Natural pigment production by monascus purpureus: improving the yield in a bioreactor based on statistical analysis

Due to the especial properties such as high growth rates, easy extraction as well as high yields, using microorganisms in comparison to other sources is more chosen for pigment production. Pigments are used in food industries as natural colorants and preservatives, they also have pharmaceutical applications. In this study, fungus Monascus purpureus PTCC 5303 have been used to produce red, orange and yellow pigments. At first significant variables were screened based on plackett-Burman design and then the optimized value of two effectivefactors such as yeast extract and K[2] HPO[4] concentrations wasoptimized byresponse surface method. Optimal levels of factors were found to be 2/75 g/L yeast extract and1/5 g/LK[2] PO[4] respectively. Antimicrobial activity of pigments was evaluated on Gram-positive foodborne bacteria under optimal conditionswhich resultsshowed inhibitory effects. Moreover Pigments production at optimal conditions in a bioreactor was evaluatedand the rate of production of red, orange and yellow pigments, 2.05, 1.55 and 0.78 [ODU/ml] were observed respectively

enhancement of biodesulfurization activity in a novel indigenous engineered pseudomonas putida

The combustion of sulfur-rich fossil fuels leads to release of sulfur oxide pollution in the environment. In biodesulfurization process, an organism is able to remove sulfur from fossil fuels without decreasing the caloric value of those substrates. The main aim of this research was to design a recombinant microorganism to remove the highest amount of sulfur compounds in fossil fuels. Three genes [dszA,B,C] from dsz operon are responsible for the 4S pathway [biodesulfurization pathway] in Rhodococcus erythropolis IGTS8 were inserted into the chromosome of a novel indigenous Pseudomonas putida. The reaction catalyzed by products of dszA,B,C genes require FMNH2 supplied by dszD enzyme. Thus, pVLT31 vector harboring dszD gene was transferred into this recombinant strain. The results demonstrated a higher biodesulfurization activity when the flavin reductase gene was transferred into recombinant P. putida harboring dszA,B,C. These results were approved by the Gibbs test and HPLC analysis. These analyses showed that this novel indigenous engineered P. putida could be a promising candidate for an industrial and environmental application for Biodesulfurization process