| 摘要 |
PURPOSE:To produce the titled organic acid in high efficiency, suppressing the production of unnecessary by-products, with many industrial merits, by immobilizing a specific microbial strain to a material for holding microorganisms and contacting the obtained immobilized microorganisms with substrate. CONSTITUTION:A foamed material made of an olefin polymer, etc. or a porous material of ceramic or metal having a porosity of 70-99% and a number of pores of 2-50 per 1cm, is formed to a sphere of 1-100mm in diameter or a block of 1-100mm of side length. The obtained holding material is sterilized with steam, added to a base medium such as glucose, inoculated with a microbial strain such as Aspergillus niger and cultured at 2-5pH and about 28 deg.C under aeration for about 100hr. The microorganisms are adsorbed to the holding material to obtain immobilized microorganisms. Citric acid or gluconic acid can be produced by the batch-wise or continuous aerobic cultivation with the immobilized microorganism at 25-35 deg.C and 2-5pH while repeatedly replacing the substrate of the culture medium with fresh substrate.
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