锌离子提高絮凝酵母乙酸胁迫耐受性  

Improvement of acetic acid tolerance of self-flocculating yeast by zinc supplementation

作　　者：徐桂红[1] 赵心清[1] 李宁[1] 白凤武[1] 

机构地区：[1]大连理工大学生命科学与技术学院,辽宁大连116023

出　　处：《化工学报》2012年第6期1823-1829,共7页CIESC Journal

基　　金：教育部中央高校基本科研业务费专项资金资助项目(DUT10JN09)~~

摘　　要：研究了锌离子对絮凝酵母SPSC01乙酸胁迫条件下乙醇发酵的影响,结果表明,添加适当浓度的锌离子可以缓解乙酸对自絮凝酵母生长的抑制,进而缩短其发酵周期;其中添加0.03g.L-1锌离子对乙酸胁迫下细胞活性的保护作用最明显,可使15g.L-1乙酸存在时发酵周期缩短近30h,最终生物量得率提高27.8%,乙醇产率提高66.7%。同时锌离子还可以使乙酸抑制条件下,发酵液中副产物乳酸和丙酸的含量降低。Acetic acid is one of the major inhibitory compounds for cell growth and ethanol fermentation of Saccharomyces cerevisiae,and is present in cellulosic hydrolysate as well as in industrial culture broth contaminated by acetic-acid producing bacteria.Therefore,improvement of acetic acid tolerance plays an important role for efficient ethanol production.Although adjustment of pH to 5 or 6 has been proved to be effective against acetic acid toxicity,it is impractical for large scale industrial production due to the cost and increased risk of contamination.Zinc is an essential metal for yeast cell growth and metabolism,however,the important role of zinc is often neglected due to its status as a trace element.Previous studies showed that zinc has protective effect on yeast ethanol tolerance and thermal tolerance of self-flocculating yeast SPSC01.In this study,the effect of different concentrations of zinc sulfate on ethanol production of self-flocculating yeast SPSC01 in the presence of high concentration of acetic acid was studied in batch fermentation in the 3L bioreactor using 100 g·L-1 glucose.The results showed that zinc exhibited protective effect against acetic acid toxicity.Of the different concentrations of zinc sulfate tested in this work,0.03 g·L-1 zinc sulfate showed the best protective effect.Addition of 0.03 g·L-1 zinc sulfate shortened the lag phase time of cell growth of the self-flocculating yeast in the presence of 10 g·L-1 and 15 g·L-1 acetic acid,and the fermentation time was also subsequently reduced.The lag phase time was shortened nearly by 30 h,with a 27.8% increase in the biomass yield and a 66.7% increase in the ethanol productivity comparing with the non-addition control.The by-products lactic acid and propionic acid were repressed by zinc addition,and significant reduction of propionic acid production was observed upon zinc addition,while no apparent effect was observed on succinic acid and citric acid biosynthesis.The results from this study showed the important role of zinc in cell gr

关 键 词：自絮凝酵母 锌离子 乙酸胁迫 乙醇发酵 

分 类 号：Q819[生物学—生物工程]