Isolation and characterization of Candida tropicalis B: a promising yeast strain for biodegradation of petroleum oil in marine environments.

The increasing interest in environmental protection laws has compelled companies to regulate the disposal of waste organic materials. Despite efforts to explore alternative energy sources, the world remains heavily dependent on crude petroleum oil and its derivatives. The expansion of the petroleum industry has significant implications for human and environmental well-being. Bioremediation, employing living microorganisms, presents a promising approach to mitigate the harmful effects of organic hydrocarbons derived from petroleum. This study aimed to isolate and purify local yeast strains from oil-contaminated marine water samples capable of aerobically degrading crude petroleum oils and utilizing them as sole carbon and energy sources. One yeast strain (isolate B) identified as Candida tropicalis demonstrated high potential for biodegrading petroleum oil in seawater. Physiological characterization revealed the strain's ability to thrive across a wide pH range (4-11) with optimal growth at pH 4, as well as tolerate salt concentrations ranging from 1 to 12%. The presence of glucose and yeast extract in the growth medium significantly enhanced the strain's biomass formation and biodegradation capacity. Scanning electron microscopy indicated that the yeast cell diameter varied based on the medium composition, further emphasizing the importance of organic nitrogenous sources for initial growth. Furthermore, the yeast strain exhibited remarkable capabilities in degrading various aliphatic and aromatic hydrocarbons, with a notable preference for naphthalene and phenol at 500 and 1000 mg/l, naphthalene removal reached 97.4% and 98.6%, and phenol removal reached 79.48% and 52.79%, respectively. Optimization experiments using multi-factorial sequential designs highlighted the influential role of oil concentration on the bioremediation efficiency of Candida tropicalis strain B. Moreover, immobilized yeast cells on thin wood chips demonstrated enhanced crude oil degradation compared to thick wood chips, likely due to increased surface area for cell attachment. These findings contribute to our understanding of the potential of Candida tropicalis for petroleum oil bioremediation in marine environments, paving the way for sustainable approaches to address oil pollution.

Superior anti-pulmonary viral potential of Natrialba sp. M6-producing surfactin and C50 carotenoid pigment with unveiling its action modes.

BACKGROUND: Respiratory viruses, particularly adenoviruses (ADV), influenza A virus (e.g., H1N1), and coronaviruses (e.g., HCoV-229E and SARS-CoV-2) pose a global public health problem. Therefore, developing natural wide-spectrum antiviral compounds for disrupting the viral life cycle with antioxidant activity provides an efficient treatment approach. Herein, biosurfactant (Sur) and C50 carotenoid pigment (Pig) of haloalkaliphilic archaeon Natrialba sp. M6 which exhibited potent efficacy against hepatitis and anti-herpes simplex viruses, were investigated against pulmonary viruses. METHODS: The cytotoxicity of the extracted Sur and Pig was examined on susceptible cell lines for ADV, HIN1, HCoV-229E, and SARS-CoV-2. Their potential against the cytopathic activity of these viruses was detected with investigating the action modes (including, virucidal, anti-adsorption, and anti-replication), unveiling the main mechanisms, and using molecular docking analysis. Radical scavenging activity was determined and HPLC analysis for potent extract (Sur) was performed. RESULTS: All current investigations stated higher anti-pulmonary viruses of Sur than Pig via mainly virucidal and/or anti-replicative modes. Moreover, Sur had stronger ADV's capsid protein binding, ADV's DNA polymerase inhibition, suppressing hemagglutinin and neuraminidase of H1N1, and inhibiting chymotrypsin-like (3CL) protease of SARS-CoV-2, supporting with in-silico analysis, as well as radical scavenging activity than Pig. HPLC analysis of Sur confirmed the predominate presence of surfactin in it. CONCLUSION: This study declared the promising efficacy of Sur as an efficient pharmacological treatment option for these pulmonary viruses and considered as guide for further in vivo research.

Investigation of the optimum conditions for electricity generation by haloalkaliphilic archaeon Natrialba sp. GHMN55 using the Plackett-Burman design: single and stacked MFCs.

The production of bioelectricity via the anaerobic oxidation of organic matter by microorganisms is recently receiving much interest and is considered one of the future alternative technologies. In this study, we aimed to produce electrical current by using facultative halophilic archaeon Natrialba sp. GHMN55 as a biocatalyst at the anode of a microbial fuel cell (MFC) to generate electrons from the anaerobic breakdown of organic matter to produce electrical current. Since the MFC's performance can be affected by many factors, the Plackett-Burman experimental design was applied to optimize the interaction between these factors when tested together and to identify the most significant factors that influence bioelectricity generation. We found that the factors that significantly affected electrical current generation were casein, inoculum age, magnet-bounded electrodes, NaCl, resistor value, and inoculum size; however, the existence of a mediator and the pH showed negative effects on bioelectricity production, where the maximum value of the 200 mV voltage was achieved after 48 h. The optimum medium formulation obtained using this design led to a decrease in the time required to produce bioelectricity from 20 days (in the basal medium) to 2 days (in the optimized medium). Also, the overall behavior of the cell could be enhanced by using multiple stacked MFCs with different electrical configurations (such as series or parallel chambers) to obtain higher voltages or power densities than the single chambers where the series chambers were recorded at 27.5 mV after 48 h of incubation compared with 12.6 mV and 1.1 mV for parallel and single chambers, respectively. These results indicate that the order of preferred MFC designs regarding total power densities would be series > parallel > single.

Conversion of Uric Acid into Ammonium in Oil-Degrading Marine Microbial Communities: a Possible Role of Halomonads.

Uric acid is a promising hydrophobic nitrogen source for biostimulation of microbial activities in oil-impacted marine environments. This study investigated metabolic processes and microbial community changes in a series of microcosms using sediment from the Mediterranean and the Red Sea amended with ammonium and uric acid. Respiration, emulsification, ammonium and protein concentration measurements suggested a rapid production of ammonium from uric acid accompanied by the development of microbial communities containing hydrocarbonoclastic bacteria after 3 weeks of incubation. About 80 % of uric acid was converted to ammonium within the first few days of the experiment. Microbial population dynamics were investigated by Ribosomal Intergenic Spacer Analysis and Illumina sequencing as well as by culture-based techniques. Resulting data indicated that strains related to Halomonas spp. converted uric acid into ammonium, which stimulated growth of microbial consortia dominated by Alcanivorax spp. and Pseudomonas spp. Several strains of Halomonas spp. were isolated on uric acid as the sole carbon source showed location specificity. These results point towards a possible role of halomonads in the conversion of uric acid to ammonium utilized by hydrocarbonoclastic bacteria.

Microbial dynamics, chemical profile, and bioactive potential of diverse Egyptian marine environments from archaeological wood to soda lake.

Halophilic archaea are a unique group of microorganisms that thrive in high-salt environments, exhibiting remarkable adaptations to survive extreme conditions. Archaeological wood and El-Hamra Lake serve as a substrate for a diverse range of microorganisms, including archaea, although the exact role of archaea in archaeological wood biodeterioration remains unclear. The morphological and chemical characterizations of archaeological wood were evaluated using FTIR, SEM, and EDX. The degradation of polysaccharides was identified in Fourier transform infrared analysis (FTIR). The degradation of wood was observed through scanning electron microscopy (SEM). The energy dispersive X-ray spectroscopy (EDX) revealed the inclusion of minerals, such as calcium, silicon, iron, and sulfur, into archaeological wood structure during burial and subsequent interaction with the surrounding environment. Archaea may also be associated with detected silica in archaeological wood since several organosilicon compounds have been found in the crude extracts of archaeal cells. Archaeal species were isolated from water and sediment samples from various sites in El-Hamra Lake and identified as Natronococcus sp. strain WNHS2, Natrialba hulunbeirensisstrain WNHS14, Natrialba chahannaoensis strain WNHS9, and Natronococcus occultus strain WNHS5. Additionally, three archaeal isolates were obtained from archaeological wood samples and identified as Natrialba chahannaoensisstrain W15, Natrialba chahannaoensisstrain W22, and Natrialba chahannaoensisstrain W24. These archaeal isolates exhibited haloalkaliphilic characteristics since they could thrive in environments with high salinity and alkalinity. Crude extracts of archaeal cells were analyzed for the organic compounds using gas chromatography-mass spectrometry (GC-MS). A total of 59 compounds were identified, including free saturated and unsaturated fatty acids, saturated fatty acid esters, ethyl and methyl esters of unsaturated fatty acids, glycerides, phthalic acid esters, organosiloxane, terpene, alkane, alcohol, ketone, aldehyde, ester, ether, and aromatic compounds. Several organic compounds exhibited promising biological activities. FTIR spectroscopy revealed the presence of various functional groups, such as hydroxyl, carboxylate, siloxane, trimethylsilyl, and long acyl chains in the archaeal extracts. Furthermore, the archaeal extracts exhibited antioxidant effects. This study demonstrates the potential of archaeal extracts as a valuable source of bioactive compounds with pharmaceutical and biomedical applications.

A scalable overexpression of a thermostable recombinant poly-histidine tag carboxyl esterase under lambda promoter: purification, characterization, and protein modelling.

BACKGROUND: As a white biotechnological trend, esterases are thought to be among the most active enzymes' classes in biocatalysis and synthesis of industrially importance organic compounds. Esterases are used in many applications such as the manufacture of pharmaceuticals, cosmetics, leather, textile, paper, food, dairy products, detergents, and treatment of some environmental pollutants. RESULTS: A poly-histidine moiety was added to the C-terminal end of the Geobacillus sp. gene encoding carboxyl esterase (EstB, ac: KJ735452) to facilitate one-step purification. This recombinant protein was successfully expressed in Escherichia coli (E. coli) under control of Lambda promoter (λ). An open reading frame (ORF) of 1500 bps encoding a polypeptide of 499 amino acid residues and a calculated molecular weight (54.7 kD) was identified as carboxyl-esterase B due to its conserved glycine-X-serine-X-glycine motif (G-X-S-X-G) and its high similarity toward other carboxyl esterases, where the 3-D tertiary structure of EstB was determined based on high homology % (94.8) to Est55. The expression was scaled up using 7-L stirred tank bioreactor, where a maximum yield of enzyme was obtained after 3.5 h with SEA 51.76 U/mg protein. The expressed protein was purified until unity using immobilized metal affinity chromatography (IMAC) charged with cobalt and then characterized. The purified enzyme was most active at pH 8.0 and remarkably stable at pH (8-10). Temperature optimum was recorded at 65 °C, and it kept 70% of its activity after 1-h exposure to 60 °C. The active half-live of enzyme was 25 min at 70 °C and a calculated T melting (Tm) at 70 °C. The determined reaction kinetics Michaelis-Menten constant (Km), maximum velocity rate (Vmax), the turnover number (Kcat), and catalytic efficiency (Kcat/Km) of the pure enzyme were found 22.756 mM, 164.47 U/ml (59.6 min-1), and (2.619 mol/ min), respectively. CONCLUSION: Creation of a recombinant 6 × -His estB derived from a thermophile Geobacillus sp. was performed successfully and then overexpressed under λ-promoter. In a bench scale bioreactor, the overexpression was grown up, followed by one-step purification and biochemical characterization. The recorded promising pH and temperature stability properties suggest that this expressed carboxyl esterase could be used in many industrial sectors.

Isotherm and kinetic studies of cadmium biosorption and its adsorption behaviour in multi-metals solution using dead and immobilized archaeal cells.

It is crucial to identify more biological adsorbents that can efficiently uptake metals from wastewater. Dry haloalkaliphilic archaea Natronolimnobius innermongolicuswas evaluated for Cd ions biosorption. The optimal operating conditions (pH, biomass dose, initial metal concentration, contact time, and isotherms models) were tested. Biosorption process is influenced by the metal's solution pH with maximum removal of 83.36% being achieved at pH 8. Cadmium ions uptake reaches equilibrium in about 5 min of biosorption process. The Langmuir model was determined to better fit the Cd(II) biosorption by dry archaea. The maximal uptake capacity (qmax) of Cd(II) was 128.21 mg/g. The effect of multi-component system on biosorption behaviour of Pb, Ni, Cu, Fe, and Cd ions by immobilized dried archaeal cells, dried archaeal cells, and dried bryozoa was studied using Plackett-Burman experimental design. The investigated biosorbents were effective at removing metals from contaminated systems, particularly for Fe, Pb, and Cd ions. Moreover, the interaction behaviour of these metals was antagonistic, synergistic, or non-interactive in multi-metals system. SEM, EDX, and FTIR spectra revealed changes in surface morphology of the biomass through the biosorption process. Finally, continuous adsorption experiment was done to examine the ability of immobilized biomass to adsorb metals from wastewater.

Cloning of cellulase gene using metagenomic approach of soils collected from Wadi El Natrun, an extremophilic desert valley in Egypt.

BACKGROUND: Wadi El Natrun microorganisms have been considered as a new resource for natural products due to its extreme condition of salinity and alkalinity. Therefore, this study was devoted to generate metagemic library from soils collected from such an extreme environment in order to clone a novel cellulase for physique industrial applications. RESULTS: Total soil-DNA was successfully extracted, and then digested by different restriction enzymes. Purified fragments ranged ~ 200-6500 bp were ligated and were cloned into plasmid cloning vector (pUC19) by using Escherichia coli DH5α (E. coli) host cells. A constructed metagenomic library composed of 270 clones was screened on carboxymethylcellulose (CMC) agar plate where the active clones had been characterized by the formation of the yellowish halo zone. Thereafter, clone 1 was selected as the most active as being based on cellulase activity quantification (19 µ/ml). Plasmid related to clone 1 encoded cellSNSY gene of approximately 1.5 kb was subjected to molecular characterization; the obtained partial sequence of 861 bps encoded 287 amino acids showing 76% similarity to the endoglucanase gene of Bacillus amyloliquefaciens. The recombinant cellSNSY was expressed under lacz promoter at 1 mM of isopropyl ß-d-1-thiogalactopyranoside (IPTG), giving 21 µ/ml cellulase after ~ 27 h. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and an activity staining of the recombinant cellSNSY which revealed an active band with a molecular mass ~ 59 kDa appeared in the induced sample. The maximum enzyme activity of crude cellSNSY was observed at 45 °C and for a pH of 8.5. Interestingly, the enzyme activity was slightly inhibited by ethylenediamine tetraacetic acid (EDTA) and methanol. It showed high resistance to the tested heavy metals and the surfactant which ordered Zn> (SDS,Fe)>Mn>Cu. CONCLUSIONS: This study established an easy and a skillful way to clone/express a new found cellulase gene(s) under lacZ promoter. The isolated recombinant cellSNSY showed 76% similarity to endoglucanase gene, and the enzyme showed tolerance to the mostly tested agents including heavy metals, surfactant, solvents, and EDTA. Additionally, the studied recombinant showed a high stability up to 55 °C and for alkaline pH 8.5. These features make it an ample and viable for many applications.

Bioprocess development for bacterial cellulose biosynthesis by novel Lactiplantibacillus plantarum isolate along with characterization and antimicrobial assessment of fabricated membrane.

Bacterial cellulose (BC) is an ecofriendly biopolymer with diverse commercial applications. Its use is limited by the capacity of bacterial production strains and cost of the medium. Mining for novel organisms with well-optimized growth conditions will be important for the adoption of BC. In this study, a novel BC-producing strain was isolated from rotten fruit samples and identified as Lactiplantibacillus plantarum from 16S rRNA sequencing. Culture conditions were optimized for supporting maximal BC production using one variable at a time, Plackett-Burman design, and Box Behnken design approaches. Results indicated that a modified Yamanaka medium supported the highest BC yield (2.7 g/l), and that yeast extract, MgSO4, and pH were the most significant variables influencing BC production. After optimizing the levels of these variables through Box Behnken design, BC yield was increased to 4.51 g/l. The drug delivery capacity of the produced BC membrane was evaluated through fabrication with sodium alginate and gentamycin antibiotic at four different concentrations. All membranes (normal and fabricated) were characterized by scanning electron microscope, Fourier transform-infrared spectroscopy, X-ray diffraction, and mechanical properties. The antimicrobial activity of prepared composites was evaluated by using six human pathogens and revealed potent antibacterial activity against Escherichia coli, Klebsiella pneumoniae, Staphylococcus aureus, and Streptococcus mutans, with no detected activity against Pseudomonas aeruginosa and Candida albicans.