Search

The current research aims to evaluate the susceptibility of the tomato of the tomato (Solanum lycopersicum) cultivars 65,015 (CV1), Basma (CV2), Dalia (CV3), 320 (CV4), and 844 (CV5) to early blight disease caused by Alternaria solani, A. alternata, and Curvularia lunata under greenhouse conditions. All five cultivars were inoculated with the tested pathogenic fungi. The results showed that CV1 was highly resistant to early blight disease whereas CV5 was most susceptible to it. The causal pathogens decreased the total chlorophyll contents of the tomato cultivars and caused the accumulation of hydrogen peroxide, superoxide anions, and lipid peroxidation, having the greatest effect in CV5 followed by CV4 and the least effect in CV1. The pathogenic fungi also significantly stimulated the synthesis of ascorbic acid and reduced the production of glutathione, salicylic acid, soluble phenolic compounds, phenylalanine ammonialyase, and polyphenol oxidase in all the infected tomato cultivars except CV4 or CV5, with CV1 showing the greatest changes. Histopathological studies of the infection phases of A. solani and C. lunata on the highly resistant cultivar CV1 and the susceptible cultivar CV5 under the light microscope demonstrated that the leaves of CV1 were coated with thick epidermal hairs and glandular hairs and had relatively few stomata, whereas those of CV5 had a limited number of hairs and many stomata. Electron microscopy further showed that the fungal mycelia of A. solani and C. lunata easily attacked the open stomata of the hypersensitive cultivar CV5.

Fungi are increasingly gaining interest from aquatic microbial ecologists. The application of new molecular tools has revealed that they are a ubiquitous and highly diverse organismic group in aquatic environments with essential contributions to aquatic food web dynamics and biogeochemical cycles at the global scale. However, there remain many open questions and knowledge gaps about the consequences of human activities for fungi in aquatic ecosystems. Urban development and anthropogenic pollution provide aquatic fungi with new habitats and substrates but also challenge their adaptive behavior to withstand toxicity and frequent disturbances. In this article, we focus on fungal metabolic capabilities in the light of increasing urbanization. In particular, we investigate the multiple and yet largely unknown effects of microplastics, a steadily increasing anthropogenic pollutant, on aquatic fungal communities. We also make the case that by studying the multiple ecological roles of aquatic fungi, we will better understand the impacts of urban development and anthropogenic pollution on human and environmental health. UCR::Vicerrectoría de Docencia::Ciencias Básicas::Facultad de Ciencias::Escuela de Biología

In this study, two highly thermotolerant and methanol-tolerant lipase-producing bacteria were isolated from cooking oil and they exhibited a high number of catalytic lipase activities recording 18.65 ± 0.68 U/mL and 13.14 ± 0.03 U/mL, respectively. Bacterial isolates were identified according to phenotypic and genotypic 16S rRNA characterization as Kocuria flava ASU5 (MT919305) and Bacillus circulans ASU11 (MT919306). Lipases produced from Kocuria flava ASU5 showed the highest methanol tolerance, recording 98.4% relative activity as well as exhibited high thermostability and alkaline stability. Under the optimum conditions obtained from 3D plots of response surface methodology design, the Kocuria flava ASU5 biocatalyst exhibited an 83.08% yield of biodiesel at optimized reaction variables of, 60 ○C, pH value 8 and 1:2 oil/alcohol molar ratios in the reaction mixture. As well as, the obtained results showed the interactions of temperature/methanol were significant effects, whereas this was not noted in the case of temperature/pH and pH/methanol interactions. The obtained amount of biodiesel from cooking oil was 83.08%, which was analyzed by a GC/Ms profile. The produced biodiesel was confirmed by Fourier-transform infrared spectroscopy (FTIR) approaches showing an absorption band at 1743 cm−1, which is recognized for its absorption in the carbonyl group (C=O) which is characteristic of ester absorption. The energy content generated from biodiesel synthesized was estimated as 12,628.5 kJ/mol. Consequently, Kocuria flava MT919305 may provide promising thermostable, methanol-tolerant lipases, which may improve the economic feasibility and biotechnology of enzyme biocatalysis in the synthesis of value-added green chemicals.

A reduction in crop spoilage and an increase in shelf-life is the goal of effective disease control methods. This study aimed to assess ZnO-nanoparticles (ZnO-NPs) as a safe, new protectant against Rhizopus soft rot of sweet potato. ZnO-NPs had a fungicidal effect against Rhizopus stolonifer when used at concentrations above 50 ppm. The results showed that tubers treated with ZnO-NPs exhibited fewer fungal populations (1.2 CFU per segment) than those that did not receive the treatment. Tubers infected with Rhizopus stolonifer and treated with ZnO-NPs showed no visible decay for up to 15 days, indicating that ZnO-NPs act as a coating layer on tuber surface. The greatest weight loss after 15 days of storage was reported in infected tubers (8.98%), followed by infected tubers treated with ZnO (6.54%) and infected tubers treated with ZnO-NPs (3.79%). The activity of cell-wall degrading enzymes, α-amylase and cellulase, were significantly increased in both infected tubers and those treated with ZnO, compared to the tubers treated with ZnO-NPs. These results confirm that coating with ZnO-NPs is an effective method of protecting sweet potato tubers from infection, maintaining their quality and increasing their shelf-life for up to 2 months in storage.

In this study, an antagonistic yeast isolate, Wickerhamiella versatilis was considered as a promising biocontrol agent against Pectobacterium carotovorum subsp. Carotovorum (Pcc) the causal...

This work was aimed to evaluate the efficacy of arbuscular mycorrhizal fungi (AMF) and the endophytic fungal strain Epicoccum nigrum ASU11 (Epi) to control potato blackleg caused by bacterial stain Pectobacterium carotovora subsp. atrosepticum PHY7 (Pca). E. nigrum showed unique colonization frequency properties of potato plants (73.3% colonization frequency). Furthermore, the endophytic fungus exhibited antagonistic capability against pathogenic bacteria with inhibition zone 18 ± 0.5 mm. The AMF and Epi individually or in combination reduced Pca population in vivo experiment. The highest level of reduction was recorded in combination of AMF+ Epi. Also, infected potato plants treated with the two bioagents showed the highest weight of potato tubers in comparison to infected control. The enhancement of potato plants growth and the elevation of blackleg disease symptoms by bioagents (Epi + AMF) could be attributed to promoting the systemic plant resistance through the decrease of reactive oxygen species (ROS), malondialdehyde content (MDA), glutathione-s-transferase (GST), soluble peroxidase (SPO), ionic peroxidase (IPO), polyphenol oxidase (PPO), phenyl alanine ammonialyase (PAL) and lignin content. Moreover, they enhance the content of potato phenolics, superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX) and glutathione peroxidase (GPX) content. These results detected the potentiality of AMF and E. nigrum to promote potato growth and decrease the disease severity of blackleg disease. These biocontrol agents may have promising prospective strategies in potato crop protection and increase the feasibility of agriculture crop protection. The results reported herein are expected to provide competitive economic outcomes for sustainable cropping protection systems.

The current study purposed to improve vegetative growth, nodules formation and biological dinitrogen fixation of Vicia faba L. (faba bean) grown in sandy soil by inoculation with bacterial feather hydrolysate fertilizer (BFH) and arbuscular mycorrhizal fungi (AMF). A potent feather-degrading bacterium was isolated from chicken feathers and molecular identified as Bacillus licheniformis ASU (Accession number KF446641 ). Two different native AMF were recovered from the sandy soil and identified as Acaulospora bireticulata and Glomus caesaris. Bacillus licheniformis has the capability to degrade the chicken feathers efficiently. Furthermore, it can solubilize tricalcium phosphate and produce ammonia and IAA (indole acetic acid). Faba bean seeds were grown in pot experiments containing sandy soil inoculated with AMF or BFH individually or in combination. The application of AMF and BFH in combination significantly increased nodule formation and N2-fixation. The total dry biomass of plants co-inoculated with AMF and BFH was increased significantly compared with non-inoculated plants. So, the combination with AMF and BFH has the potential to be developed as a useful biofertilizer in future. This paper is expected to afford a competitive economic outcome for sustainable cropping systems.

Botrytis umbel blight caused by Botrytis allii is a major disease that attacks onion crop. In vitro, Trichoderma viride, Penicillium chrysogenum, and Saccharomyces cerevisiae and extract of bitter apple fruits (Citrullus colocynthis) showed antagonistic effect and inhibited the mycelial growth of B. allii. Gas chromatography–mass spectrometry (GC-MS) analysis of bitter apple fruits showed the existence of 37 compounds and their derivatives. Among them, 10 compounds constituted 58.66% of the total analyses. Greenhouse experiment approved that the extract of bitter apple fruits was the most effective in reducing disease incidence and severity, followed by P. chrysogenum, when they were applied 2 days pre-inoculation with the pathogen. All treatments significantly increased the total phenolic contents than the untreated control, but the highest increase was obtained when S. cerevisiae and P. chrysogenum were applied. A positive correlation was found between the activity of bioagents and improvement of peroxidase and phenylalanine ammonia-lyase enzymes in onion plants to resist infection with the pathogen. P. chrysogenum caused the highest increase in polyphenoloxidase activity in infected onion plants, while S. cerevisiae showed the lowest level of this enzyme. The study approved that application of the bioagents not only protected the onions against Botrytis disease but also enhanced the content of antioxidant compounds in onions. This encourages the application of such preparations to manage the production of onion crop, especially in the organic farming that bans the application of any chemicals.

In this study, a fungal isolate was isolated from avocado fruit collected from a market in Makkah city, Saudi Arabia, and identified as Neopestalotiopsis clavispora ASU1. The biomass of Neopestalotiopsis clavispora ASU1 was used as a natural bio-sorbent for removal of Cd(II) and Zn(II) from aqueous solutions. Characterization of fungal biomass was performed using Fourier transform infrared spectroscopy, X-ray Diffractometer, and BET surface area. Different factors on Cd(II) and Zn(II) biosorption were studied to evaluate the maximum conditions for metals biosorption. The (qmax) for Cd(II) and Zn (II) by N. clavispora ASU1 calculated from the Langmuir adsorption isotherm was 185.3 ± 0.25 and 153.8 ± 0.21 mg/g, respectively. Based on r2, the equilibrium biosorption isotherms fitted well with Langmuir model than Freundlich isotherm. The adsorption kinetics was studied, and the biosorption followed to the pseudo-second-order model. Thus, the current study indicated that the biomass of N. clavispora ASU1 is an effective adsorbent for the removal of heavy metals from aqueous solutions.

Lipase-catalyzed biotransformation of fungal lipids into biodiesel via bacterial enzymes or whole cell catalysts has been considered as one of the most promising methods to produce applicable, renewable and environmentally friendly alternative liquid fuels. Four highly lipolytic bacterial isolates were isolated from seeds and grains of some plant species and screened for their potentiality to synthesis of fatty acid methyl esters (FAME) by lipase esterification process for the production of cost-competitive biodiesel. The four isolates were identified based on phenotypic and gene encoding 16S rRNA as Bacillus vallismortis ASU 3 (KP777551), Bacillus tequilensis ASU 11 (KP777550), Bacillus amyloliquefaciens ASU 16 (KP777549) and Bacillus firmus ASU 32 (KP777552). Among the four tested bacterial lipases, extracellular lipase of B firmus ASU 32 (KP777552) showed the highest activity toward the transesterification of fungal lipids as 71.2% of total fatty acid methyl eseters (FAMEs). B. firmus ASU 32 lipases displayed a higher thermal stability and methanol tolerance ensuring their application as a promising biocatalyst for FAME synthesis. The results proved that, the most active acyl acceptors for biodiesel production from fungal lipids by B. firmus lipase were methanol and ethyl acetate. B. firmus has applicable future as a whole cell biocatalyst for FAME synthesis from fungal lipids. Alleviation the inhibitory effect of methanol in the transesterification process of fungal lipids by lipases might be performed through separation of hydrolysis step from esterification process by methanol for FAME synthesis. This paper is expected to provide a competitive economic outcome for industrial FAME synthesis.

Biodiesel was produced by direct esterification of Cunninghamella echinulata dry mass using sugarcanemolasses as substrate in the first stage of fermentation. GC/MS results for fatty acid methyl estersrevealed abundant low degree unsaturated long chain fatty acids and saturated long chain fatty acidsthat are similar to plant oils. In the second stage, the spent medium of C. echinulata culture was used asthe fermentation medium for hydrogen production by Clostridium acetobutylicum ATCC 824. Themaximum total H 2 yield was 1450 ml H 2 /l after 48 h fermentation. In the third stage, the spent mediumof Clostridium containing volatile organic acids was used for methane production by methanogenicbacteria. The highest cumulative methane yield was 1690 ml l 1 spent medium obtained after 48 h. Thegross energy content of biodesel, H 2 and methane generated through three successive stages fermen-tation from 84 g molasses was 3928 kJ mol 1 . The results presented in this study suggest a possibility ofinterlinking biodiesel production technology byfungi with hydrogenproduction byC. acetobutylicum andmethane production by methanogenic bacteria to exploit the residual sugars and organic acids in thespent medium and therefore increase the economic feasibility of the bioenergy production frommolasses.© 2014 Elsevier Ltd. All rights reserved.

In the present study biodiesel was produced by various fungal species isolated from Egypt using sugarcane molasses as substrate. In the first stage 6 oleaginous fungi, namely, Alternaria alternata, Cladosporium cladosporioides, Epicoccum nigrum, Fusarium oxysporum, Aspergillus parasiticus and Emericella nidulans var. lata were used for lipid production. Subsequent to fungal cultivation on sugarcane molasses the cultures were filtered and biodiesel was prepared by direct esterification of dry fungal biomass. Methyl esters of palmitic, stearic, linoleic and elaidic represented the major components while palmitoleic represented a minor component of biodiesel produced from tested oleaginous fungi. In the second stage, the spent medium of fungal culture was used as the fermentation medium for hydrogen production by Clostridium acetobutylicum ATCC 824. The maximum total H2 yield was obtained with the spent medium of E. nigrum and A. alternata. The results presented in this study suggest a possibility of interlinking the biodiesel production technology by fungi with hydrogen production by C. acetobutylicum ATCC 824 to exploit the residual sugars in the spent media and therefore increase the economic feasibility of the biofuel production from molasses.

Root rot and charcoal rot diseases caused by Macrophomina phaseolina are the major factors that affect the growth of sunflower plants. The aim of this work was to manage these diseases by employing an effective mutual strategy, in which an antagonistic and growth-promoting yeast Brettanomyces naardensis was combined with arbuscular mycorrhizal fungi (AMF), inoculated into the soil and cultivated with the crop. The results demonstrated that B. naardensis is a potent biocontrol agent for M. phaseolina that colonizes fungal hyphae, causing malformation and damage. In vitro, the yeast produced indole acetic acid and ammonia and showed good phosphate solubilization activity, confirming its growth-promoting characteristics. Dual inoculation of sunflower plants with both yeast and AMF involved in a reduction of the disease incidence of root rot and charcoal rot, caused by M. phaseolina, to 11.11% and 5.55%, respectively. Inoculation with yeast and AMF significantly enhanced growth parameters (plant height, dry weight and leaf number) in both healthy and infected plants. The results approved the induction of the immune system in sunflower plant via decreasing malondialdehyde content (MDA) and increasing the nutrient availability by dual inoculation with yeast and AMF that was confirmed by the enhancement of plant growth and alleviation of the disease symptoms. The double bioagents offer a promising biocontrol strategy in crop protection as a biofungicide and biofertilizer together in one bioformulation.

An in situ batch fermentation technique was employed for biohydrogen, acetone, butanol, ethanol and microdiesel production from oleaginous fungal biomass using the anaerobic fermentative bacterium Clostridium acetobutylicum ATCC 824. Oleaginous fungal Cunninghamella echinulata biomass which has ability to accumulate up to 71% cellular lipid was used as the substrate carbon source. The maximum cumulative hydrogen by C. acetobutylicum ATCC 824 from crude C. echinulata biomass was 260 ml H 2 l −1 , hydrogen production efficiency was 0.32 mol H 2 mole −1 glucose and the hydrogen production rate was 5.2 ml H 2 h −1 . Subsequently, the produced acids (acetic and butyric acids) during acidogenesis phase are re-utilized by ABE-producing clostridia and converted into acetone, butanol, and ethanol. The total ABE produced by C . acetobutylicum ATCC 824 during batch fermentation was 3.6 g l −1 from crude fungal biomass including acetone (1.05 g l −1 ), butanol (2.19 g l −1 ) and ethanol (0.36 g l −1 ). C. acetobutylicum ATCC 824 has ability to produce lipolytic enzymes with a specific activity 5.59 U/mg protein to hydrolyze ester containing substrates. The lipolytic potential of C . acetobutylicum ATCC 824 was used as a biocatalyst for a lipase transesterification process using the produced ethanol from ABE fermentation for microdiesel production. The fatty acid ethyl esters (microdiesel) generated from the lipase transesterification of crude C. echinulata dry mass was analyzed by GC/MS as 15.4% of total FAEEs. The gross energy content of biohydrogen, acetone, butanol, ethanol and biodiesel generated through C. acetobutylicum fermentation from crude C. echinulata dry mass was 3113.14 kJ mol −1 . These results suggest a possibility of integrating biohydrogen, acetone, butanol and ethanol production technology by C. acetobutylicum with microdiesel production from crude C. echinulata dry mass and therefore improve the feasibility and commercialization of bioenergy production.

In this current study 45 fungal isolates were isolated from chicken's litter on Feather Agar Medium (FAM) were screened for determining the potent keratinase producing isolates. Out of these fungal isolates, twelve species and one species variety exhibited various degrees of keratinolytic activities from which A. terreus showed the highest keratinase production (12.6U/ml). The optimum temperature and initial pH for keratinase production by A. terreus were 40°C and 8, respectively. The highest keratinase production was observed for a period 25 days. The optimum ionic strength for the enzyme production was 80mM NaCl. Deprivation of K+, Fe2+, Mg2+, Ca2+ or Zn2+ from the culture medium drastically reduced the keratinase production by A. terreus. In contrast, sulfur deprivation did not significantly affect the keratinase production. The Km and Vmax values for A. terreus keratinase were 8.64mg keratin and 56.7U/mg proteins, respectively. The optimum temperature, pH and ionic strength for keratinase activity were 35°C, 7.8 and 80-100mM NaCl, respectively.