Explore the vast range of titles available.

Objectives This study was conducted to isolate, screening and purification of cellulase from bacteria present in sugar industry waste (molasses) and characterization by morphological and biochemical analysis. Results Based on experiments, three bacterial strains produced clear transparent zone into carboxymethyl cellulose (CMC) agar plate were identified as cellulase producing bacteria. Different culture parameters such as pH, temperature, incubation period, substrate concentration and carbon sources were optimized for enzyme production. According to the morphological and biochemical tests, the isolated strains were identified as Paenibacillus sp., Bacillus sp. and Aeromonas sp. The first strain Paenibacillus sp. showed high potentiality for maximum cellulase production (0.9 µmol ml −1  min −1 ) at pH 7.0 after 24 h of incubation at 40 °C in a medium containing 1.0% CMC. Then Paenibacillus sp. was selected for enzyme purification by ammonium sulfate precipitation, DEAE-cellulose and CM-cellulose column chromatography, respectively. In last step of purification, specific activity, recovery and purification fold were 2655 U/mg, 35.7% and 9.7, respectively. The molecular weight of the purified cellulase was found to be 67 kDa by SDS-PAGE, had an optimal pH and temperature at 7.0 and 40 °C. According to substrate specificity, the purified cellulase had high specificity on CMC substrate which indicated it to be an endo-β-1,4-glucanase.

New xylanase (XylUS570) was purified from the Bacillus pumilus US570 strain. It has a molecular mass of about 232 kDa. This is the first report on the highest molecular weight monomeric xylanase produced by bacteria. The optimum pH and temperature recorded for enzyme activity were 7 and 55 °C, respectively with a half-life time of 10 min at 60 °C. At 37 °C, the enzyme retains more than 50% of its activity at a pH ranging from 6 to 9.5 for 24 h. The XylUS570 exhibited a high activity on xylan, but no activity was detected for cellulosic substrates. The V max and K m values exhibited by the purified enzyme on beechwood xylan were 37.05 U mL −1 and 4.189 mg mL −1 , respectively. The XylUS570 was used in banana and orange peels hydrolysis and showed potential efficiency to liberate reducing sugars. It could be a good candidate for bio-ethanol production from fruit waste. The purified enzyme was used also as an additive in breadmaking. A decrease in water absorption, an increase in dough rising and improvements in volume and specific volume of the bread were recorded.

Bacteriophages infect and replicate within bacteria and play a key role in the environment, particularly in microbial ecosystems and bacterial population dynamics. The increasing recognition of their significance stems from their wide array of environmental and biotechnological uses, which encompass the mounting issue of antimicrobial resistance (AMR). Beyond their therapeutic potential in combating antibiotic-resistant infections, bacteriophages also find vast applications such as water quality monitoring, bioremediation, and nutrient cycling within environmental sciences. Researchers are actively involved in isolating and characterizing bacteriophages from different natural sources to explore their applications. Gaining insights into key aspects such as the life cycle of bacteriophages, their host range, immune interactions, and physical stability is vital to enhance their application potential. The establishment of diverse phage libraries has become indispensable to facilitate their wide-ranging uses. Consequently, numerous protocols, ranging from traditional to cutting-edge techniques, have been developed for the isolation, detection, purification, and characterization of bacteriophages from diverse environmental sources. This review offers an exploration of tools, delves into the methods of isolation, characterization, and the extensive environmental applications of bacteriophages, particularly in areas like water quality assessment, the food sector, therapeutic interventions, and the phage therapy in various infections and diseases.

l -Glutaminase is an amidohydrolase which can act as a vital chemotherapeutic agent against various malignancies. In the present work, l -glutaminase productivity from Aspergillus versicolor Faesay4 was significantly increased by 7.72-fold (from 12.33 ± 0.47 to 95.15 ± 0.89 U/mL) by optimizing submerged fermentation parameters in Czapek’s Dox (CZD) medium including an incubation period from 3 (12.33 ± 0.47 U/mL) to 6 days (23.36 ± 0.58 U/mL), an incubation temperature from 30 °C (23.36 ± 0.49 U/mL) to 25 °C (31.08 ± 0.60 U/mL), initial pH from pH 5.0 (8.49 ± 0.21 U/mL)  to pH 7.0 (32.18 ± 0.57 U/mL), replacement of glucose (30.19 ± 0.52 U/mL) by sucrose (48.97 ± 0.67 U/mL) as the carbon source at a concentration of 2.0% (w/v), increasing glutamine concentration as the nitrogen source from 1.0% (w/v, 48.54 ± 0.48 U/mL) to 1.5% (w/v, 63.01 ± 0.60 U/mL), and addition of a mixture of KH 2 PO 4 and NaCl (0.5% w/v for both) to SZD as the metal supplementation (95.15 ± 0.89 U/mL). Faesay4 l -glutaminase was purified to yield total activity 13,160 ± 22.76 (U), specific activity 398.79 ± 9.81 (U/mg of protein), and purification fold 2.1 ± 3.18 with final enzyme recovery 57.22 ± 2.17%. The pure enzyme showed a molecular weight of 61.80 kDa, and it was stable and retained 100.0% of its activity at a temperature ranged from 10 to 40 °C and pH 7.0. In our trials, to increase the enzyme activity by optimizing the assay conditions (which were temperature 60 °C, pH 7.0, substrate glutamine, substrate concentration 1.0%, and reaction time 60 min), the enzyme activity increased by 358.8% after changing the assay temperature from 60 to 30 °C and then increased by 138% after decreasing the reaction time from 60 to 40 min. However, both pH 7.0 and glutamine as the substrate remain the best assay parameters for the l -glutaminase activity. When the glutamine in the assay as the reaction substrate was replaced by asparagine, lysine, proline, methionine, cysteine, glycine, valine, phenylalanine, l -alanine, aspartic acid, tyrosine, and serine, the enzyme lost 23.86%, 29.0%, 31.0%, 48.3%, 50.0%, 73.6%, 74.51%, 80.42%, 82.5%, 83.43%, 88.36%, and 89.78% of its activity with glutamine, respectively. Furthermore, Mn 2+ , K + , Na + , and Fe 3+ were enzymatic activators that increased the l -glutaminase activity by 25.0%, 18.05%, 10.97%, and 8.0%, respectively. Faesay4 l -glutaminase was characterized as a serine protease enzyme as a result of complete inhibition by all serine protease inhibitors (PMSF, benzamidine, and TLCK). Purified l -glutaminase isolated from Aspergillus versicolor Faesay4 showed potent DPPH scavenging activities with IC 50  = 50 μg/mL and anticancer activities against human liver (HepG-2), colon (HCT-116), breast (MCF-7), lung (A-549), and cervical (Hela) cancer cell lines with IC 50 39.61, 12.8, 6.18, 11.48, and 7.25 μg/mL, respectively.

Introduction Fungal L-glutaminase has recently attracted growing interest due to its potential applications in medical therapy and biotechnology. This study aimed to develop a cost-effective bioprocess for L-glutaminase production using agricultural by-products under solid-state fermentation (SSF). Several fungal isolates were screened for extracellular L-glutaminase production, and the native isolated strain Aspergillus tamarii AUMC 10198 was identified as a potent high-yield producer. Process parameters influencing enzyme production were systematically optimized using a one-variable-at-a-time (OVAT) approach. The enzyme was subsequently purified through a three-step procedure and characterized for its biochemical properties. Notably, the purified L-glutaminase also exhibited antimicrobial activity, suggesting potential therapeutic applications. Results The native fungus Aspergillus tamarii AUMC 10198, registered under GenBank accession number OQ976977, was identified as a potent producer of L-glutaminase under solid-state fermentation (SSF) using wheat bran as the solid substrate. The solid-state yield of L-glutaminase exhibited a 3.20-fold increase in comparison to the unoptimized state. L-glutaminase produced by Aspergillus tamarii AUMC 10198 was purified through three successive steps, leading to a 12.90-fold enhancement in enzyme activity. As a result of the purification process, the final enzyme recovery was 18.45%. The isolated L-glutaminase exhibited optimal activity at a pH of 8, a temperature of 45 °C, and partial stability up to 60 °C, as determined by characterization. The purified L-glutaminase exhibited a Vmax of 10.10 U/ml and a km of 0.28 mg/ml when glutamine was used as the substrate. The metal ions Fe 2+ , Ca 2+ , K + , Mg 2+ , and Na + of 0.01 M concentration exhibited notable enzyme-activating effects, leading to an increase in L-glutaminase activity. The molecular mass was estimated to be approximately 62 kDa by SDS-PAGE. The produced enzyme showed notable antimicrobial activity, with the strongest effect against Staphylococcus aureus (36.80 ± 1.20 mm), followed by Bacillus subtilis (30.40 ± 0.60 mm), while the weakest inhibition was observed against Pseudomonas aeruginosa (12.80 ± 1.20 mm); moderate antifungal activity was also recorded highlighting its potential for broad therapeutic and pharmaceutical applications. Conclusion This study highlights the remarkable properties of L-glutaminase produced by the native potent fungal isolate Aspergillus tamarii AUMC 10198, underscoring its significant potential for industrial applications and pharmaceutical drug development.

Superoxide dismutase is an important antioxidative stress enzyme which is found in honeybee venom and has a wide pharmaceutical and medical applications. We reported the purification and characterization of venom SOD from Egyptian honeybee Apis mellifera lamarckii and termed BVSOD. It was purified to homogeneity from the Egyptian honeybee venom. The purification procedures included crude extraction, DEAE-cellulose anion exchange column chromatography, and Sephacryl S-300 gel filtration column chromatography. The purified BVSOD is found to be homogeneous as investigated by native PAGE. It exhibited homodimeric structure with a molecular weight of native form of 32 kDa and subunits of 16.0 kDa. It displayed the maximum activity at pH 7.4. CuCl.sub.2, ZnCl.sub.2, and MgCl.sub.2 and elevated the activity of BVSOD, while CoCl.sub.2, FeCl.sub.2, and NiCl.sub.2 inhibited BVSOD activity. Potassium cyanide and hydrogen peroxide were most potent inhibitors for BVSOD activity suggesting that it is a Cu/Zn-SOD type. The purified BVSOD is found to have antimicrobial and antitumor activities which can be used for various medical and clinical applications.

Xylanases (EC 3.2.1.8) have been considered as a potential green solution for the sustainable development of a wide range of industries including pulp and paper, food and beverages, animal feed, pharmaceuticals, and biofuels because they are the key enzymes that degrade the xylosidic linkages of xylan, the major component of the second most abundant raw material worldwide. Therefore, there is a critical need for the industrialized xylanases which must have high specific activity, be tolerant to organic solvent or detergent and be active during a wide range of conditions, such as high temperature and pH. In this study, an extracellular xylanase was purified from the culture broth of Aspergillus niger VTCC 017 for primary structure determination and properties characterization. The successive steps of purification comprised centrifugation, Sephadex G-100 filtration, and DEAE-Sephadex chromatography. The purified xylanase (specific activity reached 6596.79 UI/mg protein) was a monomer with a molecular weight of 37 kDa estimating from SDS electrophoresis. The results of LC/MS suggested that the purified protein is indeed an endo-1,4-β-d-xylanase. The purified xylanase showed the optimal temperature of 55 °C, and pH 6.5 with a stable xylanolytic activity within the temperature range of 45–50 °C, and within the pH range of 5.0–8.0. Most divalent metal cations including Zn2+, Fe2+, Mg2+, Cu2+, Mn2+ showed some inhibition of xylanase activity while the monovalent metal cations such as K+ and Ag+ exhibited slight stimulating effects on the enzyme activity. The introduction of 10–30% different organic solvents (n-butanol, acetone, isopropanol) and several detergents (Triton X-100, Tween 20, and SDS) slightly reduced the enzyme activity. Moreover, the purified xylanase seemed to be tolerant to methanol and ethanol and was even stimulated by Tween 80. Overall, with these distinctive properties, the putative xylanase could be a successful candidate for numerous industrial uses.Graphic Abstract

▪ Abstract  The author describes studies that led to the resolution and reconstitution of the cytochrome P450 enzyme system in microsomal membranes. The review indicates how purification and characterization of the cytochromes led to rigorous evidence for multiple isoforms of the oxygenases with distinct chemical and physical properties and different but somewhat overlapping substrate specificities. Present knowledge of the individual steps in the P450 and reductase reaction cycles is summarized, including evidence for the generation of multiple functional oxidants that may contribute to the exceptional diversity of the reactions catalyzed.

G protein-coupled receptors (GPCRs) are an important family of membrane proteins responsible for many physiological functions in human body. High resolution GPCR structures are required to understand their molecular mechanisms and perform rational drug design, as GPCRs play a crucial role in a variety of diseases. That is difficult to obtain for the wild-type proteins because of their low stability. In this review, we discuss how this problem can be solved by using protein design strategies developed to obtain homogeneous stabilized GPCR samples for crystallization and cryoelectron microscopy.

A novel bacteriocin-producing strain, Lactobacillus plantarum JY22 isolated from golden carp intestine, was screened and identified by its physiobiochemical characteristics and 16S rRNA gene sequence analysis. This bacteriocin, named plantaricin JY22, was purified using ethyl acetate extraction and gel filtration. Its molecular weight was approximately 4.1 kDa by SDS-PAGE analysis. The partial amino acid sequence of plantaricin JY22 was DFGFDIPDEV. It was highly heat-stable and remained active at pH range from 2.5 to 5.5, but was sensitive to protease. Plantaricin JY22 had a bactericidal mode. Scanning electron microscope analysis indicated that plantaricin JY22 damaged the morphology of cells and spores for Bacillus cereus. Moreover, the plantaricin JY22 destroyed cell membrane integrity as confirmed by the leakage of electrolytes, the losses of Na+K+-ATP, AKP, nucleic acids (OD260nm) and proteins. SDS-PAGE of B. cereus proteins further demonstrated that plantaricin JY22 had a remarkable effect on bacterial proteins.