Employing Chlorella protothecoides for metal bioavailability studies under acidic conditions

Zeng, Zhi Ling, Menzies, Neal W. and Kerven, Graham (2009) Employing Chlorella protothecoides for metal bioavailability studies under acidic conditions. Journal of Plankton Research, 31 3: 325-336. doi:10.1093/plankt/fbn117


Author Zeng, Zhi Ling
Menzies, Neal W.
Kerven, Graham
Title Employing Chlorella protothecoides for metal bioavailability studies under acidic conditions
Formatted title
Employing Chlorella protothecoides for metal bioavailability studies under acidic conditions
Journal name Journal of Plankton Research   Check publisher's open access policy
ISSN 0142-7873
Publication date 2009-03
Year available 2009
Sub-type Article (original research)
DOI 10.1093/plankt/fbn117
Volume 31
Issue 3
Start page 325
End page 336
Total pages 10
Editor Roger Harris
Place of publication United Kingdom
Publisher Oxford University Press
Collection year 2010
Language eng
Subject C1
960912 Urban and Industrial Water Management
Abstract We report the challenges and resolutions facing the use of Chlorella protothecoides for metal bioavailability and toxicity research under acidic conditions. In our study, we found that a simplified growth medium recommended for metal bioavailability research did not support the optimum growth of C. protothecoides at pH 5.5, possibly due to nutrient deficiencies, rendering it unsuitable for bioavailability studies under acidic conditions. On the other hand, a modified Woods Hole MBL growth medium supplying all macro and micro nutrients, with chelators Tris and EDTA removed, and (NH4)2Fe(SO4)2 supplemented as the source of iron, produced excellent growth of the algae under identical conditions. This medium is therefore recommended as the alternative growth medium. While a pH increase of up to 2 units a day was observed in unbuffered media during algal growth, incorporation of CO2 into the aeration stream at a fixed partial pressure stabilized the medium pH. By initiating the metal (e.g. Cu) treatment at a culture optical density (750 nm) of 0.04, where the algal population was just entering the rapid growth phase, the Chlorella assay was completed within 48 h. This minimized metal speciation changes and nutrient limitation that may occur over longer test durations. As demonstrated with the case of Cu, a cell density of 7.5 x 105 cells mL–1 at the time of metal addition, caused only 5% initial loss of solution Cu, addressing the concern that such an initial cell density might deplete the metal from solution as a result of metal binding to algal cells. Overall, this study provides a valid means of employing Chlorella for metal bioavailability and toxicity research under acidic conditions, which ensures that algal growth is not impeded by nutrient deficiency, experimental duration is short, and more importantly, solution pH and metal speciation do not change significantly over the experimental period.
Keyword UNICELLULAR GREEN-ALGAE
Q-Index Code C1
Q-Index Status Confirmed Code

Document type: Journal Article
Sub-type: Article (original research)
Collections: 2010 Higher Education Research Data Collection
School of Agriculture and Food Sciences
 
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Created: Thu, 03 Sep 2009, 08:44:32 EST by Mr Andrew Martlew on behalf of School of Land, Crop and Food Sciences