Whole cell enzyme composition containing fumed silica

DETAILED DESCRIPTION According to a preferred embodiment of this invention, flocculated whole cells of a glucose isomerase-producing strain of the microorganism Arthrobacter are treated with from about 2 to about 40% by weight of fumed silica, based on dry cell weight, and the resulting cell mass is extruded, dried, ground and sieved to produce dried aggregate particles of desired size.
Although the preferred microorganism cells are glucose isomerase-containing microorganism cells of the genus Arthrobacter, the invention is also applicable to glucose isomerase-containing cells derived from other Arthrobacter strains, and from other genera of microorganisms.
The invention is also applicable to enzyme-containing microorganism cells having enzyme activities other than glucose isomerase activity.
The most preferred strain of Arthrobacter for the purpose of this invention is NRRL B-3728.
Another desirable Arthrobacter strain is NRRL B-3726.
Cells of the selected Arthrobacter strain are cultivated in a sterile medium containing sources of carbohydrate, nitrogen, and inorganic salts, as described in U.
S.
Pat.
No.
3,645,848.
Arthorbacter microorganisms are preferred over other glucose isomerase-containing microorganisms because the glucose isomerase activity in Arthrobacter microorganisms is inherently fixed or stabilized within the cells, so that no treatment is necessary in order to stabilize the glucose isomerase activity, which is required for long term continuous or repeated use of the cells.
Other glucose isomerase producing microorganisms, such as Streptomyces, Bacillus coagulans and Actinoplanes missouriensis can be used in place of Arthrobacter if desired, provided they are treated prior to use to stabilize their glucose isomerase activity.
These microorganisms may be cultivated according to methods known in the art.
Other microorganisms in which an enzyme is produced intracellularly may also be processed and used according to this invention.
Microorganism cells masses which are treated according to this invention are principally in the form of whole cells