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The exploitation of chitinous materials seems to be an infinite treasure. To this end, using shellfish waste as the sole carbon/nitrogen source solves environmental challenges while lowering microbial chitinase production costs. Bioconversion of shellfish chitin wastes such as shrimp shells has recently been investigated for the production of enzymes and bioactive materials in order to maximize the utilization of chitin-containing seafood processing wastes. In this study, the bioconversion of chitin to chitosan by Alcaligenes faecalis Alca F2018 revealed the highest chitin deacetylase (CDA) activity of 40.6 U/μg. The resulted low K m and high V max values explain the high affinity of the purified CDA to the p-nitroacetanilide substrate. CDA with a molecular weight of 66 KDa was purified from F2018 strain, with a 14.5% yield. FT-IR revealed distinct chitosan peaks and XRD revealed that chitosan samples had lower crystallinity than chitin. TGA analysis revealed that the recovered chitosan samples were more thermally stable. The deacetylation degree percentages of the produced chitosan are in the same range as that of the commercial chitosan, suggesting the promising potential of A. faecalis Alca F2018 to utilize shrimp shells in their raw form in the fermentation media based on its CDA enzyme activity., (Copyright © 2021 Elsevier B.V. All rights reserved.)

The Pan-Drug Resistant (PDR), Helicobacter pylori remains an intractable challenge in public health worldwide and this pathogenicity is mainly due to the presence of a cytotoxin-associated gene A (CagA) and vacuolating cytotoxin A (VacA). On the other hand, plant extracts such as Syzygium aromaticum contain a diverse array of secondary metabolites, which could be potentially used to combat H. pylori pathogens. To our knowledge, this is the first report on the biomedical potential of S. aromaticum extract against cytotoxin-associated genes producing PDR H. pylori . In this investigation, out of 45 gastric antral biopsy specimens of dyspeptic patients, 20 strains were confirmed as H. pylori. Eight (40%) out of 20 strains were PDR H. pylori while the rest of the strains were Multi-Drug Resistant (MDR) strains. Genotypic analyses of PDR H. pylori strains showed that cagA and vacA genes were found to be 75% and 87.5%, respectively and m2s2 was the most common subtype of vacA gene. S. aromaticum showed a significant higher anti- H. pylori activity compared to that of Cinnamomum zeylanicum and Thymus vulgaris . Eugenol was the major phenolic compound (28.14%) detected in the methanolic extract of S. aromaticum . Clearly, results of the toxicological assessment confirmed the safety of S. aromaticum for use. Hence, these results suggest that S. aromaticum could be a new useful natural antimicrobial agent that could potentially combat cytotoxin genes-producing drug-resistant H. pylori . Moreover, these findings provide a scientific basis for the development of antimicrobial agents from traditional herbal medicines for gastroprotection against gastric ulcer., (© 2019 Center for Food and Biomolecules, National Taiwan University. Production and hosting by Elsevier Taiwan LLC.)

Objectives: Pseudomonas aeruginosa producing extended spectrum β-lactamase (ESβL) enzyme had the ability for antimicrobial resistance mechanisms and its multidrug-resistant (MDR) phenotype, has been increasingly reported as a major clinical concern worldwide. The aim of this study was to (i) characterize ESβL-producing MDR P. aeruginosa isolated from burn wound infections phenotypically and molecularly, (ii) evaluate the antibacterial activity of some essential oils (EOs) against selected ESβL-producing drug resistant P. aeruginosa and (iii) characterize a promising EO., Methods: Identification and antibiotic susceptibility tests were performed for all isolates. ESβL production was detected phenotypically by an initial screening test (IST) and a phenotypic confirmatory test (PCT). Additionally, ESβL-producing isolates were also characterized molecularly. The antibacterial activity was detected using a disc diffusion method. Mechanisms of antibacterial action, the fatty acid profile, and functional groups characterization of the promising EO were analyzed using scanning and transmission electron microscopy (SEM & TEM), gas chromatography-mass spectrometry (GC-MS), and Fourier transform infrared (FTIR) spectroscopy, respectively., Results: A total of 50 non duplicated P. aeruginosa isolates from the wound samples of burn patients were identified. Of these, MDR and pan-drug resistance (PDR) showed a high prevalence in 38 (76%) isolates obtained from 10 clusters, while 21 (42%) were identified as ESβL-producing MDR or PDR P. aeruginosa isolates. Phenotypic detection of ESβL production showed that 20% were considered positive ESβL-producing P. aeruginosa using the IST, and were increased to 56% by the PCT. The most prevalent ESβL-encoding gene was bla OXA-2 (60.7%), followed by bla IMP-7 (53.6%) and bla OXA-50 (42.8%). Ginger oil is the most efficient antibacterial agent and its antibacterial action mechanism is attributed to the morphological changes in bacterial cells. The oil characterization revealed that 9,12-Octadecadienoic acid methyl ester is the major fatty acid (50.49%) identified., Conclusion: The high incidence of drug-resistance in ESβL-producing P. aeruginosa isolated from burn wounds is alarming. As proven in vitro, EOs may represent promising natural alternatives against ESβL-producing PDR or MDR P. aeruginosa isolates., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

The growth of Nostoc muscorum and Anabaena subcylindrica in sterilized sewage wastewater and N. muscorum in sterilized wastewater of El-Soda Company was higher than those grown in Allen synthetic medium. Whereas, the growth of A. subcylindrica in El-Soda Company sterilized wastewater and N. muscorum as well as A. subcylindrica grown in Verta Company sterilized wastewater was slightly lower than that grown in the standard synthetic medium. The contents of chlorophyll a, carotenoids and protein of N. muscorum and A. subcylindrica grown in sterilized sewage wastewater were higher than those grown in the standard medium. Similarly, N. muscorum and the bio-mixture of N. muscorum and A. subcylindrica grown in the sterilized wastewater of El-Soda Company showed high pigments and protein contents more than those reared in Allen medium. On the other hand, the bio-mixture of N. muscorum and A. subcylindrica grown in the sterilized sewage wastewater, A. subcylindrica grown in El-Soda Company and Verta Company sterilized wastewater showed lower contents of pigments and protein compared to synthetic medium. Heavy metals, copper, cobalt, lead and manganese were removed by 12.5-81.8, 11.8-33.7, 26.4-100 and 32.7-100%, respectively, from wastewater by using cyanobacterial cultures. The metal sorption efficiency depended on the type of biosorbent, the physiological state of the cells, availability of heavy metal, concentration of heavy metal and chemical composition of wastewater. It was observed also that the single cultures in most cases was better than the mixed cultures in heavy metal removal, this may be due to the cyanobacterial competition for nutrients in mixed cultures.

Forty different isolates of streptomycetes from Egyptian soil were screened for their proteolytic activity in eight different media, for different time intervals and under different culture conditions. One of them, an isolate of Streptomyces corchorusi ST36 was the most active and glucose-aspartic acid-ammonium nitrate medium (GAA) was the best medium. Maximum production of the extracellular proteolytic activity by S. corchorusii ST36 (383 U/ml) was obtained at 30 degrees C after 5 days in shaked cultures. The optimal medium for maximum production of protease contained the soluble starch 2% (w/v), aspartic acid at 0.25% (w/v) and ammonium nitrate at 0.1% (w/v), at initial pH 6.0.