Study on Thermodynamics and Adsorption kinetics of Purified endoglucanase (CMCase) from Penicillium notatum NCIM NO-923 produced under mixed solid-state fermentation of waste cabbage and Bagasse
Abstract:In the current study, one thermostable endoglucanase was purified from Penicillium notatum NCIM through mixed solid state fermentation of waste cabbage and bagasse. The molecular weight of the purified enzyme was 55kDa as determined by SDS polyacrylamide gel electrophoresis (SDS-PAGE). The enzyme had low activation energy (E a ) of 36.39KJ mol -1 for carboxymethyl cellulose hydrolysis and the enthalpy and entropy for irreversible inactivation was 87 kJ mol −1 and 59.3 J mol −1 K −1 respectively. The enzyme wa… Show more
“…Increasing [P0] from 100 µg mL -1 to 263 µg mL -1 adsorption increased from 45.62 µg mL -1 to 199.0 µg mL -1 for 100 mg of Protobind as shown in Figure 18 as well. The adsorption profiles were in agreement with that of published literature [Lu et al, 2002;Chen et al, 2006;Jagar et al, 2010;Li et al, 2011;Das et al, 2012;Machado et al, 2014;Karmakar and Ray, 2015] for adsorption of enzymes on various substrates. [Baig et al, 2016] The maximum adsorption was achieved at 40 minutes of contact time.…”
Section: Adsorption Of Cellulases On Avicel and Protobindsupporting
Desorption of active cellulases from lignocellulosic substrates is a potential technique to reuse cellulases for the production of bioethanol. For desorption studies, adsorption of cellulases had to be performed first. Adsorption of cellulases NS 50013 onto microcrystalline cellulose (Avicel PH 101) and wheat straw lignin (Protobind 1000) was studied. It was found that Protobind adsorbed twice the amount of cellulases than Avicel did. An adsorption strategy developed was to work at pH 5 and a temperature less than 323 K to get maximum adsorption on the cellulose component, less adsorption on the lignin component of lignocellulosic materials, and to harmonize adsorption temperature with the industrial hydrolysis situation. Desorption of cellulases from Avicel and Protobind over a range of 298 K to 343 K and a pH of 6 to 9 was studied. Desorption obtained at pH 9 and 333K was optimum for both Avicel and Protobind. Hence, desorption was enhanced by 21 % and 11% for Avicel and Protobind respectively. The cellulases activity for Avicel was 48 FPU mL-1 at pH 9, 333 K, 5% glycerol, representing 91 % of the initial activity and for Protobind, the activity was 33 FPU mL-1 which represents about 66 % of the initial activity. All of these values were higher than ever reported in literature. At pH 5 and 298 K the amount of cellulases desorbed from untreated wheat straw (WS) was 33 % of those initially used for the adsorption step. It was increased to 42 % when 30 % delignified WS was used, and was further increased to 48 % for 60 % delignified WS. Desorption obtained for 60 % delignified WS was 75 % at pH 9, 333K and 5% glycerol. The desorption strategy recommended for bioethanol producing industries, is: 1) removal of lignin; 2) adsorption of cellulases at pH 5 and lower than 323K; 3) hydrolysis of lignocellulosic material; and 4) desorption of cellulases from non-hydrolyzed material at 333 K, pH 9, with 5-10 % glycerol. The proposed strategic desorption of cellulases may reduce the cost of Canadian bioethanol production by 26.5 % due to 75 % recyclability of active cellulases.
“…Increasing [P0] from 100 µg mL -1 to 263 µg mL -1 adsorption increased from 45.62 µg mL -1 to 199.0 µg mL -1 for 100 mg of Protobind as shown in Figure 18 as well. The adsorption profiles were in agreement with that of published literature [Lu et al, 2002;Chen et al, 2006;Jagar et al, 2010;Li et al, 2011;Das et al, 2012;Machado et al, 2014;Karmakar and Ray, 2015] for adsorption of enzymes on various substrates. [Baig et al, 2016] The maximum adsorption was achieved at 40 minutes of contact time.…”
Section: Adsorption Of Cellulases On Avicel and Protobindsupporting
Desorption of active cellulases from lignocellulosic substrates is a potential technique to reuse cellulases for the production of bioethanol. For desorption studies, adsorption of cellulases had to be performed first. Adsorption of cellulases NS 50013 onto microcrystalline cellulose (Avicel PH 101) and wheat straw lignin (Protobind 1000) was studied. It was found that Protobind adsorbed twice the amount of cellulases than Avicel did. An adsorption strategy developed was to work at pH 5 and a temperature less than 323 K to get maximum adsorption on the cellulose component, less adsorption on the lignin component of lignocellulosic materials, and to harmonize adsorption temperature with the industrial hydrolysis situation. Desorption of cellulases from Avicel and Protobind over a range of 298 K to 343 K and a pH of 6 to 9 was studied. Desorption obtained at pH 9 and 333K was optimum for both Avicel and Protobind. Hence, desorption was enhanced by 21 % and 11% for Avicel and Protobind respectively. The cellulases activity for Avicel was 48 FPU mL-1 at pH 9, 333 K, 5% glycerol, representing 91 % of the initial activity and for Protobind, the activity was 33 FPU mL-1 which represents about 66 % of the initial activity. All of these values were higher than ever reported in literature. At pH 5 and 298 K the amount of cellulases desorbed from untreated wheat straw (WS) was 33 % of those initially used for the adsorption step. It was increased to 42 % when 30 % delignified WS was used, and was further increased to 48 % for 60 % delignified WS. Desorption obtained for 60 % delignified WS was 75 % at pH 9, 333K and 5% glycerol. The desorption strategy recommended for bioethanol producing industries, is: 1) removal of lignin; 2) adsorption of cellulases at pH 5 and lower than 323K; 3) hydrolysis of lignocellulosic material; and 4) desorption of cellulases from non-hydrolyzed material at 333 K, pH 9, with 5-10 % glycerol. The proposed strategic desorption of cellulases may reduce the cost of Canadian bioethanol production by 26.5 % due to 75 % recyclability of active cellulases.
“…Generally, two carboxyls are involved in the catalytic mechanism of most hydrolases; one donates protons to the substrate while the other stabilizes it . Result showed the p K a1 for proton donating ionizable group and p K a2 for proton receiving residues were 2.94 and 6.53, respectively (Fig.…”
Section: Discussionmentioning
confidence: 93%
“…Dialyzed enzyme preparation was applied to a DEAE cellulose column (50 × 1 cm 2 ), pre equilibrated with buffer solution (0.05 M sodium acetate buffer; pH 5.0). The enzyme fractions were eluted with a linear gradient of 0.1–1 M NaCl at a flow rate of 0.3 ml min −1 . The fractions were collected using an auto fraction collector.…”
Section: Methodsmentioning
confidence: 99%
“…After electrophoresis, the gel was incubated for 30 min in 0.05 M acetate buffer (pH‐5.0). Clear cellulose hydrolyzing zone that corresponded to enzyme activity was visualized using 0.5% w/v Congo red . Homogeneity of the purified enzyme was also verified by matrix assisted laser desorption/ionization time of flight mass spectrometry (MALDI‐TOF MS).…”
Section: Methodsmentioning
confidence: 99%
“…The optimum temperature for hydrolysis of carboxymethyl cellulose (CMC) was determined in 0.05 M acetate buffer (pH 5.0) after incubating the mixture of the purified enzyme and 1% w/v CMC for 30 min at different temperatures ranging from 30 to 70 °C. The activation energy ( E a ) for substrate hydrolysis under the given experimental conditions was determined by plotting the data as an Arrhenius plot . The free energy for substrate binding and transition state formation was calculated using the following derivations : where K a = 1/ K m , R is the universal gas constant (8.314 J K −1 mol −1 ) and T is the absolute temperature (K).…”
An endoglucanase from Aspergillus fumigatus ABK9 was purified from the culture extract of solid-state fermentation and its some characteristics were evaluated. The molecular weight of the purified enzyme (56.3 kDa) was determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, zymogram analysis and confirmed by MALDI-TOF mass spectrometry. The enzyme was active optimally at 50 °C, pH 5.0 and stable over a broad range of pH (4.0-7.0) and NaCl concentration of 0-3.0 M. The pKa1 and pKa2 of the ionizable groups of the active sites were 2.94 and 6.53, respectively. The apparent Km , Vmax , and Kcat values for carboxymethyl cellulose were 6.7 mg ml(-1), 775.4 µmol min(-1) , and 42.84 × 10(4) s(-1), respectively. Thermostability of the enzyme was evidenced by the high activation energy (91.45 kJ mol(-1)), large enthalpy for activation of denaturation (88.77 kJ mol(-1)), longer half-life (T1/2) (433 min at 50 °C), higher melting temperature (Tm ) (73.5 °C), and Q10 (1.3) values. All the characteristics favors its suitability as halotolerant and thermostable enzyme during bioprocessing of lignocellulosic materials.
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