In this paper,we studied the effects of the adding time of alkane on the expression of P450 and production of dicarboxylic acid.A novel fermentation process,in which no or a little alkane was added to make the cells growing more quickly during the growth stage,followed by the addition of alkane to induce cytochromes P450 for 6~8 hours,was established.The results showed that the new process was much better than the old process on inductivities of cytochromes P450 and production of dicarboxylic acid.The new process improved nearly 14.56% expression of P450 and 14.15% production of dicarboxylic acid.
A method of reduced CO\|difference spectrum was established to study the cytochrome P450 activity of the whole cell of \%Candida tropicalis\% during the alkane converting process. Using this method, the cytochrome P450 activities of the whole cells that were cultured in the different concentrations of alkane were studied. The results showed that the 5% alkane could induce the cytochrome P450 activity obviously but not inhibit the growth of cells, so it was determined preliminarily that the alkane concentration of the seed medium was 5%. The cytochrome P450 activities of dicarboxylic acid (DCA) fermentation processing were further studied. During the exponential phase of growth, the cytochrome P450 activity increased smoothly. However, during the phase of production of dicarboxylic acid, the cytochrome P450 activities increased rapidly after a sort decrease. The results still showed that the rate of production of dicarboxylic acid increased with the cytochrome P450 activity.