Biomedical Engineering Reference
In-Depth Information
need additional carbon dioxide supplied for optimal growth and photosynthesis, as well as
an adequate supply of inorganic nutrients. Heterotrophic microalgae require an organic
carbon source such as glucose and can be grown in fermentors that have been developed for
cultivation of other microorganisms, such as bacteria. Because the organic carbon also
supports growth of bacteria, it is important that microalgae grown in fermentors are axenic
(i.e. bacteria free). Otherwise the microalgae are soon overwhelmed by bacteria that multiply
rapidly under such conditions. For further details on heterotrophic growth see Lee (2004)
and references therein. Whether autotrophic or heterotrophic, controlled microalgal
production is a renewable resource and offers the potential to produce a range of bioproducts.
9.4 ALGAL CULTURE COLLECTIONS
Of the vast diversity of species of naturally occurring microalgae only several thousand have
been isolated from nature and cultured. Many of these cultured microalgal strains are
maintained in algal culture collections in various parts of the world. Information on the
major algal culture collections is available from the World Federation of Culture Collections
(http://www.wfcc.nig.ac.jp/wfcc.html). Some of these collections are listed in Table 9.1.
The physiological, biochemical and genetic characterisation of cultured microalgae,
including type species held long term in algal culture collections, highlights the value of
collections as repositories of global microalgal biodiversity. Many of the culture collections
make their strains available to researchers, educational institutions and industry, often for a
modest charge, thus providing a reliable base for all microalgal applications, including
bioproducts. Note that some countries may impose strict import restrictions on microalgae
from outside sources, making the isolation, identification and maintenance of native
microalgae an essential part of the development of algal industries.
Culture collections usually maintain microalgal strains in liquid or solid agar (nutrient
media in water) contained in small scale culture vessels, such as glass tubes and flasks or
sterile disposable plastic tissue culture flasks or Petri dishes. For autotrophic (photosynthetic)
microalgae cultures are usually maintained in constant-environment rooms or cabinets with
artificial lighting, usually with a photoperiod and dark period, simulating night and day
(Plate 9.1a). Jeffrey and LeRoi (1997) recommended the use of a light-dark cycle for algal
culture, although some algal production systems successfully use continuous light. The
choice of growth medium is very species-dependent and will depend on whether the
microalga comes from a fresh, brackish or seawater environment. Media contain
Table 9.1 Selected major algal culture collections.
Algal Culture Collection
Web site
Australian National Algae Culture Collection - ANACC
www.csiro.au/ANACC
Culture Collection of Algae and Protozoa - CCAP
www.ccap.ac.uk
The Provasoli-Guillard National Centre for Culture of Marine
Phytoplankton - CCMP
ccmp.bigelow.org
Microbial Culture Collection at the National Institute
of Environmental Studies - NIES
mcc.nies.go.jp
Culture Collection of Algae at Goettingen - SAG
www.epsag.uni-goettingen.de
The Culture Collection of Algae - UTEX
web.biosci.utexas.edu/utex/
 
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