Growth and fatty acid profiles ofHalophytophthoravesiculaandSalispinaspinosafrom Philippine mangrove leaves

Abstract

Studies on marine‐sourced fatty acids have gathered significant interest recently as an important component of aquaculture feeds and of biofuel production. Of the organisms capable of producing fatty acids, marine oomycetes are promising model organisms. One group of marine oomycetes are the Halophytophthora spp. which is known to have an important role in leaf decomposition, thereby changing the plant debris into exudates which are usable to consumers in the mangrove ecosystems. This study reports the three mangrove oomycetes isolated from Philippine mangrove forests, identified herein as Halophytophthora vesicula AK1YB2 (Aklan), H. vesicula PQ1YB3 (Quezon) and Salispina spinosa ST1YB3 (Davao del Norte). These isolates were subjected to growth analyses using varying incubation parameters (salinity level and pH), and for fatty acid production. Results revealed the presence of different fatty acids such as Arachidonic acid, Linoleic acid and Vaccenic acid when grown on V8S and PYGS media. This study is the first observation of fatty acids from S. spinosa and H. vesicula from the Philippines. Significance and Impact of the Study Tropical Philippines straddling west of the Pacific Ocean and East of South China Sea is rich in marine and estuarine oomycetes. These micro‐organisms, hitherto poorly known and unstudied in the country, play an important role in the nutritive cycle of the mangrove ecosystem. Due to the increasing demand for an alternative source of fatty acids, species of Oomycetes isolated from select mangrove forests in Luzon, Visayas and Mindanao were analysed for their fatty acid contents. Prospects for industrially‐important fatty acids make these Oomycetes all‐important to study in applied microbiology in the Philippine setting where these structurally simple micro‐organisms abound.

An overview on Philippine estuarine oomycetes

“…Members of Salispina are reported as estuarine species, whereas Rhipidiaceae thrive in freshwater biomes (Dick 2001). In the Philippines, Salispina hoi, S. lobata, and S. spinosa have been isolated from mangrove leaf litter (Leaño 2001, Bennett et al 2018, Caguimbal et al 2019.…”

“…elongata, and S. bahamensis. Recently, several studies explored the fatty acid composition of Philippine mangrove oomycetes, and some isolates produced good amounts of polyunsaturated fatty acids (Say et al 2017, Caguimbal et al 2019. Despite these taxonomic proposals and applied studies, oomycete research in the Philippines, particularly reagarding the saprotrophic and marine groups, is still underexplored.…”

“…1.5%) are considered as mangrove or saltmarsh oomycetes (Table 2). Species classified in this group are distributed in three Fell and Master 1975, Nakagiri 2000, Leaño 2001, Li et al 2016, S. spinosa Rhizophora Bahamas, Colombia, Grand Cayman, Haiti, Japan, Philippines, Thailand, Taiwan, The Netherlands, Trinidad and Tobago Fell and Master 1975, Pang et al 2014, Li et al 2016, Caguimbal et al 2019 Phytophthora, and Phytopythium), Salispinaceae (Salispina), and Salisapiliaceae (Salisapilia). Thus, the genus concept of Halophytophthora encompassing all Phytophthora-like species in estuarine environments is obsolete since several groups of saprotrophic oomycetes are found in the mangrove environment (i.e.…”

Unravelling the Lipids Content and the Fatty Acid Profiles of Eight Recently Described Halophytophthora Species and H. avicennae from the South Coast of Portugal

“…Several aquatic microorganisms have also been explored, with microalgae and thraustochytrids giving promising results in terms of the production of PUFAs, in particular omega-3 FAs [26][27][28]. Oomycetes have mostly been overlooked, although several studies showed that members from several genera, including Halophytophthora, Phytophthora, Pythium and Salispina, can produce a wide variety of FAs [29][30][31][32][33]. Pang et al [31] reported, for the first time, the production of arachidonic acid (ω-6, ARA) and eicosapentaenoic acid (ω-3, EPA) by different Halophytophthora species isolated from fallen mangrove leaves in Taiwan, suggesting these oomycetes as a potential alternative source of such compounds.…”

Accurate method for rapid biomass quantification based on specific absorbance of microalgae species with biofuel importance

“…2015; Caguimbal et al . 2019). One of these factors is the monitoring and cell growing control; which despite the efforts made, still presents opportunity areas, mainly regarding adequate measuring, wavelengths selection and the establishment of specific standard curves for each microalgae species and/or specific culture conditions (Lee et al .…”