Transfer of carbon dioxide within cultures of microalgae: Plain bubbling versus hollow-fiber modules

• Type: Article in International Scientific Journal
• Date: 2001

Authors

Carvalho, AP (Author) Other; F. Xavier Malcata (Author) Other

Journal

Title: Biotechnology Progress

Vol. 17

Pages: 265-272

ISSN: 8756-7938

Publisher: Wiley-Blackwell

Indexing

ISI Web of Knowledge - 55 Citations

Scopus - 69 Citations

Other information

Authenticus ID: P-000-W6D

DOI: 10.1021/bp000157v

Abstract (EN): In attempts to improve the metabolic efficiency in closed photosynthetic reactors, availability of light and CO2 are often considered as limiting factors, as they are difficult to control in a culture. The carbon source is usually provided via bubbling of CO2-enriched air into the culture medium; however, this procedure is not particularly effective in terms of mass transfer. Besides, it leads to considerable waste of that gas to the open atmosphere, which adds to operation costs. Increase in the interfacial area of contact available for gas exchange via use of membranes might be a useful alternative; microporous membranes, in hollow-fiber form, were tested accordingly. Two hollow-fiber modules, different in both hydrophilicity and outer surface area, were tested and duly compared, in terms of mass transfer, versus traditional plain bubbling. Overall volumetric coefficients (K(L)a) for CO2 transfer were 1.48 x 10(-2) min(-1) for the hydrophobic membrane, 1.33 x 10(-2) min(-1) for the hydrophilic membrane, and 7.0 x 10(-3) min(-1) for plain bubbling. A model microalga, viz. Nannochloropsis sp., was cultivated using the two aforementioned membrane systems and plain bubbling. The produced data showed slight (but hardly significant) increases in biomass productivity when the hollow-fiber devices were used. However, hollow-fiber modules allow recirculation of unused CO2 thus reducing feedstock costs. Furthermore, such indirect way of supplying CO2 offers the additional possibility for use of lower gas pressures, as no need to counterbalance hydrostatic heads exists.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 8