Screening of antibacterial and antifungal activities in green and brown algae from the coast of Sidi Bouzid (El Jadida, Morocco)

Six organic extracts prepared with different solvents (methanol, acetone, hexane, chloroform and dichloromethane-methanol) and aqueous extract of 27 species of marine algae belonging to the Chlorophyta and Phaeophyta were studied for antibacterial and antifungal activities against pathogenic microorganism: eight Gram-positive bacteria: Bacillus cereus, Bacillus thuringiensis, Bacillus subtillus, Clostridium sporogenes, Staphylococcus aureus, Mycobacterium smegmatis, Streptococcus faecalis and Bacillus sp, two Gram-negative bacteria: Escherichia coli and Pseudomonas sp and against fungi: Candida tropicalis and Cryptococcus neoformans. The best activity was observed in methanolic extract followed by acetonic extract and that prepared with methanol–dichloromethane. Of the 27 species tested, those belonging to Phaeophyceae were the most active in comparison with Chlorophyceae. The Gram-positive bacteria presented a sensibility superior to the Gram-negative and S. aureus ssp. aureus was the more sensitiveKey words: Macroalgae, algal extracts, antibacterial activity, antifungal activity, pathogenic microorganism

INHIBITIVE ACTIVITY OF 17 MARINE ALGAE FROM THE COAST OF EL JADIDA-MOROCCO AGAINST ERWINIA CHRYSANTHEMI

Objective: The objective of our work was to search for a new biopesticides extracted from marine algae found on the coast of El Jadida, Sidi Bouzid-Morocco.Methods: Extracts of 17 species of algae (Rhodophyceae, Rhodophyceae, Chlorophyceae) collected from the coast of El Jadida, Morocco, were tested for their antibacterial activity against the bacterial strain Erwinia chrysanthemi that causes soft rot in potato (Solanum tuberosum L.).Results: Of the 17 species studied, those belonging to the Phaeophyceae and Rhodophyceae were the most active, while Chlorophyceae have a low inhibition. Maximum inhibition of the growth of Erwinia chrysanthemi was obtained by extracts prepared in dichloromethane and methanol, and by dichloromethane extract. No activity was observed in the aqueous extracts.Conclusion: The results obtained in this study clearly indicated that macroalgae from the coast of Sidi Bouzid can be used in the treatment of plant diseases especially soft rot of potato.Â

Correlation of the Diffusion Parameters and the Biological Activities in the Formulation of <i>Pinus halepensis</i> Essential Oil in Phosphogypsum Material

The use of natural biopesticides, specifically essential oils, is being explored as an alternative solution to protect stored foodstuffs. This study focuses on a formulation of phosphogypsum–Pinus halepensis essential oil as a pesticidal product. First, the essential oil chemical composition was determined using gas chromatography with mass spectrometry (GC-MS), while the phosphogypsum (waste from the phosphate mining industry) was analyzed using scanning electron microscopy, X-ray fluorescence, X-ray diffraction, Fourier-transform infrared spectroscopy, and thermogravimetric–differential thermal analysis; thus, physico-chemical properties and heavy metal contents were determined. In a second step, the preparation of the formulation consists in grafting the essential oil on the phosphogypsum (adsorption) in a cylindrical geometric shape adapted to the models applied in the bioprocesses of storage. The study of essential oil transfers in the material in the case of desorption along the axis (Oz) was carried out using analytical and numerical models of the Fickian diffusion process to understand the behavior of the oil and determine physicochemical parameters such as diffusivity (D) and evaporation flux (F). By using statistical methods such as experimental design and principal component analysis, these parameters can help explain the mechanisms involved in the insecticidal activities against the primary pest of lentils (Bruchus signaticornis) and in the parameters of lentil seed germination