Beier Andy, Hahn Veronika, Bornscheuer Uwe T, Schauer Frieder
Institute of Microbiology, Department of Applied Microbiology, Greifswald University, Friedrich-Ludwig-Jahn-Str. 15, Greifswald, 17487, Germany ; Institute of Biochemistry, Department of Biotechnology & Enzyme Catalysis, Greifswald University, Felix-Hausdorff-Str. 4, Greifswald, 17487, Germany.
Institute of Microbiology, Department of Applied Microbiology, Greifswald University, Friedrich-Ludwig-Jahn-Str. 15, Greifswald, 17487, Germany.
AMB Express. 2014 Oct 10;4:75. doi: 10.1186/s13568-014-0075-2. eCollection 2014.
Knowledge is scarce about the degradation of ketones in yeasts. For bacteria a subterminal degradation of alkanes to ketones and their further metabolization has been described which always involved Baeyer-Villiger monooxygenases (BVMOs). In addition, the question has to be clarified whether alkenes are converted to ketones, in particular for the oil degrading yeast Candida maltosa little is known. In this study we show the degradation of the aliphatic ketone dodecane-2-one by Candida maltosa and the related yeasts Candida tropicalis, Candida catenulata and Candida albicans as well as Trichosporon asahii and Yarrowia lipolytica. One pathway is initiated by the formation of decyl acetate, resulting from a Baeyer-Villiger-oxidation of this ketone. Beyond this, an initial reduction to dodecane-2-ol by a keto reductase was clearly shown. In addition, two different ways to metabolize dodec-1-ene were proposed. One involved the formation of dodecane-2-one and the other one a conversion leading to carboxylic and dicarboxylic acids. Furthermore the induction of ketone degrading enzymes by dodecane-2-one and dodec-1-ene was shown. Interestingly, with dodecane no subterminal degradation products were detected and it did not induce any enzymes to convert dodecane-2-one.
关于酵母中酮类物质的降解，目前所知甚少。对于细菌而言，已描述了烷烃向酮类物质的亚末端降解及其进一步的代谢过程，这一过程总是涉及到拜耳-维利格单加氧酶（BVMOs）。此外，还需要明确烯烃是否会转化为酮类物质，特别是对于降解油脂的酵母麦芽糖假丝酵母，人们了解甚少。在本研究中，我们展示了麦芽糖假丝酵母以及相关酵母热带假丝酵母、链状假丝酵母、白色念珠菌、浅白隐球酵母和解脂耶氏酵母对脂肪族酮2-十二酮的降解。一条途径是由该酮经拜耳-维利格氧化形成乙酸癸酯引发的。除此之外，还清楚地表明了一种酮还原酶将其初步还原为2-十二醇。此外，还提出了两种代谢1-十二烯的不同方式。一种涉及2-十二酮的形成，另一种则是导致羧酸和二羧酸的转化。此外，还展示了2-十二酮和1-十二烯对酮降解酶的诱导作用。有趣的是，对于十二烷，未检测到亚末端降解产物，并且它也未诱导任何将2-十二酮转化的酶。
