Hassan M. Awad

Preparation of Some Fused Pyridopyrimidine and Pyridothienotriazine Derivatives for Biological Evaluation

Compounds 2 and 9 were formed using 3-(4-chloro-phenyl)-1-pyridin-2-yl propenone ( 1 ) and malononitrile or ethyl cyanoacetate, respectively. The pyridine derivative 2 was in turn used as a precursor for the preparation of some pyridopyrimidine and fused pyridopyrimidine derivatives 3–8 On the other hand, the pyridine derivative 9 was used for the preparation of thienopyridine derivatives 11 and 12 Nitrozation of compound 12 afforded pyridothienotriazine derivative 13 Some of the prepared products showed potent antimicrobial activity.

Optimization Conditions of Extracellular Proteases Production from a Newly Isolated Streptomyces Pseudogrisiolus NRC-15

Microbial protease represents the most important industrial enzymes, which have an active role in biotechnological processes. The objective of this study was to isolate new strain of Streptomyces that produce proteolytic enzymes with novel properties and the development of the low-cost medium. An alkaline protease producer strain NRC-15 was isolated from Egyptian soil sample. The cultural, morphological, physiological characters and chemotaxonomic evidence strongly indicated that the NRC-15 strain represents a novel species of the genus Streptomyces, hence the name Strptomyces pseudogrisiolus NRC-15. The culture conditions for higher protease production by NRC-15 were optimized with respect to carbon and nitrogen sources, metal ions, pH and temperature. Maximum protease production was obtained in the medium supplemented with 1% glucose, 1% yeast extract, 6% NaCl and 100 μmol/L of Tween 20, initial pH 9.0 at 50 °C for 96 h. The current results confirm that for this strain, a great ability to produce alkaline proteases, which supports the use of applications in industry.

A new chitinase-producer strain Streptomyces glauciniger WICC-A03: isolation and identification as a biocontrol agent for plants phytopathogenic fungi

This study discusses the isolation and identification of a new Streptomycetes highly active chitinase producer. Fifteen strains were isolated from Malaysian soil samples. The isolate WICC-A03 was found to be the most active chitinase producer. Its antifungal activity was evaluated against many phytopathogens. The identification of WICC-A03 using phenotypic and genotypic methods strongly indicated that strain WICC-A03 belonged to the genus Streptomyces and displayed similarity (91%) with Streptomyces glauciniger. Thus, it was given the suggested name S. glauciniger WICC-A03 with accession number: JX139754. WICC-A03 produces extracellular chitinase in a medium containing 1.5% colloidal chitin in submerged culture on 144 h. The produced enzyme was partially characterised and its molecular weight of 50 kDa was determined by using SDS-PAGE. This study indicates that WICC-A03 is a potential chitinase producer for biocontrol of plant pathogens. Further experiments are being carried out to optimise medium composition and cultivation conditions under lab and bioreactor scale.

Microwave-Assisted Synthesis and Antimicrobial Activity of Some Novel Isatin Schiff Bases Linked to Nicotinic Acid via Certain Amino Acid Bridge

The coupling reaction of nicotinic acid with certain L-amino acid methyl esters including valine, leucine, and phenylalanine was done by the use of acid chloride method. The products were reacted with hydrazine hydrate 99% to give the corresponding hydrazides that were reacted with indoline-2,3-dione (isatin) to get Schiff bases under the application of microwave irradiation technique. These novel compounds were characterized by means of their FT-IR, 1H NMR, and mass spectral data. Additionally, the specific optical rotation and elemental analysis were measured. The in vitro antimicrobial activity of the synthesized compounds was evaluated by agar diffusion method. The compounds showed a strong antimicrobial inhibitory activity. Most of the test compounds possessed a broad spectrum of activities having MIC values ranging from 50 µg/mL to 500 µg/mL.

Efficient production process for food grade acetic acid by acetobacter aceti in shake flask and in bioreactor cultures

Acetic acid is one of the important weak acids which had long history in chemical industries. This weak organic acid has been widely used as one of the key intermediate for many chemical, detergent, wood and food industries. The production of this acid is mainly carried out using submerged fermentation system and the standard strain Acetobacter aceti. In the present work, six different media were chosen from the literatures and tested for acetic acid production. The highest acetic acid production was produced in medium composed of glucose, yeast extract and peptone. The composition of this medium was optimized by changing the concentration of medium components. The optimized medium was composed of (g/L): glucose, 100; yeast extract, 12 and peptone 5 and yielded 53 g/L acetic acid in shake flask after 144 h fermentation. Further optimization in the production process was achieved by transferring the process to semi-industrial scale 16-L stirred tank bioreactor and cultivation under controlled pH condition. Under fully aerobic conditions, the production of acetic acid reached maximal concentration of about 76 g/L and 51 g/L for uncontrolled and controlled pH cultures, respectively.

Synthesis and Antimicrobial Evaluation of a New Series of Heterocyclic Systems Bearing a Benzosuberone Scaffold

A series of novel benzosuberone derivatives were synthesized and evaluated as antimicrobial agents by using substituted benzosuberone derivatives 1a,b as starting materials. Treatment of 1a,b with phenyl isothiocyanate in dimethylformamide was followed by treatment with cold HCl solution to afford the thioamides 4a,b, which was reacted with methyl iodide to obtain methylated products 5a,b. Cyclocondensation of 4a,b with chloroacetone 6 and phenacyl chloride 7 gave the corresponding thiophene derivatives 9a–c. Reaction of 4a,b with C-acetyl-N-arylhydrazonoyl chlorides 14a and 14b in boiling EtOH in the presence of triethylamine, afforded the corresponding 1,3,4-thiadiazoline derivatives 16a–d. The thioamides 4a,b were reacted with C-ethoxycarbonyl-N-arylhydrazonoyl chlorides 18a,b which afforded 1,3,4-thiadiazoline derivatives 19a–d. The benzosuberones 1a,b were treated with 3-mercaptopropanoic acid to give compounds 21a,b, which were cyclized to tricyclic thiopyran-4(5H)-one derivatives 22a,b. The latter compounds 22a,b were reacted with 3-mercaptopropanoic acid to give compounds 23a,b, which were cyclized tetracyclic ring systems 24a,b. Finally, compounds 24a,b were oxidized using hydrogen peroxide under reflux conditions to afford the oxidized form of the novel tetracyclic heterogeneous ring systems 25a,b. The newly synthesized compounds were screened for antimicrobial activities. The structures of new compounds were characterized by 1H-NMR, 13C-NMR, IR, and EI-MS.

The Synthesis of Molecular Docking Studies, In Vitro Antimicrobial and Antifungal Activities of Novel Dipeptide Derivatives Based on N-(2-(2-Hydrazinyl-2-oxoethylamino)-2-oxoethyl)-nicotinamide

A series of linear dipeptide derivatives (4–10) were prepared and evaluated as antimicrobial agents via the synthesis of N-(2-(2-hydrazinyl-2-oxoethylamino)-2-oxoethyl) nicotinamide (4). Compound 4 was reacted with 4-chlorobenzaldehyde or 4-hydroxybenzaldehyde, to give the hydrazones 5 and 6, respectively. On the other hand, Compound 4 was coupled with phenylisocyanate or methylisothiocyanate to give Compounds 7 and 8, respectively. The latter compounds (7 and 8) were coupled with chloroacetic acid to give oxazolidine (9) and thiazolidine (10), respectively. The newly synthesized dipeptide compounds were confirmed by means of their spectral data. The antimicrobial activity of the newly synthesized compounds 4–10 was evaluated by agar well diffusion, and they showed good activity. Compounds 4, 5, and 9 gave the most promising activity in this study. Most of the tested compounds possessed MIC values ranging from 50 to 500 µg/mL. Furthermore, docking studies were carried out on enoyl reductase from E. coli and cytochrome P450 14 α-sterol demethylase (Cyp51) from Candida albicans active sites. The MolDock scores of the seven tested compounds ranged between −117 and −171 and between −107 and −179, respectively.

Enhanced production of thermostable lipase from Bacillus cereus ASSCRC-P1 in waste frying oil based medium using statistical experimental design -

This study aim to isolate, identify and optimize lipase producing strains using frying oil waste. Nine strains were isolated from an Egyptian soil samples. Among the isolates, a potent bacterial candidate ASSCRC-P1 was found to be the most potent lipase producer strain at 60 °C. Genotypic identification of ASSCRC-P1 showed 94% similarity with Bacillus sp. strains. Phylogenetic tree confirmed that ASSCRC-P1 was nearly similar to Bacillus cereus. Therefore, it was given the name Bacillus cereus ASSCRC-P1 and its 16S rRNA nucleotide has been deposited in the GenBank Data Library under the accession number: KJ531440. A sequential optimization strategy, based on statistical experimental designs, was employed to enhance the lipase production by this strain. A 2-level Plackett–Burman design was applied to differentiate between the bioprocess parameters that significantly influence lipase production followed by Box-Behnken design to optimize the amounts of variables which have the highest positive significant effect on lipase production. Overall more than 2.15-fold improvement in lipase production was achieved due to optimization compared to that obtained using the basal medium.

Production of Extracellular 5-Aminolevulinic Acid by Rhodopseudomonas Palustris in Solid-State Fermentation

Nowadays, 5-aminolevulinic acid (ALA) is widely used as non-toxic herbicide, as insecticide, and also as plant growth enhancer in agricultural application. However, their use is limited by high production cost via the route of chemical synthesis. Agricultural waste, which serves as inexpensive solid support medium, can be used to produce ALA through solid-state fermentation (SSF). In this study, production of ALA using empty fruit bunch (EFB) as solid support medium inoculated with Rhodopseudomonas palustris (R. palustris) NRRL-B4276 was conducted through SSF. Several environmental factors for the SSF process including the initial pH (2, 3, 4, 5, and 6), initial moisture content (40, 50, 60, 70, and 80 %) of the solid support medium, and incubation period (1–5 days) were investigated to study their effects for the production of ALA in SSF. The maximal yield of ALA was achieved at 38.22 ± 0.15 mg/kg substrate at the total viable cell count of 35 ± 3 × 106 CFU/g in SSF using EFB as the solid support medium inoculated with R. palustris. The optimized operating parameters including the initial pH, initial moisture content of the solid support medium, and incubation period were found to be pH 3, 60 %, and 3 days (72 h), respectively, in the presence of 40 % (v/w) inoculum at 37 °C aerobically with light under static condition.

Evaluation of Antioxidant, Antimicrobial and Cytotoxicity of Alcea kurdica Alef

The purpose of this study is to evaluate the aqueous extract of Alcea kurdica Alef for antioxidant and antimicrobial activity as well as potential toxicity. Antioxidant activities were evaluated using 1,1-diphenyl-2- picrylhydrazyl (DPPH) free radical scavenging and Ferric Reducing Antioxidant Power (FRAP) reducing capacity assays as well as total phenolic compounds (TPC). Antimicrobial activity was assessed against some Gram-positive and Gram-negative bacteria, yeasts and filamentous fungi using the agar dilution method. The plant extract was also assessed for in-vitro toxicity using the Promega Cell Titer 96 AQueous Non-Radioactive Cell Proliferation (MTS) assay. The aqueous extract of A. kurdica demonstrated potent free radical scavenging activity of 64% ± 1.64% and ferric reduction capacity of 2955.0 ± 0.04 mmol/g, as well as having 88.0 ± 0.002 mg gallic acid equivalents /gram plant extract. The aqueous extract of A. kurdica had modest antimicrobial activity against most tested microorganisms. Moreover, the plant extract did not have any toxic effects on human lung fibroblasts. Based on these findings, we conclude that A. kurdica may be utilized to prevent the growth of some microorganisms. The plant constituents behind these effects are the antioxidants and phenols. Further studies are needed to evaluate the therapeutic utility of A. kurdica extracts as antimicrobial agents.