THE PRESENT STATUS OF SOME ASPECTS OF MARINE MICROBIOLOGY
157
approximately in a central position and the resulting fragments are
repeatedly split centrally leading to the production of shorter and
shorter units. Consequently in (a) a small amount of cnzyme would
lead to detectable quantities of free sugar whereas in (b) even large
amounts of enzyme acting on highly polymerized cellulosc would result
in the production of small amounts of reducing sugar. This latter type
of enzyme can be looked on as the weathering ” type and the former
as the ‘‘ liquefying ’’ or saccharogenic type. As a result of his experiments with cotton fishing nets submc!rgetl in sea water during the summer months, Kadota (1956) believes that the deterioration in this case
is mainly of the “ weathering ” type.
3. Prevention of deterioration
Since natural fibres are so susceptible to microbial attack i t is not
surprising that various measures have been taken to circumvent it.
The “ cutching ” of nets has been widely used from time immemorial,
and it is rather surprising to know that concentrations up to 1% are
relatively non-toxic to the microorganisms concerned (Kadota, 1956).
It would appear that the heat treatment the organisms undergo
during cutching is the effective agent. Mercuric salts, copper salts,
phenol, pentachlorophenol and 5 nitro-2 furfural-semi-carbazide, are
all said to be effective in concentrations lower than 1% (Kadota, 1956).
Indeed, mercuric chloride, which showed the highest potency, was very
effective in concentrations of the order of 1 : 10 000.
Modifications of the cellulose moleciile has also been tried and of
the various derivatives tested-methyl and ethyl cellulose, cellulose
acetate, carboxy-methyl cellulose-cellulose triacetate was found to be
particularly resistant to microbial attack.
Indeed, results suggest that where at least one acetyl group is
present on every anhydroglucose unit in its structure no attack by
marine aerobic cellulolytic bacteria can occur. This corresponds to an
acetyl content of the cellulose acetate of a t least 26.6% and according
t o Kadota fishing nets made from such cellulose acetate fibre would be
Particularly resistant to biodeterioration.
B. Microbiology of fresh and spoiling marine fish
Fish constitutes a n important part of the protein diet of the world
Population and is consequently one of the more valuable commercial
Products from the sea, According to the most recent F.A.O. statistics
(Anon, 1963) approximately 40 million metric tons of live marine fish
were caught in 1962. I n Great Britain alone the yearly landings of
157
approximately in a central position and the resulting fragments are
repeatedly split centrally leading to the production of shorter and
shorter units. Consequently in (a) a small amount of cnzyme would
lead to detectable quantities of free sugar whereas in (b) even large
amounts of enzyme acting on highly polymerized cellulosc would result
in the production of small amounts of reducing sugar. This latter type
of enzyme can be looked on as the weathering ” type and the former
as the ‘‘ liquefying ’’ or saccharogenic type. As a result of his experiments with cotton fishing nets submc!rgetl in sea water during the summer months, Kadota (1956) believes that the deterioration in this case
is mainly of the “ weathering ” type.
3. Prevention of deterioration
Since natural fibres are so susceptible to microbial attack i t is not
surprising that various measures have been taken to circumvent it.
The “ cutching ” of nets has been widely used from time immemorial,
and it is rather surprising to know that concentrations up to 1% are
relatively non-toxic to the microorganisms concerned (Kadota, 1956).
It would appear that the heat treatment the organisms undergo
during cutching is the effective agent. Mercuric salts, copper salts,
phenol, pentachlorophenol and 5 nitro-2 furfural-semi-carbazide, are
all said to be effective in concentrations lower than 1% (Kadota, 1956).
Indeed, mercuric chloride, which showed the highest potency, was very
effective in concentrations of the order of 1 : 10 000.
Modifications of the cellulose moleciile has also been tried and of
the various derivatives tested-methyl and ethyl cellulose, cellulose
acetate, carboxy-methyl cellulose-cellulose triacetate was found to be
particularly resistant to microbial attack.
Indeed, results suggest that where at least one acetyl group is
present on every anhydroglucose unit in its structure no attack by
marine aerobic cellulolytic bacteria can occur. This corresponds to an
acetyl content of the cellulose acetate of a t least 26.6% and according
t o Kadota fishing nets made from such cellulose acetate fibre would be
Particularly resistant to biodeterioration.
B. Microbiology of fresh and spoiling marine fish
Fish constitutes a n important part of the protein diet of the world
Population and is consequently one of the more valuable commercial
Products from the sea, According to the most recent F.A.O. statistics
(Anon, 1963) approximately 40 million metric tons of live marine fish
were caught in 1962. I n Great Britain alone the yearly landings of