微生物による炭化水素の利用 : (II)Pichia guilliermondii Wickerhamによる炭化水素資化とビタミンB_2生産

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Sixty-three kinds microorganisms were isolated from soils collected near gas stations and a petrochemical factory. Thirteen of the sixty-three microorganisns isolated were found capable of producing vitamin B_2 in a hydrocarbon medium. The most excellent vitamin B_2-producer of them was identified as a yeast strain, Pichia guilliermondii Wickerham. Investigations were made on the effect of culture conditions on the growth of this yeast and its vitamin B_2 production. The optimal initial pH for its vitamin B_2 production was 6.5. The combined. use of NH_4H_2PO_4 and (NH_4)_2SO_4 as the nitrogen source was more effective than any others tested. The yeast utilized n-alkanes of C_10-C_15 well, but no n-alkanes with longer carbon chains were utilized under the conditions employed. Of all the pure n-alkanes tested, n-dodecane was best for vitamin B_2 porduction but one of the n-alkane mixture samples, KN -1,was even better for this purpose. An addition of one of non-ionic surface detergents, such as Tween 20,Tween 60,etc. to the culture stimulated the vitamin production. The maximal vitamin B_2 production by the yeast under the optimal condition was 117 mg/l in the culture fluid and 521 μg/g in the cells.
社団法人日本生物工学会の論文