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Effect of extruder screw speed, temperature, and enzyme levels on sugar recovery from different biomasses.

Karunanithy C, Muthukumarappan K, Gibbons WR - ISRN Biotechnol (2012)

Bottom Line: Biofuels from biomass have the potential to reduce the dependency on fossil fuels.Screw speed, barrel temperature, and their interaction had a significant influence on sugar recovery from the selected biomasses.Extrusion pretreatment of these biomasses used only 28-37% of the rated extruder power.

View Article: PubMed Central - PubMed

Affiliation: Department of Agricultural Biosystems Engineering, South Dakota State University, 1400 North Campus Drive, Brookings, SD 57007, USA.

ABSTRACT
Biofuels from biomass have the potential to reduce the dependency on fossil fuels. An efficient pretreatment method is required to accomplish the target of the Energy Act 2005. Extrusion could be a viable continuous pretreatment method to be explored. The objectives of the current study were to investigate the influence of screw speed and barrel temperature on sugar recovery from the selected warm season grasses and to select a suitable enzyme combination and dose for enzymatic hydrolysis. The ground, moisture-balanced biomasses were pretreated using a single screw extruder at various screw speeds (100, 150, and 200 rpm) and barrel temperatures (50, 75, 100, 150, and 200°C). Cellulase or multienzyme with β-glucosidase was varied from 1 : 1 to 1 : 4 during enzymatic hydrolysis to accomplish the second objective. Screw speed, barrel temperature, and their interaction had a significant influence on sugar recovery from the selected biomasses. A maximum of 28.2, 66.2, and 49.2% of combined sugar recoverywasachieved for switchgrass, big bluestem, prairie cord grass when pretreated at a screw speed of 200, 200, and 150 rpm and at a barrel temperature of 75, 150, and 100°C, respectively, using cellulase and β-glucosidase at a ratio of 1 :  4. Extrusion pretreatment of these biomasses used only 28-37% of the rated extruder power.

No MeSH data available.


Related in: MedlinePlus

Effect of screw speed and barrel temperature on sugar recovery from prairie cord grass ((a, d)—1 : 1 cellulase and β-glucosidase, (b, e)—1 : 4 cellulase and β-glucosidase, and (c, f)—1 : 1 multienzyme and β-glucosidase).
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fig3: Effect of screw speed and barrel temperature on sugar recovery from prairie cord grass ((a, d)—1 : 1 cellulase and β-glucosidase, (b, e)—1 : 4 cellulase and β-glucosidase, and (c, f)—1 : 1 multienzyme and β-glucosidase).

Mentions: The main effect analysis of screw speed on sugar recovery from switchgrass, big bluestem, and prairie cord grass is depicted in Figures 1(a)–1(c)through 3(a)–3(c) when cellulase, multienzyme, and β-glucosidase was used with different ratios during hydrolysis. In general, the screw speed had a positive influence on sugar recovery from switchgrass regardless of enzyme combinations and their ratios used during hydrolysis as seen from Figure 1. Muthukumarappan and Julson [14] reported sugar recovery increasing trend for switchgrass pretreated using a twin screw extruder while varying the screw speed from 200 to 400 rpm. Although the trend was same, they achieved lower sugar recovery than that of the present study. The difference might be due to type of extruder and pretreatment conditions, apart from chemical composition of switchgrass. In the present study, the change in sugar recovery was insignificant when the screw speed was increased from 100 to 150 rpm; however, further increase in screw speed had a significant increase only for glucose recovery when cellulase and β-glucosidase was used with 1 : 1 ratio (Figure 1(a)). When amount of β-glucosidase was increased by four times with cellulase amount kept constant, similar sugar recovery pattern was observed as that of 1 : 1 cellulase with β-glucosidase ratio (Figure 1(b)). Karunanithy et al. [15] reported a similar trend for corn stover pretreated in a single screw extruder. The glucose recovery increasing trend found in this study is in agreement with previous study of alkali-microwave pretreated switchgrass and bermudagrass [37]; however, the glucose recovery was less in the present study. The possible reason for higher amount of glucose recovered might be due to delignification of switchgrass by alkali. Statistical analysis showed that the increase in sugar recovery across the screw speed was not significant when cellulase and β-glucosidase was used at 1 : 4 ratio. The glucose recovery was comparable between cellulase with different β-glucosidase ratios, whereas xylose recovery differed among them. When multienzyme with β-glucosidase was used during hydrolysis, the screw speed showed significant difference on sugar recovery from switchgrass. The sugar recovery was less than 50% as compared to that of 1 : 1 ratio of cellulase with β-glucosidase (Figure 1(c)). When the screw was increased from 100 to 200 rpm, the glucose, xylose, and combined sugar recovery increased between 16–30, 6–23, and 14–25%, respectively, depending upon the enzyme combinations and their ratios. These results showed that the rate of shear development was more important than the mean residence time.


Effect of extruder screw speed, temperature, and enzyme levels on sugar recovery from different biomasses.

Karunanithy C, Muthukumarappan K, Gibbons WR - ISRN Biotechnol (2012)

Effect of screw speed and barrel temperature on sugar recovery from prairie cord grass ((a, d)—1 : 1 cellulase and β-glucosidase, (b, e)—1 : 4 cellulase and β-glucosidase, and (c, f)—1 : 1 multienzyme and β-glucosidase).
© Copyright Policy - open-access
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC4403594&req=5

fig3: Effect of screw speed and barrel temperature on sugar recovery from prairie cord grass ((a, d)—1 : 1 cellulase and β-glucosidase, (b, e)—1 : 4 cellulase and β-glucosidase, and (c, f)—1 : 1 multienzyme and β-glucosidase).
Mentions: The main effect analysis of screw speed on sugar recovery from switchgrass, big bluestem, and prairie cord grass is depicted in Figures 1(a)–1(c)through 3(a)–3(c) when cellulase, multienzyme, and β-glucosidase was used with different ratios during hydrolysis. In general, the screw speed had a positive influence on sugar recovery from switchgrass regardless of enzyme combinations and their ratios used during hydrolysis as seen from Figure 1. Muthukumarappan and Julson [14] reported sugar recovery increasing trend for switchgrass pretreated using a twin screw extruder while varying the screw speed from 200 to 400 rpm. Although the trend was same, they achieved lower sugar recovery than that of the present study. The difference might be due to type of extruder and pretreatment conditions, apart from chemical composition of switchgrass. In the present study, the change in sugar recovery was insignificant when the screw speed was increased from 100 to 150 rpm; however, further increase in screw speed had a significant increase only for glucose recovery when cellulase and β-glucosidase was used with 1 : 1 ratio (Figure 1(a)). When amount of β-glucosidase was increased by four times with cellulase amount kept constant, similar sugar recovery pattern was observed as that of 1 : 1 cellulase with β-glucosidase ratio (Figure 1(b)). Karunanithy et al. [15] reported a similar trend for corn stover pretreated in a single screw extruder. The glucose recovery increasing trend found in this study is in agreement with previous study of alkali-microwave pretreated switchgrass and bermudagrass [37]; however, the glucose recovery was less in the present study. The possible reason for higher amount of glucose recovered might be due to delignification of switchgrass by alkali. Statistical analysis showed that the increase in sugar recovery across the screw speed was not significant when cellulase and β-glucosidase was used at 1 : 4 ratio. The glucose recovery was comparable between cellulase with different β-glucosidase ratios, whereas xylose recovery differed among them. When multienzyme with β-glucosidase was used during hydrolysis, the screw speed showed significant difference on sugar recovery from switchgrass. The sugar recovery was less than 50% as compared to that of 1 : 1 ratio of cellulase with β-glucosidase (Figure 1(c)). When the screw was increased from 100 to 200 rpm, the glucose, xylose, and combined sugar recovery increased between 16–30, 6–23, and 14–25%, respectively, depending upon the enzyme combinations and their ratios. These results showed that the rate of shear development was more important than the mean residence time.

Bottom Line: Biofuels from biomass have the potential to reduce the dependency on fossil fuels.Screw speed, barrel temperature, and their interaction had a significant influence on sugar recovery from the selected biomasses.Extrusion pretreatment of these biomasses used only 28-37% of the rated extruder power.

View Article: PubMed Central - PubMed

Affiliation: Department of Agricultural Biosystems Engineering, South Dakota State University, 1400 North Campus Drive, Brookings, SD 57007, USA.

ABSTRACT
Biofuels from biomass have the potential to reduce the dependency on fossil fuels. An efficient pretreatment method is required to accomplish the target of the Energy Act 2005. Extrusion could be a viable continuous pretreatment method to be explored. The objectives of the current study were to investigate the influence of screw speed and barrel temperature on sugar recovery from the selected warm season grasses and to select a suitable enzyme combination and dose for enzymatic hydrolysis. The ground, moisture-balanced biomasses were pretreated using a single screw extruder at various screw speeds (100, 150, and 200 rpm) and barrel temperatures (50, 75, 100, 150, and 200°C). Cellulase or multienzyme with β-glucosidase was varied from 1 : 1 to 1 : 4 during enzymatic hydrolysis to accomplish the second objective. Screw speed, barrel temperature, and their interaction had a significant influence on sugar recovery from the selected biomasses. A maximum of 28.2, 66.2, and 49.2% of combined sugar recoverywasachieved for switchgrass, big bluestem, prairie cord grass when pretreated at a screw speed of 200, 200, and 150 rpm and at a barrel temperature of 75, 150, and 100°C, respectively, using cellulase and β-glucosidase at a ratio of 1 :  4. Extrusion pretreatment of these biomasses used only 28-37% of the rated extruder power.

No MeSH data available.


Related in: MedlinePlus