The present work deals with intensification of delignification and subsequent enzymatic hydrolysi... more The present work deals with intensification of delignification and subsequent enzymatic hydrolysis of sustainable biomass such as groundnut shells, coconut coir and pistachio shells using ultrasound assisted approach so as to develop an economical approach for obtaining bioethanol. Process intensification, in the current context, is referred to as any improvements giving enhanced rates possibly with lower energy and chemical as well as enzyme requirement for delignification and hydrolysis respectively. Conventional processing for both delignification and enzymatic hydrolysis has also been investigated for establishing the degree of intensification. The obtained results for delignification of biomass established that for conventional alkaline treatment, the extent of delignification for the case of groundnut shells, coconut coir and pistachio shells were 41.8, 45.9 and 38% which increased to 71.1, 89.5 and 78.9% respectively giving almost 80-100% increase for the ultrasound assisted approach. Under optimized conditions, the conventional approach resulted in reducing sugar yields as 10.2, 12.1 and 8.1g/L for groundnut shells, coconut coir and pistachio shells respectively whereas for the case of ultrasound-assisted enzymatic hydrolysis, the obtained yields were 21.3, 23.9 and 18.4g/L in same order of biomass. The material samples were characterized by several characterization techniques for establishing the morphological changes obtained due to the use of ultrasound which were found to be favorable for enhanced delignification and hydrolysis for the ultrasound assisted approach. Overall, the results of this work establish the process intensification benefits due to the application of ultrasound for different sustainable biomass with mechanistic understanding based on the morphological analyses.
The present work investigates the effectiveness of application of low intensity ultrasonic irradi... more The present work investigates the effectiveness of application of low intensity ultrasonic irradiation for the intensification of enzymatic depolymerization of aqueous guar gum solution. The extent of depolymerization of guar gum has been analyzed in terms of intrinsic viscosity reduction. The effect of ultrasonic irradiation on the kinetic and thermodynamic parameters related to the enzyme activity as well as the intrinsic viscosity reduction of guar gum using enzymatic approach has been evaluated. The kinetic rate constant has been found to increase with an increase in the temperature and cellulase loading. It has been observed that application of ultrasound not only enhances the extent of depolymerization but also reduces the time of depolymerization as compared to conventional enzymatic degradation technique. In the presence of cellulase enzyme, the maximum extent of depolymerization of guar gum has been observed at 60 W of ultrasonic rated power and ultrasonic treatment time of 30 min. The effect of ultrasound on the kinetic and thermodynamic parameters as well as the molecular structure of cellulase enzyme was evaluated with the help of the chemical reaction kinetics model and fluorescence spectroscopy. Application of ultrasound resulted in a reduction in the thermodynamic parameters of activation energy (Ea), enthalpy (DH), entropy (DS) and free energy (DG) by 47%, 50%, 65% and 1.97%, respectively. The changes in the chemical structure of guar gum treated using ultrasound assisted enzymatic approach in comparison to the native guar gum were also characterized by FTIR. The results revealed that enzymatic depolymerization of guar gum resulted in a polysaccharide with low degree of polymerization, viscosity and consistency index without any change in the core chemical structure which could make it useful for incorporation in food products.
Ultrasound assisted intensification of synthesis of biodiesel from waste cooking oil using methyl... more Ultrasound assisted intensification of synthesis of biodiesel from waste cooking oil using methyl acetate and immobilized lipase obtained fromThermomyces lanuginosus(Lipozyme TLIM) as a catalyst has been investigated in the present work. The reaction has also been investigated using the conventional approach based on stirring so as to establish the beneficial effects obtained due to the use of ultrasound. Effect of operating conditions such as reactant molar ratio (oil and methyl acetate), temperature and enzyme loading on the yield of biodiesel has been investigated. Optimum conditions for the conventional approach (without ultrasound) were established as reactant molar ratio of 1:12 (oil:methyl acetate), enzyme loading of 6% (w/v), temperature of 40C and reaction time of 24 h and under these conditions, 90.1% biodiesel yield was obtained. The optimum conditions for the ultrasound assisted approach were oil to methyl acetate molar ratio of 1:9, enzyme loading of 3% (w/v), and reaction time of 3 h and the biodiesel yield obtained under these conditions was 96.1%. Use of ultrasound resulted in significant reduction in the reaction time with higher yields and lower requirement of the enzyme loading. The obtained results have clearly established that ultrasound assisted interesterification was a fast and efficient approach for biodiesel production giving significant benefits, which can help in reducing the costs of production. Reusability studies for the enzyme were also performed but it was observed that reuse of the catalyst under the optimum experimental condition resulted in reduced enzyme activity and biodiesel yield
The present work deals with intensification of bioethanol production from waste newspaper using
S... more The present work deals with intensification of bioethanol production from waste newspaper using Saccharomyces cerevisiaeusing ultrasonic irradiations. The effect of different process parameters such as application of ultrasonic irradiation at different growth phases, irradiation time, ultrasonic power and duty cycle on the bioethanol production has been investigated. The favorable conditions for the maximum yield were established as application of ultrasonic irradiation (duration of 10 min) to fermentation broth at 12 h of growth phase with 25 kHz frequency, 160 W power and 20% duty cycle. The bioethanol productivity was increased by 1.8 times from 7.8 to 14.1 g/L compared with the non-sonicated control fermentation. Decrease in glucose concentration from 0.63% to 0.2% w/v in ultrasound-assisted fermentation confirmed the improved substrate uptake of the microbial cell due to the application of ultrasound. ESEM analysis also confirmed the changes in the cell morphology leading to improved cell permeability. Results were fitted to an unstructured kinetic model comprising of the kinetic and physiological parameters. Overall, the work has demonstrated an intensified approach for the bioethanol production based on the use of ultrasound.
The synthesis of biodiesel from sunflower oil and methanol based on transesterification using the... more The synthesis of biodiesel from sunflower oil and methanol based on transesterification using the immobilized lipase fromThermomyces lanuginosus(Lipozyme TL-IM) has been investigated under silent conditions and under an ultrasound field. Ultrasound assisted process led to reduced processing time and requirement of lower enzyme dosage. We found for the first time that oil to methanol ratio of 1:3 was favored for the ultrasound assisted enzymatic process which is lower than that observed for the case of conventional stirring based approach (ratio of 1.4). Our results indicate that intensification provided by ultrasound suppresses the need of the excess of the methanol reactant during the enzymatic biodiesel production. Ultrasound assisted enzymatic biodiesel production is therefore a faster and a cleaner processes
BACKGROUND: Cell permeabilization techniques allow selective release of an enzyme and specific re... more BACKGROUND: Cell permeabilization techniques allow selective release of an enzyme and specific reactions without breaking the cells. A mathematical model has been developed for selective permeabilization of Saccharomyces cerevisiae to recover invertase at high purity. The effect of thiols on the cell walls of S. cerevisiae was studied under different conditions of pH, cysteine concentration, speed of agitation and solid suspension density. RESULT: The rate of release of invertase was a function of pH and cysteine (or thiolate ion) concentration.The maximum recovery of invertase was obtained at pH 10.0, 10 mmol dm −3 cysteine concentration and 15% (w/v) yeast loading. CONCLUSION: Thiols are capable of permeabilizing the cell walls of S. cerevisiae and releasing the invertase under basic conditions. The insignificant effect of agitation shows that the external mass transfer resistance does not play any role in the release of invertase. NOTATION Kinematic viscosity of liquid, m 2 s −1 Viscosity of liquid, kg s −1 m −1 d Diameter of impeller m D Diffusivity coefficient of invertase m 2 s −1 D e Effective diffusivity m 2 s −1 D m molecular diffusivity m 2 s −1 d p diameter of solid particles m K a Dissociation constant k sl solid liquid mass transfer coefficients m s −1 n Speed of agitation rpm N p Power number P Power W V Volume of liquid m 3 x
An effective conversion of lignocellulose into fermentable sugars is a key step in producing bioe... more An effective conversion of lignocellulose into fermentable sugars is a key step in producing bioethanol in an eco-friendly and cost effective manner. In this study, the effect of ultrasound on enzymatic hydrolysis of newspaper, a potential feedstock for bioethanol production due to its high cellulosic content, was investigated. The effect of substrate loading, enzyme loading, temperature, ultrasonic power and duty cycle on the hydrolysis has been studied. Optimum conditions for conventional enzymatic hydrolysis were substrate loading of 5% (w/v), enzyme loading of 0.14% (w/v), temperature of 323 K, and under these conditions and 72 h of hydrolysis, reducing sugar yield of 11.569 g/L was obtained. In case of ultrasoundassisted enzymatic hydrolysis approach, optimum conditions obtained were substrate loading of 3% (w/v), enzyme loading of 0.8% (w/v), sonication power of 60 W, duty cycle of 70%, hydrolysis time of 6.5 h and the reducing sugar yield obtained under these conditions was 27.6 g/L. Approximately 2.4 times increase in the release of reducing sugar concentration was obtained by the ultrasound-assisted enzymatic hydrolysis approach. Results indicate that there is a synergistic effect obtained from the combination of ultrasound and enzymes which lowers the diffusion-limiting barrier to enzyme/substrate binding and results in an increase in reaction rate. The experimental data were also fitted in a simple three parameter kinetic model.
The present work investigates the effect of low intensity ultrasonic irradiation on the cellulase... more The present work investigates the effect of low intensity ultrasonic irradiation on the cellulase activity. The effect on the kinetic and thermodynamic parameters as well as the molecular structure of cellulase enzyme was evaluated with the help of the chemical reaction kinetics model, Arrhenius equation, Eyring transition state theory, Michaelis-Menten equation, fluorescence spectroscopy and circular dichroism (CD) spectroscopy. It has been established that ultrasound had a positive effect on the activity of cellulase enzyme, though the selection of operating conditions played a crucial role in deciding the intensification. The maximum cellulase activity was observed at 17.33 W/cm 2 intensity and ultrasonic treatment time of 30 min, under which the enzyme activity was increased by about 25% over the untreated enzyme. After the ultrasonic treatment, thermodynamic parameters E a , H, S and G were reduced by 64.7%, 68%, 37.3% and 1.3%, respectively. In addition, fluorescence and CD spectra revealed that the ultrasonic treatment had increased the number of tryptophan on cellulase surface, and changed the molecular structure of cellulase enzyme favourably to provide more access to the active sites.
Alkaline and ultrasound-assisted alkaline pretreatment under mild operating conditions have been ... more Alkaline and ultrasound-assisted alkaline pretreatment under mild operating conditions have been investigated for intensification of delignification. The effect of NaOH concentration, biomass loading, temperature, ultrasonic power and duty cycle on the delignification has been studied. Most favorable conditions for only alkaline pretreatment were alkali concentration of 1.75 N, solid loading of 0.8% (w/v), temperature of 353 K and pretreatment time of 6 h and under these conditions, 40.2% delignification was obtained. In case of ultrasound-assisted alkaline approach, most favorable conditions obtained were alkali concentration of 1 N, paper loading of 0.5% (w/v), sonication power of 100 W, duty cycle of 80% and pretreatment time of 70 min and the delignification obtained in ultrasound-assisted alkaline approach under these conditions was 80%. The material samples were characterized by FTIR, SEM, XRD and TGA technique. The lignin was recovered from solution by precipitation method and was characterized by FTIR, GPC and TGA technique.
Improvements in enzymatic hydrolysis for production of bioethanol from sustainable biomass are ne... more Improvements in enzymatic hydrolysis for production of bioethanol from sustainable biomass are necessary in order to reduce enzyme requirements and the overall processing times. Conventional techniques for pretreatment of lignocelluloses are quite costly, time-consuming, and also require substantial downstream processing. Ultrasound can be effectively used to improve the hydrolysis process by reducing the structural rigidity of lignocellulose and by eliminating the mass-transfer resistances, which can contribute to increase in the product yield with reduced processing time and enzyme consumption. The present work initially presents an overview of different pretreatment methods involved in the enzymatic hydrolysis of lignocellulosic biomass highlighting its limitations. Expected mechanism of intensification due to the use of ultrasound has been discussed, also giving recommendations for optimum operating conditions. An overview of the different studies related to enzymatic hydrolysis using ultrasound for bioethanol production has been presented, along with discussion related to types of sonochemical reactors and scale-up aspects. Possible combination of sonication by coupling with traditional pretreatment processes has also been discussed. Overall, it appears that ultrasonic irradiations can be effectively used for the intensification of the enzymatic hydrolysis process for efficient bioethanol production.
Metformin hydrochloride, polyacrylic acid and b-cyclodextrin were taken for the preparation of sp... more Metformin hydrochloride, polyacrylic acid and b-cyclodextrin were taken for the preparation of spray dried sustained released micro particles in a different ratios. These sustained release micro particles were used for the preparation of tablets. Hardness of tablet increases with increase in concentration of polymer while the percentage friability decreases with increase in polymer concentration in tablet. The encapsulated drug shows better sustained release than the conventional tablet. The kinetics of the dissolution process were studied by analyzing the dissolution data using three kinetic equations-the zero-order equation, the first-order equation and the Hixson-Crowell cube root law equation.
The present work deals with intensification of delignification and subsequent enzymatic hydrolysi... more The present work deals with intensification of delignification and subsequent enzymatic hydrolysis of sustainable biomass such as groundnut shells, coconut coir and pistachio shells using ultrasound assisted approach so as to develop an economical approach for obtaining bioethanol. Process intensification, in the current context, is referred to as any improvements giving enhanced rates possibly with lower energy and chemical as well as enzyme requirement for delignification and hydrolysis respectively. Conventional processing for both delignification and enzymatic hydrolysis has also been investigated for establishing the degree of intensification. The obtained results for delignification of biomass established that for conventional alkaline treatment, the extent of delignification for the case of groundnut shells, coconut coir and pistachio shells were 41.8, 45.9 and 38% which increased to 71.1, 89.5 and 78.9% respectively giving almost 80-100% increase for the ultrasound assisted approach. Under optimized conditions, the conventional approach resulted in reducing sugar yields as 10.2, 12.1 and 8.1g/L for groundnut shells, coconut coir and pistachio shells respectively whereas for the case of ultrasound-assisted enzymatic hydrolysis, the obtained yields were 21.3, 23.9 and 18.4g/L in same order of biomass. The material samples were characterized by several characterization techniques for establishing the morphological changes obtained due to the use of ultrasound which were found to be favorable for enhanced delignification and hydrolysis for the ultrasound assisted approach. Overall, the results of this work establish the process intensification benefits due to the application of ultrasound for different sustainable biomass with mechanistic understanding based on the morphological analyses.
The present work investigates the effectiveness of application of low intensity ultrasonic irradi... more The present work investigates the effectiveness of application of low intensity ultrasonic irradiation for the intensification of enzymatic depolymerization of aqueous guar gum solution. The extent of depolymerization of guar gum has been analyzed in terms of intrinsic viscosity reduction. The effect of ultrasonic irradiation on the kinetic and thermodynamic parameters related to the enzyme activity as well as the intrinsic viscosity reduction of guar gum using enzymatic approach has been evaluated. The kinetic rate constant has been found to increase with an increase in the temperature and cellulase loading. It has been observed that application of ultrasound not only enhances the extent of depolymerization but also reduces the time of depolymerization as compared to conventional enzymatic degradation technique. In the presence of cellulase enzyme, the maximum extent of depolymerization of guar gum has been observed at 60 W of ultrasonic rated power and ultrasonic treatment time of 30 min. The effect of ultrasound on the kinetic and thermodynamic parameters as well as the molecular structure of cellulase enzyme was evaluated with the help of the chemical reaction kinetics model and fluorescence spectroscopy. Application of ultrasound resulted in a reduction in the thermodynamic parameters of activation energy (Ea), enthalpy (DH), entropy (DS) and free energy (DG) by 47%, 50%, 65% and 1.97%, respectively. The changes in the chemical structure of guar gum treated using ultrasound assisted enzymatic approach in comparison to the native guar gum were also characterized by FTIR. The results revealed that enzymatic depolymerization of guar gum resulted in a polysaccharide with low degree of polymerization, viscosity and consistency index without any change in the core chemical structure which could make it useful for incorporation in food products.
Ultrasound assisted intensification of synthesis of biodiesel from waste cooking oil using methyl... more Ultrasound assisted intensification of synthesis of biodiesel from waste cooking oil using methyl acetate and immobilized lipase obtained fromThermomyces lanuginosus(Lipozyme TLIM) as a catalyst has been investigated in the present work. The reaction has also been investigated using the conventional approach based on stirring so as to establish the beneficial effects obtained due to the use of ultrasound. Effect of operating conditions such as reactant molar ratio (oil and methyl acetate), temperature and enzyme loading on the yield of biodiesel has been investigated. Optimum conditions for the conventional approach (without ultrasound) were established as reactant molar ratio of 1:12 (oil:methyl acetate), enzyme loading of 6% (w/v), temperature of 40C and reaction time of 24 h and under these conditions, 90.1% biodiesel yield was obtained. The optimum conditions for the ultrasound assisted approach were oil to methyl acetate molar ratio of 1:9, enzyme loading of 3% (w/v), and reaction time of 3 h and the biodiesel yield obtained under these conditions was 96.1%. Use of ultrasound resulted in significant reduction in the reaction time with higher yields and lower requirement of the enzyme loading. The obtained results have clearly established that ultrasound assisted interesterification was a fast and efficient approach for biodiesel production giving significant benefits, which can help in reducing the costs of production. Reusability studies for the enzyme were also performed but it was observed that reuse of the catalyst under the optimum experimental condition resulted in reduced enzyme activity and biodiesel yield
The present work deals with intensification of bioethanol production from waste newspaper using
S... more The present work deals with intensification of bioethanol production from waste newspaper using Saccharomyces cerevisiaeusing ultrasonic irradiations. The effect of different process parameters such as application of ultrasonic irradiation at different growth phases, irradiation time, ultrasonic power and duty cycle on the bioethanol production has been investigated. The favorable conditions for the maximum yield were established as application of ultrasonic irradiation (duration of 10 min) to fermentation broth at 12 h of growth phase with 25 kHz frequency, 160 W power and 20% duty cycle. The bioethanol productivity was increased by 1.8 times from 7.8 to 14.1 g/L compared with the non-sonicated control fermentation. Decrease in glucose concentration from 0.63% to 0.2% w/v in ultrasound-assisted fermentation confirmed the improved substrate uptake of the microbial cell due to the application of ultrasound. ESEM analysis also confirmed the changes in the cell morphology leading to improved cell permeability. Results were fitted to an unstructured kinetic model comprising of the kinetic and physiological parameters. Overall, the work has demonstrated an intensified approach for the bioethanol production based on the use of ultrasound.
The synthesis of biodiesel from sunflower oil and methanol based on transesterification using the... more The synthesis of biodiesel from sunflower oil and methanol based on transesterification using the immobilized lipase fromThermomyces lanuginosus(Lipozyme TL-IM) has been investigated under silent conditions and under an ultrasound field. Ultrasound assisted process led to reduced processing time and requirement of lower enzyme dosage. We found for the first time that oil to methanol ratio of 1:3 was favored for the ultrasound assisted enzymatic process which is lower than that observed for the case of conventional stirring based approach (ratio of 1.4). Our results indicate that intensification provided by ultrasound suppresses the need of the excess of the methanol reactant during the enzymatic biodiesel production. Ultrasound assisted enzymatic biodiesel production is therefore a faster and a cleaner processes
BACKGROUND: Cell permeabilization techniques allow selective release of an enzyme and specific re... more BACKGROUND: Cell permeabilization techniques allow selective release of an enzyme and specific reactions without breaking the cells. A mathematical model has been developed for selective permeabilization of Saccharomyces cerevisiae to recover invertase at high purity. The effect of thiols on the cell walls of S. cerevisiae was studied under different conditions of pH, cysteine concentration, speed of agitation and solid suspension density. RESULT: The rate of release of invertase was a function of pH and cysteine (or thiolate ion) concentration.The maximum recovery of invertase was obtained at pH 10.0, 10 mmol dm −3 cysteine concentration and 15% (w/v) yeast loading. CONCLUSION: Thiols are capable of permeabilizing the cell walls of S. cerevisiae and releasing the invertase under basic conditions. The insignificant effect of agitation shows that the external mass transfer resistance does not play any role in the release of invertase. NOTATION Kinematic viscosity of liquid, m 2 s −1 Viscosity of liquid, kg s −1 m −1 d Diameter of impeller m D Diffusivity coefficient of invertase m 2 s −1 D e Effective diffusivity m 2 s −1 D m molecular diffusivity m 2 s −1 d p diameter of solid particles m K a Dissociation constant k sl solid liquid mass transfer coefficients m s −1 n Speed of agitation rpm N p Power number P Power W V Volume of liquid m 3 x
An effective conversion of lignocellulose into fermentable sugars is a key step in producing bioe... more An effective conversion of lignocellulose into fermentable sugars is a key step in producing bioethanol in an eco-friendly and cost effective manner. In this study, the effect of ultrasound on enzymatic hydrolysis of newspaper, a potential feedstock for bioethanol production due to its high cellulosic content, was investigated. The effect of substrate loading, enzyme loading, temperature, ultrasonic power and duty cycle on the hydrolysis has been studied. Optimum conditions for conventional enzymatic hydrolysis were substrate loading of 5% (w/v), enzyme loading of 0.14% (w/v), temperature of 323 K, and under these conditions and 72 h of hydrolysis, reducing sugar yield of 11.569 g/L was obtained. In case of ultrasoundassisted enzymatic hydrolysis approach, optimum conditions obtained were substrate loading of 3% (w/v), enzyme loading of 0.8% (w/v), sonication power of 60 W, duty cycle of 70%, hydrolysis time of 6.5 h and the reducing sugar yield obtained under these conditions was 27.6 g/L. Approximately 2.4 times increase in the release of reducing sugar concentration was obtained by the ultrasound-assisted enzymatic hydrolysis approach. Results indicate that there is a synergistic effect obtained from the combination of ultrasound and enzymes which lowers the diffusion-limiting barrier to enzyme/substrate binding and results in an increase in reaction rate. The experimental data were also fitted in a simple three parameter kinetic model.
The present work investigates the effect of low intensity ultrasonic irradiation on the cellulase... more The present work investigates the effect of low intensity ultrasonic irradiation on the cellulase activity. The effect on the kinetic and thermodynamic parameters as well as the molecular structure of cellulase enzyme was evaluated with the help of the chemical reaction kinetics model, Arrhenius equation, Eyring transition state theory, Michaelis-Menten equation, fluorescence spectroscopy and circular dichroism (CD) spectroscopy. It has been established that ultrasound had a positive effect on the activity of cellulase enzyme, though the selection of operating conditions played a crucial role in deciding the intensification. The maximum cellulase activity was observed at 17.33 W/cm 2 intensity and ultrasonic treatment time of 30 min, under which the enzyme activity was increased by about 25% over the untreated enzyme. After the ultrasonic treatment, thermodynamic parameters E a , H, S and G were reduced by 64.7%, 68%, 37.3% and 1.3%, respectively. In addition, fluorescence and CD spectra revealed that the ultrasonic treatment had increased the number of tryptophan on cellulase surface, and changed the molecular structure of cellulase enzyme favourably to provide more access to the active sites.
Alkaline and ultrasound-assisted alkaline pretreatment under mild operating conditions have been ... more Alkaline and ultrasound-assisted alkaline pretreatment under mild operating conditions have been investigated for intensification of delignification. The effect of NaOH concentration, biomass loading, temperature, ultrasonic power and duty cycle on the delignification has been studied. Most favorable conditions for only alkaline pretreatment were alkali concentration of 1.75 N, solid loading of 0.8% (w/v), temperature of 353 K and pretreatment time of 6 h and under these conditions, 40.2% delignification was obtained. In case of ultrasound-assisted alkaline approach, most favorable conditions obtained were alkali concentration of 1 N, paper loading of 0.5% (w/v), sonication power of 100 W, duty cycle of 80% and pretreatment time of 70 min and the delignification obtained in ultrasound-assisted alkaline approach under these conditions was 80%. The material samples were characterized by FTIR, SEM, XRD and TGA technique. The lignin was recovered from solution by precipitation method and was characterized by FTIR, GPC and TGA technique.
Improvements in enzymatic hydrolysis for production of bioethanol from sustainable biomass are ne... more Improvements in enzymatic hydrolysis for production of bioethanol from sustainable biomass are necessary in order to reduce enzyme requirements and the overall processing times. Conventional techniques for pretreatment of lignocelluloses are quite costly, time-consuming, and also require substantial downstream processing. Ultrasound can be effectively used to improve the hydrolysis process by reducing the structural rigidity of lignocellulose and by eliminating the mass-transfer resistances, which can contribute to increase in the product yield with reduced processing time and enzyme consumption. The present work initially presents an overview of different pretreatment methods involved in the enzymatic hydrolysis of lignocellulosic biomass highlighting its limitations. Expected mechanism of intensification due to the use of ultrasound has been discussed, also giving recommendations for optimum operating conditions. An overview of the different studies related to enzymatic hydrolysis using ultrasound for bioethanol production has been presented, along with discussion related to types of sonochemical reactors and scale-up aspects. Possible combination of sonication by coupling with traditional pretreatment processes has also been discussed. Overall, it appears that ultrasonic irradiations can be effectively used for the intensification of the enzymatic hydrolysis process for efficient bioethanol production.
Metformin hydrochloride, polyacrylic acid and b-cyclodextrin were taken for the preparation of sp... more Metformin hydrochloride, polyacrylic acid and b-cyclodextrin were taken for the preparation of spray dried sustained released micro particles in a different ratios. These sustained release micro particles were used for the preparation of tablets. Hardness of tablet increases with increase in concentration of polymer while the percentage friability decreases with increase in polymer concentration in tablet. The encapsulated drug shows better sustained release than the conventional tablet. The kinetics of the dissolution process were studied by analyzing the dissolution data using three kinetic equations-the zero-order equation, the first-order equation and the Hixson-Crowell cube root law equation.
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Papers by Preeti Subhedar
the intensification of enzymatic depolymerization of aqueous guar gum solution. The extent of depolymerization of guar gum has been analyzed in terms of intrinsic viscosity reduction. The effect of ultrasonic irradiation on the kinetic and thermodynamic parameters related to the enzyme activity as well
as the intrinsic viscosity reduction of guar gum using enzymatic approach has been evaluated. The kinetic
rate constant has been found to increase with an increase in the temperature and cellulase loading. It has
been observed that application of ultrasound not only enhances the extent of depolymerization but also
reduces the time of depolymerization as compared to conventional enzymatic degradation technique. In
the presence of cellulase enzyme, the maximum extent of depolymerization of guar gum has been
observed at 60 W of ultrasonic rated power and ultrasonic treatment time of 30 min. The effect of ultrasound on the kinetic and thermodynamic parameters as well as the molecular structure of cellulase
enzyme was evaluated with the help of the chemical reaction kinetics model and fluorescence spectroscopy. Application of ultrasound resulted in a reduction in the thermodynamic parameters of activation energy (Ea), enthalpy (DH), entropy (DS) and free energy (DG) by 47%, 50%, 65% and 1.97%,
respectively. The changes in the chemical structure of guar gum treated using ultrasound assisted enzymatic approach in comparison to the native guar gum were also characterized by FTIR. The results
revealed that enzymatic depolymerization of guar gum resulted in a polysaccharide with low degree
of polymerization, viscosity and consistency index without any change in the core chemical structure
which could make it useful for incorporation in food products.
and immobilized lipase obtained fromThermomyces lanuginosus(Lipozyme TLIM) as a catalyst has been
investigated in the present work. The reaction has also been investigated using the conventional
approach based on stirring so as to establish the beneficial effects obtained due to the use of ultrasound.
Effect of operating conditions such as reactant molar ratio (oil and methyl acetate), temperature and
enzyme loading on the yield of biodiesel has been investigated. Optimum conditions for the conventional
approach (without ultrasound) were established as reactant molar ratio of 1:12 (oil:methyl acetate),
enzyme loading of 6% (w/v), temperature of 40C and reaction time of 24 h and under these conditions,
90.1% biodiesel yield was obtained. The optimum conditions for the ultrasound assisted approach were
oil to methyl acetate molar ratio of 1:9, enzyme loading of 3% (w/v), and reaction time of 3 h and the biodiesel yield obtained under these conditions was 96.1%. Use of ultrasound resulted in significant reduction in the reaction time with higher yields and lower requirement of the enzyme loading. The obtained
results have clearly established that ultrasound assisted interesterification was a fast and efficient
approach for biodiesel production giving significant benefits, which can help in reducing the costs of production. Reusability studies for the enzyme were also performed but it was observed that reuse of the
catalyst under the optimum experimental condition resulted in reduced enzyme activity and biodiesel
yield
Saccharomyces cerevisiaeusing ultrasonic irradiations. The effect of different process parameters such
as application of ultrasonic irradiation at different growth phases, irradiation time, ultrasonic power
and duty cycle on the bioethanol production has been investigated. The favorable conditions for the maximum yield were established as application of ultrasonic irradiation (duration of 10 min) to fermentation
broth at 12 h of growth phase with 25 kHz frequency, 160 W power and 20% duty cycle. The bioethanol
productivity was increased by 1.8 times from 7.8 to 14.1 g/L compared with the non-sonicated control
fermentation. Decrease in glucose concentration from 0.63% to 0.2% w/v in ultrasound-assisted fermentation confirmed the improved substrate uptake of the microbial cell due to the application of ultrasound.
ESEM analysis also confirmed the changes in the cell morphology leading to improved cell permeability.
Results were fitted to an unstructured kinetic model comprising of the kinetic and physiological parameters. Overall, the work has demonstrated an intensified approach for the bioethanol production based on
the use of ultrasound.
requirement of lower enzyme dosage. We found for the first time that oil to methanol ratio of 1:3 was
favored for the ultrasound assisted enzymatic process which is lower than that observed for the case
of conventional stirring based approach (ratio of 1.4). Our results indicate that intensification provided
by ultrasound suppresses the need of the excess of the methanol reactant during the enzymatic biodiesel
production. Ultrasound assisted enzymatic biodiesel production is therefore a faster and a cleaner
processes
the intensification of enzymatic depolymerization of aqueous guar gum solution. The extent of depolymerization of guar gum has been analyzed in terms of intrinsic viscosity reduction. The effect of ultrasonic irradiation on the kinetic and thermodynamic parameters related to the enzyme activity as well
as the intrinsic viscosity reduction of guar gum using enzymatic approach has been evaluated. The kinetic
rate constant has been found to increase with an increase in the temperature and cellulase loading. It has
been observed that application of ultrasound not only enhances the extent of depolymerization but also
reduces the time of depolymerization as compared to conventional enzymatic degradation technique. In
the presence of cellulase enzyme, the maximum extent of depolymerization of guar gum has been
observed at 60 W of ultrasonic rated power and ultrasonic treatment time of 30 min. The effect of ultrasound on the kinetic and thermodynamic parameters as well as the molecular structure of cellulase
enzyme was evaluated with the help of the chemical reaction kinetics model and fluorescence spectroscopy. Application of ultrasound resulted in a reduction in the thermodynamic parameters of activation energy (Ea), enthalpy (DH), entropy (DS) and free energy (DG) by 47%, 50%, 65% and 1.97%,
respectively. The changes in the chemical structure of guar gum treated using ultrasound assisted enzymatic approach in comparison to the native guar gum were also characterized by FTIR. The results
revealed that enzymatic depolymerization of guar gum resulted in a polysaccharide with low degree
of polymerization, viscosity and consistency index without any change in the core chemical structure
which could make it useful for incorporation in food products.
and immobilized lipase obtained fromThermomyces lanuginosus(Lipozyme TLIM) as a catalyst has been
investigated in the present work. The reaction has also been investigated using the conventional
approach based on stirring so as to establish the beneficial effects obtained due to the use of ultrasound.
Effect of operating conditions such as reactant molar ratio (oil and methyl acetate), temperature and
enzyme loading on the yield of biodiesel has been investigated. Optimum conditions for the conventional
approach (without ultrasound) were established as reactant molar ratio of 1:12 (oil:methyl acetate),
enzyme loading of 6% (w/v), temperature of 40C and reaction time of 24 h and under these conditions,
90.1% biodiesel yield was obtained. The optimum conditions for the ultrasound assisted approach were
oil to methyl acetate molar ratio of 1:9, enzyme loading of 3% (w/v), and reaction time of 3 h and the biodiesel yield obtained under these conditions was 96.1%. Use of ultrasound resulted in significant reduction in the reaction time with higher yields and lower requirement of the enzyme loading. The obtained
results have clearly established that ultrasound assisted interesterification was a fast and efficient
approach for biodiesel production giving significant benefits, which can help in reducing the costs of production. Reusability studies for the enzyme were also performed but it was observed that reuse of the
catalyst under the optimum experimental condition resulted in reduced enzyme activity and biodiesel
yield
Saccharomyces cerevisiaeusing ultrasonic irradiations. The effect of different process parameters such
as application of ultrasonic irradiation at different growth phases, irradiation time, ultrasonic power
and duty cycle on the bioethanol production has been investigated. The favorable conditions for the maximum yield were established as application of ultrasonic irradiation (duration of 10 min) to fermentation
broth at 12 h of growth phase with 25 kHz frequency, 160 W power and 20% duty cycle. The bioethanol
productivity was increased by 1.8 times from 7.8 to 14.1 g/L compared with the non-sonicated control
fermentation. Decrease in glucose concentration from 0.63% to 0.2% w/v in ultrasound-assisted fermentation confirmed the improved substrate uptake of the microbial cell due to the application of ultrasound.
ESEM analysis also confirmed the changes in the cell morphology leading to improved cell permeability.
Results were fitted to an unstructured kinetic model comprising of the kinetic and physiological parameters. Overall, the work has demonstrated an intensified approach for the bioethanol production based on
the use of ultrasound.
requirement of lower enzyme dosage. We found for the first time that oil to methanol ratio of 1:3 was
favored for the ultrasound assisted enzymatic process which is lower than that observed for the case
of conventional stirring based approach (ratio of 1.4). Our results indicate that intensification provided
by ultrasound suppresses the need of the excess of the methanol reactant during the enzymatic biodiesel
production. Ultrasound assisted enzymatic biodiesel production is therefore a faster and a cleaner
processes