Dynamic behavior of Yarrowia lipolytica in response to pH perturbations: dependence of the stress response on the culture mode
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- 作者：Asma Timoumi ; Mégane Cléret ; Carine Bideaux…
- 关键词：Batch ; Chemostat ; Dynamic response ; Morphology ; pH stress ; Yarrowia lipolytica
- 刊名：Applied Microbiology and Biotechnology
- 出版年：2017
- 出版时间：January 2017
- 年：2017
- 卷：101
- 期：1
- 页码：351-366
- 全文大小：
- 刊物类别：Chemistry and Materials Science
- 刊物主题：Microbiology; Microbial Genetics and Genomics; Biotechnology;
- 出版者：Springer Berlin Heidelberg
- ISSN：1432-0614
- 卷排序：101
文摘
Yarrowia lipolytica, a non-conventional yeast with a promising biotechnological potential, is able to undergo metabolic and morphological changes in response to environmental conditions. The effect of pH perturbations of different types (pulses, Heaviside) on the dynamic behavior of Y. lipolytica W29 strain was characterized under two modes of culture: batch and continuous. In batch cultures, different pH (4.5, 5.6 (optimal condition), and 7) were investigated in order to identify the pH inducing a stress response (metabolic and/or morphologic) in Y. lipolytica. Macroscopic behavior (kinetic parameters, yields, viability) of the yeast was slightly affected by pH. However, contrary to the culture at pH 5.6, a filamentous growth was induced in batch experiments at pH 4.5 and 7. Proportions of the filamentous subpopulation reached 84 and 93 % (v/v) under acidic and neutral conditions, respectively. Given the significant impact of neutral pH on morphology, pH perturbations from 5.6 to 7 were subsequently assayed in batch and continuous bioreactors. For both process modes, the growth dynamics remained fundamentally unaltered during exposure to stress. Nevertheless, morphological behavior of the yeast was dependent on the culture mode. Specifically, in batch bioreactors where cells proliferated at their maximum growth rate, mycelia were mainly formed. Whereas, in continuous cultures at controlled growth rates (from 0.03 to 0.20 h−1) even closed to the maximum growth rate of the stain (0.24 h−1), yeast-like forms predominated. This pointed out differences in the kinetic behavior of filamentous and yeast subpopulations, cell age distribution, and pH adaptive mechanisms between both modes of culture.