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Enhanced xylose fermentation and hydrolysate inhibitor tolerance of Scheffersomyces shehatae for efficient ethanol production from non-detoxified lignocellulosic hydrolysate.

Senatham S, Chamduang T, Kaewchingduang Y, Thammasittirong A, Srisodsuk M, Elliston A, Roberts IN, Waldron KW, Thammasittirong SN - Springerplus (2016)

Bottom Line: A maximum ethanol concentration of 29.04 g/L was produced from 71.31 g/L xylose, which was 58.95 % higher than that of the wild-type.This mutant also displayed significantly improved hydrolysate inhibitors tolerance and increased ethanol production from non-detoxified lignocellulosic hydrolysates.The ethanol yield, productivity and theoretical yield by TTC79 from sugarcane bagasse hydrolysate were 0.46 g/g, 0.20 g/L/h and 90.61 %, respectively, while the corresponding values for the wild-type were 0.20 g/g, 0.04 g/L/h and 39.20 %, respectively.

View Article: PubMed Central - PubMed

Affiliation: Department of Microbiology, Faculty of Liberal Arts and Science, Kasetsart University, Kamphaeng Saen Campus, Nakhon Pathom, 73140 Thailand.

ABSTRACT
Effective conversion of xylose into ethanol is important for lignocellulosic ethanol production. In the present study, UV-C mutagenesis was used to improve the efficiency of xylose fermentation. The mutated Scheffersomyces shehatae strain TTC79 fermented glucose as efficiently and xylose more efficiently, producing a higher ethanol concentration than the wild-type. A maximum ethanol concentration of 29.04 g/L was produced from 71.31 g/L xylose, which was 58.95 % higher than that of the wild-type. This mutant also displayed significantly improved hydrolysate inhibitors tolerance and increased ethanol production from non-detoxified lignocellulosic hydrolysates. The ethanol yield, productivity and theoretical yield by TTC79 from sugarcane bagasse hydrolysate were 0.46 g/g, 0.20 g/L/h and 90.61 %, respectively, while the corresponding values for the wild-type were 0.20 g/g, 0.04 g/L/h and 39.20 %, respectively. These results demonstrate that S. shehatae TTC79 is a useful non-recombinant strain, combining efficient xylose consumption and high inhibitor tolerance, with potential for application in ethanol production from lignocellulose hydrolysates.

No MeSH data available.


Related in: MedlinePlus

Sugar consumption and ethanol production by TTC79 and the wild-type in non-detoxified sugarcane bagasse hydrolysate. Wild-type/ethanol (filled triangle), wild-type/glucose (filled square), wild-type/xylose (filled circle), TTC79/ethanol (open triangle), TTC79/glucose (open square), TTC79/xylose (open circle). Data represent the mean ± SD from three independent experiments
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Fig3: Sugar consumption and ethanol production by TTC79 and the wild-type in non-detoxified sugarcane bagasse hydrolysate. Wild-type/ethanol (filled triangle), wild-type/glucose (filled square), wild-type/xylose (filled circle), TTC79/ethanol (open triangle), TTC79/glucose (open square), TTC79/xylose (open circle). Data represent the mean ± SD from three independent experiments

Mentions: In addition to pentose and hexose sugars, the numerous types of inhibitors are produced during acid hydrolysis process and usually a detoxification step is needed to improve fermentability. Detoxification results in sugar loss and increase production cost (Buhner and Agblevor 2004). Xylose-fermenting yeast with high inhibitor tolerance that is able to ferment non-detoxified hydrolysate to ethanol would be very attractive for commercial lignocellulosic ethanol production. The results in Fig. 3 showed that simultaneous consumption of glucose with xylose was observed in TTC79 and the wild-type. TTC79 consumed the sugar mixture in undetoxified sugarcane bagasse hydrolysate containing 6.45 g/L acetic acid, 0.28 g/L furfural and 1.60 g/L HMF to a greater extent than the wild-type and this led to higher ethanol production. The maximum ethanol concentration, yield and the theoretical yield by TTC79 were 12.15 g/L, 0.46 g/g and 90.61 %, respectively (Table 2). Ethanol productivity of TTC79 was also considerably faster than the wild-type. The maximum ethanol productivity by TTC79 was 0.20 g/L/h, while the wild-type showed productivity of 0.04 g/L/h. No xylitol production was detected in this fermentation (data not shown). One possible explanation might be that the delay in consumption rate of xylose in the hydrolysate, xylitol therefore could be completely converted to ethanol.Fig. 3


Enhanced xylose fermentation and hydrolysate inhibitor tolerance of Scheffersomyces shehatae for efficient ethanol production from non-detoxified lignocellulosic hydrolysate.

Senatham S, Chamduang T, Kaewchingduang Y, Thammasittirong A, Srisodsuk M, Elliston A, Roberts IN, Waldron KW, Thammasittirong SN - Springerplus (2016)

Sugar consumption and ethanol production by TTC79 and the wild-type in non-detoxified sugarcane bagasse hydrolysate. Wild-type/ethanol (filled triangle), wild-type/glucose (filled square), wild-type/xylose (filled circle), TTC79/ethanol (open triangle), TTC79/glucose (open square), TTC79/xylose (open circle). Data represent the mean ± SD from three independent experiments
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4940357&req=5

Fig3: Sugar consumption and ethanol production by TTC79 and the wild-type in non-detoxified sugarcane bagasse hydrolysate. Wild-type/ethanol (filled triangle), wild-type/glucose (filled square), wild-type/xylose (filled circle), TTC79/ethanol (open triangle), TTC79/glucose (open square), TTC79/xylose (open circle). Data represent the mean ± SD from three independent experiments
Mentions: In addition to pentose and hexose sugars, the numerous types of inhibitors are produced during acid hydrolysis process and usually a detoxification step is needed to improve fermentability. Detoxification results in sugar loss and increase production cost (Buhner and Agblevor 2004). Xylose-fermenting yeast with high inhibitor tolerance that is able to ferment non-detoxified hydrolysate to ethanol would be very attractive for commercial lignocellulosic ethanol production. The results in Fig. 3 showed that simultaneous consumption of glucose with xylose was observed in TTC79 and the wild-type. TTC79 consumed the sugar mixture in undetoxified sugarcane bagasse hydrolysate containing 6.45 g/L acetic acid, 0.28 g/L furfural and 1.60 g/L HMF to a greater extent than the wild-type and this led to higher ethanol production. The maximum ethanol concentration, yield and the theoretical yield by TTC79 were 12.15 g/L, 0.46 g/g and 90.61 %, respectively (Table 2). Ethanol productivity of TTC79 was also considerably faster than the wild-type. The maximum ethanol productivity by TTC79 was 0.20 g/L/h, while the wild-type showed productivity of 0.04 g/L/h. No xylitol production was detected in this fermentation (data not shown). One possible explanation might be that the delay in consumption rate of xylose in the hydrolysate, xylitol therefore could be completely converted to ethanol.Fig. 3

Bottom Line: A maximum ethanol concentration of 29.04 g/L was produced from 71.31 g/L xylose, which was 58.95 % higher than that of the wild-type.This mutant also displayed significantly improved hydrolysate inhibitors tolerance and increased ethanol production from non-detoxified lignocellulosic hydrolysates.The ethanol yield, productivity and theoretical yield by TTC79 from sugarcane bagasse hydrolysate were 0.46 g/g, 0.20 g/L/h and 90.61 %, respectively, while the corresponding values for the wild-type were 0.20 g/g, 0.04 g/L/h and 39.20 %, respectively.

View Article: PubMed Central - PubMed

Affiliation: Department of Microbiology, Faculty of Liberal Arts and Science, Kasetsart University, Kamphaeng Saen Campus, Nakhon Pathom, 73140 Thailand.

ABSTRACT
Effective conversion of xylose into ethanol is important for lignocellulosic ethanol production. In the present study, UV-C mutagenesis was used to improve the efficiency of xylose fermentation. The mutated Scheffersomyces shehatae strain TTC79 fermented glucose as efficiently and xylose more efficiently, producing a higher ethanol concentration than the wild-type. A maximum ethanol concentration of 29.04 g/L was produced from 71.31 g/L xylose, which was 58.95 % higher than that of the wild-type. This mutant also displayed significantly improved hydrolysate inhibitors tolerance and increased ethanol production from non-detoxified lignocellulosic hydrolysates. The ethanol yield, productivity and theoretical yield by TTC79 from sugarcane bagasse hydrolysate were 0.46 g/g, 0.20 g/L/h and 90.61 %, respectively, while the corresponding values for the wild-type were 0.20 g/g, 0.04 g/L/h and 39.20 %, respectively. These results demonstrate that S. shehatae TTC79 is a useful non-recombinant strain, combining efficient xylose consumption and high inhibitor tolerance, with potential for application in ethanol production from lignocellulose hydrolysates.

No MeSH data available.


Related in: MedlinePlus