7 research outputs found
Production of Raw Cassava Starch-Digesting Amylase of Streptomyces sp. No.4 by Solid State Fermentation
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The effect of culture conditions and medium components on raw cassava starch-digesting enzyine production were investigated with Streptomyces sp. No. 4 under solid state fermentation. The enzyme production on a basal solid medium cbmposed of rice or wheat bran as a main component by the strain reached the maximum after 3 days cultivation. The optimum pH, temperature, moisture content of medium for the enzyme production were around 6.0, 35C and 50-60%, respectively. Addition of 12%(w/w) raw cassava starch, 0.24%(w/w)CSL and 20 mM MgS0 4 into those medium improved the enzyme production. The maximum production of the enzyme on improved medium was performed after 4 days cultivation. The main enzymatic products from hydrolysis of raw and gelatinized cassava starch by the enzyme were mainly maltose and maltotriose
Fracture Mode Analysis, Geomechanics, Petrophysics, and Fracture Characterization: An Experimental Investigation on Whitby Shales and Various Other Rock Types
No full textThe rapidly decreasing reserves of conventional gas has forced oil and gas industries to conduct more exploration on unconventional resources, like shale gas. To produce gas from shales in economically viable manner, stimulation techniques like hydraulic fracturing are required. One important factor for a successful hydraulic fracturing is knowing the fracture characteristics such as the fracture mode occurrence. Unfortunately, the factors controlling the fracture mode occurrence are not known yet. This study tries to find out the factors controlling the fracture mode occurrence by investigating the relation between fracture angle, confining pressure, and several rock properties. The fracture mode analysis being developed in this study suggests that for low strength rock like Bad Bentheim sandstone (46.65 MPa) and Indiana limestone (36.5 MPa), fracture modes are not dependent to the confining pressure. Fractures are already at mode II at zero confining pressure, while stronger rocks like Belgium limestone and Granite (125 and 128 MPa respectively) show fracture mode I at zero confining pressure. The experiments convey that the strength of the rock, which is related to its porosity, is the dominant factor controlling the occurrence of fracture mode I and mode II. This study also evaluates the prospectivity of the Whitby mudstone formation in the United Kingdom, which is a depositionally- and time-equivalent shale to the Posidonia Shale Formation (PSF). The PSF is one of the potential resource rocks for shale gas exploration in the Netherlands. Brittleness indices and fraccability indices of WMF from various methods are also determined and analyzed in this study. The results of WMF characterization show that WMF has high heterogeneity, which could imply that it is less favorable for hydraulic fracturing. Comparing the results of WMF to other producing gas shale shows that the WMF has a low range in: porosity, Young’s modulus, and quartz content, and high range in: laminations, and clay contents, suggesting that WMF is less potential for the shale gas resource. However, based on its characteristics, if WMF is divided into four zones, our experiments show that several zones (top and bottom part of WMF) can be considered as the most favorable ones for hydraulic fracturing in the WMF formation.Section Petroleum EngineeringSection Petroleum EngineeringCivil Engineering and Geoscience
Cassava Pulp as a Biofuel Feedstock of an Enzymatic Hydrolysis Proces
Get PDFCassava pulp, a low cost solid byproduct of cassava starch industry, has been proposed as a high potential ethanolic fermentation substrate due to its high residual starch level, low ash content and small particle size of the lignocellulosic fibers. As the economic feasibility depends on complete degradation of the polysaccharides to fermentable glucose, the comparative hydrolytic potential of cassava pulp by six commercial enzymes were studied. Raw cassava pulp (12% w/v, particle sizeμm) hydrolyzed by both commercial pectinolytic (1) and amylolytic (2) enzymes cocktail, yielded 70.06% DE. Hydrothermal treatment of cassava pulp enhanced its susceptibility to enzymatic cleavageas compared to non-hydrothermal treatment raw cassava pulp. Hydrothermal pretreatment has shown that a glucoamylase (3) was the most effective enzyme for hydrolysis process of cassava pulp at temperature 65 °C or 95 °C for 10 min and yielded approximately 86.22% and 90.18% DE, respectively. Enzymatic pretreatment increased cassava pulp vulnerability to cellulase attacks. The optimum conditions for enzymatic pretreatment of 30% (w/v) cassava pulp by a potent cellulolytic/ hemicellulolytic enzyme (4) was achieves at 50 °C for 3, meanwhile for liquefaction and saccharification by a thermo-stable α-amylase (5) was achieved at 95 °C for 1 and a glucoamylase (3) at 50 °C for 24 hours, respectively, yielded a reducing sugar level up to 94,1% DE. The high yield of glucose indicates the potential use of enzymatic-hydrothermally treated cassava pulp as a cheap substrate for ethanol production
Cassava Pulp as a Biofuel Feedstock of an Enzymatic Hydrolysis Process
Get PDFCassava pulp, a low cost solid byproduct of cassava starch industry, has been proposed as a high potential ethanolic fermentation substrate due to its high residual starch level, low ash content and small particle size of the lignocellulosic fibers. As the economic feasibility depends on complete degradation of the polysaccharides to fermentable glucose, the comparative hydrolytic potential of cassava pulp by six commercial enzymes were studied. Raw cassava pulp (12% w/v, particle size <320 μm) hydrolyzed by both commercial pectinolytic (1) and amylolytic (2) enzymes cocktail,yielded 70.06% DE. Hydrothermal treatment of cassava pulp enhanced its susceptibility to enzymatic cleavageas compared to non-hydrothermal treatment raw cassava pulp. Hydrothermal pretreatment has shown that a glucoamylase (3) was the most effective enzyme for hydrolysis process of cassava pulp at temperature 65 °C or 95 °C for 10 min and yielded approximately 86.22% and 90.18% DE, respectively. Enzymatic pretreatment increased cassava pulp vulnerability to cellulase attacks. The optimum conditions for enzymatic pretreatment of 30% (w/v) cassava pulp by apotent cellulolytic/ hemicellulolytic enzyme (4) was achieves at 50 °C for 3, meanwhile for liquefaction and saccharification by a thermo-stable α-amylase (5) was achieved at 95 °C for 1 and a glucoamylase (3) at 50 °C for 24 hours, respectively, yielded a reducing sugar level up to 94,1% DE. The high yield of glucose indicates the potential use of enzymatic-hydrothermally treated cassava pulp as a cheap substrate for ethanol production
Hydroxypropylation for functional enhancement of sago starch: The effects of low propylene oxide concentration using response surface methodology
No full textNative sago starch is currently limited to food and adhesives due to its functional constraints, requiring improvement for broader industrial use. Hydroxypropylation is a modification technique used to enhance the functional properties of starches. However, propylene oxide usage is restricted owing to safety and environmental concerns during the modification process. Therefore, hydroxypropylation with a low dose of propylene oxide was selected to improve the functional characteristics of the sago starch with the desired molar substitution. The Response Surface Methodology (RSM) was chosen to optimize hydroxypropylation with the following factorial process variables: volume of 7 % w/w propylene oxide (6–18 ml), reaction pH (9−12), reaction time (3–8 h), and the desired molar substitution (MS) as a response variable was 0.100. The optimization was achieved at 17.03 ml of 7 % wt. of propylene oxide, reaction pH 11.92, and reaction time of 3 h. Hydroxypropylation has effectively increased the functional properties of sago starch including swelling power, water-holding capacity, oil-holding capacity, and solubility of sago starch as well as paste and setback viscosity. However, hydroxypropylation reduced the amylose content, gelatinization temperature, and breakdown viscosity. The RSM with a low propylene oxide concentration successfully optimized sago starch hydroxypropylation and enhanced its functional properties. Hydroxypropylated sago starch using low propylene oxide could be further studied as a potential thickener in the food industry
Functional properties and optimization of dietary fiber concentrate from sago hampas using response surface methodology
No full textSago hampas, whose major components are fiber and starch, is an underutilized by-product generated from starch extraction of sago stems. In order to increase its added value and applications, sago hampas could be developed into dietary fiber concentrate. This research purposed to obtain the optimum condition of enzymatic hydrolysis process of sago hampas to isolate the dietary fiber components. A central composite design of response surface methodology (RSM) was used to optimize processing variables, namely, sago hampas slurry concentration (0.1–0.2 kg/kg), reaction time (45–135 min), and enzyme concentration in the substrate (10–35 mL/kg). Enzymatic hydrolysis using α-amylase at 108 °C was employed to remove starch components (becoming maltodextrin), escalate dietary fiber content, and modify the crystallinity of fiber. The goals of optimization were to maximize total dietary fiber (TDF), water-holding capacity (WHC), and oil-holding capacity (OHC) of the dietary fiber concentrate and to maximize dextrose equivalent (DE) of the maltodextrin solution obtained. The optimum process condition was found when the variables sago hampas slurry concentration, reaction time, and enzyme concentration were 0.14 kg/kg, 121 min, and 25 mL/kg, respectively. The optimal condition was verified by laboratory experiment resulting in TDF, WHC, OHC, and DE of 92.98 %, 26.34 g of water per g of sample, 5.64 g of oil per g of sample, and 10.37 %, respectively. TDF increased while the starch decreased significantly following conversion to dietary fiber. It is associated with the improvement in the functional properties of dietary fiber. The OHC, cation exchange capacity, emulsifying activity, swelling capacity, and solubility all exhibited significant increases. The morphological structure of the dietary fiber concentrate revealed a fiber matrix degradation with a high level of fiber porosity while the crystallinity was decreased from 61 % to 42 %. The properties of dietary fiber concentrate indicate appropriate parameters for food industry applications
CASSAVA PULP AS A BIOFUEL FEEDSTOCK OF AN ENZYMATIC HYDROLYSIS PROCESS
Get PDFCassava pulp, a low cost solid byproduct of cassava starch industry, has been proposed as a high potential ethanolic fermentation substrate due to its high residual starch level, low ash content and small particle size of the lignocellulosic fibers. As the economic feasibility depends on complete degradation of the polysaccharides to fermentable glucose, the comparative hydrolytic potential of cassava pulp by six commercial enzymes were studied. Raw cassava pulp (12% w/v, particle size <320 μm) hydrolyzed by both commercial pectinolytic (1) and amylolytic (2) enzymes cocktail,yielded 70.06% DE. Hydrothermal treatment of cassava pulp enhanced its susceptibility to enzymatic cleavageas compared to non-hydrothermal treatment raw cassava pulp. Hydrothermal pretreatment has shown that a glucoamylase (3) was the most effective enzyme for hydrolysis process of cassava pulp at temperature 65 °C or 95 °C for 10 min and yielded approximately 86.22% and 90.18% DE, respectively. Enzymatic pretreatment increased cassava pulp vulnerability to cellulase attacks. The optimum conditions for enzymatic pretreatment of 30% (w/v) cassava pulp by apotent cellulolytic/ hemicellulolytic enzyme (4) was achieves at 50 °C for 3, meanwhile for liquefaction and saccharification by a thermo-stable α-amylase (5) was achieved at 95 °C for 1 and a glucoamylase (3) at 50 °C for 24 hours, respectively, yielded a reducing sugar level up to 94,1% DE. The high yield of glucose indicates the potential use of enzymatic-hydrothermally treated cassava pulp as a cheap substrate for ethanol production.Keywords: Cassava pulp, bio-alcohol feedstock, enzymatic hydrolysis, dextrose equivalent (DE
