Cellulolytic Fungi Research Articles

The Potential for Cellulose Deconstruction in Fungal Genomes

Fungal cellulolytic enzymes are carbohydrate active enzymes (CAzymes) essential for the deconstruction of the plant cell wall. Cellulolytic activity is described in some glycoside hydrolases (GH-cellulases) and in auxiliary activities (AA-cellulases) families. Across environments, these enzymes are mostly produced by some fungi and some bacteria. Cellulolytic fungi secrete these enzymes to deconstruct polysaccharides into simple and easy to metabolize oligo- and mono-saccharides. The fungal ability to degrade cellulose result from their repertoire of CAZymes-encoding genes targeting many substrates (e.g., xylan, arabinose). Over the past decade, the increased number of sequenced fungal genomes allowed the sequence-based identification of many new CAZyme-encoding genes. Together, the predicted cellulolytic enzymes constitute the fungal potential for cellulose deconstruction. As not all fungi have the same genetic makeup, identifying the potential for cellulose deconstruction across different lineages can help identify the various fungal strategies to access and degrade cellulose (conserved vs. variable genomic features) and highlight the evolution of cellulase-encoding genes. Here, the potential for cellulose deconstruction identified across publicly accessible, and published, fungal genomes is discussed.

Intron retention coupled with nonsense-mediated decay is involved in cellulase biosynthesis in cellulolytic fungi

BackgroundKnowledge on regulatory networks associated with cellulase biosynthesis is prerequisite for exploitation of such regulatory systems in enhancing cellulase production with low cost. The biological functions of intron retention (IR) and nonsense-mediated mRNA decay (NMD) in filamentous fungi is lack of study, let alone their roles in cellulase biosynthesis.ResultsWe found that major cellulase genes (cel7a, cel7b, and cel3a) exhibited concomitant decrease in IR rates and increase in their gene expression in T. reesei under cellulase-producing condition (cellulose and lactose) that was accompanied with a more active NMD pathway, as compared to cellulase non-producing condition (glucose). In the presence of the NMD pathway inhibitor that successfully repressed the NMD pathway, the mRNA levels of cellulase genes were sharply down-regulated, but the rates of IR in these genes were significantly up-regulated. Consistently, the cellulase activities were severely inhibited. In addition, the NMD pathway inhibitor caused the downregulated mRNA levels of two important genes of the target of rapamycin (TOR) pathway, trfkbp12 and trTOR1. The absence of gene trfkbp12 made the cellulase production in T. reesei more sensitive to the NMD pathway inhibitor.ConclusionsAll these findings suggest that the IR of cellulase genes regulates their own gene expression by coupling with the NMD pathway, which might involve the TOR pathway. Our results provide better understanding on intron retention, the NMD pathway, and cellulase production mechanism in filamentous fungi.

The microbial mechanisms of enhanced humification by inoculation with Phanerochaete chrysosporium and Trichoderma longibrachiatum during biogas residues composting

This study investigated effects of composite microbes (CMs) (Phanerochaete chrysosporium and Trichoderma longibrachiatum) on humification during co-composting of biogas residue, spent mushroom substrate and rice straw. Results showed that CMs inoculation elevated degradation ratios of cellulose, hemicellulose and lignin by 7.86%, 8.87% and 6.45%, and contents of humus and humic acid were correspondingly promoted by 15.5% and 23.6%, respectively. Relative abundances of bacteria associated with refractory macromolecules degradation (Flavobacterium, Anseongella and Actinomadura) and cellulolytic fungi (Hypocreales_Incertae_sedis, Hypocreaceae and Psathyrellaceae) were raised by CMs addition. Redundancy analysis demonstrated a positive correlation between microbial communities and temperature, fulvic acid and lignocellulose contents. Moreover, CMs inoculation promoted pathways of xenobiotics biodegradation and metabolism, and biosynthesis of other secondary metabolites, which was closely associated with lignocellulose degradation and humus formation. These results suggested that biological inoculation could enhance composting efficiency and improve compost quality, benefiting biogas residues composting.

Cellulolytic fungi modify the nitrogen, phosphorus, and potassium contents of organic fertilizers

Cellulolytic fungi are involved in releasing nutrients from organic sources. The objective of this study was to determine the effect of cellulolytic fungi on the total nitrogen (N), total phosphorus (P), and total potassium (K) contents in different organic fertilizers. This study was arranged in randomized block design 3 X 3 with three replications. There were two factors, cellulolytic fungi (Talaromyces pinophilus strain MR107, Penicillium sp. isolate SR18, and Purpureocillium lilacinum isolate PIGD23i) and organic fertilizers (cow manure, compost, and vermicompost). The results indicated that Penicillium sp. isolate SR18 had a better effect than other cellulolytic fungi species on tot. N, tot. P and tot. K contents of cow manure; tot. N and tot. K contents of compost; and tot. P content of vermicompost while P. lilacinum isolate PIGD23i showed a better effect on tot. N and tot. K contents of vermicompost. The highest tot. N, and tot. K contents were found in P. lilacinum isolate PIGD23i-inoculated vermicompost while the tot. P content was in Penicillium sp. isolate SR18-inoculated vermicompost. Overall, adding cellulolytic fungi is an alternative way to improve the nutrient content of organic fertilizer.

Grazing greatly reduces the temporal stability of soil cellulolytic fungal community in a steppe on the Tibetan Plateau

Excessive livestock grazing degrades grasslands ecosystem stability and sustainability by reducing soil organic matter and plant productivity. However, the effects of grazing on soil cellulolytic fungi, an important indicator of the degradation process for soil organic matter, remain less well understood. Using T-RFLP and sequencing methods, we investigated the effects of grazing on the temporal changes of cellulolytic fungal abundance and community structure in dry steppe soils during the growing months from May to September, on the Tibetan Plateau using T-RFLP and sequencing methods. The results demonstrated that the abundance of soil cellulolytic fungi under grazing treatment changed significantly from month to month, and was positively correlated with dissolved organic carbon (DOC) and soil temperature, but negatively correlated with soil pH. Contrastingly, cellulolytic fungal abundance did not change within the fencing treatment (ungrazed conditions). Cellulolytic fungal community structure changed significantly in the growing months in grazed soils, but did not change in fenced soils. Grazing played a key role in determining the community structure of soil cellulolytic fungi by explaining 8.1% of the variation, while pH and DOC explained 4.1% and 4.0%, respectively. Phylogenetically, the cellulolytic fungi were primarily affiliated with Ascomycota (69.65% in relative abundance) and Basidiomycota (30.35%). Therefore, grazing substantially reduced the stability of soil cellulolytic fungal abundance and community structure, as compared with the fencing treatment. Our finding provides a new insight into the responses of organic matter-decomposing microbes for grassland managements.

Isolation of Cellulolytic Fungi from Rice Husk

Aim: To isolate cellulose degrading fungi from rice husk.
 Study Design: The experiment was carried out under aseptic condition in 3 replicates.
 Place and Duration of Study: Department of Biological Sciences, Microbiology Programme, Clifford University, Ihie Campus, Owerrinta, Abia State, Nigeria, between May 2021 to August 2021.
 Methodology: Rice husk from a rice mill was collected and kept until visible microbial growth was noticed. The organisms were isolated, characterized and screened for enzyme activities.
 Results: Cellulolytic organisms were isolated from rice husk, an agricultural by-product of rice milling. The isolates were identified as Penicillium and Aspergillus species. The two fungal isolates were screened for enzyme activity using 0.5 ml Carboxymethyl cellulose (CMC) as carbon source, the highest cellulase activity of 0.448 µg/ml/min was recorded for Aspergillus sp. at 48 hours while Penicillium sp, had enzyme activity of 0.388 µg/ml/min at day 1.
 Conclusion: The result of this study shows that Aspergillus and Penicillium spp were isolated from rice husk and were able to secrete the enzyme cellulase which is a very important enzyme in so many industries and also very expensive. Thus isolating organism that can secrete this enzyme is an added advantage to many industries.

Cellulose-containing waste recycling using fungi

Accumulation of plant waste is a serious environmental problem. Mushrooms with high cellulolytic activity can process it into valuable products that will be useful in solving various industries and agriculture problems. The enzymes of the cellulolytic complex include 1,4-β-D-glucan-4-glucanohydrolase, exo-1,4-β-glucosidase, cellobiohydrolase, β-glucosidase. 1,4-β-D-glucan-4-glucanohydrolases destroy β-1,4-glycosidic bonds within the chain of cellulose and lichenin polysaccharides. Exoglucanases destroy β-1,3- and β-1,4-glycosidic bonds at the end of the molecule. Cellobiohydrolases cleave β-1,4-glycosidic bonds to form cellobiose and glucose. β-glucosidase complete the process of destruction. Fungi with high cellulolytic activity include both representatives of the Ascomycota and Basidiomycota divisions. Ascomycete Chaetomium globosum produces endoglucanases of two families and 8 cellobiohydrolases. Myceliophthora thermophila also produces endoglucanases and cellobiohydrolases, the most abundant of which is Mt Cel7A. The fungus is a promising producer of thermostable enzymes. Trichoderma reesei has a long history of safe use as a source of highly active cellulolytic enzymes and other valuable metabolites. LPMOs of the cellulolytic fungus Thielavia terrestris are considered auxiliary enzymes, but can negatively affect the main enzymes of the complex. Irpex lacteus also produces LPMO and a complete cellulolytic enzyme complex. The cellulolytic activity of fungi and their ability to grow on cheap substrates can be used to bioconvert plant waste into valuable products. One of the ways to utilize them is to convert into compound feed with a high protein content through the use of starter cultures. The use of mushrooms will increase the content of protein and simple carbohydrates, enrich the feed with fats. Another method is to obtain cellulases, which are widely used in many industries. Thanks to the production of biodiesel and bioethanol from cellulose-containing raw materials it is possible to solve the problem of lack of fuel by replacing energy carriers from non-renewable energy sources with their environmentally friendly counterparts. They are less toxic than diesel and gasoline and are also made from renewable resources.

Suppression of damping-off disease causative agents using cellulase enzyme extracts of locally isolated cellulolytic fungi and their co-cultures

The Ceylon Journal of Science is a peer-reviewed journal published quarterly by the University of Peradeniya, Sri Lanka in March, June, September and December. It is aimed at publishing high quality research articles on topics related to different disciplines in Science. The journal accepts original research articles, book reviews, reviews and mini-reviews, short communications, opinions, research notes, and commentaries and notes. The journal strictly adheres to publication ethics as emphasized by the Committee on Publication Ethics (COPE). The Journal has its own website.The Ceylon Journal of Science is indexed in Sri Lanka Journals Online (SLJOL), Directory of Open Access Journals (DOAJ), Google Scholar and Zoological Records. According to the Google Scholar; H5-Index: 12H5-Median: 15According to the Exaly (1970 – 2021); Impact Factor: 0.6 (top 19%)Extended IF: 0.6 (top 19%) H-Index: 8 (top 28%)Citations/paper: 1.42

Drafting Penicillium oxalicum calcineurin-CrzA pathway by combining the analysis of phenotype, transcriptome, and endogenous protein–protein interactions

Fungi sense environmental signals and coordinate growth, development, and metabolism accordingly. Calcium-calmodulin-calcineurin signaling is a conserved cascade pathway in fungi. One of the most important downstream targets of this pathway is the transcription factor Crz1/CrzA, which plays an essential role in various cellular processes. The putative collaborators of Penicillium oxalicum CrzA (PoCrzA) were found, through tandem affinity purification followed by mass spectrometric analysis (TAP-MS). A total of 50 protein–protein interaction collaborators of PoCrzA were observed. Among them, some collaborators, such as the catalytic subunit of calcineurin (Cna1, calcineurin A), the regulatory catalytic subunit of calcineurin (Cnb1, calcineurin B), and a 14-3-3 protein Bmh1, which were previously reported in yeast, were identified. Some putative collaborators, including two karyopherins (exportin Los1 and importin Srp1), two kinases (Fus3 and Slt2p), and a general transcriptional corepressor (Cyc8), were also found. The CrzA deletion mutant ΔPocrzA exhibited slow hyphal growth, impaired conidiogenesis, and reduced extracellular cellulase synthesis. Phenotype and transcriptome analysis showed that PoCrzA regulated fungal development in a Flbs-BrlA-dependent manner and participated in cellulase synthesis by modulating cellulolytic gene expression. On the basis of the results of TAP-MS, transcriptome, and phenotypic analysis in P. oxalicum, our study was the first to draft the calcineurin-CrzA pathway in cellulolytic fungi.

Carbon catabolite repression involves physical interaction of the transcription factor CRE1/CreA and the Tup1\u2013Cyc8 complex in Penicillium oxalicum and Trichoderma reesei

BackgroundCellulolytic enzyme production in filamentous fungi requires a release from carbon catabolite repression (CCR). The protein CRE1/CreA (CRE = catabolite responsive element) is a key transcription factor (TF) that is involved in CCR and represses cellulolytic gene expression. CRE1/CreA represents the functional equivalent of Mig1p, an important Saccharomyces cerevisiae TF in CCR that exerts its repressive effect by recruiting a corepressor complex Tup1p–Cyc8p. Although it is known from S. cerevisiae that CRE1/CreA might repress gene expression via interacting with the corepressor complex Tup1–Cyc8, this mechanism is unconfirmed in other filamentous fungi, since the physical interaction has not yet been verified in these organisms. The precise mechanism on how CRE1/CreA achieves transcriptional repression after DNA binding remains unknown.ResultsThe results from tandem affinity purification and bimolecular fluorescence complementation revealed a direct physical interaction between the TF CRE1/CreA and the complex Tup1–Cyc8 in the nucleus of cellulolytic fungus Trichoderma reesei and Penicillium oxalicum. Both fungi have the ability to secrete a complex arsenal of enzymes to synergistically degrade lignocellulosic materials. In P. oxalicum, the protein PoCyc8, a subunit of complex Tup1–Cyc8, interacts directly with TF PoCreA and histone H3 lysine 36 (H3K36) methyltransferase PoSet2 in the nucleus. The di-methylation level of H3K36 in the promoter of prominent cellulolytic genes (cellobiohydrolase-encoding gene Pocbh1/cel7A and endoglucanase-encoding gene Poegl1/cel7B) is positively correlated with the expression levels of TF PoCreA. Since the methylation of H3K36 was also demonstrated to be a repression marker of cellulolytic gene expression, it appears feasible that the cellulolytic genes are repressed via PoCreA-Tup1–Cyc8-Set2-mediated transcriptional repression.ConclusionThis study verifies the long-standing conjecture that the TF CRE1/CreA represses gene expression by interacting with the corepressor complex Tup1–Cyc8 in filamentous fungi. A reasonable explanation is proposed that PoCreA represses gene expression by recruiting complex PoTup1–Cyc8. Histone methyltransferase Set2, which methylates H3K36, is also involved in the regulatory network by interacting with PoCyc8. The findings contribute to the understanding of CCR mechanism in filamentous fungi and could aid in biotechnologically relevant enzyme production.

Two C1-oxidizing AA9 lytic polysaccharide monooxygenases from Sordaria brevicollis differ in thermostability, activity, and synergy with cellulase.

Cellulolytic fungi usually have multiple genes for C1-oxidizing auxiliary activity 9 (AA9) lytic polysaccharide monooxygenases (LPMOs) in their genomes, but their potential functional differences are less understood. In this study, two C1-oxidizing AA9 LPMOs, SbLPMO9A and SbLPMO9B, were identified from Sordaria brevicollis, and their differences, particularly in terms of thermostability, reducing agent specificity, and synergy with cellulase, were explored. The two enzymes exhibited weak binding to cellulose and intolerance to hydrogen peroxide. Their oxidative activity was influenced by cellulose crystallinity and surface morphology, and both enzymes tended to oxidize celluloses of lower crystallinity and high surface area. Comparably, SbLPMO9A had much better thermostability than SbLPMO9B, which may be attributed to the presence of a carbohydrate binding module 1 (CBM1)-like sequence at its C-terminus. In addition, the two enzymes exhibited different specificities and responsivities toward electron donors. SbLPMO9A and SbLPMO9B were able to boost the catalytic efficiency of endoglucanase I (EGI) on physically and chemically pretreated substrates but with different degrees of synergy. Substrate- and enzyme-specific synergism was observed by comparing the synergistic action of SbLPMO9A or SbLPMO9B with commercial Celluclast 1.5L on three kinds of cellulosic substrates. On regenerated amorphous cellulose and PFI (Papirindustriens Forskningsinstitut)-fibrillated bleached eucalyptus pulp, SbLPMO9B showed a higher synergistic effect than SbLPMO9A, while on delignified wheat straw, the synergistic effect of SbLPMO9A was higher than that of SbLPMO9B. On account of its excellent thermostability and boosting effect on the enzymatic hydrolysis of delignified wheat straw, SbLPMO9A may have high application potential in biorefineries for lignocellulosic biomass. KEY POINTS: • C1-oxidizing SbLPMO9A displayed higher thermostability than SbLPMO9B, probably due to the presence of a CBM1-like module. • The oxidative activity of the two SbLPMO9s on celluloses increased with decreasing cellulose crystallinity or increasing beating degree. • The two SbLPMO9s boosted the catalytic efficiency of cellulase, but the synergistic effect was substrate- and enzyme-specific.

Characterization of phosphate solubilizing and cellulolytic fungi isolated from soil under Eurycoma longifolia stands

Eurycoma longifolia is one of the potential medicinal plants and has a high economic value if developed. The bioactive compound produced by E. longifolia has potential as medicine, thus causing increased exploitation of their habitat. This condition resulted in the decreasing population of E .longifolia in nature. The distribution of E. longifolia is influenced by soil fertility conditions. The presence of phosphate solubilizing fungi and cellulolytic fungi in the soil can support the growth of E. longifolia in nature. The purpose of this study was to calculate the population of phosphate solubilizing and cellulolytic fungi and to identify the types of phosphate solubilizing and cellulolytic fungi found in the soil under E. longifolia stands. Soil samples were taken randomly at a depth of 0–20 cm in a natural forest of Papaso Village, Lubu Sutam District, Padang Lawas Regency, North Sumatra. Population and isolation of phosphate solubilizing and cellulolytic fungi were obtained by dilution methods. The isolates obtained were identified morphologically to the genus level by macroscopic and microscopic observation of colonies. The results showed that the population of phosphate solubilizing and cellulolytic fungi were 6.64 × 104 CFU/mL and 9.31 × 103 CFU/mL, respectively. The isolation results in 11 isolates of phosphate solubilizing and 10 isolates of cellulolytic fungi. Based on the morphological identification of phosphate solubilizing fungi isolates consisted of 5 genera, namely Aspergillus, Penicillium, Rhizopus, Fusarium, and Mucor, while isolates of cellulolytic fungi also included 5 genera, namely Aspergillus, Cladosporium, Penicillium, Rhizopus, and Mucor.

Isolation and screening of local cellulolytic fungi from the digestive tract larvae of Oryctes rhinoceros L., North Sumatra

Cellulose, which is the main component of plant cell walls from higher plants, has been studied from different aspects. It is insoluble in a wide variety of solvents and is resistant to various chemicals treatments. Fungi are a group of cellulose-degrading microbes and plays major role in recycling of lignocellulosic material in nature. This study aimed to obtain cellulolytic fungi from the digestive tract of Oryctes rhinoceros L. larvae and to determine cellulolytic activity. Isolation and screening of cellulolytic fungi in the digestive tract of insects were carried out with specific medium Carboxymethyl Cellulose (CMC) and the Congo Red method to obtain potential cellulolytic isolates. Eleven fungal isolates showed positive results as cellulolytic fungi. The highest cellulolytic activity was obtained from isolate F05L with a cellulolytic index of 0.90 and isolate F10L of 0.66. The smallest cellulolytic activity was obtained from isolate F02L with a cellulolytic index of 0.14. All isolates would be identified to the species level and analyzed its potential applications. Our result can provide in addition to the environmental and industrial fields, cellulolytic fungi can a solution to the problem of pollution, namely reducing the amount of cellulose waste, and can be added value to the use of waste into processed organic fertilizers to be able to provide solutions to the problem of organic waste degradation.

Morphological identification of phosphate solubilizing and cellulolytic fungi from mangrove soil under Rhizophora stylosa stands

Mangrove forest is one of the forest ecosystems that can be found in tidal areas. Mangrove forest have ecological, socio-economic benefits for organisms that live in the sea. One of the microorganism that live in mangrove forest is fungus. Therefore, this study aimed to isolate and identify phosphate solubilizing and cellulolytic fungi from mangrove soil. Soil samples were collected from a stands of Rhizophora stylosa in Lubuk Kertang Village, West Brandan District, Langkat Regency, North Sumatra. Soil samples were taken randomly with a dept of 0-20 cm. Isolation of phosphate solubilizing fungi was carried out using Pikovskaya medium and cellulolytic fungi using carboxyl methyl cellulose (CMC) medium. To determine the effectiveness of fungi qualitatively, the phosphate solubility and cellulolytic index were calculated. All isolates obtained were identified morphologically by observing colonies macroscopically and microscopically. This study obtained 12 isolates of phosphate solubilizing and 8 isolates of cellulolytic fungi. Phosphate solubility index ranging from 2.06-2.87 and cellulolytic index of 0.33-3.00. Morphological identifications showed that all isolates of phosphate solubilizing fungi belonged to the genus Aspergillus, while all isolates of cellulolytic fungi belonged to the genus Chaetomium.

The Role of Laccase from Zygomycetous Fungus Mortierella elasson in Humic Acids Degradation

Biochemical stability of soil humus is an important factor affecting soil quality. Fungi are among the most efficient decomposers of humic matter due to presence of oxidative enzymes, including phenoloxidase laccase. Production of laccase by zygomycetes, a group of cellulolytic fungi widespread in soil, is poorly studied. The potential role of laccase from zygomycetes in humus turnover is unknown. Here, we show for the first time that laccase of zygomycetous fungus Mortierella elasson can effectively depolymerize humic acids in vitro. The fungus produced laccase extracellularly in a liquid culture medium. Unlike in case of laccases in ligninolytic basidiomycetes, attempts to increase enzyme activity using inductors, changes in the source of nitrogen and carbon failed to lead to any increase in laccase production. Laccase was purified using ion exchange chromatography and gel filtration. The molecular weight of the laccase was 51.75 kDa. The laccase catalyzed the oxidation of ABTS and K4[Fe(CN)6], phenolic compounds, but not tyrosine. The laccase activity was inhibited by NaN3 and NaF. The pH optimum of the laccase activity was 3.0 for ABTS and 5.0 for 2,6-dimethoxy phenol. The enzyme had moderate thermal stability and was rapidly inactivated at 70 °C. Purified laccase depolymerized humic acids from retisol, compost and peat more effectively than culture liquid containing laccase. The results of the study extend our knowledge of the role of laccases from different producers in the transformation of natural organic matter.

Coordination of consolidated bioprocessing technology and carbon dioxide fixation to produce malic acid directly from plant biomass in Myceliophthora thermophila

BackgroundConsolidated bioprocessing (CBP) technique is a promising strategy for biorefinery construction, producing bulk chemicals directly from plant biomass without extra hydrolysis steps. Fixing and channeling CO2 into carbon metabolism for increased carbon efficiency in producing value-added compounds is another strategy for cost-effective bio-manufacturing. It has not been reported whether these two strategies can be combined in one microbial platform.ResultsIn this study, using the cellulolytic thermophilic fungus Myceliophthora thermophila, we designed and constructed a novel biorefinery system DMCC (Direct microbial conversion of biomass with CO2 fixation) through incorporating two CO2 fixation modules, PYC module and Calvin–Benson–Bassham (CBB) pathway. Harboring the both modules, the average rate of fixing and channeling 13CO2 into malic acid in strain CP51 achieved 44.4, 90.7, and 80.7 mg/L/h, on xylose, glucose, and cellulose, respectively. The corresponding titers of malic acid were up to 42.1, 70.4, and 70.1 g/L, respectively, representing the increases of 40%, 10%, and 7%, respectively, compared to the parental strain possessing only PYC module. The DMCC system was further improved by enhancing the pentose uptake ability. Using raw plant biomass as the feedstock, yield of malic acid produced by the DMCC system was up to 0.53 g/g, with 13C content of 0.44 mol/mol malic acid, suggesting DMCC system can produce 1 t of malic acid from 1.89 t of biomass and fix 0.14 t CO2 accordingly.ConclusionsThis study designed and constructed a novel biorefinery system named DMCC, which can convert raw plant biomass and CO2 into organic acid efficiently, presenting a promising strategy for cost-effective production of value-added compounds in biorefinery. The DMCC system is one of great options for realization of carbon neutral economy.

Endoglucanase Activity of Novel Aspergillus sydowii Isolate WIU-01 and Application for Hydrophyte Degradation

<p>Many eutrophic lakes contain rapidly growing hydrophytes. Overgrown biomass is usually me-chanically harvested and thrown away, leading to resource waste and secondary environmental pollution. Microbial degradation is an economically and environmentally friendly approach for managing hydrophytic waste, fuelling the search for efficient biomass degraders. Here, we present isolation and characterization of Aspergillus sydowii WIU-01, a novel cellulolytic fungus. Strain WIU-01 was isolated from air. The degradation rate (29.75 vs. 21.95%) and endoglucanase activi-ty (0.31 vs. 0.16 U mL–1) of the fungus were higher in Canna indica (emergent plant) medium than in Hydrilla verticillata (submerged plant) medium, accordingly. Further, fungal endoglucanase ac-tivity was significantly positively correlated with the degradation rate, neutral detergent fiber con-tent, and acid detergent fiber content of hydrophyte powder. Fungal biomass was significantly negatively correlated with reducing sugar and cellulose content of hydrophyte medium, but was significantly positively correlated with hemicellulose, acid detergent lignin, and ash content of the medium. Collectively, these observations indicate that A. sydowii decomposes emergent and sub-merged plant mass without acid–base sample pretreatment, albeit its endoglucanase activity is rela-tively low. This highlights the role of cellulolytic microorganisms in the natural environment and the notion that the environment can be a source of cellulolytic microorganisms for potential envi-ronmentally friendly applications.</p>

Valorization of the green seaweed Ulva rigida for production of fungal biomass protein using a hypercellulolytic terrestrial fungus

The green macroalgae biomass accumulated in eutrophicated coastal waters has negative ecological and economic impacts. Green macroalgae have an interesting nutritional profile that can be exploited for production of feeds. Bioconversion of green seaweed by microbial fermentation allows the production of microbial biomass protein. This research aimed to study the saccharification and fermentation of green macroalgae biomass by a cellulolytic fungus to provide a product with a nutritional added-value. For this purpose, green seaweed Ulva rigida was directly saccharified and fermented in batch using the filamentous fungus Trichoderma reesei Rut-C30. The fermentation product obtained from the growth of T. reesei Rut-C30 on Ulva rigida as the sole carbon source in 72 h was called fungal biomass protein (FBP) from fermented Ulva rigida. FBP from fermented Ulva rigida contained all essential amino acids and compared favorably with the FAO guideline profiles. Besides, the content of limiting amino acid methionine of FBP from Ulva rigida increased 4-folds compared to the raw alga (from 0.65% to 3% of the total protein content) and was similar to the methionine levels of ovalbumin protein. The in vitro digestibility of FBP from fermented Ulva rigida increased from 71% to 94% compared to the raw alga, and was higher than that of leguminous seeds and similar to that of soybean meal. The results of our work demonstrate that Ulva rigida can be saccharified and fermented in a single step by a terrestrial fungus in 72 h under submerged fermentation to provide high-quality proteins suitable to produce feeds.

Screening Cellulolytic Fungi Isolated From Malaysia Cocoa Pod Husk and Its Culture Conditions for Cellulases Production

The aim of this study was to screen few fungal isolates from local cocoa pod husks (CPH) which able to secrete cellulases. The isolates were plated on carboxymethyl cellulose (CMC) agar plates which then incubated for two days at 28ºC. Then, these plates were stained with congo red dye for 0.5-1 h followed by destaining with 1 M NaCl solution for 15-20 minutes to observe its cellulolytic activity. One isolates which exposed the largest cellulolytic zone on CMC agar plate was selected for further study. In this study, culture conditions with respect to pH, incubation time, amount of substrate (CPH) and temperature were screened using Design expert @version 8.0 by employing two-level factorial design. The selected fungus isolate was cultured in shake flask at 37°C with agitation of 200 rpm for 5 days in incubator shaker. During fermentation period, samples were collected every day for fungal-cellulases activity of filter paper activity (FPase) and carboxymethyl cellulase (CMCase) activity. Analysis of variance (ANOVA) of this study showed that the most significant parameters that affects the production of cellulases from the selected fungi isolates were the amount of substrate (CPH) used followed by the interaction of amount of substrate with pH (p< 0.05). It showed that the cellulases activity was high when the pH 9 with more amount of substrate used. However, it was observed that less significant changes of celllulases activity when different amount of substrate was used at same pH of 3. Based on the microscopic observation of isolate, it morphology was closed to Rhizopus sp.. In conclusion, it is suggested to optimize the selected culture parameters obtained in this study in order to maximize the activity of cellulases from the selected isolates.

Screening and identification of cellulolytic fungi at rhizosphere of safira taro plant

Agriculture waste and pathogen cell wall of plant contain a lot of cellulose which are very difficult to degrade. One of the ways to hydrolyse them is through utilizing cellulase, an enzyme produced from secondary metabolite of cellulolytic fungi. This research was aimed at isolating fungi from rhizosphere of safira taro plant and testing the isolate capability to produce cellulase enzyme to be able to act as decomposer and biocontrol of the plant. The research methods are isolating rhizosphere fungi, testing isolate capability in producing cellulase enzyme and identifying potential isolate producing cellulolytic fungi. It obtained 10 fungi isolates, 4 were negative and 6 positive in producing cellulase enzyme with cellulolytic index 1.16 – 1.66. The highest index was RTB14 isolate which belongs to Aspergillus flavus.