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Background Antibiotic resistance is a growing problem that can be ameliorated by the discovery of novel drug candidates. Bacterial associates are often the source of pharmaceutically active natural products isolated from marine invertebrates, and thus, important targets for drug discovery. While the microbiomes of many marine organisms have been extensively studied, microbial communities from chemically-rich nudibranchs, marine invertebrates that often possess chemical defences, are relatively unknown. Methods We applied both culture-dependent and independent approaches to better understand the biochemical potential of microbial communities associated with nudibranchs. Gram-positive microorganisms isolated from nudibranchs collected in the Red Sea were screened for antibacterial and antitumor activity. To assess their biochemical potential, the isolates were screened for the presence of natural product biosynthetic gene clusters, including polyketide synthase (PKS) and non-ribosomal peptide synthetase (NRPS) genes, using PCR. The microbiomes of the nudibranchs were investigated by high-throughput sequencing of 16S rRNA amplicons. Results In screens against five model microorganisms, 51% of extracts displayed antimicrobial activity against more than one organism, and 19% exhibited antitumor activity against Ehrlich’s ascites carcinoma. Sixty-four percent of isolates contained PKS and NRPS genes, suggesting their genomes contain gene clusters for natural product biosynthesis. Thirty-five percent were positive for more than one class of biosynthetic gene. These strains were identified as belonging to the Firmicutes and Actinobacteria phyla via 16S rRNA gene sequencing. In addition, 16S rRNA community amplicon sequencing revealed all bacterial isolates were present in the uncultured host-associated microbiome, although they were a very small percentage of the total community. Taken together, these results indicate that bacteria associated with marine nudibranchs are potentially a rich source of bioactive compounds and natural product biosynthetic genes.

is capable of producing approximately 106kg of sugar and 46kg of molasses. A typical molasses to ethanol conversion rate is 4kg of molasses/L ethanol (Lavarack, 2001). However, this rate can vary based on production practices and sugar content of the molasses (Nguyen et al., 2009 andSilalertruksa &Gheewala, 2010).Molasses composition is usually influenced by the variety and maturity of the cane and beet, soil, climate and the processing conditions in the factory (El-Gendy et al., 2013). High yielding and efficient fermentation of molasses with varying composition requires selection of special yeast strains having high tolerances to inhibitory conditions as well as ability of fast fermentation. Other natural requirements like tolerance to high alcohol, sugar and temperature are also necessary (Bazmi et al., 2007

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A total of 56 Gram negative bacterial isolates were recovered from twenty ground beef samples and were screened for their potentiality to produce lipase. Forty four bacterial isolates were recorded as positive producers for lipase on tween as carbon source in solid medium. Also, the highly producer isolates were screened for lipase activity in submerged culture using olive oil as carbon and the most active isolate was 2043 which gave an activity of 20.0 ± 0.29 U/ml. The bacterial isolate 2403 was identified phenotypically according to Bergey's Manual and genotypically using 16S rRNA genes analysis as Pseudomonas monteilli. Effect of some different factors on lipase activity were studied and the maximum lipase activity was achieved at reaction medium of pH 6 and incubated at 40°C for 60 min. Also, addition of Ba 2+ in the reaction medium enhanced the lipase activity, while the other tested metals reduced the enzyme activity.

The biggest problem in the world today is antimicrobial resistance, which undermines human health and increases morbidity and mortality associated with life-threatening serious diseases. Scientists from different fields are therefore examining plants for their antimicrobial use in the face of multidrug-resistant bacteria with a new eye. So, the aim of this research to find a new antibacterial from five aqueous extracts of Nigella sativa, Ziziphus spina-christi, Rosmarinus officinalis, Origanum majorana, and Allium sativum medicinal plants tested against the most multidrug-resistant bacterial isolates from clinical specimens which were Klebsiella pneumoniae (Gram-negative), Escherichia coli (Gram-negative), Pseudomonas aeruginosa (Gram-negative), Staphylococcus aureus (Gram-positive) and Methicillin-resistant Staphylococcus aureus (Gram-positive). Also, to investigate the antibiofilm activity of the most potent extract. From all tested plants, the total extract of Z. spina-christi appeared a strong antibacterial effect against all tested MDR-strains. Besides, its polyphenol fraction showed a stronger effect. Furthermore, the total extract MIC ranged between 3.125-12.5 mg/ml with MBC was 3.125-25 mg/ml against previous strains. While, polyphenol fraction MIC and MBC were about 0.312-1.25 mg/ml and 0.312-2.5 mg/ml, respectively. In contrast to the antibacterial strength of polyphenol fraction, the antibiofilm effect was weaker than the total extract antibiofilm effect, where at ½ MIC, the reduction of biofilm was about 78.18%, 81.9% and 99.48% against S. aureus, MRSA and P. aeruginosa, respectively. While, in the case of polyphenol fraction, the biofilm reduction effect against previous strains was 63.82%, 59.97%, and 87.95%, respectively.

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