RESUMEN
The current study describes a straightforward, biologically and environmentally friendly method for creating magnetic iron oxide (γ-Fe2O3) nanoparticles. We report here that the Bacillus subtilis SE05 strain, isolated from offshore formation water near Zaafarana, the Red Sea, Hurghada, Egypt, can produce highly magnetic iron oxide nanoparticles of the maghemite type (γ-Fe2O3). To the best of our knowledge, the ability of this bacterium to reduce Fe2O3 has yet to be demonstrated. As a result, this study reports on the fabrication of enzyme-NPs and the biological immobilization of α-amylase on a solid support. The identified strain was deposited in GenBank with accession number MT422787. The bacterial cells used for the synthesis of magnetic nanoparticles produced about 15.2 g of dry weight, which is considered a high quantity compared to the previous studies. The XRD pattern revealed the crystalline cubic spinel structure of γ-Fe2O3. TEM micrographs showed the spherically shaped IONPs had an average size of 7.68 nm. Further, the importance of protein-SPION interaction and the successful synthesis of stabilized SPIONs in the amylase enzyme hybrid system are also mentioned. The system showed the applicability of these nanomaterials in biofuel production, which demonstrated significant production (54%) compared to the free amylase enzyme (22%). Thus, it is predicted that these nanoparticles can be used in energy fields.
Asunto(s)
Amilasas , Biocombustibles , alfa-Amilasas , Nanopartículas Magnéticas de Óxido de HierroRESUMEN
Extracellular ß-1,3-1,4-glucanase-producing strain Halomonas meridiana ES021 was isolated from Gabal El-Zeit off shore, Red Sea, Egypt. The Extracellular enzyme was partially purified by precipitation with 75% acetone followed by anion exchange chromatography on DEAE-cellulose, where a single protein band was determined with molecular mass of approximately 72 kDa. The Km value was 0.62 mg ß-1,3-1,4-glucan/mL and Vmax value was 7936 U/mg protein. The maximum activity for the purified enzyme was observed at 40 °C, pH 5.0, and after 10 min of the reaction. ß-1,3-1,4-glucanase showed strong antibacterial effect against Bacillus subtilis, Streptococcus agalactiae and Vibrio damsela. It also showed antifungal effect against Penicillium sp. followed by Aspergillus niger. No toxicity was observed when tested on Artemia salina. Semi-purified ß-1,3-1,4-glucanase was noticed to be effective in clarification of different juices at different pH values and different time intervals. The maximum clarification yields were 51.61% and 66.67% on mango juice at 40 °C and pH 5.3 for 2 and 4 h, respectively. To our knowledge, this is the first report of ß-1,3-1,4-glucanase enzyme from halotolerant Halomonas species.
Asunto(s)
Halomonas , Halomonas/metabolismo , Temperatura , Concentración de Iones de Hidrógeno , Glicósido Hidrolasas/metabolismoRESUMEN
An alginate lyase with high specific enzyme activity was purified from Pseudomonas stutzeri MSEA04, isolated from marine brown algae. The alginate lyase was purified by precipitation with ammonium sulphate, acetone and ethanol individually. 70% ethanol fraction showed maximum specific activity (133.3 U/mg). This fraction was re-purified by anion exchange chromatography DEAE- Cellulose A-52. The loaded protein was separated into 3 peaks. The second protein peak was the major one which contained 48.2% of the total protein recovered and 79.4% of the total recovered activity. The collected fractions of this peak were subjected to further purification by re-chromatography on Sephadex G-100. Alginate lyase activity was fractionated in the Sephadex column into one major peak, and the specific activity of this fraction reached 116 U/mg. The optimal substrate concentration, pH and temperature for alginate lyase activity were 8 mg/ml, pH 7.5 and 37 °C, respectively. While, Km and Vmax values were 1.07 mg alginate/ ml and 128.2 U/mg protein, respectively. The enzyme was partially stable below 50 °C, and the activity of the enzyme was strongly enhanced by K(+), and strongly inhibited by Ba(+2), Cd(+2), Fe(+2) and Zn(+2). The purified enzyme yielded a single band on SDS-PAGE with molecular weight (40.0 kDa).
Asunto(s)
Proteínas Bacterianas/aislamiento & purificación , Polisacárido Liasas/aislamiento & purificación , Pseudomonas stutzeri/enzimología , Microbiología del Agua , Alginatos/metabolismo , Proteínas Bacterianas/química , Proteínas Bacterianas/metabolismo , Cromatografía DEAE-Celulosa , Cromatografía en Gel , DEAE-Celulosa/química , Dextranos/química , Electroforesis en Gel de Poliacrilamida , Estabilidad de Enzimas , Ácido Glucurónico/metabolismo , Ácidos Hexurónicos/metabolismo , Concentración de Iones de Hidrógeno , Cinética , Peso Molecular , Polisacárido Liasas/química , Polisacárido Liasas/metabolismo , Desnaturalización Proteica , TemperaturaRESUMEN
BACKGROUND: Nowadays, the Egyptian coasts of the Aqaba and Suez Gulfs, and the Red Sea proper, are under the direct effects of many recreational resorts, urban agglomeration, marine shipping, activity of the phosphate industry, fishing ports, and limited freshwater and sewage surfaces. Therefore, the water, especially those used for recreational activities, must be of a very good quality to be able to increase the national income. OBJECTIVES: To investigate the conventional water-quality bacteria, total coliforms (TC), Escherichia coli (EC), and fecal streptococci (FS), in the Egyptian coastal waters of Suez and Aqaba Gulfs and the Red Sea. MATERIALS AND METHODS: A total of 2372 surface water samples were collected from 42 sampling sites during 12 years (1998-2009) to detect and estimate TC, EC, and FS using the membrane filtration method. RESULTS: On the basis of the national and international bacterial standards, 540 samples (22.8%) out of 2372 were found to exceed the guide values (positive samples) and were not accepted for marine recreational purposes. During the course of the study, Suez Gulf showed the highest positive records of 54 and 96 for TC and EC, respectively, whereas FS recorded 94 and 88 positive samples in the Red Sea and Suez Gulf, respectively. The lowest positive records were found in 1998 and 2009, whereas the highest were in 2000 and 2002-2004. The highest polluted sampling sites were recorded in Su7 (Suez Gulf), Aq2 (Aqaba Gulf), and Re15 (Red Sea), and were generally affected by sewage disposal and/or anthropogenic influences. CONCLUSION AND RECOMMENDATIONS: The most polluted sites were in the Suez Gulf, reaching 238 sites, followed by 194 sites in the Red Sea, whereas the Aqaba Gulf had only 108 polluted sites. Moreover, the most polluted sample locations throughout the study were Su7, Aq2, and Re15, without implementation of corrective actions from authorized organizations. The data of the current study must be taken into consideration by the government for a safer and cleaner seawater in the eastern Egyptian coasts, especially those in which critical limitations in terms of microbial pollution are found.