engleski

Influence of zeolite on the concentrations of sphingoid bases in the yeast Candida lipolytica

Zeolites, crystalline aluminosilicates of microporous structure have been shown to influence yeast metabolism, for example by improving ethanol production from glucose. The main approach to our study was to investigate if natural zeolite clinoptilolite had any effect on sphingolipid metabolism in the yeast Candida lipolytica. Sphingoid long-chain bases were released from complex sphingolipids by acid hydrolysis with methanolic HCl and analysed via high performance liquid chromatography after derivatization with the OPA (ortho-phthaldialdehyde) reagent. Here we present the first evidence that zeolite induces a raise in the concentrations of sphingoid bases, with the largest increase seen in C18 phytosphingosine. Comparison of the pH profiles between control (i.e. without zeolite) and zeolite-supplemented cells showed no difference, suggesting that ion-exchange capacity of zeolite was not critical for the alteration in sphingolipid metabolism. Scanning electron microscopy revealed an unexpected finding that zeolite addition gave rise to the change in the shape and size of the cells, implying that zeolite could have affected cell growth. Cells cultured without zeolite were oval-shaped and approximately 0.7-2.7 mm in size in comparison with zeolite-supplemented cells that were rounded and larger in size (1.3-2.9 mm).

yeast; sphingolipids; zeolite

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