Biology Reference
In-Depth Information
tuna condensate. Shrimp-blanching water was also used to dilute tuna
condensate, and an increase in growth rate (0.031-0.033 h
-1
), biomass (4.1-4.6
g/L) and COD removal (77-80%) was reported. Furthermore, the addition
of 1.0-5.0% (w/v) acetate, pyruvate, glucose, glutamate, propionate or
malate to the tuna condensate did not increase cell yield, carotenoid or
bacteriochlorophyll content or biomass protein. A maximum cell mass of
5.6 g/l (containing 50% protein) and 86% COD removal were observed
after 5 d of incubation (Prasertsan et al., 1993).
Cultures of indigenous nitrifying bacteria (
Nitrobacter
and
Nitrosomonas
species) were immobilised onto porous clay pellets and tested for the TAN
removal from prawn aquaculture water. Bacteria cultures were enriched
from prawn pond water using open (continuous) and closed (batch)
enrichment techniques. The results indicated that for both cultures TAN
removal increased with increasing initial TAN concentrations (from 10
to 200 mg/l). Batch-enriched immobilised cultures were able to achieve
maximum TAN removal (4.2-6.7 mg TAN/l per day) in pond water at
density 1 pellet per 100 ml. At lowest pellet density (0.1 pellet /l) of pond
water, after a 2-d lag phase, TAN concentration maintained at 0.5 mg/l
under the fed-batch culture conditions of 3.2 mg TAN/l/ day (Shan and
Obbard, 2001).
Tal et al. (2006) isolated and utilised the anaerobic ammonium-oxidising
(Anammox) bacteria (
Planctomycetales
taxon), which were part of the
bacterial community of the aerobic (nitrifying) and anaerobic (denitrifying)
biofi lter of the marine recirculating system, for inorganic nitrogen waste
removal. Samples from both biofi lters were cultured under anammox
conditions, and ammonia and nitrite or hydrazine and nitrite oxidation
rates were tested under anaerobic conditions. The removal rates recorded
from the denitrifying biofi lter were 1.08 µM nitrate N/bead/h under
denitrifying conditions, and 0.098 µM ammonia N/bead/h and 0.16 µM
hydrazine/ bead/
h under anammox conditions. On the other hand, in the
nitrifying biofi lter no signifi cant hydrazine removal was reported.
Sponge clones of
Hymeniacidon perleve
were added to sterilised natural
seawater
(SNSW) supplemented seperately with
Escherichia coli
and
Vibrio
anguillarum II
with defi ned density, and to natural seawater samples
with signifi cant bacteria in order to evaluate the ability of marine sponge
H. perleve
of removing the two pathogenic bacteria in aquaculture waters.
In SNSW,
H. perleve
effectively removed 96% of
E. coli
within 10.5 h of
treatment. For the tests on
V. anguillarum II
in SNSW, about 1.5 g fresh
sponges kept pathogen growth at a lower initial density 3.6x10
4
cells/
ml of 200 ml water volume. In natural seawater concentrations of
E. coli
,
V. anguillarum II
, and total bacteria were signifi cantly lower, at about
0.9%, 6.2%-34.5%, and 13.7%-22.5%, respectively, compared to untreated
samples (Fu et al
.
, 2006).
