Environmental Engineering Reference
In-Depth Information
taBle 26.2
summary of Principal Fatty acids for the major classes of microalgae
class
Major Fatty Acids
Representative Genera
Cyanophyceae
14:0, 16:0, 16:1(
n
-7), 18:1, 18:2(
n
-3), 18:3(
n
-3)
Oscillatoria
,
Spirulina
Rhodophyceae
16:0, 20:4(
n
-6), 20:5(
n
-3)
Porphyridium
,
Rhodella
Cryptophyceae
14:0, 16:0, 16:1(
n
-7), 18:3(
n
-3), 18:4(
n
-3), 20:5(
n
-3)
Chroomonas
,
Rhodomonas
Bacillariophyceae
14:0, 16:0,16:1(
n
-7),16:3(
n
-4), 20:5(
n
-3)
Chaetoceros
,
Navicula
,
Phaeodactylum
,
Skeletonema
Raphidophyceae
14:0; 16:0;18:4(
n
-3) 20:5(
n
-3)
Chattonella
Pavlovophyceae
14:0, 16:0,16:1(
n
-7), 20:5(
n
-3)
Pavlova
Prymnesiophyceae
14:0, 18:3(
n
-3), 18:4(
n
-3), 18:5(
n
-3), 22:6(
n
-3)
Emiliania
,
Gephyrocapsa
,
Pleurochrysis
Eustigmatophyceae
14:0, 16:0, 16:1(
n
-7), 20:5(
n
-3)
Nannochloropsis
Xanthophyceae
14:0, 16:0, 16:1(
n
-9), 16:1(
n
-7), 18:1, 20:5(
n
-3)
Monodus
Dinophyceae
[14:0], 16:0, [18:0], [18:1(
n
-9)]; 18:5(
n
-3), [22:2],
[22:6(
n
-3)]
Alexandrium
,
Amphidinium
,
Coolia;
Gymnodinium
,
Heterocapsa
Prasinophyceae
16:0, 16:4(
n
-3), 18:1(
n
-9), 18:3(
n
-3), 18:3(
n
-4),
20:5(
n
-3), [22:6(
n
-3)]
Isochrysis
,
Tetraselmis
Chlorophyceae
16:0, 16:4(
n
-3), 18:1, 18:3(
n
-3), [20:4(
n
-6)]
a
Botryococcus
,
Chlorella
,
Dunaliella
,
Oocystis
Source:
Borowitzka, M.A.,
Micro-algal Biotechnology
, Cambridge University Press, Cambridge, United Kingdom, pp 257-287,
1998; Volkman, J.K., et al.
J Exp Mar Biol Ecol
., 128, 219-240, 1989; Volkman, J.K., et al.
Phytochemistry
, 30, 1855-
1859, 1991; Volkman, J.K., et al.,
J Phycol
, 29, 69-78, 1993; Yongmanitchai, W. and Ward, O.P.,
Phytochemistry
, 30,
2963-2967, 1991; Viso, A.C. and Marty, J.C.,
Phytochemistry
, 34, 1521-1533, 1993; Zhukova, N.V. and Aizdaicher,
N.A.,
Phytochemistry
, 39, 351-356, 1995; Pond, D.W. and Harris, R.P.,
J Mar Biol Assoc UK
, 76, 579-594, 1996;
Cohen, Z.,
Spirulina platensis (Arthrospira): Physiology, Cell-Biology and Biochemistry
. Taylor & Francis, London,
pp 175-204, 1997; Mostaert, A.S., et al.
Phycol Res
., 46, 213-220, 1998; Tzovenis I. et al. (2003); Mansour, M.P., et al.
J Appl Phycol
., 17, 287-300, 2005; Khozin-Goldberg I. and Cohen Z.,
Phytochemistry,
67, 696-701, 2006; Patil, V., et al.
Aquacult Int
., 15, 1-9, 2007; Petkov, G. and Garcia, G.,
Biochem Syst Ecol
., 35, 281-285, 2007; Usup G., et al.
Phycologia
, 47, 105-111, 2008; Xu Z, et al.
J
Appl Phycol
., 20, 237-243, 2008.
a
Only reported for
Parietochloris incisa
(Bigogno C., et al.
Phytochemistry
60, 497-503, 2002.)
Only the major fatty acids making up approximately 75% of the total fatty acids are listed. Note fatty acids in brackets are
observed in only some species.
methanol or ethanol (Demirbas 2003). Methanol is more reactive than ethanol, and the fatty
acid methyl esters (FAMEs) produced are more volatile than the fatty acid ethyl esters (FAEEs)
produced when ethanol is used. Methanol is also cheaper; however, methanol is produced from
nonrenewable fossil fuel feedstocks whereas ethanol can be produced from renewable feedstocks
(sugars). The transesterification processes are catalyzed with alkalis, such as NaOH, KOH, or
sodium metoxide. Alternatively, acid-catalyzed transesterification with simultaneous esterification
of free fatty acids can be carried out using sulfuric, hydrochloric, phosphoric, or sulfonic acid
(Meher et al. 2006). However, acid-catalyzed transesterification has a slower reaction rate than
alkali-catalyzed transesterification, and the acids are more corrosive, thus making the process
more expensive. Other methods under development are lipase-enzyme-catalyzed transesterification
(Ranganathan et al. 2008; Robles-Medina et al. 2009), noncatalytic conversion by transesterification
and esterification under supercritical alcohol conditions (Kudsiana and Saka 2001), and the use of
metal-oxide base catalysts at high pressure and temperature (McNeff et al. 2008). A range of solid
heterogeneous catalyst processes that are potentially more effective than current methods are also
under development (Helwani et al. 2010).
