Steven Peretti - Academia.edu (original) (raw)

Papers by Steven Peretti

Chemical engineering education, Jan 30, 2015

RSC Advances, 2015

Organic synthesis with surface-displayed lipase: alkyl esters of fatty acids. Compared performanc... more Organic synthesis with surface-displayed lipase: alkyl esters of fatty acids. Compared performance to commercial preparations. Catalyst is reusable and stable up to 50–60 °C. Kinetics of surface-displayed synthesis of butyl decanoate.

RSC Advances, 2015

Yeast surface display (YSD) of two lipases. Measured expression level and copy number. Synthetic ... more Yeast surface display (YSD) of two lipases. Measured expression level and copy number. Synthetic and hydrolytic activity comparable to commercial lipase. Cost analysis of YSD system vs. commercial formulations.

37th Symposium on Biotechnology for Fuels and Chemicals, Apr 28, 2015

A basic tenet of learning theory is that people learn by doing, not by watching and listening. En... more A basic tenet of learning theory is that people learn by doing, not by watching and listening. Engineering laboratory courses are consequently crucial to the learning and retention of engineering principles. The traditional laboratory course has several shortcomings, however, that violate other learning theory principles. Virtually all cognitive and educational psychologists agree that students learn by discovery, by confronting new problems and challenges, working out how to deal with them, and reflecting on implications of their solutions. In many laboratory courses, students often perform rigidly prescribed experiments mechanically, without having to analyze what they are doing, why they are doing it, or what the results have to do with the theory they may have studied in other courses. A massive body of research on cooperative learning indicates that team projects are most effective if they are structure to assure both positive interdependence and individual accountability. In most laboratory courses, there is little to prevent one or two team members from actually doing most of the work, all team members receiving credit for it, and no one being held individually accountable for any of the material covered. The chemical engineering laboratory course sequence at North Carolina State University is currently being restructured to conform more closely to principles of effective pedagogy. The following features of the new sequence constitute the principal departures from the traditional instructional model:

Biotechnology and Bioengineering, Feb 7, 2013

In situ Raman spectroscopy was employed for real-time monitoring of simultaneous saccharification... more In situ Raman spectroscopy was employed for real-time monitoring of simultaneous saccharification and fermentation (SSF) of corn mash by an industrial strain of Saccharomyces cerevisiae. An accurate univariate calibration model for ethanol was developed based on the very strong 883 cm À1 CC stretching band. Multivariate partial least squares (PLS) calibration models for total starch, dextrins, maltotriose, maltose, glucose, and ethanol were developed using data from eight batch fermentations and validated using predictions for a separate batch. The starch, ethanol, and dextrins models showed significant prediction improvement when the calibration data were divided into separate high-and low-concentration sets. Collinearity between the ethanol and starch models was avoided by excluding regions containing strong ethanol peaks from the starch model and, conversely, excluding regions containing strong saccharide peaks from the ethanol model. The two-set calibration models for starch (R 2 ¼ 0.998, percent error ¼ 2.5%) and ethanol (R 2 ¼ 0.999, percent error ¼ 2.1%) provide more accurate predictions than any previously published spectroscopic models. Glucose, maltose, and maltotriose are modeled to accuracy comparable to previous work on less complex fermentation processes. Our results demonstrate that Raman spectroscopy is capable of real time in situ monitoring of a complex industrial biomass fermentation. To our knowledge, this is the first PLS-based chemometric modeling of corn mash fermentation under typical industrial conditions, and the first Raman-based monitoring of a fermentation process with glucose, oligosaccharides and polysaccharides present.

Biotechnology and Bioengineering, Feb 5, 1998

A strain of Pseudomonas putida harboring plasmids RK2 and pDLB101 was exposed to a pure culture b... more A strain of Pseudomonas putida harboring plasmids RK2 and pDLB101 was exposed to a pure culture biofilm of Bacillus azotoformans grown in a rotating annular reactor under three different concentrations of the limiting nutrient, succinate. Experimental results demonstrated that the broad host range RSF1010 derivative pDLB101 was transferred to and expressed by B. azotoformans. At the lower concentrations, donor mediated plasmid transfer increased with increasing nutrient levels, but the highest nutrient concentration yielded the lowest rate of donor to recipient plasmid transfer. For transconjugant initiated transfer, the rate of transfer increased with increasing nutrient concentrations for all cases. At the lower nutrient concentrations, the frequency of plasmid transfer was higher between donors and recipients than between transconjugants and recipients. The reverse was true at the highest succinate concentration. The rates and frequencies of plasmid transfer by mobilization were compared to gene exchange by retrotransfer. The initial rate of retrotransfer was slower than mobilization, but then increased dramatically. Retrotransfer produced a plasmid transfer frequency more than an order of magnitude higher than simple mobilization.

Breakdown of energy flows in sliding vane rotary compressors. Comprehensive model to simulate the... more Breakdown of energy flows in sliding vane rotary compressors. Comprehensive model to simulate the performances of industrial machines. Experimental campaign at different outlet pressure levels and revolution speeds. Identification of the friction coefficient. Optimization of several design parameters to achieve mechanical efficiency improvements.

Applied Catalysis A: General, 2017

Highlights  Effect of nickel loading on catalyst properties of Ni/HZSM-5 synthesized via excess ... more Highlights  Effect of nickel loading on catalyst properties of Ni/HZSM-5 synthesized via excess depositionprecipitation times was studied.  Ni(15)/HZSM-5 with 16 h DP time and calcined at 673 K has desirable particle size and dispersion.  Ni/HZSM-5 prepared by this method has promising properties for hydrogenolysis

2003 Annual Conference Proceedings

Although numerous articles in engineering disciplines focus on incorporating communication into c... more Although numerous articles in engineering disciplines focus on incorporating communication into courses and curricula, minimal scholarship exists that addresses the specific instruction and assessment issues involved with multidisciplinary teaming competence. As multidisciplinary teams are increasingly being implemented in engineering industry and academic courses (specifically in senior design courses), it is critical to explore the strategies for instruction and assessment of multidisciplinary teams. This study does just that by describing a tri-phased instructional and assessment protocol for multidisciplinary teaming instruction. Additionally, this study presents preliminary assessment results that contributed to iterative redesign of this tri-phased protocol. Ultimately, the protocols presented in this study can be tailored for other institutions and further tested for effectiveness in building multidisciplinary teaming competence. Rationale Industry uses multidisciplinary (MD) teams to enhance the success of new product development 1. Multidisciplinary teams are also essential components of knowledge management practices in organizations. The combination of MD teams and optimizing emerging technologies enables organizations to manage the human side of learning and complex decision-making 2. Because the needs of industry often influence the professional preparation of new entrants into the workforce, it is critical to attend to those educational issues involved with multidisciplinary teams. The current study provides insight into the under explored area of multidisciplinary teaming instruction and assessment within a senior capstone design course. Numerous curricular changes in engineering disciplines nationwide have focused instruction on communication and teamwork skills 3. While some programs have engaged in comprehensive curricular change, others have designed new stand-alone communication courses for engineering students 4. Many of these communication-intensive courses target technical communication as a key critical skill to learn 5. Other such communication courses for engineers focus on different communication skills such as listening, teamwork, visual aids, group creativity, and audience analysis 6 .

There is a significant interest in developing renewable solid base catalysts from agricultural wa... more There is a significant interest in developing renewable solid base catalysts from agricultural wastes for the use in the transesterification of fats into fatty acid methyl esters (FAME). In this study, an inexpensive base catalyst was synthesized by impregnating waste oyster shell with 50% sodium hydroxide solution, followed by calcination at 1000°C for 3 h. The resulting solid catalyst was used to catalyze transesterification of soybean oil. Transesterification using the catalyst was studied by systematically varying molar ratio (MR) (methanol to oil) and catalyst loading (CL). Results indicated that the highest FAME yield was 93.9% using MR of 12 and CL of 10%. Reusability tests suggested that the catalyst could be used for at least three runs without any significant decrease in FAME yield.

2012 ASEE Annual Conference & Exposition Proceedings

Enzyme and microbial technology, 2018

An innovative chemoenzymatic catalytic system for functionalizing lignin from Organosolv and Kraf... more An innovative chemoenzymatic catalytic system for functionalizing lignin from Organosolv and Kraft pulping processes to obtain oxirane rings was investigated. Novozym435 (immobilized C. antarctica lipase B: CalB) was used to catalyze the peroxidation of caprylic acid to peroxycaprylic acid, which in turn reacted with unsaturated CC bonds to form the oxirane ring. The conversion of OH groups to oxirane rings (epoxides) reached 90% and 55% after 12 h for the two processes, respectively. The residual enzyme activity over the time course of the reactions indicated transient denaturing due to association with the lignin substrate (10-50%) as well as irreversible denaturation due to exposure to hydrogen peroxide. Functionalized lignin has potential applications in the production of epoxy adhesive resins, and chemoenzymatic synthesis represents a "greener" pathway to this synthesis.

Plant Cell Reports, 1994

An endo-pectate lyase (PL; EC 4.2.2.2), originally cloned fiom the phytopathogenic bacterium Erwi... more An endo-pectate lyase (PL; EC 4.2.2.2), originally cloned fiom the phytopathogenic bacterium Erwinia chrysanthemi EC16, was expressed in recA (-) E. coli strain DK1, purified to a single band by isoelectric focusing and used to induce berberine production in established plant suspension cultures of Thalictrum minus L. subsp. saxatile. Addition of 10(-9)M pectate lyase c (PLc) stimulated berberine production and enhanced secretion of the alkaloid into the medium. A lower concentration of PLc, 10(-11)M, stimulated a transient two-fold increase in cell growth rate relative to untreated cultures. Parallel changes in L-phenylalanine ammonia lyase (PAL; EC 4.3.1.5) activity with the rate of berberine synthesis and the inverse relationship between cell growth and berberine synthesis imply that berberine synthesis is stress-related in this cell line.

2004 Annual Conference Proceedings

ABET 2000 Criterion 3 explicitly states that engineering graduates must have "an understanding of... more ABET 2000 Criterion 3 explicitly states that engineering graduates must have "an understanding of professional and ethical responsibility," "an ability to communicate effectively," and "the broad education necessary to understand the impact of engineering solutions in a global and societal context." Service-learning is the approach we chose to enhance our students' capacities in these areas. For the past two years, senior projects containing a significant service-learning component have been offered in the capstone chemical engineering senior design course at NC State University. Students have worked with an economically disadvantaged community facing pollutant emissions resulting from a high concentration of local industries. Students characterized the pollutant problem and its sources and provided the community with process-related information useful in their discussions with regulatory bodies. This paper will review the conceptual foundations of service-learning, discuss potential applications of service-learning in engineering curricula, and summarize the strategies used and the challenges faced in the design and implementation of a service-learning component in chemical engineering senior design.

2004 Annual Conference Proceedings

2003 Annual Conference Proceedings

2003 Annual Conference Proceedings

Applied Biochemistry and Biotechnology, 1993

A quantitative comparision is offered between a kinetic model for product-inhibited, immobilized ... more A quantitative comparision is offered between a kinetic model for product-inhibited, immobilized cell, metabolism and a high-resolution scanning microfluorimetric characterization of variation of cell growth rates with position in immobilized cell cultures. The kinetic model is based exclusively on kinetic parameters derived from free cell suspension cultures and literature data for diffusion in biomass-loaded gels; the scanning microfluorimetry provides a

Chemical engineering education, Jan 30, 2015

RSC Advances, 2015

Organic synthesis with surface-displayed lipase: alkyl esters of fatty acids. Compared performanc... more Organic synthesis with surface-displayed lipase: alkyl esters of fatty acids. Compared performance to commercial preparations. Catalyst is reusable and stable up to 50–60 °C. Kinetics of surface-displayed synthesis of butyl decanoate.

RSC Advances, 2015

Yeast surface display (YSD) of two lipases. Measured expression level and copy number. Synthetic ... more Yeast surface display (YSD) of two lipases. Measured expression level and copy number. Synthetic and hydrolytic activity comparable to commercial lipase. Cost analysis of YSD system vs. commercial formulations.

37th Symposium on Biotechnology for Fuels and Chemicals, Apr 28, 2015

A basic tenet of learning theory is that people learn by doing, not by watching and listening. En... more A basic tenet of learning theory is that people learn by doing, not by watching and listening. Engineering laboratory courses are consequently crucial to the learning and retention of engineering principles. The traditional laboratory course has several shortcomings, however, that violate other learning theory principles. Virtually all cognitive and educational psychologists agree that students learn by discovery, by confronting new problems and challenges, working out how to deal with them, and reflecting on implications of their solutions. In many laboratory courses, students often perform rigidly prescribed experiments mechanically, without having to analyze what they are doing, why they are doing it, or what the results have to do with the theory they may have studied in other courses. A massive body of research on cooperative learning indicates that team projects are most effective if they are structure to assure both positive interdependence and individual accountability. In most laboratory courses, there is little to prevent one or two team members from actually doing most of the work, all team members receiving credit for it, and no one being held individually accountable for any of the material covered. The chemical engineering laboratory course sequence at North Carolina State University is currently being restructured to conform more closely to principles of effective pedagogy. The following features of the new sequence constitute the principal departures from the traditional instructional model:

Biotechnology and Bioengineering, Feb 7, 2013

In situ Raman spectroscopy was employed for real-time monitoring of simultaneous saccharification... more In situ Raman spectroscopy was employed for real-time monitoring of simultaneous saccharification and fermentation (SSF) of corn mash by an industrial strain of Saccharomyces cerevisiae. An accurate univariate calibration model for ethanol was developed based on the very strong 883 cm À1 CC stretching band. Multivariate partial least squares (PLS) calibration models for total starch, dextrins, maltotriose, maltose, glucose, and ethanol were developed using data from eight batch fermentations and validated using predictions for a separate batch. The starch, ethanol, and dextrins models showed significant prediction improvement when the calibration data were divided into separate high-and low-concentration sets. Collinearity between the ethanol and starch models was avoided by excluding regions containing strong ethanol peaks from the starch model and, conversely, excluding regions containing strong saccharide peaks from the ethanol model. The two-set calibration models for starch (R 2 ¼ 0.998, percent error ¼ 2.5%) and ethanol (R 2 ¼ 0.999, percent error ¼ 2.1%) provide more accurate predictions than any previously published spectroscopic models. Glucose, maltose, and maltotriose are modeled to accuracy comparable to previous work on less complex fermentation processes. Our results demonstrate that Raman spectroscopy is capable of real time in situ monitoring of a complex industrial biomass fermentation. To our knowledge, this is the first PLS-based chemometric modeling of corn mash fermentation under typical industrial conditions, and the first Raman-based monitoring of a fermentation process with glucose, oligosaccharides and polysaccharides present.

Biotechnology and Bioengineering, Feb 5, 1998

A strain of Pseudomonas putida harboring plasmids RK2 and pDLB101 was exposed to a pure culture b... more A strain of Pseudomonas putida harboring plasmids RK2 and pDLB101 was exposed to a pure culture biofilm of Bacillus azotoformans grown in a rotating annular reactor under three different concentrations of the limiting nutrient, succinate. Experimental results demonstrated that the broad host range RSF1010 derivative pDLB101 was transferred to and expressed by B. azotoformans. At the lower concentrations, donor mediated plasmid transfer increased with increasing nutrient levels, but the highest nutrient concentration yielded the lowest rate of donor to recipient plasmid transfer. For transconjugant initiated transfer, the rate of transfer increased with increasing nutrient concentrations for all cases. At the lower nutrient concentrations, the frequency of plasmid transfer was higher between donors and recipients than between transconjugants and recipients. The reverse was true at the highest succinate concentration. The rates and frequencies of plasmid transfer by mobilization were compared to gene exchange by retrotransfer. The initial rate of retrotransfer was slower than mobilization, but then increased dramatically. Retrotransfer produced a plasmid transfer frequency more than an order of magnitude higher than simple mobilization.

Breakdown of energy flows in sliding vane rotary compressors. Comprehensive model to simulate the... more Breakdown of energy flows in sliding vane rotary compressors. Comprehensive model to simulate the performances of industrial machines. Experimental campaign at different outlet pressure levels and revolution speeds. Identification of the friction coefficient. Optimization of several design parameters to achieve mechanical efficiency improvements.

Applied Catalysis A: General, 2017

Highlights  Effect of nickel loading on catalyst properties of Ni/HZSM-5 synthesized via excess ... more Highlights  Effect of nickel loading on catalyst properties of Ni/HZSM-5 synthesized via excess depositionprecipitation times was studied.  Ni(15)/HZSM-5 with 16 h DP time and calcined at 673 K has desirable particle size and dispersion.  Ni/HZSM-5 prepared by this method has promising properties for hydrogenolysis

2003 Annual Conference Proceedings

Although numerous articles in engineering disciplines focus on incorporating communication into c... more Although numerous articles in engineering disciplines focus on incorporating communication into courses and curricula, minimal scholarship exists that addresses the specific instruction and assessment issues involved with multidisciplinary teaming competence. As multidisciplinary teams are increasingly being implemented in engineering industry and academic courses (specifically in senior design courses), it is critical to explore the strategies for instruction and assessment of multidisciplinary teams. This study does just that by describing a tri-phased instructional and assessment protocol for multidisciplinary teaming instruction. Additionally, this study presents preliminary assessment results that contributed to iterative redesign of this tri-phased protocol. Ultimately, the protocols presented in this study can be tailored for other institutions and further tested for effectiveness in building multidisciplinary teaming competence. Rationale Industry uses multidisciplinary (MD) teams to enhance the success of new product development 1. Multidisciplinary teams are also essential components of knowledge management practices in organizations. The combination of MD teams and optimizing emerging technologies enables organizations to manage the human side of learning and complex decision-making 2. Because the needs of industry often influence the professional preparation of new entrants into the workforce, it is critical to attend to those educational issues involved with multidisciplinary teams. The current study provides insight into the under explored area of multidisciplinary teaming instruction and assessment within a senior capstone design course. Numerous curricular changes in engineering disciplines nationwide have focused instruction on communication and teamwork skills 3. While some programs have engaged in comprehensive curricular change, others have designed new stand-alone communication courses for engineering students 4. Many of these communication-intensive courses target technical communication as a key critical skill to learn 5. Other such communication courses for engineers focus on different communication skills such as listening, teamwork, visual aids, group creativity, and audience analysis 6 .

There is a significant interest in developing renewable solid base catalysts from agricultural wa... more There is a significant interest in developing renewable solid base catalysts from agricultural wastes for the use in the transesterification of fats into fatty acid methyl esters (FAME). In this study, an inexpensive base catalyst was synthesized by impregnating waste oyster shell with 50% sodium hydroxide solution, followed by calcination at 1000°C for 3 h. The resulting solid catalyst was used to catalyze transesterification of soybean oil. Transesterification using the catalyst was studied by systematically varying molar ratio (MR) (methanol to oil) and catalyst loading (CL). Results indicated that the highest FAME yield was 93.9% using MR of 12 and CL of 10%. Reusability tests suggested that the catalyst could be used for at least three runs without any significant decrease in FAME yield.

2012 ASEE Annual Conference & Exposition Proceedings

Enzyme and microbial technology, 2018

An innovative chemoenzymatic catalytic system for functionalizing lignin from Organosolv and Kraf... more An innovative chemoenzymatic catalytic system for functionalizing lignin from Organosolv and Kraft pulping processes to obtain oxirane rings was investigated. Novozym435 (immobilized C. antarctica lipase B: CalB) was used to catalyze the peroxidation of caprylic acid to peroxycaprylic acid, which in turn reacted with unsaturated CC bonds to form the oxirane ring. The conversion of OH groups to oxirane rings (epoxides) reached 90% and 55% after 12 h for the two processes, respectively. The residual enzyme activity over the time course of the reactions indicated transient denaturing due to association with the lignin substrate (10-50%) as well as irreversible denaturation due to exposure to hydrogen peroxide. Functionalized lignin has potential applications in the production of epoxy adhesive resins, and chemoenzymatic synthesis represents a "greener" pathway to this synthesis.

Plant Cell Reports, 1994

An endo-pectate lyase (PL; EC 4.2.2.2), originally cloned fiom the phytopathogenic bacterium Erwi... more An endo-pectate lyase (PL; EC 4.2.2.2), originally cloned fiom the phytopathogenic bacterium Erwinia chrysanthemi EC16, was expressed in recA (-) E. coli strain DK1, purified to a single band by isoelectric focusing and used to induce berberine production in established plant suspension cultures of Thalictrum minus L. subsp. saxatile. Addition of 10(-9)M pectate lyase c (PLc) stimulated berberine production and enhanced secretion of the alkaloid into the medium. A lower concentration of PLc, 10(-11)M, stimulated a transient two-fold increase in cell growth rate relative to untreated cultures. Parallel changes in L-phenylalanine ammonia lyase (PAL; EC 4.3.1.5) activity with the rate of berberine synthesis and the inverse relationship between cell growth and berberine synthesis imply that berberine synthesis is stress-related in this cell line.

2004 Annual Conference Proceedings

ABET 2000 Criterion 3 explicitly states that engineering graduates must have "an understanding of... more ABET 2000 Criterion 3 explicitly states that engineering graduates must have "an understanding of professional and ethical responsibility," "an ability to communicate effectively," and "the broad education necessary to understand the impact of engineering solutions in a global and societal context." Service-learning is the approach we chose to enhance our students' capacities in these areas. For the past two years, senior projects containing a significant service-learning component have been offered in the capstone chemical engineering senior design course at NC State University. Students have worked with an economically disadvantaged community facing pollutant emissions resulting from a high concentration of local industries. Students characterized the pollutant problem and its sources and provided the community with process-related information useful in their discussions with regulatory bodies. This paper will review the conceptual foundations of service-learning, discuss potential applications of service-learning in engineering curricula, and summarize the strategies used and the challenges faced in the design and implementation of a service-learning component in chemical engineering senior design.

2004 Annual Conference Proceedings

2003 Annual Conference Proceedings

2003 Annual Conference Proceedings

Applied Biochemistry and Biotechnology, 1993

A quantitative comparision is offered between a kinetic model for product-inhibited, immobilized ... more A quantitative comparision is offered between a kinetic model for product-inhibited, immobilized cell, metabolism and a high-resolution scanning microfluorimetric characterization of variation of cell growth rates with position in immobilized cell cultures. The kinetic model is based exclusively on kinetic parameters derived from free cell suspension cultures and literature data for diffusion in biomass-loaded gels; the scanning microfluorimetry provides a