known to be relatively difficult to dissolve. The largest oil spills from the tankers are
shown in the Table 1.2.
Crude oil components with a low boiling point, such as gasoline, kerosene, and
diesel, volatilize when leaked into the ocean and thus present almost no concerns.
The problem lies in heavy oil components that do not volatilize readily. Today, the
search is on for microbes with outstanding abilities to dissolve these components. In
microbiological common sense terms, microbes cannot be viewed as a panacea
capable of completely dissolving petroleum components in all their complexity. It is
therefore essential to use many different kinds of microbes together to dissolve
petroleum mixtures.
To obtain a mixed colony in nature, crude oil is applied to seawater and sand.
After about a month, around 20% of the crude oil will have been dissolved by the
seawater microbes. A portion of the mixture of these microbes and petroleum must
then be extracted and applied to sterilized seawater (with no microbes present) and
crude oil. As this process is repeated, it is possible to produce microbes with
outstanding crude oil dissolution properties. In Japan, this method was used to
separate a natural colony known as SM8 from sand. Among the components of
crude oil, SM8 was capable of dissolving 30% of paraffin compounds and 20% of
aromatic compounds. As the most any single microbe had been able to dissolve
before was 15% of paraffin compounds and 5% of aromatic compounds, SM8 was
clearly an outstanding colony.
In some cases, microbes known to have properties absent from natural colonies
have been combined to produce artificial colonies. An artificial colony known as
M4, which was a mixture of four kinds of microbes, was capable of dissolving 50%
of paraffin compounds and 30% of aromatic compounds. A natural colony includes
over four kinds of microbes, but it was found that only those four could dissolve
crude oil with efficiency equaling a natural colony. This finding will be of some
importance going ahead for the establishment of petroleum dissolution techniques.
Genetic studies of petroleum-dissolving microbes have also been taking place. In
particular, attempts are being made to study the genes of enzymes that are involved
in petroleum dissolution and making improvements to increase their effectiveness.
For some cases in the development of technology for application in environmental
recovery, one may come across situations that could not be predicted from test tube
levels alone. Because it takes so long to conduct a single environmental recovery
experiment using microbes, it is very difficult to test everything. For this reason, it
may be necessary to use techniques that can take the entire situation into account
from numerical models that predict activities in seawater affected by an oil spill.
In the past, we have arguably been too casual in our response to the oil spills that
have occurred. We have done little more than to apply surfactants or erect oil fences
to stop the spreading. In many cases, the surfactants themselves have been of poor
quality and failed to function properly; instead, the oil has clumped onto the surfactants and attached to the ocean floor, wreaking havoc on the ecosystem there.
Today we stand in the 21st century. Contributing to environmental preservation
with the development of new oil pollution prevention technologies suited to the
times appears to be an important task that urgently needs to be addressed.
1.4 Marine Life Sciences: The Future Is in Sight
15
shown in the Table 1.2.
Crude oil components with a low boiling point, such as gasoline, kerosene, and
diesel, volatilize when leaked into the ocean and thus present almost no concerns.
The problem lies in heavy oil components that do not volatilize readily. Today, the
search is on for microbes with outstanding abilities to dissolve these components. In
microbiological common sense terms, microbes cannot be viewed as a panacea
capable of completely dissolving petroleum components in all their complexity. It is
therefore essential to use many different kinds of microbes together to dissolve
petroleum mixtures.
To obtain a mixed colony in nature, crude oil is applied to seawater and sand.
After about a month, around 20% of the crude oil will have been dissolved by the
seawater microbes. A portion of the mixture of these microbes and petroleum must
then be extracted and applied to sterilized seawater (with no microbes present) and
crude oil. As this process is repeated, it is possible to produce microbes with
outstanding crude oil dissolution properties. In Japan, this method was used to
separate a natural colony known as SM8 from sand. Among the components of
crude oil, SM8 was capable of dissolving 30% of paraffin compounds and 20% of
aromatic compounds. As the most any single microbe had been able to dissolve
before was 15% of paraffin compounds and 5% of aromatic compounds, SM8 was
clearly an outstanding colony.
In some cases, microbes known to have properties absent from natural colonies
have been combined to produce artificial colonies. An artificial colony known as
M4, which was a mixture of four kinds of microbes, was capable of dissolving 50%
of paraffin compounds and 30% of aromatic compounds. A natural colony includes
over four kinds of microbes, but it was found that only those four could dissolve
crude oil with efficiency equaling a natural colony. This finding will be of some
importance going ahead for the establishment of petroleum dissolution techniques.
Genetic studies of petroleum-dissolving microbes have also been taking place. In
particular, attempts are being made to study the genes of enzymes that are involved
in petroleum dissolution and making improvements to increase their effectiveness.
For some cases in the development of technology for application in environmental
recovery, one may come across situations that could not be predicted from test tube
levels alone. Because it takes so long to conduct a single environmental recovery
experiment using microbes, it is very difficult to test everything. For this reason, it
may be necessary to use techniques that can take the entire situation into account
from numerical models that predict activities in seawater affected by an oil spill.
In the past, we have arguably been too casual in our response to the oil spills that
have occurred. We have done little more than to apply surfactants or erect oil fences
to stop the spreading. In many cases, the surfactants themselves have been of poor
quality and failed to function properly; instead, the oil has clumped onto the surfactants and attached to the ocean floor, wreaking havoc on the ecosystem there.
Today we stand in the 21st century. Contributing to environmental preservation
with the development of new oil pollution prevention technologies suited to the
times appears to be an important task that urgently needs to be addressed.
1.4 Marine Life Sciences: The Future Is in Sight
15