as polyvinyl alcohol having a polymerization degree of 1400 it is a polymer having a molecular weight small enough to be soluble in water and one which can be polymerized with ionizing radiation to a large molecular weight and water insoluble polymer the resulting water insoluble polymer may be a homopolymer or a copolymer or a mixture thereof these monomers or polymers can be used singly or by combining two or more of them further the concentration of monomer or polymer solutions is not critical and thus the concentration can be selected freely also n n 39 methylene bis acrylamide and divinyl sulfone can be added as a cross linking agent in suitable quantities water insoluble or slightly water soluble fluids oils and solvents can be used typical oils are vegetable oils such as soybean oil seasame oil olive oil mineral oils such as volatile oils kerosene and light oils typical solvents include aliphatic hydrocarbons such as n hexane petroleum ether aromatic hydrocarbons such as toluene xylenes alcohols higher than propyl alcohols such as butyl alcohols amyl alcohols ethers such as ethyl ether esters such as ethyl acetate ketones such as methyl ethyl ketone further a surface active agent can be added if desired in the present invention a fluid of which solubility in water is at most about 15 can be used as a slightly water soluble fluid as an example of such a fluid iso butanol and ethyl ether are shown further gasolines having boiling points of about 30 u00b0 200 u00b0 c can be used as volatile oils a monomer or polymer solution containing an enzyme is added to said fluid while agitating the fluid or adding the solution dropwise by.