Comparison of different media for isolation and enumeration of yeasts occurring in blue-veined cheese. Preliminary communication

Comparison of eleven selective media for detecting and enumerating foodborne yeasts in blue-veined cheese showed that rose bengal chloramphenicol agar (RBC), dichloran rose bengal chloramphenicol agar (DRBC), oxytetracycline gentamycin glucose yeast extract agar (OGGY) and dichloran 18% glycerol agar (DG18) were the most efficient. Other examined media failed to be suitable for either inhibiting bacteria and suppressing the spread of moulds or supporting the growth of all yeasts present. Significant differences (P≯0.05) were obtained on different media, however counts obtained were overlapping on three groups of media. Yeast extract eugenol agar (YEE) medium significantly differed from all others

Hydrophobic substrate utilisation by the yeast Yarrowia lipolytica, and its potential applications.

The alkane-assimilating yeast Yarrowia lipolytica degrades very efficiently hydrophobic substrates such as n-alkanes, fatty acids, fats and oils for which it has specific metabolic pathways. An overview of the oxidative degradation pathways for alkanes and triglycerides in Y. lipolytica is given, with new insights arising from the recent genome sequencing of this yeast. This includes the interaction of hydrophobic substrates with yeast cells, their uptake and transport, the primary alkane oxidation to the corresponding fatty alcohols and then by different enzymes to fatty acids, and the subsequent degradation in peroxisomal beta-oxidation or storage into lipid bodies. Several enzymes involved in hydrophobic substrate utilisation belong to multigene families, such as lipases/esterases (LIP genes), cytochromes P450 (ALK genes) and peroxisomal acyl-CoA oxidases (POX genes). Examples are presented demonstrating that wild-type and genetically engineered strains of Y. lipolytica can be used for alkane and fatty-acid bioconversion, such as aroma production, for production of SCP and SCO, for citric acid production, in bioremediation, in fine chemistry, for steroid biotransformation, and in food industry. These examples demonstrate distinct advantages of Y. lipolytica for their use in bioconversion reactions of biotechnologically interesting hydrophobic substrates.Journal ArticleResearch Support, Non-U.S. Gov'tinfo:eu-repo/semantics/publishe