Previously we reported that accelerating aggregation of cellulose-fiber by cells of
Geotrichum sp. M 111 needed addition of at least 2×10
7 cells per ml to the process. To reduce the cultivation of such a large cell quantity, we treated strain M 111 with UV-irradiation and selected 7 mutants. Mutant strain M 111-M 3 showed faster growth and achieved higher final cell concentration (12.0×10
7 cells/m
l) than the wild type strain M 111 (6.0×10
7 cells/m
l) in a medium containing 2% glucose, 2% polypeptone, 1% yeast extract and 0.3% citric acid as well as in the supernatant separated from the waste of
shochu distillation. Thus, a unit volume of the medium cultivated with the mutant had two times as high acceleration ability as that with the wild type strain though a single cell of the two strains had the same level of acceleration ability. It was also found that larger volume of the liquid was separated from the waste when cells of mutant strain M 111-M 3 were added to solid-liquid separation process of the waste (residue) remained after
shochu distillation. We think that these characteristics of the mutant, especially the high yield of cells, are industrially useful for the solid-liquid separation from the waste of
shochu distillation.
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