The risk of contamination may be reduced and the culturing process simplified by
dividing microorganisms into various groups rather than culturing large volumes all
at once. While in some instances only the bacteria or seaweed bodies are used after
mass culturing and centrifuge harvesting, the culture solution should be examined for
activity, as it can yield surprisingly large amounts of active substances.
10.2.4 Extracting Substances
Extraction is the first stage in the separation of substances from collected specimens. Because substance types and yields vary by extraction method, suitable
solvent selection is crucial. A good approach when extracting a specific component
from a sample is to finely chop or freeze-dry and pulverize it. Not only can one
reduce the amount of solvent consumed in the extraction, but the extraction yield
can also be improved and the enrichment time reduced.
A. Extraction Methods by Sample Type
• Frozen Sample: Thaw, place in solvent roughly triple the wet sample weight,
and grind to extract.
• Dry Sample: Due to low moisture content and cell contraction, place in
solvent of roughly five times the weight or higher and leave for several hours
to extract; repeat extraction three times.
B. Extraction Solvent
Various types of solvent with different polarities are used in extraction.
Sequential extraction is performed, proceeding from non-polar to polar solvents.
By performing the initial extraction with non-polar solvent, it is possible to
separate and remove or use unneeded soluble sample components such as fats,
lead, resins, and oil. It is also possible to extract substances from within the cell
membrane, which is destroyed by polar solvents. Extraction solvents can provide
information about which specific components enter which solvent fractions,
allowing estimation of the chemical properties of those components and providing ample information for substance refinement and structure analysis.
From low to high polarity:
Petroleum ether < hexane < benzene < chloroform < methylene chloride < ether
< ethyl acetate < acetone < butanol < isopropanol < ethanol < methanol <
water.
C. Enrichment
A rotary evaporator is used for extract enrichment. To minimize change in
specimen components, solvent should be removed at as low a temperature as
possible during enrichment (40 °C or less).
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dividing microorganisms into various groups rather than culturing large volumes all
at once. While in some instances only the bacteria or seaweed bodies are used after
mass culturing and centrifuge harvesting, the culture solution should be examined for
activity, as it can yield surprisingly large amounts of active substances.
10.2.4 Extracting Substances
Extraction is the first stage in the separation of substances from collected specimens. Because substance types and yields vary by extraction method, suitable
solvent selection is crucial. A good approach when extracting a specific component
from a sample is to finely chop or freeze-dry and pulverize it. Not only can one
reduce the amount of solvent consumed in the extraction, but the extraction yield
can also be improved and the enrichment time reduced.
A. Extraction Methods by Sample Type
• Frozen Sample: Thaw, place in solvent roughly triple the wet sample weight,
and grind to extract.
• Dry Sample: Due to low moisture content and cell contraction, place in
solvent of roughly five times the weight or higher and leave for several hours
to extract; repeat extraction three times.
B. Extraction Solvent
Various types of solvent with different polarities are used in extraction.
Sequential extraction is performed, proceeding from non-polar to polar solvents.
By performing the initial extraction with non-polar solvent, it is possible to
separate and remove or use unneeded soluble sample components such as fats,
lead, resins, and oil. It is also possible to extract substances from within the cell
membrane, which is destroyed by polar solvents. Extraction solvents can provide
information about which specific components enter which solvent fractions,
allowing estimation of the chemical properties of those components and providing ample information for substance refinement and structure analysis.
From low to high polarity:
Petroleum ether < hexane < benzene < chloroform < methylene chloride < ether
< ethyl acetate < acetone < butanol < isopropanol < ethanol < methanol <
water.
C. Enrichment
A rotary evaporator is used for extract enrichment. To minimize change in
specimen components, solvent should be removed at as low a temperature as
possible during enrichment (40 °C or less).
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10 Marine Natural Substances