适应性进化提高酿酒酵母糠醛耐受性及其机理研究

Improving Furfural Tolerance of Saccharomyces cerevisiae by Adaptive Evolution and Its Mechanism

中文关键词:  酿酒酵母  糠醛  适应性进化  乙醇

Key Words:Saccharomyces cerevisiae  furfural  adaptive evolution  ethanol

中文摘要:

      燃料乙醇的原材料多样、对环境污染小，是一种真正意义上的可再生绿色能源。为了加大生物质能源的工业化进程，并克服预处理过程中产生的抑制剂对酵母的抑制作用，本研究以酿酒酵母（Saccharomyces cerevisiae）CEN. PK 1B-7D为出发菌株进行适应性进化培养，得到了对糠醛耐受性高且生长延滞期明显缩短的进化菌株CEN. PK 1B-7D 385。进一步比较原始菌株和进化菌株在4 g/L糠醛条件下细胞膜的通透性、膜电位变化情况和细胞内活性氧含量（ROS）。结果发现，相对于原始菌株，碘化丙啶（PI）染色细胞数降低了45.2%，去极化细胞数量减少了66.7%，说明在糠醛胁迫下进化菌株的细胞膜更加完整。同时，进化菌株胞内ROS含量从原始菌株的9.1%降低为6.5%，说明在糠醛胁迫下进化菌株胞内ROS有所下降。结合生物量、乙醇产量、细胞膜通透性及膜电位等诸多因素，进化菌株CEN. PK 1B-7D 385对糠醛的耐受性较原始菌株有明显提升。

Abstract:

      Bioethanol could be produced from various raw materials and has little impact on environmental pollution. It is truly a renewable green energy. In order to increase the industrialization process of bioenergy and overcome the inhibitory effect of various inhibitors produced in the pretreatment process on yeast， here Saccharomyces cerevisiae CEN. PK 1B-7D was used as the starting strain for adaptive evolution. An evolutionary strain with highest tolerance to furfural was obtained and named as CEN. PK 1B-7D 385. Further analysis showed that the permeability of cell membrane of the evolved strain was decreased. The number of PI stained cells was decreased by 45.2%， and the number of depolarized cells was decreased by 66.7%， indicating that cell membrane of S. cerevisiae after adaptive evolution were more complete under furfural stress. At the same time， the intracellular ROS content of the evolved strain was decreased from 9.1% of the original strain to 6.5% of the evolved strain. Combined with biomass， ethanol yield， cell membrane permeability and membrane potential， the evolved strain CEN PK 1B-7D 385 is more tolerant to furfural than the starting strain.