Effects of Different Inducers on Higher Alcohol Dehydrogenase from Geotrichum candidum

The inducers of the chemical or physical factors could affect the gene expression and transcription of strain directly or indirectly. In order to explore the inductive effect of higher alcohol on Geotrichum candidum, the G. candidum S12, derived from the soil, was induced by five higher alcohols, including n-propanol, n-butanol, isobutanol, n-hexanol and isoamyl alcohol. The effects of induction dose and induction time for degradation activity of different higher alcohols by strain S12 and its transforming enzyme were studied. The results showed that the enzyme activity formed by strain S12 was higher when the inducers were chosen as n-hexanol and isobutanol. The optimum induction time was 6 h when n-propanol, n-butanol, isobutanol and n-hexanol were used as inducers. While the optimum induction time of strain S12 and enzyme induced by isoamyl alcohol was 12 h. When n-propanol and n-hexanol were used as inducers, the optimal concentration was 1.5 g/L. While the optimal concentrations of strain S12 and enzyme induced by n-butanol, isobutanol and isoamyl alcohol were 1.0, 0.5 and 2.5 g/L, respectively. The results of native polyacryplamide gel electrophoresis (Native-PAGE) indicated that dehydrogenase formation, molecular weight about 223 kDa, was induced by five higher alcohols. In particular, the strain, induced by hexanol, had much higher capability in degrading five higher alcohols at the same time. The products of the above five higher alcohols after catalyzing by G. geotrichum S12 induced by hexanol were their corresponding acids and esters.