Browsing by Author "Undugoda, L. J. S."

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Bioremediation potential of leaf endophytic fungi in Allium ampeloprasum and Brassica oleracea var. capitata
(Faculty of Science, University of Kelaniya Sri Lanka, 2024) Amarasekara, R. C. J.; Kannangara, B. T. S. D. P.; Undugoda, L. J. S.
Polyaromatic Hydrocarbons (PAHs) are one of the major hazardous air pollutants which resulted mainly from vehicular emissions. Those PAHs can be subsequently deposited on many surfaces including vegetation which are referred to the human consumption, causing serious effects on human health. The present study attempts to investigate the PAHs (Naphthalene, Phenanthrene, Anthracene, and Pyrene) degradation capability of leaf endophytic fungi inhabiting Allium ampeloprasum and Brassica oleracea var. capitata which are the major economic green leafy vegetable crops in upcountry area, Sri Lanka. The leaf samples were randomly collected from vegetable beds located along the roadsides of highly urbanized areas (Nuwara Eliya town, Nanu Oya and Sent Clairs) to isolate fungal endophytes. Endophytic fungi were isolated following the surface sterilization method. Subsequently their potential in degrading PAHs (Naphthalene, Phenanthrene, Anthracene and Pyrene) was investigated using plate assay and spectrophotometric analysis. The sixteen fungal endophytes isolated from A. ampeloprasum leaves collected, belonged to 11 genera such as Trichoderma, Alternaria, Aspergillus, Cochliobolus, Pestalotiopsis, Humicola, Acremonium, Fusarium, White sterile sp., Gray sterile sp., and Brown sterile sp. Most of the fungal endophytes isolated from B. oleracea var. capitata leaves were more or less similar to the fungal consortium isolated from A. ampeloprasum. Almost all the endophytic fungi isolated from A. ampeloprasum and B. oleracea var. capitata were able to grow in Bacto Bushnell Haas (BBH) medium incorporated with Naphthalene, Phenanthrene, Anthracene and Pyrene, separately with colony diameters more than 20 mm. Among the tested fungi Alternaria sp.1 was able to grow in Naphthalene, Phenanthrene, Anthracene incorporated media displaying the highest colony diameters; 39.45 ± 1.23 mm, 38.25 ± 1.56 mm and 36.67 ± 0.34 mm respectively. As per the results from spectrophotometric analysis Alternaria sp.1 and Trichoderma sp.1 efficiently degraded Naphthalene, Phenanthrene, Anthracene and Pyrene more than 70%. Alternaria sp.1 exhibited the highest Naphthalene (75.63%), Phenanthrene (76.26%), and Pyrene (70.02%) degradation efficiencies respectively. Significantly the highest efficiency in degrading Anthracene (73.04%) was exhibited by Trichoderma sp.1. Among the tested fungi Alternaria sp.1, Trichoderma sp.1, Aspergillus sp.1 and Aspergillus sp.2 were the effective degraders of all the tested PAHs more than 50% degradation. The findings of the present investigation provide some insight into how these endophytic fungi could be used for bioremediation of PAHs in contaminated environmental sites.
Depolymerization of polyaromatic hydrocarbons by Penicillium spp. inhabit the phyllosphere of urban ornamental plants
(Environmental Quality Management, 2022) Dharmasiri, R. B. N.; Undugoda, L. J. S.; Nilmini, A. H. L.; Pathmalal, M. M.; Nugara, N. N. R. N.; Udayanga, D.; Kannangara, S.
A variety of anthropogenic sources release hazardous polyaromatic hydrocarbons (PAHs) into the phyllosphere which is an excellent niche for diverse fungi, and some of them have PAHs degradation capabilities. Therefore, this research attempted to determine the PAHs (phenanthrene, anthracene, naphthalene, and pyrene) degradation capability of phyllosphere inhabited Penicillium species. The leaf samples were collected from highly polluted urban areas (Panchikawatta, Pettah, Orugodawatta, Maradana, Sapugaskanda, and Colombo Fort) in Sri Lanka to isolate fungal species inhabiting the phyllosphere. Furthermore, their distribution patterns among the leaf tissue layers were studied using bright-field microscopic observations. Moreover, the best PAHdegraders were screened out using plate assays and confirmed throughHigh Performance Liquid Chromatography (HPLC) analysis. Further, their enzymatic activities during the PAHs degradation were analyzed. As per the microscopic observations, the highest fungal distribution was in the upper epidermis of the leaves followed by the fungal distribution in the interspaces of palisade mesophyll layers. Out of isolated fungal species, two Penicillium spp. (Penicillium citrinum P23B-91 and Penicillium griseofulvum P9B - 30) showed the highest PAHs (phenanthrene, anthracene, naphthalene, and pyrene) degradation capabilities. Manganese peroxidase (MnP) enzyme dominated phenanthrene degradation in P. griseofulvum P9B - 30, which showed the highest phenanthrene degradation ability (61%). In addition, P. citrinum P23B-91 was good at degrading anthracene (88%) and also displayed a higher MnP activity during the anthracene degradation than laccase and lignin peroxidase activities. The discoveries from the toxicity assay during the PAHs degradation processes revealed that the produced byproducts had no toxic effects on the fungal growth cycle and the phyllosphere. Therefore this phyllosphere Penicillium spp. are ideal for the bioremediation of polluted air in urbanized areas.
Enzymatic approach to green air: Depolymerization of polycyclic aromatic hydrocarbons (PAHS) by Aspergillus sp. isolated from phyllosphere of urban areas
(Faculty of Science, University of Kelaniya Sri Lanka, 2022) Dharmasiri, R. B. N.; Undugoda, L. J. S.; Nilmini, A. H. L.; Pathmalal, M. M.; Nugara, N. N. R. N.; Udayanga, D.
Polycyclic aromatic hydrocarbons (PAHs) are hazardous air pollutants that are toxic to many life forms. Biodegradation is an eco-friendly efficient option found to remediate these toxic PAHs. Air pollutants from many sources get settled over the phyllosphere through atmospheric deposition. Phyllosphere is a large niche for many fungal species and some of them metabolize many PAHs to nontoxic concentrations. The present study was to determine the PAHs (phenanthrene, anthracene, naphthalene and pyrene) degradation capability of phyllosphere inhabited Aspergillus species. Fungal isolations were made from leaf samples (Amaranthus cruentus, Hibiscus rosa-sinensis, Ervatamia divaricate, Plumeria sp., and Ixora chinensis) grown in Panchikawatta, Orugodawatta, Pettah, Maradana, Colombo Fort and Sapugaskanda oil refinery sites in Sri Lanka. Out of morphologically different thirty-five fungal isolations, Aspergillus spp. were identified to the genus level using identification keys and pre-existing identified reference cultures. PAHs degradation ability of isolated Aspergillus spp. was screened using a plate assay and confirmed by High Performance Liquid Chromatography (HPLC). Further, phyto-toxicity assays were performed using Vigna radiata seeds to test environmental toxicity and toxicity to the degrading fungal cells in the medium from the produced metabolites. Furthermore, manganese-dependent peroxidases (MnPs), lignin peroxidases (LiPs), and laccases enzyme activities of them during the PAHs depolymerization were analysed parallel to the PAHs degradation percentages. According to HPLC analysis, Aspergillus sp. P21B - 77 showed the most efficient degradation of anthracene (80%), Aspergillus sp. P11B – 34 was the most efficient degrader for naphthalene (82%) and Aspergillus sp. P22T – 82 was the most efficient degrader for pyrene (84%) and phenanthrene (86%). MnP enzyme activity dominated the highest anthracene depolymerization ability of Aspergillus P21B – 77 However; LiPs activity dominated the highest phenanthrene and pyrene depolymerization in Aspergillus sp. P22T – 82. Moreover, Aspergillus sp. P11B – 34 showed the best naphthalene degradation, and laccases enzyme activity dominated the degradation. The toxicity assay revealed that the generated metabolites were not toxic to the growth of Aspergillus spp. and, also verified that those by-products were not destructive compounds to the phyllosphere. Aspergillus spp. could be useful as a potential biological agent for an effective bioremediation process in polluted environments contaminated with phenanthrene, anthracene, naphthalene and pyrene like polycyclic aromatic hydrocarbons.