Diversity and biotechnological potential of marine fungi from Ria de Aveiro

• Autor(a) principal: Abreu, Alberto António Coelho de
• Data de Publicação: 2020
• Tipo de documento: Dissertação
• Idioma: eng
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: http://hdl.handle.net/10773/29327
• topic: Lignicolous marine fungi; Fungal diversity; Taxonomy; Phylogeny; Biotechnological potential; Ria de Aveiro

Although knowledge about the ecological group of lignicolous marine fungi is still scarce, especially in Portugal, it is known that they play an essential ecological role in marine and estuarine ecosystems, namely in the degradation of organic matter present in wood and consequent contributing to the functioning of the aquatic “microbial ring” that drives the biogeochemical cycles and the maintenance of trophic relationships. In addition to their environmental contribution, they are also a source of compounds with biotechnological potential, with applications in various industrial and pharmaceutical areas. In this study, in order to investigate the occurrence of lignicolous marine fungi in the estuary of Ria de Aveiro, blocks of wood (Pinus pinaster) were submerged in a marina, for one year. Seventeen different fungal species were successfully identified, with a high prevalence of species belonging to the family Lulwortiaceae. Through phylogenetic analyses based on the ribosomal ITS (internal transcribed spacer), LSU (large ribosomal subunit) and SSU (small ribosomal subunit) regions combined with morphological and physiological studies, two genera (Lulworthiopsis and Marinomyces) were introduced to accommodate Lulworthia cf. purpurea and Papulaspora halima, respectively. In the same way, Lulworthiopsis maritima sp. nov., Halosphaeria submersa sp. nov. and Zalerion pseudomaritima sp. nov. were proposed as novel species. To assess their biotechnological potential, isolates of interest were selected and enzymatic and antibacterial tests were carried out. As expected from lignicolous species, most isolates tested positive for cellulolytic and pectinolytic activities. Halosphaeria submersa, M. halima and Z. maritima revealed an interesting potential in several extracellular enzymatic activities. Differences were also detected in enzyme production in the presence and absence of salt, thus proposing that these activities can be stimulated or inhibited depending on the salinity. Regarding the results of antibacterial activity, the selected isolates showed more effective against Gram-positive bacteria. Lulworthiopsis purpurea and M. halima showed antibacterial activity against the multiresistant Gram-negative bacteria of Pseudomonas aeruginosa and Klebsiella pneumoniae, respectively, representing an anti-bacterial potential effective in combating these pathogenic strains. Future taxonomic and biotechnological studies focused on lignicolous marine fungi may bring benefits to several areas of research.