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Author Hulatt, C.J.; Thomas, D.N. url  doi
openurl 
  Title Productivity, carbon dioxide uptake and net energy return of microalgal bubble column photobioreactors Type Journal Article
  Year 2011 Publication Bioresource Technology Abbreviated Journal Bioresour Technol  
  Volume 102 Issue 10 Pages 5775-5787  
  Keywords *Bioreactors; Carbon Dioxide/*metabolism; Energy Metabolism; Equipment Design; Microalgae/growth & development/*metabolism; Photochemistry  
  Abstract This work examined the energy return of Chlorella vulgaris and Dunaliella tertiolecta cultivated in a gas-sparged photobioreactor design where the power input for sparging was manipulated (10, 20, and 50 Wm(-3)). Dry weight, organic carbon and heating values of the biomass were measured, plus a suite of variables including Fv/Fm and dissolved oxygen. A model for predicting the higher heating value of microalgal biomass was developed and used to measure the energetic performance of batch cultivations. High power inputs enhanced maximum biomass yields, but did not improve the energy return. Cultivation in 10 Wm(-3) showed up to a 39% higher cumulative net energy return than 50 Wm(-3), and increased the cumulative net energy ratio up to fourfold. The highest net energy ratio for power input was 19.3 (D. tertiolecta, 12% CO(2), 10 Wm(-3)). These systems may be a sustainable method of biomass production, but their effectiveness is sensitive to operational parameters.  
  Address School of Ocean Sciences, College of Natural Sciences, Bangor University, Askew Street, Menai Bridge, Isle of Anglesey LL59 5AB, UK. osp418@bangor.ac.uk  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition (up)  
  ISSN 0960-8524 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:21376576 Approved no  
  Call Number refbase @ user @ Serial 12983  
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Author Hulatt, C.J.; Thomas, D.N. url  doi
openurl 
  Title Energy efficiency of an outdoor microalgal photobioreactor sited at mid-temperate latitude Type Journal Article
  Year 2011 Publication Bioresource Technology Abbreviated Journal Bioresour Technol  
  Volume 102 Issue 12 Pages 6687-6695  
  Keywords Biomass; *Bioreactors; Climate; Geography; Microalgae/growth & development/*metabolism; Oxygen/metabolism; Scenedesmus/growth & development/*metabolism; Seasons; Solar Energy  
  Abstract This work examined the energetic performance of a 6-month semi-continuous cultivation of Scenedesmus obliquus in an outdoor photobioreactor at mid-temperate latitude, without temperature control. By measuring the seasonal biomass production (mean 11.31, range 1.39-23.67 g m(-2)d(-1)), higher heating value (22.94 kJ g(-1)) and solar irradiance, the mean seasonally-averaged photosynthetic efficiency (2.18%) and gross energy productivity (0.27 MJ m(-2) d(-1)) was calculated. When comparing the solar energy conversion efficiency to the energy investment for culture circulation, significant improvements in reactor energy input must be made to make the system viable. Using the data collected to model the energetic performance of a substitute photobioreactor design, we conclude that sustainable photobioreactor cultivation of microalgae in similar temperate climates requires a short light path and low power input, only reasonably obtained by flat-panel systems. However, temperature control was not necessary for effective long-term cultivation.  
  Address School of Ocean Sciences, College of Natural Sciences, Bangor University, Askew Street, Menai Bridge, Anglesey LL59 5AB, UK. osp418@bangor.ac.uk  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition (up)  
  ISSN 0960-8524 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:21511466 Approved no  
  Call Number refbase @ user @ Serial 12984  
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Author Lakaniemi, A.-M.; Hulatt, C.J.; Thomas, D.N.; Tuovinen, O.H.; Puhakka, J.A. url  doi
openurl 
  Title Biogenic hydrogen and methane production from Chlorella vulgaris and Dunaliella tertiolecta biomass Type Journal Article
  Year 2011 Publication Biotechnology for Biofuels Abbreviated Journal Biotechnol Biofuels  
  Volume 4 Issue 1 Pages 34  
  Keywords  
  Abstract BACKGROUND: Microalgae are a promising feedstock for biofuel and bioenergy production due to their high photosynthetic efficiencies, high growth rates and no need for external organic carbon supply. In this study, utilization of Chlorella vulgaris (a fresh water microalga) and Dunaliella tertiolecta (a marine microalga) biomass was tested as a feedstock for anaerobic H2 and CH4 production. RESULTS: Anaerobic serum bottle assays were conducted at 37 degrees C with enrichment cultures derived from municipal anaerobic digester sludge. Low levels of H2 were produced by anaerobic enrichment cultures, but H2 was subsequently consumed even in the presence of 2-bromoethanesulfonic acid, an inhibitor of methanogens. Without inoculation, algal biomass still produced H2 due to the activities of satellite bacteria associated with algal cultures. CH4 was produced from both types of biomass with anaerobic enrichments. Polymerase chain reaction-denaturing gradient gel electrophoresis profiling indicated the presence of H2-producing and H2-consuming bacteria in the anaerobic enrichment cultures and the presence of H2-producing bacteria among the satellite bacteria in both sources of algal biomass. CONCLUSIONS: H2 production by the satellite bacteria was comparable from D. tertiolecta (12.6 ml H2/g volatile solids (VS)) and from C. vulgaris (10.8 ml H2/g VS), whereas CH4 production was significantly higher from C. vulgaris (286 ml/g VS) than from D. tertiolecta (24 ml/g VS). The high salinity of the D. tertiolecta slurry, prohibitive to methanogens, was the probable reason for lower CH4 production.  
  Address Department of Chemistry and Bioengineering, Tampere University of Technology, PO Box 541, FI-33101 Tampere, Finland. aino-maija.lakaniemi@tut.fi  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition (up)  
  ISSN 1754-6834 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:21943287; PMCID:PMC3193024 Approved no  
  Call Number refbase @ user @ Serial 12985  
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Author Raike, A.; Kortelainen, P.; Mattsson, T.; Thomas, D.N. url  doi
openurl 
  Title 36 year trends in dissolved organic carbon export from Finnish rivers to the Baltic Sea Type Journal Article
  Year 2012 Publication The Science of the Total Environment Abbreviated Journal Sci Total Environ  
  Volume 435-436 Issue Pages 188-201  
  Keywords Baltic States; Carbon/*chemistry; Finland; Hydrology; Oceans and Seas; Rivers/*chemistry; Seasons; Soil/chemistry  
  Abstract Increasing dissolved organic carbon (DOC) concentrations in lakes, rivers and streams in northern mid latitudes have been widely reported during the last two decades, but relatively few studies have dealt with trends in DOC export. We studied the export of DOC from Finnish rivers to the Baltic Sea between 1975 and 2010, and estimated trends in DOC fluxes (both flow normalised and non-normalised). The study encompassed the whole Finnish Baltic Sea catchment area (301,000 km(2)) covering major land use patterns in the boreal zone. Finnish rivers exported annually over 900,000 t DOC to the Baltic Sea, and the mean area specific export was 3.5 t km(-2). The highest export (7.3t km(-2)) was measured in peat dominated catchments, whereas catchments rich in lakes had the lowest export (2.2 t km(-2)). Inter-annual variation in DOC export was high and controlled mainly by hydrology. There was no overall trend in the annual water flow, although winter flow increased in northern Finland over 36 years. Despite the numerous studies showing increases in DOC concentrations in streams and rivers in the northern hemisphere, we could not find any evidence of increases in DOC export to the northern Baltic Sea from Finnish catchments since 1975.  
  Address Finnish Environment Institute (SYKE), P.O. Box 140, FI-00251, Helsinki, Finland. antti.raike@ymparisto.fi  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition (up)  
  ISSN 0048-9697 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:22854090 Approved no  
  Call Number refbase @ user @ Serial 12986  
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Author Lakaniemi, A.-M.; Hulatt, C.J.; Wakeman, K.D.; Thomas, D.N.; Puhakka, J.A. url  doi
openurl 
  Title Eukaryotic and prokaryotic microbial communities during microalgal biomass production Type Journal Article
  Year 2012 Publication Bioresource Technology Abbreviated Journal Bioresour Technol  
  Volume 124 Issue Pages 387-393  
  Keywords Bacteria/classification/genetics/metabolism; *Biomass; Electrophoresis, Polyacrylamide Gel; Eukaryotic Cells; Microalgae/*metabolism; Phylogeny; Polymerase Chain Reaction; Prokaryotic Cells  
  Abstract Eukaryotic and bacterial communities were characterized and quantified in microalgal photobioreactor cultures of freshwater Chlorella vulgaris and marine Dunaliella tertiolecta. The microalgae exhibited good growth, whilst both cultures contained diverse bacterial communities. Both cultures included Proteobacteria and Bacteroidetes, while C. vulgaris cultures also contained Actinobacteria. The bacterial genera present in the cultures were different due to different growth medium salinities and possibly different extracellular products. Bacterial community profiles were relatively stable in D. tertiolecta cultures but not in C. vulgaris cultures likely due to presence of ciliates (Colpoda sp.) in the latter. The presence of ciliates did not, however, cause decrease in total number of C. vulgaris or bacteria during 14 days of cultivation. Quantitative PCR (qPCR) reliably showed relative microalgal and bacterial cell numbers in the batch cultures with stable microbial communities, but was not effective when bacterial communities varied. Raw culture samples were successfully used as qPCR templates.  
  Address Department of Chemistry and Bioengineering, Tampere University of Technology, Tampere, Finland. aino-maija.lakaniemi@tut.fi  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition (up)  
  ISSN 0960-8524 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:22995170 Approved no  
  Call Number refbase @ user @ Serial 12987  
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