ABSTRACT
Background: lipase enzymes have applications in a wide range of industries. A crucial determining factor of industrial prices of these enzymes is the culture media composition that is constantly under review by researchers. In this work, for maximum lipase production by Bacillus sp. ZR-5, culture media compositions were optimized using "one variable at a time" strategy
Methods: for this purpose, the culture medium parameters such as low and high cost carbon and nitrogen sources, substrates and incubation times were evaluated
Results: maximum lipase activity was achieved after 24 hr of incubation with 1.5% of glucose syrup [1600+/-69.1u/mg], 1% of fish powder [1238+/-36.7 u/mg] and olive oil [1407+/-2.1 u/mg] as low cost carbon and nitrogen sources and substrate, respectively
Conclusion: our results show a significant increase in lipase activity with usage of low cost sources; this could help in reducing the media prices for industrial application of lipase enzyme
ABSTRACT
Reteplase is a part of tissue plasminogen activator [t-PA] used for the removal of thrombi in blood vessels. In the present study we express the Reteplase gene in Escherichia coli TOP10 and then its thrombolytic activity was measured. The recombinant plasmid pBADgIIIA was transformed into the competent Escherichia coli TOP10 and then transformed bacteria was seeded into bioreactor containing 1.5 L LB medium and induced by 0.02% L-Arabinoseat 37 degreeC, pH 7, and 180 rpm until OD 600 of 0.6 was reached. Samples were analyzed by SDS-PAGE and western blotting and the expression of Reteplase was examined. Finally the activity of this recombinant protein was evaluated using Chromogenic Activity Assay Kit. The presence of Reteplase in transformed Escherichia coli TOP10 was examined by western blotting which revealed that the target protein in form inclusion body was expressed as a unique band at 39 and the refolded Reteplase was 66 KDa. The amount of protein produced was 90.5 microg/mL and its activity was determined as 0.8 units. In this study, the expression of Reteplase in Escherichia coli TOP10 was scaled up under optimum condition. Furthermore we earned Reteplase with partially suitable thrombolytic activity
ABSTRACT
One of the most important producers of high quality industrial enzymes is the Gram-positive bacterium, Bacillus subtilis [B. Subtilis]. One major limitation that hinders the wide application of B. subtilis is the secretion of high levels of extracellular proteases which degrade the secreted foreign proteins. In this study, homologus recombination technique was used to knock out its protease gene, aprE. The internal segment of the pro-sequence of aprE gene of B. subtilis 168 with a length of 80 bps and its complementary sequence were synthesized and ligated into pUB110 at EcoR1 and XbaI restriction sites. Competent cells of B. subtilis 168 were prepared and transformed by electroporation using Bio Rad gene pulser as explained in the methods section. Transformants carrying the recombinant plasmid were selected for resistance to neomycin. The success of homologous recombination was checked by PCR amplification of the neomycin gene which was part of the vector and did not exist in the genome of B. subtilis 168. The protease activity was measured using the Protease Fluorescent Detection Kit based on the proteolytic hydrolysis of fluorescein isothiocyanate [FITC]-labeled casein-substrate. The results demonstrated that aprE gene would not be able to produce further active subtilisin E. The reduction of protease activity also confirmed the efficacy of the induced mutation in this gene. It will therefore be a major challenge for future research to identify and modulate quality control systems of B. subtilis which limit the production of high quality protease- sensitive products such as lipase
ABSTRACT
The micro [mu] opioid receptors, which mediate the effects of morphine, are widely distributed in brain. The purpose of this study was to design a simple expression system for rat micro -receptor in Escherichia coli [BL21]. In this laboratory study, rat micro -receptor cDNA was isolated from pcDNA3 vector using Xba1 and Hind3 restriction enzymes. pET-15b was digested by Nco1 restriction enzyme. micro -receptor cDNA and pET-15b formed a recombinant DNA that was transformed to Escherichia coli [BL21]. The insert presence was proved by Rsa1 restriction enzyme and the induction of its expression was performed using IPTG. Finally, the presence of desired insert was confirmed using RSA1, and the colonies that had correct orientation in gene containing plasmid were used for further studies. On the SDS-page gel electrophoresis, a 33 kDa band was observed when IPTG was used at 0.5 and 1 mM concentrations, that is equal to calculated molecular weight of rat micro -receptor. At the end of this project, the expression of rat micro -receptor by IPTG induction was successfully performed
ABSTRACT
The present study was undertaken to screen the soil samples collected in Iran for the presence of the Bacillus subtilis lipase A gene. The bacterial colonies obtained from the collected soil samples were examined by physical appearance, biochemical tests and the polymerase chain reaction [PCR]. Only four colonies were identified as putative B. subtilis strains and all contained the lipase A gene. However, the intensities of the DNA bands were different and correlated with the differences obtained from the biochemical tests. Polymorphism of the lipase gene was also determined in samples using SSCP assay. In conclusion, this study demonstrates an easy and reliable method for detection of the lipase gene in B. subtilis strains. Further screening of the soil by this method will enable the detection and identification of industrially more favorable lipases