Sequential optimization of production of a thermostable and organic solvent tolerant lipase by recombinant Escherichia coli

Several medium formulations were screened for the production of a thermostable and organic solvent tolerant lipase by a recombinant Escherichia coli BL21. The highest lipase production (28.9 ± 4.1 IU/mL) was obtained in Luria Bertani medium with the addition of 1% (w/v) glucose. The medium formulation and fermentation conditions were then subjected to sequential optimization. Using a Plackett-Burman design, glucose, NaCl, temperature and induction time were found to be the most significant variables affecting lipase production, and these were then optimized using response surface methodology (RSM). The large value of R 2 (0.979) showed that the quadratic model used for the prediction is highly significant. The optimum levels of these four significant variables (glucose, NaCl, temperature and induction time) as predicted by RSM were 32.4 g/L, 5 g/L, 31.7°C and 2.1 h, respectively. The amount of lipase activity (50.2 ± 4.5 IU/mL) produced under these optimal conditions fitted well to the value (48.9 IU/mL) predicted by RSM. Production of lipase in optimized fermentation was about 2.5-fold higher than in non-optimized fermentation

Optimization of fed-batch fermentation for organic solvent tolerant and thermostable lipase production from recombinant E. coli

Objective: Lipases are industrially important enzymes especially the thermostable and organic solvent tolerant lipases. This study was planned to enhance the production using fed batch fermentation technique. Materials and Methods: The possibility of using fed-batch fermentation for improvement of organic solvent tolerant and thermostable lipase production by recombinant E.coli BL21 was studied in 2 L stirred tank bioreactor. Exponential fed-batch fermentations were operated at different specific growth rates (μ). The effect of antibiotics addition in feed medium, on the number of plasmid bearing cells was also investigated. Kinetics of the fed-batch fermentation was evaluated for the generation of kinetic parameter values. Effect of yeast extract in feed medium was also investigated. Results: The number of plasmid bearing cells was increased from 13 % to 91 % with the addition of antibiotics (2 g/L ampicillin and 1.4 g/L chloramphenicol) in the feed medium. Among the different μ investigated (0.05, 0.10 and 0.15 h-1), the highest cell concentration (30.32 g/L) and lipase production (130.5 IU/mL) were obtained in exponential fed-batch fermentation, where μ was controlled at 0.10 h-1 with 800 g/L glucose in the feed medium. No significant improvement was achieved on growth and lipase production in fed-batch fermentation with addition of yeast extract in feed medium, though μ was controlled at 0.10 h-1. Conclusion: Fed-batch was found a good technique for enhancement of lipase production from recombinant E.coli BL21 on the cost of increasing time of fermentation (fermentation time for batch fermentation was 16 h and for fed-batch was 26 h) and quantity of some medium ingredients as compared to the batch mode

Diabetes conversation map - A novel tool for diabetes management self-efficacy among type 2 diabetes patients in Pakistan: A randomized controlled trial

Background: This study aimed to measure the effect of diabetes education using the novel method of diabetes conversation map (DCM) as compared to routine counselling (RC) on diabetes management self-efficacy (DMSE) among patients living with type 2 diabetes in Karachi, Pakistan.Methods: A parallel arm randomized controlled trial among patients with type 2 diabetes aged 30-60 years, with HbA1c \u3e 7%, diagnosed for at least 5 yrs., was conducted at the national institute of diabetes and endocrinology in Karachi, Pakistan. A total 123 type 2 diabetes patients were randomized into DCM (n = 62) or RC (n = 61). Four weekly diabetes control sessions of 40 min each using the DCM or RC was provided. DMSE was measured using a validated Urdu language DMSE tool at baseline and after three months of the randomization. Change in DMSE and HbA1c levels within groups (pre-post) and between the groups after 3 months of enrollment was compared.Results: Baseline characteristics except HbA1c were similar between the two arms. After 3 months of enrollment, there was no change in the DMSE score in the RC arm however, significant increase in DMSE score was noted in the DCM arm (P = \u3c 0.001). The average difference (95% confidence interval) in DMSE score between the DCM and RC arm was 33.7(27.3, 40.0; p = \u3c 0.001) after 3 months of the enrollment. Difference in HbA1c within groups was not significant.Conclusions: DCM significantly improved DMSE among type 2 diabetes patients in a developing country setting like Pakistan. Healthcare workers caring for type 2 diabetes patients need to be trained on DCM to effectively utilize this novel tool for educating diabetes patients.Trial registration: This trial was prospectively registered. ClinicalTrials.gov Identifier: NCT03747471. Date of registration: Nov 20. 2018

In vitro anti-leishmanial and anti-fungal effects of new SbIII carboxylates

Ring opening of phthalic anhydride has been carried out in acetic acid with glycine, β-alanine, L-phenylalanine, and 4-aminobenzoic acid to yield, respectively, 2-{[(carboxymethyl)amino]carbonyl}benzoic acid (I), 2-{[(2-carboxyethyl)amino]carbonyl}benzoic acid (II), 2-{[(1-carboxy-2-phenylethyl)amino]carbonyl}benzoic acid (III), and 2-[(4-carboxyanilino)carbonyl]benzoic acid (IV). Compounds I-IV have been employed as ligands for Sb(III) center (complexes V-VIII) in aqueous medium. FTIR and 1H NMR spectra proved the deprotonation of carboxylic protons and coordination of imine group and thereby tridentate behaviour of the ligands as chelates. Elemental, MS, and TGA analytic data confirmed the structural hypothesis based on spectroscopic results. All the compounds have been assayed in vitro for anti-leishmanial and anti-fungal activities against five leishmanial strains L. major (JISH118), L. major (MHOM/PK/88/DESTO), L. tropica (K27), L. infantum (LEM3437), L. mex mex (LV4), and L. donovani (H43); and Aspergillus Flavus, Aspergillus Fumigants, Aspergillus Niger, and Fusarium Solani. Compound VII exhibited good anti-leishmanial as well as anti-fungal impacts comparable to reference drugs