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Synergistic carbon metabolism in a fast growing mixotrophic freshwater microalgal species Micractinium inermum
Smith, Richard T. Bangert, Krys Wilkinson, Stephen J. Gilmour, D. James
Smith, Richard T.
Bangert, Krys
Wilkinson, Stephen J.
Gilmour, D. James
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EPub Date
Publication Date
2015-05-11
Submitted Date
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Abstract
In recent years microalgae have attracted significant interest as a potential source of sustainable biofuel. Mixotrophic microalgae are able to simultaneously photosynthesise while assimilating and metabolising organic carbon. By combining autotrophic and heterotrophic metabolic pathways biomass productivity can be significantly increased. In this study, acetate-fed mixotrophic Micractinium inermum cultures were found to have a specific growth rate 1.74 times the sum of autotrophic and heterotrophic growth. It was hypothesised that gas exchange between the two metabolic pathways within mixotrophic cultures may have prevented growth limitation and enhanced growth. To determine the extent of synergistic gas exchange and its influence on metabolic activity, dissolved inorganic carbon (DIC), dissolved oxygen (DO) and photosynthesis and respiration rates were measured under different trophic conditions. A 32.7 fold and 2.4 fold increase in DIC and DO concentrations, relative to autotrophic and heterotrophic cultures respectively, were coupled with significant increases in rates of photosynthesis and respiration. These data strongly support the hypothesis of mixotrophic gas exchange within M. inermum cultures. In addition to enhanced growth, this phenomenon may provide reductions in aeration and oxygen stripping costs related to microalgae production.
Citation
Biomass and Bioenergy, 2015
Publisher
Elsevier
Journal
Biomass and Bioenergy
Research Unit
DOI
10.1016/j.biombioe.2015.04.023
PubMed ID
PubMed Central ID
Type
Article
Language
en
Description
This article is available open access at http://www.sciencedirect.com/science/article/pii/S0961953415001592#
Series/Report no.
ISSN
0961-9534