Improved isolation purple mebrane contain bacteriorhodopsin from Halobacterium salinarum (Article Uncorrected Proof)

Nowadays، biological substances have allocated many applications to themselves in distinct industries. In this field، biological molecules with various potentials have been identified، from which we can refer to bacteriorhodopsin (BR). Bacteriorhodopsin is found in purple membrane of halobacterium salinarum. Due to its stability and various characteristics like possession of properties of a proton pump، bacteriorhodopsin has many applications in different industries. One of the most important industrial and semi-industrial production processes for bacteriorhodopsin is the isolation and purification of the purple membrane. In this investigation، after halobacterium salinarum culture، the purification was done according to the Yucel method. So as to produce bacteriorhodopsin in semi-industrial scale، a modified method was developed by substitution of mechanical approach with enzymatically method to destruction of DNA and uses of osmotic shock instead of dialyze. This method led to decrease of time and isolation cost in comparison to Yucel method. The contamination percentage of the PM was estimated below 5% for both methods. The purification percentages were 67±1% and 68±4% for the modified method and Yucel method، respectively، which is indicating of the equal purification percentage for both methods. Bacteriorhodopsin amount was 8. 2±0. 4، 8. 1±0. 6 mg per liter for the improved method and Yucel method، respectively. The enzyme activity assay by Kuyama method indicated that the pH variation was 1 unit with the same BR amount for both methods. Hence، the modified method introduced in this investigation could reduce time and costs of the purification by maintaining the BR characteristics.