Thermotolerant yeast

Meehan C, Banat IM, McMullan G et al (2000) Decolorization of remazol black-B using a thermotolerant yeast, Kluyveromyces marxianus IMB3. Environ Int 26 75-79... 

Caridi, A., Crucitti, P., and Ramondino, D. (1999). Winemaking of musts at high osmotic strength by thermotolerant yeasts. Biotechnol. Lett. 21,617-620. 

The thermotolerant yeast directly utilizes lactose to produce ethanol and carbon dioxide ... 

Thermotolerant yeasts shift their metabolism to acetic acid and biomass production under aerobic conditions ... 

Cao et al. [60-62] examined a fractionation option that used corn cob and aspen woodchip as the substrates. In this biomass fractionation scheme (Fig. 6), the majority of lignin, alkaline extractives, and acetate were solubilized and separated from cellulose and hemicellulose fractions by alkaline treatment. Hemicellulose was then hydrolyzed to its sugar constituents with dilute acid (0.3 M HCl). Hemicellulose carbohydrates were then fermented to ethanol by a xylose-fermenting yeast strain (Fig. 7). The cellulose fraction, after separation from lignin and hemicellulose, was used as the substrate in the SSF process for ethanol production using a thermotolerant yeast strain as the biocatalyst (Fig. 8). 

Anderson et al. [70] studied several thermotolerant yeast strains isolated from sugar cane factories in Australia. Most of the good ethanol-producing yeasts be-... 

Ballesteros et al. [72] studied SSF of pure cellulose with K. maxianus and K. fragilis at 45 °C with cellulase loading of 15 FPU/g substrate. Both yeast strains produced close to 38 g/1 ethanol in 78 h. The results also confirmed the importance of using thermotolerant yeast in SSF processes in order to improve hydrolysis rates and achieve higher ethanol production. Possible benefits of using a thermotolerant yeast to carry out ethanol fermentation at a supraoptimal temperature are ... 

SSF of RPS with fungal cellulase and a thermotolerant yeast, Kluyveromyces marxianus, was used to convert cellulose fibers of RPS samples to ethanol by Lark et al. [ 112]. The cellulase loading was 8 filter paper units (FPU)/g dry RPS. About 32 and 35 g/1 of ethanol were produced from 180 and 190 g/1 dry materials, respectively, after 72 h of incubation. This indicates that at least 72 % of the cellulose in the RPS was converted into ethanol. During incubation, the thick slurry of RPS was liquefied within 24 h resulting in the reduction of the waterholding capacity of RPS to 30%-35% of the original. 

Thermotolerant yeast can be isolated from rotten strawberries. The yeast cells are immobilized on calcium alginate and can be reused eight times at 40°C with a 100% fermentation efficiency (2). 

Golias H, Dumsday GJ, Stanley GA, Pamment NB. (2002). Evaluation of a recombinant Kfeb-siella oxytoca strain for ethanol production from cellulose by simultaneous saccharification and fermentation comparison with native cellobiose utilizing yeast strains and performance in co-culture with thermotolerant yeast and Zymomonas mobilis. J Biotechnol, 96,155-168. 

Application of Cell-Surface Engineering to Thermotolerant Yeast... 

Hasunuma T, Kondo A. (2012a). Consolidated bioprocessing and simultaneous saccharification and fermentation of lignocellulose to ethanol with thermotolerant yeast strains. Process Biochem, 47, 1287-1294. 

Voronovsky AY, Rohuya OV, Abbas CA, Sibirny AA. (2009). Development of strains of the thermotolerant yeast Hansenula polymorpha capable of alcoholic fermentation of starch and xylan. Metab Eng, 11, 234—242. 

Yanase S, Hasunuma T, Yamada R, Tanaka T, Ogino C, Fukuda H, Kondo A. (2010a). Direct ethanol production from cellulosic materials at high temperature using the thermotolerant yeast Kluyveromyces marxianus displaying cellulolytic enzymes. Appl Microbiol Biotechnol, 88, 381-388. 

Yu, J., Xuzhang, Tan, T. (2008). Ethanol production by solid state fermentation of sweet sorghum using thermotolerant yeast strain. Fuel Processing Technology, 89, 1056—1059. 

Computational methods can also be focused on one selected pathway with finer detail, as opposed to the broad-sweeping computational methods described in Section 18.2.1.3. A kinetic model of xylose utilization by S. cerevisiae for ethanol production aimed to identify which portion of the poorly functioning pathway should be improved [85]. This analysis concluded that higher xylulokinase activity was needed. The authors experimentally verified that increasing xylulokinase activity via the expression of the E. coli xylB improves ethanol production and xylose consumption [85]. Since this initial report, a variety of other studies have reported strategies for increasing xylulokinase activity that also improve xylose utilization [86, 87], including those implemented in the thermotolerant yeast Hansenula polymorpha [88]. 

Prakash, G., Varma, A.J., Prabhune, A., Shouche, Y., Rao, M., 2011. Microbial production of xyKtol from D-xylose and sugarcane bagasse hemicellulose using newly isolated thermotolerant yeast Ddmryomyces hansenii. Bioresource... 

Krishna, S.H., Reddy, T.J., Chowdary, G., 2001. Simultaneous saccharification and fermentation of lignocellulosic wastes to ethanol using a thermotolerant yeast. Bioresource Technology 77 (2), 193-196. 

Pasha, C., Nagavalli, M., Venkateswar Rao, L., 2007. Lantana camara for fuel ethanol production using thermotolerant yeast. Letters in Apphed Microbiology 44 (6), 666—672. Available at http //dx.doi.Org/10.llll/j.1472-765X.2007.02116.x. 

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