Browsing by Author "Undugoda, Lanka"

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The mycoremediation potential of phyllosphere fungi in urban ornamental plants in Sri Lanka with mathematical models for PAH degradation
(2024) Dharmasiri, Nadeema; Kannangara, Sagarika; Undugoda, Lanka; Munasinghe, Jayantha; Madushika, Ruvini; Thambugala, Kasun M.; Gunathunga, Chathuri; Pavalakumar, Dayani
Currently, phylloremediation has emerged as a highly effective method for eliminating air pollutants, particularly polyaromatic hydrocarbons (PAHs). When PAHs accumulate on the phyllosphere, they significantly impact the fungal communities residing on leaf surfaces. This study aimed to investigate how pollution distribution patterns affect the diversity and PAHdegrading abilities of phyllosphere fungi, alongside identifying suitable mathematical models for PAH degradation. Leaf samples from two locations, Maradana and Sapugaskanda, were identified as having the highest PAH concentrations through principal component analysis. The fungal diversity in these highly contaminated regions was varied, with dominant species exhibiting greater PAH-degrading capabilities than those in less polluted areas. Thirty-five morphologically different epiphytic fungal strains were isolated on Potato Dextrose Agar (PDA) medium using the sample leaf wash. Two different fungal strains were selected as the best PAH degraders among those 35 different strains. These fungal strains were identified as Trichoderma harzianum P4M-16, and Fusarium solani P11M-46 based on ITS sequence data. Notably, these fungal species were more prevalent in highly polluted urban areas compared to less contaminated sites. High-Performance Liquid Chromatography (HPLC) analysis revealed that these two fungal species degrade PAHs more efficiently than others. Their kinetics assays demonstrated alignment with four degradation models when breaking down phenanthrene, naphthalene, pyrene, and anthracene. Scanning electron microscopy images showed that these fungi function as endophytes, extending their mycelium into the core leaf tissue layers beyond the epidermis. Gas Chromatography-Mass Spectrometry (GCMS) analysis indicated
Nature and activities of microfungi associated with the decomposition of rice straw in Sri Lanka
(Asian Journal of Agriculture and Biology, 2022) Undugoda, Lanka; Kannangara, Sagarika
Agricultural sustainability through crop residue biodegradation is an eco-friendly method to enrich soil fertility essential to agricultural countries. Rice straw, rich in cellulose, is the primary source of organic matter, enhancing the fertility in rice fields and is a better alternative to replace chemical fertilizer usage. Therefore, this attempt is to isolate and identify different genera of straw degrading microfungi efficient in lignocellulose biodegradation. Rice straw degrading fungal species were isolated from the partially degraded rice straw collected from selected areas in Sri Lanka, following the washing and plating techniques. They were identified into the genus level using standard identification keys, and their capacity to degrade cellulose, starch, lignin, and pectin were evaluated using substrate-specific testing protocols. Eighteen fungal species in the genera of Aspergillus, Chaetomium, Cunninghamella, Goidanichiella, Penicillium, Rhizomucor, Rhizopus, Stachybotrys, and Trichoderma were isolated from the partially degraded rice straw collected from different areas of Sri Lanka. Three Trichoderma species showed significantly the highest frequency of occurrences (40%, 45%, and 43% respectively) in rice straw and a homogenous distribution among the collected samples. Furthermore, they were significantly efficient in degrading cellulose, starch, pectin, and lignin. Since the management of crop residues has become an essential aspect of sustaining long-term fertility in cropping systems, incorporation of rice straw, which is rich with cellulose, and the application of Trichoderma species into the harvested rice fields will improve the nutrient availability and hence rice yield.
Phylloremediation of pyrene and anthracene by endophytic fungi inhabiting tea leaves (Camellia sinensis (L.) Kuntze) in Sri Lanka
(Tylor & Francis, 2023) Undugoda, Lanka; Thambugala, Kasun; Kannangara, Sagarika; Munasinghe, Jayantha; Premarathna, Nadeeka; Dharmasiri, Nadeema
Polyaromatic hydrocarbons (PAHs) released from vehicular emissions and oil refineries deposit on the phyllosphere, compromising the quality of leaf-based food products by posing many health issues. Nevertheless, the tea phyllosphere harbours a variety of endophytes that are highly effective at degrading polyaromatic hydrocarbons, anthracene, and pyrene. The present study attempts to analyse the pyrene and anthracene degrading capability of phyllosphere endophytic fungi that inhabit Camellia sinensis (L.) Kuntze leaves. The frequency of occurrence of endophytic fungi in different leaf tissue layers was examined using light and scanning electron microscopy (SEM). The best pyrene and anthracene degrading strains were selected based on the High-Performance Liquid Chromatography (HPLC) results, and further kinetic assays. Light microscopy and SEM observations highlighted a heterogeneous endophytic fungal distribution among leaf tissue layers; the upper epidermis had the highest fungal distribution compared to other leaf layers. HPLC results revealed that Phyllosticta capitalensis, Colletotrichum gloeosporioides, Colletotrichum siamense, Pseudopestalotiopsis chinensis, and Daldinia eschscholtzii, have higher pyrene and anthracene degradation respectively and their PAH degradation kinetics follow the first-order kinetic model. The best anthracene and pyrene degrader, P. capitalensis showed the lowest half-life. The present investigation highlights the potential of P. capitalensis, the best pyrene and anthracene degrader that can remediate PAHs deposited on the phyllosphere of tea leaves.