Microalgae strain catalogue:A strain selection guide for microalgae users: 4th edition

The 4th edition of this catalogue contains information on the cultivation and composition characteristics of 50 microalgae. Each entry includes relevant links to Atlantic Area stakeholders known to have a relevant connection with each of the species listed, be it in the form of culture collections, research expertise, technology developers, or biomass producers. We invite the readers to visit and/or join the EnhanceMicroAlgae Stakeholder database: an easily accessible, visual and open access database that brings together all the European Atlantic Area players working in the microalgae sector.This publication is part of the deliverables of the Interreg-funded international project EnhanceMicroAlgae. The authors gratefully acknowledge the European Regional Development Fund (ERDF) Interreg Atlantic Area programme which funded the EnhanceMicroAlgae project: EAPA_338/2016, "High added-value industrial opportunities for microalgae in the Atlantic Area"

Resilient Hymenobacter strains isolated from Icelandic environments : exploring osmo-tolerance and interspecific interactions

Microorganisms are constantly exposed to various kinds of stress in their natural environments. The mechanisms for adaptation to these stressors reflect their life strategies, determining to some extent their distribution in the environment. Bacteria live in dense communities characterised by complex interspecific interactions. Studying bacterial interactions and their competitive strategies can further explain their environmental distribution. Members of the genus Hymenobacter are often characterised with respect to their cold and radiation tolerance, but little is known about their tolerance of low water activity or their interspecific interactions. The tolerance of Hymenobacter strains H16F320, JF1031 and LW0504 to hyperosmotic shock was investigated by lowering the water activity of the culture medium with various humectants, in order to account for specific solute effects. The strains exhibited a resounding and statistically significant inability to tolerate the conditions imposed on them, which raises questions about the strategies they employ to cope in their harsh natural environments. The interspecific interactions of H16F320 and LW0504 were also assessed by culturing them with various co-isolated strains in an interaction assay. The presence of other strains unanimously reduced growth of the Hymenobacter strains, suggesting their competitive incompetence. In many of the co-cultures, a twitching motility phenotype was induced in the Hymenobacter strains, which were previously shown to be nonmotile in monoculture, revealing the benefit of studying bacteria as members of a larger community. The nutritional and physical environment of the cultures influenced this induced motile phenotype: nutrient deprivation consistently reduced the extent of twitching motility, while low agar concentrations completely inhibited it. The strains did not initiate biofilm formation when cultured individually in polystyrene microtiter wells. Further study on interspecific interactions and stress tolerance will increase our understanding of the functional and ecological role of the Hymenobacter isolates in the natural communities they inhabit.Örverur eru stöðugt berskjaldaðar gagnvart mörgum álagsþáttum í þeirra náttúrulega umhverfi. Aðlögunarhæfni þeirra mótast af ýmsum þáttum sem endurspeglast í lífsmynstri þeirra og ákvarðar að einhverju leiti útbreiðslu þeirra í umhverfinu. Bakteríur lifa þétt saman í flóknum samfélögum. Rannsóknir á víxlverkunum og samkeppnishæfni þeirra geta útskýrt nánar hvernig þær dreifast í náttúrunni. Bakteríur af ættkvísl Hymenobacter eru oft rannsakaðar með tilliti til þols þeirra gagnvart kulda og geislun. Ekki er mikið vitað um þol þeirra gagnvart lágri vatnsvirkni eða víxlverkunum við aðrar tegundir. Þol Hymenobacter stofna H16F320, JF1031 og LW0504 gagnvart osmósu-þrýstingi hefur verið rannsakað með því að lækka vatnsvirkni ætis með ýmsum lausnarefnum til að líkja eftir sérstökum áhrifum einstakra lausnarefna. Þar sýndu stofnarnir tölfræðilega marktækt óþol gagnvart osmósu-stressi, sem vakið hefur upp spurningar um hæfni þeirra til að lifa af í umhverfinu. Víxlverkanir stofna H16F320 og LW0504 við aðra stofna hafa einnig verið kannaðar með því að samrækta þær með öðrum bakteríum sem einangraðar voru úr sömu upprunalegu sýnum. Í öllum tilfellum minnkaði vöxtur H16F320 og LW0504 í nærveru annarra stofna sem bendir til vanhæfni þeirra í samkeppni. Margar samræktanir kölluðu fram yfirborðskvikleika í Hymenobacter stofnunum, sem hingað til höfðu verið taldar ókvikar. Þetta sýnir ávinningin af því að rannsaka bakteríur sem hluta af flóknum samfélögum. Þættir eins og næringar- og eðlisfræðilegt umhverfi bakteríanna höfðu einnig áhrif á yfirborðskvikleikann. Næringarskortur minnkaði kvikleikann á meðan lágur agarstyrkur kom alveg í veg fyrir hann. Stofnarnir sýndu enga tilhneigingu til að mynda biofilmur þegar þeir voru ræktaðir sér í microtiter brunnum. Frekari rannsóknir á víxlverkunum Hymenobacter stofnanna við aðrar bakteríur og þoli þeirra gagnvart mismunandi álagsþáttum munu auka skilning okkar á virkni þeirra og vistfræðilegu hlutverki í þeim náttúrulegu samfélögum sem þær lifa