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Muhammad Wajid Ullah,Waleed Ahmad Khattak,Mazhar Ul-Islam,Shaukat Khan,박중곤 한국생물공학회 2015 Biotechnology and Bioprocess Engineering Vol.20 No.3
This study was intended to develop an encapsulated yeast cell-free system (EyCFS) by confining yeast cell-free lysate within a calcium alginate capsule. The system was evaluated for bio-ethanol production at elevated temperatures and was compared to a bare yeast cell-free system (ByCFS). Fermentation of 10 g/L glucose with shaking (150 rpm), using 2 mg/mL cell-free proteins in the ByCFS produced 3.31 g/L bio-ethanol, corresponding to 65% of the maximal theoretical yield, at 45°C and pH 7.0. On the contrary, the EyCFS produced 4.12 g/L bioethanol, corresponding to 81% of the maximal theoretical yield, under the same experimental conditions. The EyCFS also retained 32% of its original activity after 15 consecutive batches. We observed an 11% increase in bio-ethanol production after replenishment of cofactors (ATP and NADH) and ATPase. The weight-based total turnover number (TTNw; 0.82 × 103), cost ratio (R value; 1.22), and yield (80.4%) indicated the economic suitability of the EyCFS for large-scale production. Connecting the EyCFS with an encapsulated saccharification system through separate hydrolysis and fermentation (SHF) resulted in production of 4.87 g/L bio-ethanol, corresponding to 87.6% of the maximal theoretical yield. This system resolved serious limitations of conventional simultaneous saccharification and fermentation in bare cell-free systems. These data demonstrates the superiority of the proposed system in terms of thermal stability, yield, efficacy, and cost-effectiveness.
Muhammad Wajid Ullah,마잘울이슬람,Shaukat Khan,Nasrullah Shah,박중곤 한국화학공학회 2017 Korean Journal of Chemical Engineering Vol.34 No.6
Conventional approaches of regulating natural biochemical and biological processes are greatly hampered by the complexity of natural systems. Therefore, current biotechnological research is focused on improving biological systems and processes using advanced technologies such as genetic and metabolic engineering. These technologies, which employ principles of synthetic and systems biology, are greatly motivated by the diversity of living organisms to improve biological processes and allow the manipulation and reprogramming of target bioreactions and cellular systems. This review describes recent developments in cell biology, as well as genetic and metabolic engineering, and their role in enhancing biological processes. In particular, we illustrate recent advancements in genetic and metabolic engineering with respect to the production of bacterial cellulose (BC) using the model systems Gluconacetobacter xylinum and Gluconacetobacter hansenii. Besides, the cell-free enzyme system, representing the latest engineering strategies, has been comprehensively described. The content covered in the current review will lead readers to get an insight into developing novel metabolic pathways and engineering novel strains for enhanced production of BC and other bioproducts formation.
Ullah, Asad,Saleem, Muhammad Wajid,Kim, Woo-Seung Elsevier 2017 International journal of greenhouse gas control Vol.66 No.-
<P><B>Abstract</B></P> <P>A capacitive deionization (CDI) device was proposed for NH<SUB>3</SUB>-based CO<SUB>2</SUB> absorption-desorption process, to reduce the stripper regeneration energy. A rate-based model, RateFrac, was developed for the absorber, along with an equilibrium-based model, RadFrac, for the stripper. The model was verified, and the results have shown good agreement with experimental data. The CO<SUB>2</SUB> capture process, which is integrated with CDI, was simulated and compared with a non-CDI CO<SUB>2</SUB> capture process based on regeneration energy. Operating parameters such as flow rate, lean CO<SUB>2</SUB> loading, and ammonia concentration in the lean solvent were used to analyze the integrated model. Stripper regeneration energy can be reduced by as much as 37.5% by using the CDI setup. Moreover, energy cost estimation was performed using two heat sources (natural gas and coal). CDI saved a maximum of 31% of the energy costs for a natural gas–fired boiler and 12.3% of the energy costs for a coal-based boiler.</P> <P><B>Highlights</B></P> <P> <UL> <LI> NH<SUB>3</SUB>-based CO<SUB>2</SUB> capture process integrated with Capacitive deionization device was proposed to reduce regeneration energy. </LI> <LI> The model was verified and the results show good agreement with the experimental data. </LI> <LI> Main operating parameters of the CO<SUB>2</SUB> capture process were analyzed to check their effects on regeneration energy. </LI> <LI> Energy Cost estimation of CO<SUB>2</SUB> capture process both with and without capacitive deionization was performed. </LI> <LI> Regeneration energy reduced up to 37.5% by integrating capacitive deionization device. </LI> </UL> </P>
Mazhar Ul-Islam,Muhammad Wajid Ullah,Shaukat Khan,박중곤 한국화학공학회 2020 Korean Journal of Chemical Engineering Vol.37 No.6
Bacterial cellulose (BC), an important biopolymer, has gained tremendous interest in several fields in the last few decades. Despite having the same chemical structure as plant cellulose, BC is superior in physical appearance and purity, as well as in mechanical, crystallinic, and biological properties for multiple applications. Despite these features, BC has limitations in production cost as well as physiological features. Notable limitations, including a non-bactericidal nature, low biocompatibility, and lack of conductive and magnetic properties, have been compensated through the development of composites using nanomaterials and polymers. Similarly, the limitation associated with cost has been reduced by developing new BC synthesis strategies, designing novel bioreactors, using genetically modified microbial species, and exploring alternative cheap fermentation media. Successful BC production has been reported from the use of industrial, confectionary, municipal and other wastes, including coconut water and fruit juices. Herein, we overview various efforts made thus far in identifying waste byproducts and inexpensive carbon sources for cost-effective BC production. It also provides information about the BC market and selling price, as well as techno-economic analysis of biotechnological BC production. This review article includes findings reported in the last few decades, and we hope it will be of great interest for readers as well as commercial BC producers.
Khattak, Waleed Ahmad,Ullah, Muhammad Wajid,Ul-Islam, Mazhar,Khan, Shaukat,Kim, Minah,Kim, Yeji,Park, Joong Kon Springer-Verlag 2014 Applied microbiology and biotechnology Vol.98 No.23
<P>Most biomanufacturing systems developed for the production of biocommodities are based on whole-cell systems. However, with the advent of innovative technologies, the focus has shifted from whole-cell towards cell-free enzyme system. Since more than a century, researchers are using the cell-free extract containing the required enzymes and their respective cofactors in order to study the fundamental aspects of biological systems, particularly fermentation. Although yeast cell-free enzyme system is known since long ago, it is rarely been studied and characterized in detail. In this review, we hope to describe the major pitfalls encountered by whole-cell system and introduce possible solutions to them using cell-free enzyme systems. We have discussed the glycolytic and fermentative pathways and their regulation at both transcription and translational levels. Moreover, several strategies employed for development of cell-free enzyme system have been described with their potential merits and shortcomings associated with these developmental approaches. We also described in detail the various developmental approaches of synthetic cell-free enzyme system such as compartmentalization, metabolic channeling, protein fusion, and co-immobilization strategies. Additionally, we portrayed the novel cell-free enzyme technologies based on encapsulation and immobilization techniques and their development and commercialization. Through this review, we have presented the basics of cell-free enzyme system, the strategies involved in development and operation, and the advantages over conventional processes. Finally, we have addressed some potential directions for the future development and industrialization of cell-free enzyme system.</P>
Khan, Shaukat,Ul-Islam, Mazhar,Ullah, Muhammad Wajid,Kim, Yeji,Park, Joong Kon Springer-Verlag 2015 CELLULOSE Vol.22 No.4
<P>This study explores the biocompatible behavior of bacterial cellulose (BC) composites with the highly conductive poly(3,4-ethylenedioxythiophene)-poly(styrene sulfonate) (PEDOT:PSS). To synthesize this novel composite, we utilized an ex situ penetration method, whereby never-dried BC sheets were incubated with aqueous PEDOT: PSS solution. The resulting composite films were characterized using several analytical tools. Field-emission scanning electron microscopy illustrated the impregnation of PEDOT: PSS into the BC matrix, while the uniform dispersion of PEDOT: PSS in the composites was confirmed with energy-dispersive X-ray spectroscopy. The conductivity of the PEDOT: PSS incorporated BC was 7.3 9 10(-2) +/- 0.021 S/cm with 29.37 +/- 2.13 weight percentage (wt%) of PEDOT: PSS. The biocompatibility of the BC-PEDOT: PSS film was tested against animal fibroblast cells. The composites showed excellent cell adhesion and proliferation. The animal cells showed filopodia formation and interconnectivity during 3 days of incubation. The cytotoxicity of the BC-PEDOT:PSS film was also assayed, confirming the non-toxic nature of this composite. Taken together, our results demonstrate that this novel biocompatible BC-PEDOT:PSS composite could potentially be used for biomedical applications, particularly in the biosensors, drug delivery devices, neural implants, and tissue engineering fields.</P>