Strain Selection for Biodiesel Production - Biotechnological Applications of Microalgae - page 26

TABLE 3.4 ( Continued )
Common Media Used for Microalgal Strains from
Diverse Aquatic Environments
Media Freshwater Marine Brackish Suitable for Ref.

MBL
medium
Woods
Hole

+ − − Freshwater algae Nichols, 1973

Medium f − + + Broad-spectrum medium

for marine algae

Jeffrey and
LeRoi, 1997

Medium G + + ND Broad-spectrum medium Blackburn

et al., 2001

MNK
medium

− + ND General medium for marine

algae, especially
coccolithophores

Noel et al.,
2004

Sato
medium,
modified

+ + + Freshwater Chlorophyceae Richmond,

1983

SN medium − + − Marine cyanophyceae Waterbury

et al., 1986

Walne's
medium

− + + Broad-spectrum medium

for marine algae
(especially designed for
mass culture)

Walne, 1970

Source: Adapted from Mutanda et al., 2011.
Note: ND, not determined; +, can be used; −, cannot be used.

Alternatively, many coccoid algae and most soil algae can be isolated on agar
plates. It is the preferred isolation method because it is simple and requires no further
processing. Streak or pour plating on suitable agar growth medium enables suc-
cessful isolation, although few algae grow embedded in agar (Brahamsha, 1996).
An improvised procedure is to make a fine or atomized spray of cells, usually a liquid
cell suspension atomized with sterile air under pressure, which can then be used to
inoculate or spread on agar plates. Similarly, a dilution method can be used, wherein
a single cell is deposited in a test tube, flask, or well of a multiwell plate (Throndsen,
1978). Selection of the appropriate maximum dilution for plating depends on the
probable cell density in natural samples. The dilutions can be effected in several
ways, such as dilution with sterile culture medium, distilled water, seawater, and
filtered water from the sample site, or some combination of these. Also, where neces-
sary, salts of ammonium, selenium, or another element can be added as supplements
to specifically isolate selected species.
When samples contain a wide variety of cells, centrifugation or settling can be
foreseen. The target of concentrating the cells instead of obtaining an axenic culture
can easily be achieved by gravity. Also, gravity comes in handy when the goal is to