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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

Cell viability of TTC79 and the wild-type in the absence (a) and in the presence of 5.25 g/L acetic acid (b), 1.75 g/L furfural (c) and 1.30 g/L HMF (d). Wild-type (filled diamond), TTC79 (open diamond). Data represent the mean ± SD from three independent experiments
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Fig2: Cell viability of TTC79 and the wild-type in the absence (a) and in the presence of 5.25 g/L acetic acid (b), 1.75 g/L furfural (c) and 1.30 g/L HMF (d). Wild-type (filled diamond), TTC79 (open diamond). Data represent the mean ± SD from three independent experiments

Mentions: Acetic acid, furfural and HMF are among the most potent inhibitors found in lignocellulosic hydrolysates (Klinke et al. 2004; Taherzadeh et al. 2000). These compounds are known to inhibit microbial growth, sugar consumption and therefore affect ethanol fermentation performance (Georgieva et al. 2008; Zhang et al. 2011). To determine if TTC79 would also exhibit enhanced tolerance to acetic acid, furfural and HMF, its growth tolerance was performed and compared with that of the wild-type by measuring cell viability in the presence of individual inhibitors. The concentrations of these inhibitors used in this study were similar to or higher than those reported in lignocellulosic hydrolysates (Agbogbo and Wenger 2007; Bajwa et al. 2009; Larsson et al. 1999). In the absence of inhibitor, no difference of growth pattern was observed between TTC79 and the wild-type (Fig. 2a). In the presence of 5.25 g/L acetic acid, cell number of TTC79 and the wild-type declined in the first 12 h by about 3 log units and 5 log units, respectively, and then TTC79 grew at a faster rate as compared to the wild-type (Fig. 2b). At 1.75 g/L furfural, TTC79 was capable of growing after lag phase of 36 h (Fig. 2c). In contrast, the wild-type was able to remain viable in 1.75 g/L furfural, but no increase in cell number was observed. The results of cell viability in the presence of 1.30 g/L HMF revealed that no difference was seen between TTC79 and the wild-type in their growth responses (Fig. 2d).Fig. 2


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)

Cell viability of TTC79 and the wild-type in the absence (a) and in the presence of 5.25 g/L acetic acid (b), 1.75 g/L furfural (c) and 1.30 g/L HMF (d). Wild-type (filled diamond), TTC79 (open diamond). 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

Fig2: Cell viability of TTC79 and the wild-type in the absence (a) and in the presence of 5.25 g/L acetic acid (b), 1.75 g/L furfural (c) and 1.30 g/L HMF (d). Wild-type (filled diamond), TTC79 (open diamond). Data represent the mean ± SD from three independent experiments
Mentions: Acetic acid, furfural and HMF are among the most potent inhibitors found in lignocellulosic hydrolysates (Klinke et al. 2004; Taherzadeh et al. 2000). These compounds are known to inhibit microbial growth, sugar consumption and therefore affect ethanol fermentation performance (Georgieva et al. 2008; Zhang et al. 2011). To determine if TTC79 would also exhibit enhanced tolerance to acetic acid, furfural and HMF, its growth tolerance was performed and compared with that of the wild-type by measuring cell viability in the presence of individual inhibitors. The concentrations of these inhibitors used in this study were similar to or higher than those reported in lignocellulosic hydrolysates (Agbogbo and Wenger 2007; Bajwa et al. 2009; Larsson et al. 1999). In the absence of inhibitor, no difference of growth pattern was observed between TTC79 and the wild-type (Fig. 2a). In the presence of 5.25 g/L acetic acid, cell number of TTC79 and the wild-type declined in the first 12 h by about 3 log units and 5 log units, respectively, and then TTC79 grew at a faster rate as compared to the wild-type (Fig. 2b). At 1.75 g/L furfural, TTC79 was capable of growing after lag phase of 36 h (Fig. 2c). In contrast, the wild-type was able to remain viable in 1.75 g/L furfural, but no increase in cell number was observed. The results of cell viability in the presence of 1.30 g/L HMF revealed that no difference was seen between TTC79 and the wild-type in their growth responses (Fig. 2d).Fig. 2

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