title: Early detection of protozoan grazers in algal biofuel cultures.
abstract: Future micro-algal biofuels will most likely be derived from open-pond production systems. These are by definition open to "invasion" by grazers, which could devastate micro-algal mass-cultures. There is an urgent requirement for methodologies capable of early detection and control of grazers in dense algal cultures. In this study a model system employing the marine alga Nannochloropsis oculata was challenged by grazers including ciliates, amoebae and a heterotrophic dinoflagellate. A FlowCAM flow-cytometer was used to detect all grazers investigated (size range <20->80 μm in length) in the presence of algae. Detection limits were <10 cells ml(-1) for both "large" and "small" model grazers, Euplotes vannus (80 × 45 μm) and an unidentified holotrichous ciliate (~18 × 8 μm) respectively. Furthermore, the system can distinguish the presence of ciliates in N. oculata cultures with biotechnologically relevant cell densities; i.e. >1.4 × 10(8) cells ml(-1) (>0.5 g l(-1) dry wt.).
authors.affiliation: Scottish Association for Marine Science, Scottish Marine Institute, Oban, Argyll PA37 1QA, UK. jgd@sams.ac.uk
authors.forename: John G
authors.initials: JG
authors.lastname: Day
authors.forename: Naomi J
authors.initials: NJ
authors.lastname: Thomas
authors.forename: Undine E M
authors.initials: UE
authors.lastname: Achilles-Day
authors.forename: Raymond J G
authors.initials: RJ
authors.lastname: Leakey
mesh_terms: D000818:Animals; D044822:Biodiversity; D000458:Cyanobacteria / Q000302:isolation & purification*; D017753:Ecosystem; D005618:Fresh Water / Q000382:microbiology*; D015048:Zooplankton / Q000145:classification* / Q000302:isolation & purification*