Biology Reference
In-Depth Information
Filleting waste of silver carp (
Hypophthalmichthys molitrix
) was mixed
with microbial transglutaminase (3 g/kg), dairy proteins, such as whey
protein and sodium caseinate (10 g/kg), and NaCl (0, 10, 20 g/kg) for 2
min at 15°C. The restructured fi sh products obtained had different levels
of salt (0, 1, and 2%). The results showed that the mechanical properties
of fi sh gels grew with increasing the salt level of the samples containing
dairy proteins. In addition, the mechanical properties of non-saltedd
and low-salted fi sh gels increased, only when dairy proteins (sodium
caseinate) were utilised for fi lleting waste treatment. Finally, microbial
transglutaminase increased expressible water (Uresti et al., 2001).
The infl uence of various TAN concentrations (1-257 mg TAN/L) and
nitrate-N concentrations (174 ± 29 mg/L) on nitrogen conversions in a
recirculating aquaculture system was evaluated by Schneider (2006c). The
effl uent slurry was supplemented with 1.7g C/l sodium acetate, due to
organic carbon defi ciency, and was converted continuously in a suspended
bacteria growth reactor with hydraulic retention time (HRT) of 6 h. The
results showed that TAN was converted up to 100%, independently of
TAN concentrations, compared to nitrate-N, while VSS production and
yield did not alter with increasing TAN concentrations.
Table 9.6 provides a synoptical presentation of techniqes based on the
use of microorganisms for fi sh waste remediation (parameters, quality
control and results).
CONCLUSIONS
Aquaculture waste production can hardly be estimated, because of the
high variety of aquaculture systems, such as ponds, fl ow through systems,
cages, and recirculation aquaculture systems, and of fi sh species, such as
herbivore, omnivore, carnivore, and of the different types of feed used,
such as natural production, agriculture by-products, trash fi sh, high
energy pellets, low protein feeds, and animal or human waste (Schneider,
2006d). The current approach to improving water quality in aquaculture
is the application of microbes/enzymes to the ponds (Moriaty 1998). They
result in a lower accumulation of slime or organic matter at the bottom of
the pond , better penetration of oxygen into the sediment and a generally
better environment for the farmed stock (Rao and Karunasagar 2000).
Bioremediation is still considered to be a developing technology. One
diffi culty is that bioremediation is carried out in the natural environment,
which contains diverse uncharacterised organisms. Another diffi culty is
that no two environmental problems occur under completely identical
conditions; for example, variations occur in the types and amounts of
pollutants, climate conditions and hydrogeodynamics (Watanabe, 2001).
In the currect study the dominant microorganisms used for aquaculture
waste remediation were
Aspergillus
sp.,
Bacillus
sp. and
Lactobacillus
sp.
