1 Backgrouds
1.1 Lignocellulosic hydrolysates and inhibitors
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   Although “Harry Potter and the Deathly Hallows” marks the termination of J. K. Rowling’s popular novels, we create a fantastic world where patronus are produced by Saccharomyces cerevisiae to fight against dementors inside the cell. Ethanol fermented by yeast from lignocellulosic materials can be an environmentally friendly fuel. However, rapid and efficient fermentation of lignocellulosic hydrolysates is limited because of inhibitors generated during pretreatment in addition to monomeric sugars. Inhibitors strongly affect the normal physiology of yeast as well as its ethanol productivity, just like the dementors taking away people’s hope and happiness. Nevertheless, we reconstruct TOR protein, a central component of major signaling transduction network controlling cell growth, to increase the tolerance of yeast. A new TOR after directional mutation will play the role of patronus to defend the inpact of inhibitors, keep the overall signaling networks in good order, and finally provide a prosperous world for ethanol production.

1 Backgrounds

1.1 Lignocellulosic hydrolysates and composite inhibitors

   This year we are aimed at increasing the tolerance of Saccharomyces cerevisiae to composite inhibitors in lignocellulosic hydrolysates, such as furans, acetate and phenol (“FAP” for short) formed during pretreatment and hydrolysis. Lignocellulosic materials such as wood provide abundant and renewable energy sources. Lignocellulosics contain sugars polymerised to cellulose and hemicelluloses which can be liberated by hydrolysing the material, and subsequently fermented to ethanol by microorganisms, such as yeast. Lignocellulose-derived ethanol can be used as an environmentally friendly liquid fuel. However, rapid and efficient fermentation of the hydrolysates is limited because a range of toxic compounds are generated during steam pretreatment and hydrolysis of lignocellulosics in addition to monomeric sugars.

  

  

   The inhibiting compounds are divided in three main groups based on origin: weak acids, furan derivatives, and phenolic compounds. Weak acids, especially acetate, which is widely known as a kind of food preservatives, could inhibit cell growth. The growth-inhibiting effect on microorganisms has been proposed to be due to the inflow of undissociated acid into the cytosol. Undissociated weak acids are liposoluble and can diffuse across the plasma membrane. In the cytosol, dissociation of the acid occurs due to the neutral intracellular pH, thus decreasing the cytosolic pH. With the obvious decrease of intracellular PH, acetate could cause severe amino acid starvation, repress the normal center carbon metabolism and thus damage the physiology of whole cell. Acetic acid has been shown to induce apoptosis in yeast, and TOR pathways (Tor1p) are involved in the signaling of acetic acid-induced apoptosis. Furan derivatives have been shown to reduce the specific growth rate, the cell-mass yield on ATP, the volumetric and specific ethanol productivities. They could give rise to production of oxidative stress, and consumption of enegy (as ATP) and reducing power (as NADPH, NADH). For example, HMF has been shown to cause accumulation of lipids and decrease the protein content in yeast cells. And furfural reduction to furfuryl alcohol by NADH dependent dehydrogenases has a higher priority than reduction of dihydroxyacetone phosphate to glycerol, and furfural causes inactivation of cell replication. Phenolic compounds partition into biological membranes may cause loss of integrity, thereby affecting their ability to serve as selective barriers and enzyme matrices. They have been suggested to exert a considerable inhibitory effect in the fermentation of lignocellulosic hydrolysates, the low molecular weight phenolic compounds being most toxic. However, the mechanism of the inhibiting effect has not been elucidated, largely due to a lack of accurate qualitative and quantitative analyses. What’s more, the three groups of inhibitors have been shown to interact synergistically and antagonistically when they coexist, making the inhibition mechanism more complicated.

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   In innovative talent cultivation, the School strives to reform course system and update course content catering to social needs and industry development. It also introduces excellent original foreign textbooks, and increases the percentage of bilingual programs in the whole curriculum. Besides, it steps up the communication and cooperation with famous universities and enterprises in the world to jointly train talents specialized in software engineering and animation who can meet the needs of the society. All these efforts are dedicated to increase the impact of Tianjin University on the Bohai Rim area, to enhance the strength of the School and to make contribution to the social and economic development of Binhai New Area.

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   On May 6, 2011, School of Electronic and Information Engineering, School of Computer Science and Technology and School of Computer Software jointly held a lecture on the history of CPC, which also launched the "Excel in the Performance" activities co-hosted by information technology and science discipline group. Chen Xuewei, a famous specialist on the theory of CPC history, and professor of Party School of the Central Committee of CPC was invited by the three schools to make a lecture on the topic of "Great Rejuvenation of CPC and the Chinese Nation". Several senior officials from the University and the hosting schools attended the ceremony, and about 420 students took part in the activity.On May 6, 2011, School of Electronic and Information Engineering, School of Computer Science and Technology and School of Computer Software jointly held a lecture on the history of CPC, which also launched the "Excel in the Performance" activities co-hosted by information technology and science discipline group. Chen Xuewei, a famous specialist on the theory of CPC history, and professor of Party School of the Central Committee of CPC was invited by the three schools to make a lecture on the topic of "Great Rejuvenation of CPC and the Chinese Nation". Several senior officials from the University and the hosting schools attended the ceremony, and about 420 students took part in the activity.On May 6, 2011, School of Electronic and Information Engineering, School of Computer Science and Technology and School of Computer Software jointly held a lecture on the history of CPC, which also launched the "Excel in the Performance" activities co-hosted by information technology and science discipline group. Chen Xuewei, a famous specialist on the theory of CPC history, and professor of Party School of the Central Committee of CPC was invited by the three schools to make a lecture on the topic of "Great Rejuvenation of CPC and the Chinese Nation". Several senior officials from the University and the hosting schools attended the ceremony, and about 420 students took part in the activity.On May 6, 2011, School of Electronic and Information Engineering, School of Computer Science and Technology and School of Computer Software jointly held a lecture on the history of CPC, which also launched the "Excel in the Performance" activities co-hosted by information technology and science discipline group. Chen Xuewei, a famous specialist on the theory of CPC history, and professor of Party School of the Central Committee of CPC was invited by the three schools to make a lecture on the topic of "Great Rejuvenation of CPC and the Chinese Nation". Several senior officials from the University and the hosting schools attended the ceremony, and about 420 students took part in the activity.

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   On May 6, 2011, School of Electronic and Information Engineering, School of Computer Science and Technology and School of Computer Software jointly held a lecture on the history of CPC, which also launched the "Excel in the Performance" activities co-hosted by information technology and science discipline group. Chen Xuewei, a famous specialist on the theory of CPC history, and professor of Party School of the Central Committee of CPC was invited by the three schools to make a lecture on the topic of "Great Rejuvenation of CPC and the Chinese Nation". Several senior officials from the University and the hosting schools attended the ceremony, and about 420 students took part in the activity.On May 6, 2011, School of Electronic and Information Engineering, School of Computer Science and Technology and School of Computer Software jointly held a lecture on the history of CPC, which also launched the "Excel in the Performance" activities co-hosted by information technology and science discipline group. Chen Xuewei, a famous specialist on the theory of CPC history, and professor of Party School of the Central Committee of CPC was invited by the three schools to make a lecture on the topic of "Great Rejuvenation of CPC and the Chinese Nation". Several senior officials from the University and the hosting schools attended the ceremony, and about 420 students took part in the activity.On May 6, 2011, School of Electronic and Information Engineering, School of Computer Science and Technology and School of Computer Software jointly held a lecture on the history of CPC, which also launched the "Excel in the Performance" activities co-hosted by information technology and science discipline group. Chen Xuewei, a famous specialist on the theory of CPC history, and professor of Party School of the Central Committee of CPC was invited by the three schools to make a lecture on the topic of "Great Rejuvenation of CPC and the Chinese Nation". Several senior officials from the University and the hosting schools attended the ceremony, and about 420 students took part in the activity.On May 6, 2011, School of Electronic and Information Engineering, School of Computer Science and Technology and School of Computer Software jointly held a lecture on the history of CPC, which also launched the "Excel in the Performance" activities co-hosted by information technology and science discipline group. Chen Xuewei, a famous specialist on the theory of CPC history, and professor of Party School of the Central Committee of CPC was invited by the three schools to make a lecture on the topic of "Great Rejuvenation of CPC and the Chinese Nation". Several senior officials from the University and the hosting schools attended the ceremony, and about 420 students took part in the activity.