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A halothermotolerant Gram-positive spore-forming bacterium was isolated from petroleum reservoirs in Iran and identified as Bacillus licheniformis sp. strain ACO1 by phenotypic characterization and 16S rRNA analysis. It showed a high capacity for bioemulsifier production and grew up to 60 degrees C with NaCl at 180 g l(-1). The optimum NaCl concentration, pH and temperature for bioemulsifier production were 4% (w/v), 8.0, and 45 degrees C, respectively. Although ACO1 did not utilize hydrocarbons, it had a high emulsifying activity (E (24) = 65 +/- 5%) on different hydrophobic substrates. Emulsification was optimal while growing on yeast extract as the sole carbon source and NaNO(3) as the nitrogen source. The efficiency of the residual oil recovery increased by 22% after in situ growth of B. licheniformis ACO1 in a sand-pack model saturated with liquid paraffin.

L-asparaginase has been used in the treatment of patients with acute lymphoblastic leukemia (ALL) for more than 30 years. Rapid clearance of the enzyme from blood stream and its L-glutaminase-dependent neurotoxicity has led to searching for new L-asparaginases with more desirable properties. In the present study, L-asparaginase coding gene of Halomonas elongata was isolated, expressed in Escherichia coli, purified, and characterized. The purified protein was found to have a molecular mass of 39.5 kDa and 1000-folds more activity towards L-asparagine than L-glutamine. Enzyme-specific activity towards L-asparagine was determined to be 1510 U/mg, which is among the highest reported values for microbial L-asparaginases. K , V, and k values were 5.6 mM, 2.2 μmol/min, and 1.96 × 10 1/S, respectively. Optimum temperature was found to be 37 °C while the enzyme showed maximum activity at a wide pH range (from 6 to 9). Enzyme half-life in the presence of human serum at 37 °C was 90 min which is three times higher when compared with reported values for E. coli L-asparaginase. Enzyme showed cytotoxic effects against Jurkat and U937 cell lines with an IC of 2 and 1 U/ml, respectively. Also, no toxic effects on human erythrocytes and Chinese hamster ovary cell lines were detected, and just minor inhibitory effects on human umbilical vein endothelial cells were observed. This is the first report describing the therapeutic potentials of a recombinant L-asparaginase isolated from a halophilic bacterium as an anticancer agent.

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Different types of microorganisms are capable of degrading azo dyes due to their high metabolic potentials. However, many of them cannot be used as degrading agents due to the harsh conditions of dyepolluted environments. Here, halophilic and halotolerant microorganisms can be the best candidates for a practical biodecolorization process as they are able to grow easily at high concentrations of salts. In addition, some of them can tolerate the presence of other stress factors such as toxic oxyanions and heavy metals which are so common in industrial wastewaters. In recent years, several studies have been focused on halophilic and halotolerant microorganisms and their abilities for decolorization of azo dyes. For example, Shewanella putrefaciens was determined to be capable of the complete removal of Reactive Black-5, Direct Red-81, Acid Red-88 and Disperse Orange-3 (all 100 mg l −1 ) within 8 h in the presence of 40 g l −1 NaCl. Another halophilic example is Halomonas sp. GTW which has shown a remarkable performance in the removal of different azo dyes within 24 h in the presence of 150 g l −1 NaCl. Although these approaches need to be studied in more detail, some studies have designed different types of fermentation processes and even specific fermentors to provide a practical methodology for industrial wastewater remediation.Sequential anaerobic EGSB (expanded granular sludge blanket) and aerobic reactor was the result of an important attempt to design an effective approach to large-scale biodecolorization.

Horseradish peroxidase (HRP) is an important heme-containing glyco-enzyme that has been used in many biotechnological fields. Valuable proteins like HRP can be obtained in sufficient amounts using Escherichia coli as an expression system. However, frequently, the expression of recombinant enzyme results in inclusion bodies, and the refolding yield is generally low for proteins such as plant peroxidases. In this study, a recombinant HRP was cloned and expressed in the form of inclusion bodies. Initially, the influence of few additives on HRP refolding was assessed by the one factor at a time method. Subsequently, factors with significant effects including glycerol, GSSG/DTT, and the enzyme concentration were selected for further optimization by means of the central composite design of response surface methodology (RSM). Under the obtained optimal condition, refolding increased about twofold. The refolding process was then monitored by the intrinsic fluorescence intensity under optimal conditions (0.35 mM GSSG, 0.044 mM DTT, 7 % glycerol, 1.7 M urea, and 2 mM CaCl2 in 20 mM Tris, pH 8.5) and the reconstitution of heme to the refolded peroxidase was detected by the Soret absorbance. Additionally, samples under unfolding and refolding conditions were analyzed by Zetasizer to determine size distribution in different media.