 and Comparison with Trichoderma reesei via Solid State Fermentation System.

Abstract: Novel design solid state bioreactor, FERMSOSTAT, had been evaluated in cellulase production studies using local isolate Aspergillus niger USM AI 1 grown on sugarcane bagasse and palm kernel cake at 1 : 1 (w/w) ratio. Under optimised SSF conditions of 0.5 kg substrate; 70% (w/w) moisture content; 30∘C; aeration at 4 L/h·g fermented substrate for 5 min and mixing at 0.5 rpm for 5 min, about 3.4 U/g of Filter paper activity (FPase) was obtained. At the same time, comparative studies of the enzymes production under the same SSF conditions indicated that FPase produced by A. niger USM AI 1 was about 35.3% higher compared to Trichoderma reesei. This shows that the performance of this newly designed SSF bioreactor is acceptable and potentially used as prototype for larger-scale bioreactor design.

Proteomic analysis of pH and strains dependent protein secretion of Trichoderma reesei.

Abstract: Bioenergy, particularly biofuel, from lignocellulosic biomass has been considered as one of the most promising renewable and sustainable energies The industrial productivity and efficiency of microbial lignocellulolytic enzymes for cellulosic biofuel applications are significantly affected by pH of culture condition This study established and compared hydrolytic protein expression profiles of Trichoderma reesei QM6a, QM9414, RUT C30 and QM9414MG5 strains at different pH in cellulosic culture media Liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis of secretome of T reesei cultured from pH 30-90 revealed significantly higher hydrolytic protein expressions at acidic pH The Bray-Curtis similarity indices, clustering, and Shannon diversity index elucidated differences in protein secretion at different pHs in individuals and among the strains This study demonstrated a comparative lignocellulolytic enzyme secretion profile of T reesei and its mutants at different pHs and provides pH sensitive and resistance enzyme targets for industrial lignocellulose hydrolysis