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Waleed Ahmad Khattak,박중곤,마잘울이슬람 한국화학공학회 2012 Korean Journal of Chemical Engineering Vol.29 No.11
This study was conducted to evaluate the presence, origination and classification of various hydrolyzing enzymes from malt and their specified hydrolyzing effects on various substrates for bioethanol production and to link these characteristics with the future prospects of bioethanol production. These enzymes are categorized as cell wall,starch, protein, lipid, polyphenol and thiol hydrolyzing enzymes based on their substrate specificity. Waste from beer fermentation broth (WBFB) has been evaluated as a rich source of malt derived hydrolyzing enzymes with significant self potential for bioethanol production. However, yeast cells cannot survive at the high temperature required for the saccharification activities of hydrolyzing enzymes during simultaneous saccharification and fermentation (SSF). This dilemma might be resolved by bioethanol production at elevated temperatures via cell-free fermentation systems in the presence of malt hydrolyzing enzymes. Moreover, emerging technologies such as genetic engineering in biomass and biotransformation in cell-free enzymatic systems will likely hasten bioethanol production in the near future. The present study adds new dimensions to eco-friendly bioethanol production from renewable and waste energy resources based on the specific hydrolyzing activities of malt enzymes.
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>
Ahmad, Dilshad,Bakairy, Abdul Karieem,Katheri, Abdull Malika,Tamimi, Waleed Asian Pacific Journal of Cancer Prevention 2015 Asian Pacific journal of cancer prevention Vol.16 No.9
Cigarette smoke contains oxidants and free radicals which are carcinogens that can induce mutations in humans. Single nucleotide polymorphisms (SNPs) are the most frequent genetic alterations found in the human genome. In the present study, we have examined the ability of the murine double minute 2 (Mdm2) (rs769412) A>G polymorphism in cigarette smokers to predict risk of cancers. Our results showed that of smokers, 87% were found with AA genotype, 10% with heterozygous AG genotype, and 3% with GG genotype. The heterozygous AG genotype was observed in a lower percentage of smokers (10%) as compared to non-smokers (18%), whereas, homozygous AA genotype was observed in lower percentage of non-smokers (81%) as compared to the smokers (87%). The results from present study support the association with an allele and AG genotype in non-smokers. However, further studies are required to establish the role of Mdm2 (rs769412) C>T in cigarettes smokers and diseases.
Dilshad, Ahmad,Abulkhair, Omalkhair,Nemenqani, Dalal,Tamimi, Waleed Asian Pacific Journal of Cancer Prevention 2012 Asian Pacific journal of cancer prevention Vol.13 No.11
Breast cancer is the most commonly diagnosed cancer in women in the world and is one of the leading causes of death due to cancer. Health benefits have been linked to additive and synergistic combinations of phytochemicals in fruits and vegetables. Nigella sativa has been shown to possess anti-carcinogenic activity, inhibiting growth of several cancer cell lines in vitro. However, the molecular mechanisms of the anti-cancer properties of Nigella sativa phytochemical extracts have not been completely understood. Our data showed that Nigella sativa extracts significantly inhibited human breast cancer MDA-MB-231 cell proliferation at doses of $2.5-5{\mu}g/mL$ (P<0.05). Apoptotic induction in MDA-MB-231 cells was observed in a dose-dependent manner after exposure to Nigella sativa extracts for 48 h. Real time PCR and flow cytometry analyses suggested that Nigella sativa extracts possess the ability to suppress the proliferation of human breast cancer cells through induction of apoptosis.
Zaid, Khaled Waleed,Nhar, Bander Mossa,Alanazi, Salman Mohammed Ghadeer,Murad, Rashad,Domani, Ahmad,Alhaf, Awadh Jamman Asian Pacific Journal of Cancer Prevention 2016 Asian Pacific journal of cancer prevention Vol.17 No.7
Recombinant human bone morphogenetic protein-2 (rhBMP-2 ), a member of the TGF-${\beta}$ family, has been used widely in recent years to regenerate defects of the maxillary and mandible bones. Such defects are sometimes caused by resection of oral squamous cell carcinoma (OSCC) yet the biologic effects of rhBMP-2 on these carcinomas are not fully clear. The objective of this study was to determine histologically whether rhBMP-2 produces adverse effects on angiogenesis during induction of OSCC, a biologic process critical for tumor formation in an experimental model in the buccal pouch of golden Syrian hamsters. Buccal cavities were exposed to painting with 0.5% DMBA in liquid paraffin three times a week for 14 weeks, then biopsies were taken. Division was into 2 groups: a study group of 10 hamsters receiving $0.25{\mu}g/ml$ of rhBMP-2 in the $3^{rd}$ and $6^{th}$ weeks; and a control group of 10 hamsters which did not receive any additional treatment. VEGF expression and microvessel density were measured but no differences were noted between the two groups. According to this study, rh-BMP-2 does not stimulate angiogenesis during induction of OCSSs.
Shaukat Khan,마잘울이슬람,Waleed Ahmad Khattak,Muhammad Wajid Ullah,유보완,박중곤 한국화학공학회 2015 Korean Journal of Chemical Engineering Vol.32 No.4
Current study illustrates the effect of high yeast cell density contained in the waste of beer fermentationbroth (WBFB) on bio-ethanol production through simultaneous saccharification and fermentation (SSF). WBFB wasdisintegrated (DW) and comparatively evaluated against nondisintegrated WBFB (NDW) for bio-ethanol production atvariant temperatures. Final bio-ethanol levels of 36.38 g/L and 18.65 g/L at 30 oC, 4.45 g/L and 43.23 g/L at 40 oC, and2.32 g/L and 6.83 g/L at 50 oC were achieved with 20% NDW and DW, respectively, after 12 h. DW carried out thesimultaneous saccharification and fermentation (SSF) process through cell free enzyme system and was capable of bioethanolproduction beyond the microbial growth temperature (>30 oC) of NDW system. The increase in sedimentconcentration in DW positively influenced the production capabilities of the system producing 43.23 g/L, 54.39 g/L and62.82 g/L bio-ethanol with 20, 30 and 40% sediments at 40 oC, respectively. The retardation of bioethanol production atelevated temperature (50 oC) was expected to be caused by denaturing or digesting of certain enzymes as observedthrough SDS-PAGE. FTIR analysis also showed the appearance of a new band at approximately 1,590 cm−1 due to unfoldingof polypeptide chains at 50 oC. The overall study reveals the positive influence of increased cell density on ethanolproduction and presents evidence for decreased fermentation beyond certain temperature limits.
( Aqsa Ahmed ),( Abdullah Ahmad ),( Renhan Li ),( Waleed Al-ansi ),( Momal Fatima ),( Bilal Sajid Mushtaq ),( Samra Basharat ),( Ye Li ),( Zhonghu Bai ) 한국미생물 · 생명공학회 2021 Journal of microbiology and biotechnology Vol.31 No.11
Violacein, a purple pigment first isolated from a gram-negative coccobacillus Chromobacterium violaceum, has gained extensive research interest in recent years due to its huge potential in the pharmaceutic area and industry. In this review, we summarize the latest research advances concerning this pigment, which include (1) fundamental studies of its biosynthetic pathway, (2) production of violacein by native producers, apart from C. violaceum, (3) metabolic engineering for improved production in heterologous hosts such as Escherichia coli, Citrobacter freundii, Corynebacterium glutamicum, and Yarrowia lipolytica, (4) biological/pharmaceutical and industrial properties, (5) and applications in synthetic biology. Due to the intrinsic properties of violacein and the intermediates during its biosynthesis, the prospective research has huge potential to move this pigment into real clinical and industrial applications.