Protein, carbohydrate, lipid
and chlorophyll a content in Isochrysis aff. galbana
(clone T-Iso) cultured with a low cost alternative to the f/2 medium
E. Valenzuela-Espinoza, R. Millán-Núñez, F. Núñez-Cebrero-2002
Aquacultural Engineering, 25(4): 207-216
Abstract
Growth, proximate composition and chlorophyll a
content was estimated in static cultures of Isochrysis aff. galbana
(clone T-Iso) to compare the quality and quantity of the biomass produced
with an agricultural fertilizer medium versus f/2 medium. Culture of
microalgae was done with controlled temperature, air flux of 4.5 l/min,
salinity of 33 ppt and an irradiance of 110±3 µmol/m2/s. Daily
samples from the cultures were taken to estimate cellular density, proximate
composition and chlorophyll a content during 7 days. Mean cellular
density from samples with f/2 medium and with agricultural fertilizer were
similar (no significance at P </= 0.05), and mean growth rates of
0.62 and 0.61 doubling per day, respectively. Maximum similar values of
protein content of 7.3 and 7.6 pg per cell were estimated on the 5th day in
f/2 and agricultural fertilizer medium, respectively. Carbohydrate and lipid
content decreased during the first 5 days corresponding to the exponential
growth in both experiments. Higher content of carbohydrate (no significance
at P </= 0.05) was found in both media during the first 2 days,
after 4 days the carbohydrates reduced three times theirs concentrations.
Generally lipid contents in the cultures with agricultural fertilizer were
significantly higher (P </= 0.05) than f/2 medium. The chlorophyll
a content increased exponentially during the culture, and its
concentration was similar in both experiments. In conclusion, the cellular
density and the biochemical constituents were similar when using either
media. This fertilizer can be used in the production of I. galbana
(T-Iso) employed in aquaculture.
(Instituto de Investigaciones Oceanológicas,
Ensenada, Baja California, Mexico, e-mail of E. Valenzuela-Espinoza: evale@faro.ens.uabc.mx,
e-mail of R. Millán-Núñez: rmillan@faro.ens.uabc.mx,
e-mail of F. Núñez-Cebrero: fnunez@faro.ens.uabc.mx)