Guo Hongwei, Liu Peiran, Madzak Catherine, Du Guocheng, Zhou Jingwen, Chen Jian
1] School of Biotechnology and Key Laboratory of Industrial Biotechnology, Ministry of Education, Jiangnan University, 1800 Lihu Road, Wuxi, Jiangsu 214122, China [2] Synergetic Innovation Center of Food Safety and Nutrition, 1800 Lihu Road, Wuxi, Jiangsu 214122, China.
School of Biotechnology and Key Laboratory of Industrial Biotechnology, Ministry of Education, Jiangnan University, 1800 Lihu Road, Wuxi, Jiangsu 214122, China.
Sci Rep. 2015 Jan 30;5:8138. doi: 10.1038/srep08138.
Production of organic acids by microorganisms is of great importance for obtaining building-block chemicals from sustainable biomass. Extracellular accumulation of organic acids involved a series of transporters, which play important roles in the accumulation of specific organic acid while lack of systematic demonstration in eukaryotic microorganisms. To circumvent accumulation of by-product, efforts have being orchestrated to carboxylate transport mechanism for potential clue in Yarrowia lipolytica WSH-Z06. Six endogenous putative transporter genes, YALI0B19470g, YALI0C15488g, YALI0C21406g, YALI0D24607g, YALI0D20108g and YALI0E32901g, were identified. Transport characteristics and substrate specificities were further investigated using a carboxylate-transport-deficient Saccharomyces cerevisiae strain. These transporters were expressed in Y. lipolytica WSH-Z06 to assess their roles in regulating extracellular keto acids accumulation. In a Y. lipolytica T1 line over expressing YALI0B19470g, α-ketoglutarate accumulated to 46.7 g·L(-1), whereas the concentration of pyruvate decreased to 12.3 g·L(-1). Systematic identification of these keto acids transporters would provide clues to further improve the accumulation of specific organic acids with higher efficiency in eukaryotic microorganisms.
微生物生产有机酸对于从可持续生物质中获取基础化学品至关重要。有机酸的细胞外积累涉及一系列转运蛋白，这些转运蛋白在特定有机酸的积累中发挥重要作用，而在真核微生物中缺乏系统的论证。为了避免副产物的积累，人们已着手研究解脂耶氏酵母WSH-Z06中的羧酸盐转运机制以寻找潜在线索。鉴定出了六个内源性推定转运蛋白基因，即YALI0B19470g、YALI0C15488g、YALI0C21406g、YALI0D24607g、YALI0D20108g和YALI0E32901g。使用缺乏羧酸盐转运功能的酿酒酵母菌株进一步研究了它们的转运特性和底物特异性。这些转运蛋白在解脂耶氏酵母WSH-Z06中表达，以评估它们在调节细胞外酮酸积累中的作用。在过表达YALI0B19470g的解脂耶氏酵母T1株系中，α-酮戊二酸积累至46.7 g·L-1，而丙酮酸浓度降至12.3 g·L-1。对这些酮酸转运蛋白的系统鉴定将为进一步提高真核微生物中特定有机酸的高效积累提供线索。
