A procedure for axenic
isolation of the marine microalga Isochrysis galbana from heavily
contaminated mass cultures
Ji-Young
Cho, Jae-Suk Choi, In-Soo Kong, Soo-Il Park, R.G. Kerr
Yong-Ki
Hong-2002
Journal of Applied Phycology, 14(5):
385-390
Abstract:
Isochrysis galbana,
one of the most widely used marine microalgae in the rearing of finfish and
shellfish larvae, is mass cultured frequently in outdoor tanks. Under
prolonged and repeated culture, severe contamination occurs. Axenic
isolation of I. galbana from such cultures was best achieved by
using a ternary procedure involving percoll-gradient centrifugation,
treatment with antibiotics, and growth on agar medium. Protozoa and other
algae were removed most effectively by isolation of I. galbana at
the 30–40% density layer on a
percoll-gradient. Removal of bacteria was accomplished using a mixture of 5
antibiotics (250 μg mL-1
ampicillin, 50 μg mL-1
gentamycin, 100 μg mL-1
kanamycin, 500 μg mL-1
neomycin, 50 μg mL-1
streptomycin). Axenic colonies were isolated from a solid medium prepared
from 1% purified agar. The ternary procedure is considered applicable to the
isolation of other axenic single-celled microalgae from heavily contaminated
cultures.
(Pukyong National
University, Department of Biotechnology, Namku, 608-737, Korea, e-mail of
Yong-Ki Hong: ykhong@pknu.ac.kr)