Humicola Grisea Research Articles

Evaluation of the Addition of Humicola Grisea Cellulase to Broiler Chicken Rations for a 21-Day Period

This study aimed to evaluate the addition of liquid cellulose, produced by Humicola grisea, in 21-day-old broiler chickens’ diets. The treatments comprised control rations of corn and soybean meal and rations to which 500 mL/t and 1000 mL/t of cellulase were added. A total of 180 male broiler chickens were used, distributed in a completely randomized design, with three treatments and six replicates. Broiler chicken performance was monitored during the period from 1 to 21 days old. Significant effects were detected for digestibility only between four and seven days old, when a reduced dry matter nitrogen intake was recorded, and for nitrogen digestibility in the broilers fed cellulase-supplemented rations at a dose of 1000 m/L. Among the analyzed digestive organs, only the biometrics of the large intestine were affected significantly at seven days old. The absolute weights of the liver and pancreas and the activities of amylase, alkaline phosphatase, and transaminases were not affected significantly, indicating that cellulase did not affect the metabolism of these organs. No significant effect was detected in the serum for electrolytes, total protein, or alkaline phosphatase. So, the addition of liquid cellulase produced by Humicola grisea did not affect performance and metabolism in 21-day-old broiler chickens.

Efficacy of Scabdel and Golden Copper Fungicides on Phytopathogenic Fungi Isolated from Guava Leaves

The objectives of the study identify the fungal species from guava leaves symptomatic with leaf spots. Six fungal species (Alternaria atra, Botryotrichium verrucosum, Cochliobolus specifer, Drechslera halodes, Humicola grisea and Stachybotrys chartarum) were isolated from infected guava leaves by the direct plate method on PDA medium at 28°C. Pathogenicity test illustrated that only two species were pathogenic to guava leaves, and B. verrucosum exhibited moderate virulent ability, but C. specifer was weakly virulent. Half of the fungal species were pathogenic to apple fruits indicating that the species were non-host-specific to the guava plant. Scabdel fungicide completely inhibited the growth of B. verrucosum at 50 ppm, but in the case of C. specifer the inhibition ranged 18.8-33.3% with dose increases. Golden Copper was stimulatory to the growth of tested fungi at 50 -1000 ppm doses.

Photodynamic treatment affects the secreted antioxidant and glycoside hydrolases activities produced by Humicola grisea var. thermoidea and Penicillium echinulatum in agro-industrial substrates

The exposure of fungi to photoactivatable dyes can modify the expression of enzymes of interest in several areas such as industrial enzyme production, bioremediation of urban residues and nanocomposites stabilization. Alternatives that favor the use of plant biomass, or improve its exploitation should be prioritized, considering the scarcity of fossil resources and their polluting nature. Here, we investigated the effect of photodynamic treatment (PDT) mediated by an aluminum-phthalocyanine chloride nanoemulsion (AlPc-NE) in two hydrolases-producing filamentous fungi, Humicola grisea and Penicillium echinulatum, and its implication in the hydrolysis of agro-industrial substrates as steam exploded sugarcane-bagasse (SCB) and wheat bran (WB). The fungi hyphae were exposed to different concentrations of AlPc-NE and photosensitizer internalization was measured by spectrophotometry and fluorescence microscopy. Once the photosensitizer retention patterns were established, PDT mediated by 300 and 600 nM AlPc-NE was performed and the cultures viability was analyzed. After PDT, H. grisea and P. echinulatum were grown in SCB, WB or glucose and subsequently analyzed after 96 h. The amount of soluble secreted proteins, total antioxidant activity in the supernatant, CMCase, xylanase and FPase enzymes activity were evaluated. After irradiation, there was no change in the cultures growth or viability. Changes in the total amount of secreted protein, total antioxidant activity, CMCase and xylanase activities were observed after PDT in a photosensitizer concentration-dependent manner, and accordingly to the evaluated substrate and fungus species. Xylanase activity was the most impacted while FPase remained virtually unchanged in both fungi species. We concluded that PDT can be employed to modulate the production of certain fungal hydrolases of industrial interest.

Bacterial and fungal communities in indoor aerosols from two Kuwaiti hospitals.

The airborne transmission of COVID-19 has drawn immense attention to bioaerosols. The topic is highly relevant in the indoor hospital environment where vulnerable patients are treated and healthcare workers are exposed to various pathogenic and non-pathogenic microbes. Knowledge of the microbial communities in such settings will enable precautionary measures to prevent any hospital-mediated outbreak and better assess occupational exposure of the healthcare workers. This study presents a baseline of the bacterial and fungal population of two major hospitals in Kuwait dealing with COVID patients, and in a non-hospital setting through targeted amplicon sequencing. The predominant bacteria of bioaerosols were Variovorax (9.44%), Parvibaculum (8.27%), Pseudonocardia (8.04%), Taonella (5.74%), Arthrospira (4.58%), Comamonas (3.84%), Methylibium (3.13%), Sphingobium (4.46%), Zoogloea (2.20%), and Sphingopyxis (2.56%). ESKAPEE pathogens, such as Pseudomonas, Acinetobacter, Staphylococcus, Enterococcus, and Escherichia, were also found in lower abundances. The fungi were represented by Wilcoxinia rehmii (64.38%), Aspergillus ruber (9.11%), Penicillium desertorum (3.89%), Leptobacillium leptobactrum (3.20%), Humicola grisea (2.99%), Ganoderma sichuanense (1.42%), Malassezia restricta (0.74%), Heterophoma sylvatica (0.49%), Fusarium proliferatum (0.46%), and Saccharomyces cerevisiae (0.23%). Some common and unique operational taxonomic units (OTUs) of bacteria and fungi were also recorded at each site; this inter-site variability shows that exhaled air can be a source of this variation. The alpha-diversity indices suggested variance in species richness and abundance in hospitals than in non-hospital sites. The community structure of bacteria varied spatially (ANOSIM r2 = 0.181–0.243; p < 0.05) between the hospital and non-hospital sites, whereas fungi were more or less homogenous. Key taxa specific to the hospitals were Defluvicoccales, fungi, Ganodermataceae, Heterophoma, and H. sylvatica compared to Actinobacteria, Leptobacillium, L. leptobacillium, and Cordycipitaceae at the non-hospital site (LefSe, FDR q ≤ 0.05). The hospital/non-hospital MD index > 1 indicated shifts in the microbial communities of indoor air in hospitals. These findings highlight the need for regular surveillance of indoor hospital environments to prevent future outbreaks.

Antimycobacterial and anti-inflammatory activities of metabolites from endophytic and soil fungi

BackgroundIncreased prevalence of high virulent strains of Mycobacterium tuberculosis and M. kansasii require the development of new antimycobacterial drugs safe and more effective. And, in this context, endophytic fungi have been known as prominent sources of bioactive compounds. PurposeTo study the antimycobacterial and anti-inflammatory activities of six fungal metabolites: austdiol (1), austdiol diacetate (2), mycoleptone A (3) and eugenitin (4) isolated from cultures of endophyte Mycoleptodiscus indicus; emodin (5) from endophyte Penicillium citrinum and δ-lactam (6) from soil fungi Humicola grisea. MethodsAntimycobacterial activity against M. bovis BCG, M. tuberculosis and M. kansasii strains was evaluated using MTT method to determine the MIC50. The anti-inflammatory activity and cytotoxicity assay were carried out in LPS-stimulated RAW 264.7 macrophages. ResultsEmodin (5) was the most active compound against high virulent M. tuberculosis and M. kansasii strains exhibiting MIC50 of 8.2 ± 1.0 and 23.9 ± 0.9 μM respectively and against intracellular M. tuberculosis H37Rv growth (MIC50 of 6.5 ± 1.5 μM). Emodin inhibitory activity has been previously described only against extracellular M. tuberculosis strains. Azaphilones (1 and 3) also showed inhibitory activity against hypervirulent M. tuberculosis culture (MIC50 ≤ 40 μM) and intracellular growth (MIC50 ≤ 30 μM) whereas compounds 1 and 2 were active against high virulent M. kansassi strains (MIC50 ≤ 40 μM). Anti-inflammatory activity to inhibit NO, TNF-α and IL-1β production on LPS-stimulated macrophages was observed notably for austdiol (1) and emodin (5) with MIC50 ≤ 10 μM and good potential for compounds 2 and 3. ConclusionAzaphilone compounds (1, 2 and 3) and emodin (5) exhibiting both activities, antimycobacterial and anti-inflammatory, being promising anti-TB agents for further investigations focusing on dual treatment of severe pulmonary TB and NMT infections associated to hyperinflammation.

A Comparative Study of the Influence of Various Fungal-Based Pretreatments of Grape Pomace on Phenolic Compounds Recovery.

Wineries produce considerable amounts of grape pomace, which is a readily available natural source of bioactive phenolic compounds. In this study, grape pomace was used as a substrate for the cultivation of eleven filamentous fungi (Trametes versicolor TV6, Trametes versicolor TV8, Trametes versicolor AG613, Trametes gibbosa, Phanerochaete chrysosporium, Ceriporiopsis subvermispora, Pleurotus eryngii, Ganoderma lucidum, Ganoderma resinaceum, Humicola grisea, and Rhizopus oryzae) under solid-state conditions (SSF) for 15 days with the aim of improving the recovery of the individual phenolic compounds. Twenty-one phenolic compounds were quantified and the recovery of seventeen of them (gallic acid, ellagic acid, p-hydroxybenzoic acid, syringic acid, vanillic acid, 3,4-dihydroxybenzoic acid, ferulic acid, o-coumaric acid, p-coumaric acid, epicatechin gallate, galocatechin gallate, quercetin, kaempferol, procyanidin B1, procyanidin B2, resveratrol, and ε-viniferin) were positively affected by SSF. Ellagic acid is the most recovered compound, whose content increased 8.8-fold after 15 days of biological treatment with Ceriporiopsis subvermispora compared to the untreated initial sample. Among the microorganisms tested, the fungi Pleurotus eryngii and Rhizopus oryzae proved to be the most effective in increasing the recovery of most phenolic compounds (1.1–4.5-fold). In addition, the nutrient composition (proteins, ash, fats) of grape pomace was positively affected by the biological treatments.

Photodynamic Treatment Affects the Activity of Hydrolases Produced by Humicola Grisea VAR. Thermoidea and Penicillium Echinulatum in Agro-Industrial Substrates

Photodynamic Treatment Affects the Activity of Hydrolases Produced by Humicola Grisea VAR. Thermoidea and Penicillium Echinulatum in Agro-Industrial Substrates

The formation and quality evaluation of agarwood induced by the fungi in Aquilaria sinensis

Agarwood has high economic value and wide uses, however, the amount of wild agarwood is scarce. Wild agarwood with high oil content may contain strains associated with agarwood production. To improve the formation of agarwood, we produced fungal inducers from a high-oil wild agarwood block containing enrichment fungi. We investigated the composition of strains and inoculated the fungal inducers into Aquilaria trees. We analyzed the content of alcohol-soluble extract, essential oil, agarotetraol, 2-(2-phenylethyl)chromone, 6,7-dimethoxy-2-(2-phenylethyl)chromone and total chromone, and the chemical components of alcohol-soluble extract. We aimed to assess agarwood quality through these evaluations. The results demonstrated that fungi extracted from wild agarwood with high oil content can effectively improve the yield and quality of agarwood, and Gongronella butleri, Saitozyma podzolica, Cladorrhinum bulbillosum, Humicola grisea and Tetracladium marchalianum were the species found novel as inoculant for agarwood formation. After 12 months of inoculation, agarwood produced using A. sinensis had higher quality, the contents of alcohol-soluble extract, essential oil, total chromones, and the total relative contents of sesquiterpenes and chromones were 21.73 % ±2.97 %, 6.07 % ±0.47 %, 12.30 % ±2.21 %, and 97.59 %, respectively. Over 6–18 months of inoculation, agarotetrol content decreased, and 2-(2-phenylethyl) chromone and 6,7-dimethoxy-2-(2-phenylethyl)chromone content first increased and then decreased.

Insights into the Lignocellulose-Degrading Enzyme System of Humicola grisea var. thermoidea Based on Genome and Transcriptome Analysis.

ABSTRACTHumicola grisea var. thermoidea is a thermophilic ascomycete and important enzyme producer that has an efficient enzymatic system with a broad spectrum of thermostable carbohydrate-active (CAZy) enzymes. These enzymes can be employed in lignocellulose biomass deconstruction and other industrial applications. In this work, the genome of H. grisea var. thermoidea was sequenced. The acquired sequence reads were assembled into a total length of 28.75 Mbp. Genome features correlate with what was expected for thermophilic Sordariomycetes. The transcriptomic data showed that sugarcane bagasse significantly upregulated genes related to primary metabolism and polysaccharide deconstruction, especially hydrolases, at both pH 5 and pH 8. However, a number of exclusive and shared genes between the pH values were found, especially at pH 8. H. grisea expresses an average of 211 CAZy enzymes (CAZymes), which are capable of acting in different substrates. The top upregulated genes at both pH values represent CAZyme-encoding genes from different classes, including acetylxylan esterase, endo-1,4-β-mannosidase, exoglucanase, and endoglucanase genes. For the first time, the arsenal that the thermophilic fungus H. grisea var. thermoidea possesses to degrade the lignocellulosic biomass is shown. Carbon source and pH are of pivotal importance in regulating gene expression in this organism, and alkaline pH is a key regulatory factor for sugarcane bagasse hydrolysis. This work paves the way for the genetic manipulation and robust biotechnological applications of this fungus.IMPORTANCE Most studies regarding the use of fungi as enzyme producers for biomass deconstruction have focused on mesophile species, whereas the potential of thermophiles has been evaluated less. This study revealed, through genome and transcriptome analyses, the genetic repertoire of the biotechnological relevant thermophile fungus Humicola grisea. Comparative genomics helped us to further understand the biology and biotechnological potential of H. grisea. The results demonstrate that this fungus possesses an arsenal of carbohydrate-active (CAZy) enzymes to degrade the lignocellulosic biomass. Indeed, it expresses more than 200 genes encoding CAZy enzymes when cultivated in sugarcane bagasse. Carbon source and pH are key factors for regulating the gene expression in this organism. This work shows, for the first time, the great potential of H. grisea as an enzyme producer and a gene donor for biotechnological applications and provides the base for the genetic manipulation and robust biotechnological applications of this fungus.

Identification of fungi from soil and sediment in Jefriz Cave; the first survey in a cave from Iran

The aim of this study was to characterize the mycobiota in soil and sediment samples of Jefriz cave in Kerman, Iran. During 2018−2019, the culturable mycobiota from several sites within the Jefriz cave, resulted in 82 fungal isolates. Morphological characteristics of the isolates, as well as molecular sequence data, were used for species identifications. The fungi were identified as species of Fusarium, Fusicolla, Geomyces (Pseudogymnoascus), Humicola, Chalastospora, Penicillium, Aspergillus, Epiciccum, Podospora and Mucor. The most prevalent was Aspergillus spelunceus, followed by Geomyces pannorum and Humicola grisea. The majority of these species have been reported as cave residents in previous studies of cave environments. Our data showed that the fungal community composition varied between the samples from the entrance and less visited sites deeper in the cave. This study is the first cave mycological investigation in Iran, and one of the identified species is reported for the first time from a cave.

Microbiota of Aquatic and Terrestrial Habitats of the Dzou Cave

Microbiota of the deep caves has been poorly explored. The most relevant issues of the caves biodiversity are the sources of the microorganisms’ propagules and characteristics of autochthonous microbiota. The investigation presents the assessment of microbiota biodiversity from the Dzou cave (Western Caucasus). The aim of the study was to identify the species composition of micromycetes and phototrophs of the cave and to assess the sanitary-indicative microbiota in different habitats depending on the anthropogenic load. Microscopic and cultural methods were used to identify the microbiota from the entrance zone of the cave, as well as from aquatic and terrestrial habitats of the unlit deepest parts of the cave. The analysis of the phototrophic communities composition developed in the entrance area of the cave was carried out, 22 species were identified, among which cyanobacteria prevailed. The biodiversity of micromycetes was determined: 48 species were identified in the entrance zone, 60 species – in the dark zone of the cave. Comparison of the species composition of the dark and illuminated zones of the cave showed that in addition to species Humicola grisea, Hemicarpenteles ornatus and Alternaria sp., all species of entrance area are found in the unlit part of the cave. Representatives of genus Penicillium and Aspergillus were dominants. Revealed increase of the micromycetes and bacteria number was driving by increase in the level of anthropogenic load, especially in places of tourist camps. It was noted that the propagules of phototrophs are present in the cave substrates even at great depth, excluding some water samples, which may indicate the periodic drift of propagules or anthropogenic factor. The largest number of micromycetes species was detected in the clay deposits and rock samples. The least number of species was isolated from the water streams of the cave. A large number of micromycetes propagules was found in substrates near tourist camps, but their biodiversity was lower than in cave soils.

Production of cellulases and xylanases by Humicola grisea var. thermoidea and application in sugarcane bagasse arabinoxylan hydrolysis

Humicola grisea var. thermoidea is a deuteromycete that secretes a large spectrum of hydrolytic enzymes when grown on lignocellulosic residues. Agricultural residues are rich in lignocellulosic material and can be used as an alternate source for the production of different value-added products. The fungus was grown on sugarcane bagasse (SCB), wheat brain (WB), rice straw (RS) and corn cob (CC) as carbon source. The major endoxylanase, cellobiohydrolase, arabinofuranosidase and avicelase activities were observed when the fungus had grown on WB, while the major endoglucanase, FPAse and β-xylosidase activities on SCB. Secreted proteins by H. grisea upon growth on WB (HgWB) and SCB (HgSCB) by 144 h were analyzed by SDS/PAGE and Zymogram. The results suggested that HgWB and HgSCB presented a different pool of cellulases and xylanases. Cellulases and xylanases are used in enzyme cocktail to cellulose hydrolysis in cellulosic ethanol plants from SCB, hemicelluloses currently represents the largest polysaccharide fraction wasted in these plants. H. grisea enzymes (HgWB and HgSCB) and recombinant hemicellulases (endoxylanase GH11 – HXYN2, β-xylosidase – HXYLA and arabinofuranosidase ABF3) were employed to design hemicellulases cocktail which were employed to recovery arabinoxylan (AX) from steam explosion sugarcane bagasse (seSCB). The hydrolysis of seSCB with hemicellulases cocktail proved to be efficient and the release of reducing sugars (RS) from AX arriving at 91% conversion and the highest hydrolysis yields were obtained when using 4.200 U g−1 (Units per gram substrate) of HXYN2, 10 U g−1 of HXYLA and 4 U g−1 of ABF3. After AX hydrolysis, the solid fraction containing cellulose was hydrolyzed with commercial cellulases and presented 28% increase in hydrolysis yield (glucose production) comparing to seSCB hydrolysis without enzymatic pre-treatment. A scanning electron microscope (SEM) was an important tool to observe the modifications in seSCB after steam explosion treatment and hydrolysis. SEM images revealed that steam explosion caused considerable damage to the fibers, such as the relaxation, fragmentation and peeling of the superficial layers of the cellulose and after enzymatic hydrolysis can be observed a greater number of cracks and more brittle in the structure. The results demonstrated that enzymatic pre-treatment with hemicellulases cocktail allowed recovery of pentoses from AX which can be converted in diverse products and improved glucose production from cellulose fraction.

Biodiversity and biological activity of the fungal microbiota derived from the medicinal plants Salvia aegyptiaca L. and Balanties aegyptiaca L.

Abstract Gebel Elba is one of the three coastal mountains in the southeast corner of Egypt facing the Red Sea and it is rich in medicinal plants. Twenty fungal species belong to 14 genera were isolated as endophytic fungi from the medical plants Salvia aegyptiaca L. and Balanties aegyptiaca L. collected from Gebel Elba. The highest colonization frequency 21.38, 20.64, 20.00, and 14.71% along with relative percentage occurrence 17.28, 16.69, 16.17 and 11.89 were recorded to Alternaria alternate, Humicola grisea, Colletotrichum sp. and Trichoderma viride in Salvia aegyptiaca but the predominant fungal species in the microbiota of Balanties aegyptiaca were Curvularia papendorfii, Cylindrocephalum sp., Chaetomium globosum, Nigrospora sphaerica and Trichoderma harzianum with colonization frequency of 23.03, 17.30, 15.00, 13.08 and 12.22% with relative percentage occurrence values 17.60, 13.22, 11.47, 9.99 and 9.34, respectively. Phytochemical analysis revealed the presence of flavonoid, saponin, tannin, sterol, quinone, terpenoid, coumarin and anthraquinone metabolites in 80.77, 50.00, 88.46, 65.39, 42.31, 76.92, 84.62 and 61.54%, respectively. The highest content of phenolic (97.23 ± 1.0 mg/g) was detected in the ethyl acetate extract of endophytic Aspergillus terreus isolated from Balanties aegyptiaca but the maximum yield of flavonoid (79.86 ± 0.04 mg/g) and tannin (35.07 ± 0.05 mg/g) were detected in endophytic Alternaria alternate and Humicola grisea isolated from Salvia aegyptiaca. Furthermore, Salvia aegyptiaca and Balanties aegyptiaca associated endophytic fungal microbiota showed potent antibacterial, antioxidant and anticancer activities. This work revealed that fungal endophytes inhabited these Egyptian medicinal plants could be effective source for bioactive compounds useful for developing better antioxidant, antibacterial or anticancer drugs with good therapeutic index value.

Mycobiota of the Saffron Cod Eleginus gracilis (Tilesius, 1810) and the Asiatic Smelt Osmerus mordaxdentex Steindachner &amp; Kner, 1870 in the Peter the Great Bay of the Sea of Japan

A mycological examination of the saffron cod Eleginus gracilis (Tilesius, 1810) and the Asiatic smelt Osmerus mordax dentex Steindachner & Kner, 1870, caught in the Amursky Bay (Peter the Great Bay of the Sea of Japan) revealed several species of filamentous fungi. In total, 105 isolates of filamentous fungi were obtained from the skin integument and internal organs (31 isolates from the saffron cod and 74 isolates from the Asiatic smelt). Three species of filamentous fungi were found in the saffron cod: Aspergillus flavus Link, Penicillium brevicompactum Dierckx, and Phialophorophoma sp. Six species of filamentous fungi were found in the Asiatic smelt: Aspergillus wentii Wehmer, Aspergillus sp., Cladosporium cladosporioides (Fresen.) de Vries, Penicillium albidum Sopp., Penicillium nigricans (Bain.) Thom, and Humicola grisea Traaen. All the identified species are anamorphic stages of ascomycetes. In the saffron cod, the organs most frequently invaded by fungi were the gills (three fungal species were found); two species of fungi were found in the muscles and liver and one species each were identified in the skin integument and in gonads. The distribution of fungi in the Asiatic smelt was different: four fungal species were revealed in the skin integument, three species in the gills, two species in muscles, one species in the liver, one species in the gonads, and two species on the fins.

The boosting effect of recombinant hemicellulases on the enzymatic hydrolysis of steam-treated sugarcane bagasse

To increase the efficiency of enzyme cocktails in deconstructing cellulose and hemicelluloses present in the plant cell wall, a combination of enzymes with complementary activities is required. Xylan is the main hemicellulose component of energy crops and for its complete hydrolysis a system consisting of several enzymes acting cooperatively, including endoxylanases (XYN), β-xylosidases (XYL) and α-l-arabinofuranosidases (ABF) is necessary. The current work aimed at evaluating the effect of recombinant hemicellulolytic enzymes on the enzymatic hydrolysis of steam-exploded sugarcane bagasse (SEB). One recombinant endoxylanase (HXYN2) and one recombinant β-xylosidase (HXYLA) from Humicola grisea var thermoidea, together with an α-l-arabinofuranosidase (AFB3) from Penicillium pupurogenum, all produced in Pichia pastoris, were used to formulate an efficient enzyme mixture for SEB hydrolysis using a 23 Central Composite Rotatable Design (CCRD). The most potent enzyme for SEB hydrolysis was ABF3. Subsequently, the optimal enzyme mixture was used in combination with commercial cellulases (Accellerase 1500), either simultaneously or in sequential experiments. The supplementation of Accellerase 1500 with hemicellulases enhanced the glucose yield from SEB hydrolysis by 14.6%, but this effect could be raised to 50% when hemicellulases were added prior to hydrolysis with commercial cellulases. These results were supported by scanning electron microscopy, which revealed the effect of enzymatic hydrolysis on SEB fibers. Our results show the potential of complementary enzyme activities to improve enzymatic hydrolysis of SEB, thus improving the efficiency of the hydrolytic process.

Optimization of Glucoamylase Production by Humicola grisea MTCC 352 in Solid State Fermentation

In the industrial processing of starch, the thermostable glucoamylase is employed in saccharification step. The thermophilic fungi Humicola grisea has been used for the glucoamylase production in solid state fermentation. The extracellular glucoamylase is estimated using glucose oxidase – peroxidase assay method. The initial screening studies revealed that wheat bran is the best substrate among the studied agricultural residues. The fermentation parameters were optimized through the response surface approach. By using central composite design, the optimal values of four important parameters viz., mineral salt solution concentration, incubation period, initial moisture content and inoculum size for glucoamylase production were found to be 65 % (v/w), 80 h, 240 % (v/w) and 13 % (v/w) respectively. The experimental activity of 282 U/gds obtained was close to the predicted activity of 288 U/gds. A high R2 value (0.9741), P values lesser than 0.05 and AARD values (1.98 %) indicate the accuracy of the proposed model.

Isolation, screening and identification of ligno-cellulolytic fungi from northern central Morocco

Description of the subject. Extracellular enzymes from filamentous fungi are increasingly used in eco-friendly biotransformation processes. Their relevant technological role and their stability towards extreme process conditions make of them the first sustainable solution for the elaboration of bio-based products from biomass conversion. Objectives. This paper describes the isolation of filamentous fungi from decaying plant material in the region of Meknes (northern central Morocco) and the assessment of their ability to breakdown lignocellulose. The objective is to select performant fungi with enzymatic machinery adapted to local environment and with potential for the breakdown of the regional specific lignocellulosic by-products into potentially high-value molecules. Method. Cereals, decaying wood, olive-pomace and -pulp and their composts were used to isolate lignocellulolytic fungi. One hundred twenty-seven pure strains were isolated and screened at 25 °C on selective media with cellulose or lignin as the sole carbon source. Performant strains were validated for the production of ligno-cellulolytic enzymes and identified using molecular technique. Results. Twenty-eight fungi had mycelial diameter on cellulose ≥ 6 cm and cellulolytic index ≥ 0.9. Twenty-two strains had the same profile on lignin medium. The production of endoglucanase, lignin peroxidase and manganese peroxidase enzymes was confirmed in performant strains using qualitative assay and molecular identification revealed that the best performing fungi were Mucor circinelloides, Mucor racemosus, Penicillium brasilianum, Penicillium crustosum, Paecilomyces sp., Fusarium oxysporum, Fusarium solani, Aspergillus fischeri, Curvularia spicifera, Humicola grisea, Trichoderma atroviride and Cosmospora viridescens. Measurement of ligno-cellulolytic activities revealed that Penicillium and Fusarium strains mainly from wood decay and compost had the best profiles among performing strains. Conclusions. Isolated fungi are high decomposers of biomass and represent a prominent solution to develop green bioprocesses in the region.

Proximate analysis of cold-press oil cakes after biological treatment with Trametes versicolor and Humicola grisea.

In order to increase the current knowledge on cold-press oil cakes composition, the present study aims to determine the chemical composition of oil cakes from hull-less pumpkin (Cucurbita pepo L.), flax (Linum usitatissimum L.), and hemp (Canabis sativa L.) before and after the biological treatment with Trametes versicolor and Humicola grisea using fungal-based solid-state technology. After 10days of treatment, the content of ash, total nitrogen, total proteins, and total organic carbon increased in all the three oil cakes, while the content of ether extracts decreased. After treatment, the concentration of soluble carbohydrates decreased in pumpkin and hemp seed oil cakes, whereas it increased in flaxseed oil cake. During treatment with T. versicolor, the content of fructose significantly increased in hull-less pumpkin seed oil cake. Fiber content decreased in pumpkin and flaxseed oil cakes after treatment with both of the fungi, whereas it increased in flaxseed oil cake.

Process optimization, purification and characterization of a novel acidic, thermostable chitinase from Humicola grisea

An extracellular acidic and thermostable chitinase (HgChi) from thermophilic Humicola grisea was purified and characterized. Enhancement in chitinase production (Qp = 2.9662 Ul−1 h−1) was achieved through derivation of optimum fermentation conditions via central composite design. H. grisea observed to produce various isoforms of chitinase, among which the major expressed form has molecular mass of about 50 kDa. Purified chitinases exhibited optimal activity at pH 3.0 and 70 °C. Chitinase showed notable stability at increasing temperatures. Half-life of chitinase is 169.06 min at optimum temperature. Chitinase has effectively catalyzed N-acetyl chitobiose (GlcNAc)2, and N-acetyl chitotriose (GlcNAc)3 and colloidal chitin. Purified chitinase from H. grisea showed high affinity towards colloidal chitin as evident by its comparatively lower Km value. Presence of metal ions viz. Mn2+, Co2+, NH4+ and Mg2+ significantly increased the chitinase activity. Thin layer chromatography (TLC) analysis revealed the significant hydrolyzing competence of HgChi for colloidal chitin, (GlcNAc)3 and (GlcNAc)2 into oligomers and N-acetyl–d-glucosamine (GlcNAc). Thermostable chitinase appeared as potential candidate for efficient conversion of chitin to bioactive oligosaccharides at industrial scale.

Detection of soil fungi from wheat cultivated area

Experiments were conducted to find out different soil fungi from wheat cultivated area during 15 April to 10 May, 2013-2014. The obtained soil fungi from wheat cultivated area were Aspergillus spp., Penicillum spp., Geotrichum spp., Gloesporium spp., Fusarium spp., Mycelia sterilia, Arthrobotrys spp., Cladosporium herbarum in district Allahabad, Various soil fungi from wheat cultivated area from Mirzapur district were which Aspergillus spp., Penicillum spp., Rizoctinia spp., Fusarium spp., Mucor spp. and In Varanasi district, various soil fungi were obtained also from wheat cultivated area which are Aspergillus spp., Penicillum spp., Rizoctinia spp., Fusarium spp., Mucor spp., Alternaria spp., Helminthosporium oryzae, and Humicola grisea. Aspergillus spp. and Penicillum spp. was common fungi presented in three different districts Allahabad, Mirzapur and Varanasi, of Uttar Pradesh.Bangladesh J. Agril. Res. 43(1): 149-157, March 2018