Agriculture Reference
In-Depth Information
The levels of those amino acids were high in the seaweed extracts, whereas these levels
were extremely low in the biodegraded culture broths of seaweeds, which implied the
disappearance of the seaweed flavor by microbial degradation. Moreover, the levels of almost
all their essential amino acids in the seaweed extracts were comparable with those amino acid
levels of the FAO/WHO requirement, whereas those amino acid levels of the biodegraded
culture broths were not comparable. Leucine, tyrosine and phenylalanine were known to be
the limiting amino acids of some species of seaweeds (Wong & Cheung, 2000); however,
these amino acids were not applicable to the seaweed extracts that were examined.
Accordingly, amino acid compositions would somewhat vary among seaweed species.
Major and Noxious Components
It is important to improve the utilization of fertilizer nutrients because fertilizer is
responsible for the growth of plants. Although the organic matter of the fertilizer directly
affects crop growth and yield, the combined use of organic and inorganic sources is essential
to augment the efficiency of nutrients (Lian, 1994). Three major soil nutrients are nitrogen
(N), phosphorus (P) and potassium (K), and their deficiency can adversely affect crop yield.
In this sense, the concentrations of the three primary nutrients (N, P, and K) with heavy
metals in the 4-d culture broths of seaweeds were analyzed and compared with those
concentrations in the fermented broth of fish waste (Table 4).
Table 4. Comparison of concentrations of major and noxious components between the
biodegraded culture broths of seaweeds and fermented broth of fish wastes
Seaweed
a
Fish wastes
b
Measurement
Green
Red
Brown
N
2.19
1.94
1.35
1.57
N, P, K
(%)
P
0.31
0.06
0.15
0.31
K
0.13
0.03
0.12
0.45
Pb
0.016
0.001
0.013
n.d.
c
As
0.078
0.176
0.47
n.d.
Cd
0.001
0.001
0.002
n.d.
Noxious
compounds
(mg kg
-1
)
Hg
n.d.
n.d.
0.054
0.02
Cr
0.083
0.034
0.029
0.26
Cu
0.078
0.061
0.029
n.d.
Ni
0.054
0.01
0.046
n.d.
Zn
0.247
0.063
0.162
1.72
a
Data that were obtained from this study.
b
Data that were obtained from the study of Kim et al. (2010).
c
n.d.: not detected.
The concentrations of N, P and K were 2.19, 0.32 and 0.13% for green seaweed culture
broth, 1.94, 0.06 and 0.03% for red seaweed culture broth, and 1.35, 0.15 and 0.12% for
brown seaweed culture broth, respectively. There were some pronounced differences among
seaweeds, and these quantities of N, P and K are small, similar to the fermented broth of fish
waste, compared with those quantities in commercial fertilizers.
In contrast, the
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