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Articles by Shafqat Farooq
Total Records ( 3 ) for Shafqat Farooq
  Amjad Hameed , Salman Akbar Malik , Nayyer Iqbal , Rubina Arshad and Shafqat Farooq
  Influence of oxidative stress induced by exogenous application of hydrogen peroxide on initial leaf and coleoptile growth in etiolated wheat seedlings was studied. Leaf and coleoptile growth parameters (mean fresh weight and length) showed a transient stress effect during very initial age, becoming non-significant (P>0.05) in later age (8th day). Mean leaf fresh weight increased steadily after 5th day in both stressed and control seedlings, however the magnitude was lower in stressed seedlings and the difference was non-significant (p>0.05). Mean coleoptile fresh weight was significantly (p<0.01) lower in stressed seedlings on all days except on 6th and 8th day where the difference was non-significant (p>0.05). Mean leaf and coleoptile length were significantly (p<0.01) lower in stressed seedlings during 5 to 7th day, however the difference was non-significant (p>0.05) on 8th day. Stress effect was more pronounced on 5th day in case of leaf and coleoptile length and coleoptile fresh weight. Collectively oxidative stress induced by exogenous application of hydrogen peroxide induces a transient and finally a non-significant effect on initial leaf and coleoptile growth, which indicated the adaptation of seedlings to applied stress.
  Rubina Arshad , Shafqat Farooq and Syed Shahid Ali
  The aim of present study was to optimize conditions for conversion of penicillin G into 6-APA using intact crude cells of locally collected PGA producing bacterial strains as biocatalyst. Corn steep liquor medium supplemented with phenylacetic acid was used for PGA production. For enzymatic conversion of penicillin G into 6-APA by PGA impregnated bacterial cells, a maximum reaction time of 4 h was found adequate. The procedure for extraction and crystallization of 6-APA from the enzyme reaction mixture was standardized. Isolation process was carried out under controlled pH conditions and 6-APA crystals were recovered from the reaction mixture via filtration, concentration and drying. The maximum PGA activity was observed in Escherichia coli strain BDCS-N-FMu12 (6.4 mg 6-APA h-1 mg-1 wet cells) whereas Bacillus megaterium (ATCC 14945 used as check) exhibited only 2.4 mg 6-APA h-1 mg-1 wet cells. The overall yield of 6-APA crystals obtained after enzymatic conversion of penicillin G ranged between 37-55 and 47-68% in foreign and local strains, respectively. BDCS-N-FMu12 was identified as the best PGA producer with 68% 6-APA conversion whereas ATCC 14945 showed the lowest conversion (37%). The recovery of 6-APA (68%) obtained by using crude intact cells as cheap biocatalyst appeared promising. The process of enzyme fermentation and 6-APA crystallization optimized during this study seems cost-effective and environment-friendly. However, further studies are required to scale up the 6-APA biosynthesis reaction for achieving 80-90% conversion of penicillin G into 6-APA by PGA hyper-producing locally collected strains of E. coli.
  Rubina Arshad , Shafqat Farooq and Syed Shahid Ali
  The present study was conducted to see the difference in production of 6-APA I) between wild strains of E. coli collected from local environment and their acridine orange (AO) induced mutants and ii) between mutants and E. coli strains (ATCC 11105 and ATCC 9637) of American Type Culture Collection (ATCC) used commercially for enzymatic production of 6-APA. The optimum conditions for bioconversion were standardized and 6-APA was obtained in crystalline form. Relative PGA activity of local and foreign E. coli strains varied significantly with the highest being 12.7 in mutant strain (BDCS-N-M36) and the lowest 4.3 mg 6-APA h-1mg-1 wet cells in foreign strain (ATCC 11105). The enzyme activity exhibited by mutant strain (BDCS-N-M36) was also two folds higher compared to that in wild parent BDCS-N-W50 (6.3 mg 6-APA h-1 mg-1 wet cells). The overall production of 6-APA and conversion ratios ranged between 0.25-0.41 g of 6-APA per 0.5 g of penicillin G and 51-83%, respectively. Maximum conversion ratio (83%) was achieved by using crude cells of mutant strain (BDCS-N-M36) which is the highest value ever reported by crude cells on a shake-flask scale whereas reported 6-APA production by immobilized cells is 60-90% in batch and continuous systems. Results are being discussed with reference to importance of local bacterial strains and their significance for industrially important enzymes.
 
 
 
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