Identification of a Novel HOG1 Homologue from an Industrial Glycerol Producer Candida glycerinogenes

Candida glycerinogenes, a glycerol production industrial strain with hyperosmo-adaptation can grow well in 15 % (w/v) NaCl or 55 % (w/v) glucose. To understand the osmo-adaptation mechanism in C. glycerinogenes, the mitogen-activated protein kinase HOG1 gene (CgHOG1), which plays an essential role in the yeast hyperosmotic response, was isolated by degenerate PCR and SEFA-Formed Adaptor PCR. The CgHOG1 gene was then transformed in Saccharomyces cerevisiae hog1Δ null mutant, which restored the recombination S. cerevisiae to the wild-type phenotype with osmo-adaptation. To further clarify the function of CgHOG1, the phosphorylation of CgHOG1 and transcription of the glycerol-3-phosphate dehydrogenase gene (GPD1) of the CgHOG1-harbouring S. cerevisiae mutant was detected, and found to be similar to that of wild-type S. cerevisiae. In addition, the recombination S. cerevisiae with CgHOG1 gene significantly accumulated intracellular glycerol when stressed with NaCl.