Breeding of High-tolerance Yeast Strains by Adaptive Evolution in PDMS Membrane Bioreactor
Yeast is one of the key factors influencing ethanol fermentation.In the study,an adaptive evolution strategy had been developed and used for the improvement of yeast strain properties.Firstly,the industrial yeast strains were inoculated into PDMS membrane bioreactor for long-term continuous and closed-circulating fermentation,and the superior strains were screened out after adaptive evolution through step-transfer cultivation.Long-term ethanol fermentation was continuously operated due to in-situ pervaporation separation by silicone rubber membrane,resulting in gradual accumulation of various non-permeating substances.And the deteriorating broth environment provided selective pressure for yeast evolution.Then the mutants were isolated from the terminal point of 500 h fermentation after reproduction for approximately 200 generations and those mutants were demonstrated to have significant evolved features including more rapid growth rate and higher ethanol productivity.Finally,the research results indicated that the use of the evolved yeast strains could prolong continuous and closed-circulating ethanol fermentation and achieve high ethanol yield,which was beneficial to the development of continuous and closed-circulating fermentation technology.
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万方数据
维普
