Rouwenhorst R J, Ritmeester W S, Scheffers W A, Van Dijken J P
Department of Microbiology and Enzymology, Kluyver Laboratory of Biotechnology, Delft University of Technology, The Netherlands.
Appl Environ Microbiol. 1990 Nov;56(11):3329-36. doi: 10.1128/aem.56.11.3329-3336.1990.
In vivo hydrolysis of inulin and sucrose was examined in selected yeasts of the genus Kluyveromyces. Cells, grown in sucrose-limited chemostat cultures, were subjected to treatments for the removal of inulinase, the enzyme responsible for the hydrolysis of both inulin and sucrose. The effects of these treatments were studied by measurement of inulin-dependent and sucrose-dependent oxygen consumption by cell suspensions. In Kluyveromyces marxianus var. marxianus, inulinase was partially secreted into the culture fluid. Removal of culture fluid inulinase by washing had no effect on sucrose-dependent oxygen consumption by this yeast. However, this treatment drastically reduced inulin-dependent oxygen consumption. Treatment of washed cells with sulfhydryls removed part of the cell wall-retained inulinase and reduced inulin-dependent oxygen consumption by another 80%. Sucrose-dependent oxygen consumption was less affected, decreasing by 40%. Cell suspensions of K. marxianus var. drosophilarum, K. marxianus var. vanudenii, and Saccharomyces kluyveri rapidly utilized sucrose but not inulin. This is in accordance with the classification of these yeasts as inulin negative. Supernatants of cultures grown at pH 5.5 did not catalyze the hydrolysis of inulin and sucrose. This suggested that these yeasts contained a strictly cell-bound invertase, an enzyme not capable of inulin hydrolysis. However, upon washing, cells became able to utilize inulin. The inulin-dependent oxygen consumption further increased after treatment of the cells with sulfhydryls. These treatments did not affect the sucrose-dependent oxygen consumption of the cells. Apparently, these treatments removed a permeability barrier for inulin that does not exist for sucrose.(ABSTRACT TRUNCATED AT 250 WORDS)
在克鲁维酵母属的特定酵母中检测了菊粉和蔗糖的体内水解情况。在蔗糖限制的恒化器培养中生长的细胞，经过处理以去除菊粉酶，该酶负责菊粉和蔗糖的水解。通过测量细胞悬液中菊粉依赖性和蔗糖依赖性的氧气消耗来研究这些处理的效果。在马克斯克鲁维酵母马克斯变种中，菊粉酶部分分泌到培养液中。通过洗涤去除培养液中的菊粉酶对该酵母的蔗糖依赖性氧气消耗没有影响。然而，这种处理极大地降低了菊粉依赖性氧气消耗。用巯基处理洗涤后的细胞去除了部分细胞壁结合的菊粉酶，并使菊粉依赖性氧气消耗又降低了80%。蔗糖依赖性氧气消耗受影响较小，降低了40%。果蝇克鲁维酵母变种、范登尼克鲁维酵母变种和克鲁维毕赤酵母的细胞悬液迅速利用蔗糖但不利用菊粉。这与这些酵母被归类为菊粉阴性一致。在pH 5.5下生长的培养物的上清液不催化菊粉和蔗糖的水解。这表明这些酵母含有一种严格细胞结合的转化酶，一种不能水解菊粉的酶。然而，洗涤后，细胞变得能够利用菊粉。用巯基处理细胞后，菊粉依赖性氧气消耗进一步增加。这些处理不影响细胞的蔗糖依赖性氧气消耗。显然，这些处理去除了对菊粉存在而对蔗糖不存在的通透性屏障。（摘要截短于250字）
