[Effect of ctpxa1 gene deletion in Candida tropicalis on long chain dicarboxylic acid accumulation].

Candida tropicalis uses alkanes and fatty acids to produce long chain dicarboxylic acids. However, the yield can be affected by β-oxidation in peroxisomes. Pxa1p was a membrane protein of Saccharomyces cerevisiae peroxisomes. Pxa1p and Pxa2p form a dimer that is involved in transporting of long chain fatty acids into peroxisomes, but the similar transporting system of Candida tropicalis has not yet been reported. In this study, a ctpxa1 gene deletion strain named C. tropicalis 1798-pxa1 was constructed by homologous single exchange method using PCR fragment. The expression of ctpxa1 gene in C. tropicalis 1798, C. tropicalis 1798-pxa1 was detected by semi-quantitative RT-PCR, and the ratio of gray value was 2.03, implying that the expression of ctpxa1 in C. tropicalis 1798-pxa1 was weakened. After 144 h fermentation, the dodecanedioic acid production of C. tropicalis 1798-pxa1 was increased 94.3% than the former strain, the maximum yield was 10.3 g/L.