Résumé: n recent decades, there has been a sustained interest in research into the production of bioactive compounds from the marine environment, as these microorganisms represent an undiscovered biological niche for future use in biotechnology. For this study, fungal strains were isolated from sea sand and their bio- logical activities were evaluated. The marine fungus strain was isolated and identified morphologically and genetically as Penicillium hordei PA2 with accession number ITS: OR513086, β-tubulin: OR545535. Accord- ing to the determined minimum inhibitory concentration, crude extract showed significant antibacterial activity against the reference strains Enterococcus faecalis, Staphylococcus aureus, Methicillin-Resistant Staphylococcus aureus, Pseudomonas aeruginosa and Bacillus cereus. This fungus strain also exhibited promis- ing antioxidant, anti-inflammatory, and anti-diabetic properties. The IC50 values of P. hordei PA2 crude extract were (12.32, 15.83, 1.82 μg/mL), respectively. The fungal extract’s high polyphenol and flavonoid content seems to be the source of its high antioxidant activity. This study’s main objective is to study the cul- tivable fungal community and identify the metabolites produced using gas chromatography-mass spectrom- etry (GC-MS) techniques. A total of 13 different metabolites were obtained: Boric acid (1), Lactic acid (2), 2,4-Imidazolidinedione (3), Ergosta-5,7-dien-3beta-ol (4), Ingenol (5), Chlorozotocin (6), Methyl glyco- cholate (7), 14-Epiandrographolide (8), Homogentisic acid (9), Butyl mannoside (10), Yohimban-17-one (11), 13-Retinoic acid (12), 5-hydroxy-7-methoxyflavanone (13). They could constitute a promising reser- voir of secondary metabolites with robust pharmacological activity.

Résumé: Environmental pollution resulting from the accumulation of plastic waste poses a ma- jor ecological challenge. Biodegradation of these polymers relies on microorganisms capable of decomposing them, generally through the biodeterioration, biofragmentation, assimilation, and mineralization stages. This study evaluates the contribution and efficacy of indigenous soil yeasts isolated from a northeastern Algerian landfill in degrading low-density polyethylene (LDPE) plastic bag films. Candida tropicalis SLNEA04 and Rhodotorula mucilaginosa SLNEA05 were identified through internal transcribed spacer (ITS) and large subunit ribosomal RNA gene sequencing. These isolates were then tested for their ability to biodegrade LDPE films and utilized as the sole carbon source in vitro in a mineral salt medium (MSM). The biodegradation effect was examined using scanning electron microscopy (SEM), attenuated total reflectance–Fourier transform infrared (ATR-FTIR) spec- troscopy, and X-ray diffraction (XRD). After 30 days of incubation at 25 ◦C, a significant weight loss was observed compared to the control for both cultures: 7.60% and 5.53% for C. tropicalis and R. mucilaginosa, respectively. SEM analysis revealed morphological alterations, including cracks and holes, ATR-FTIR detected new functional groups (alcohols, alkynes, aldehydes, alkenes and ketones), while XRD identified changes in the polymer crystallinity and phase composition. These findings underscore the potential of the two yeast isolates in LDPE biodegradation, offering promising insights for future environmental applications.

Résumé: Printed circuit boards (PCBs) are basic parts of electronic goods. Their recycling has attracted worldwide attention due to their ever-increasing production, poor environmental safety, and recovery value. The current study aims to evaluate the ecological treatment of PCBs by bacteria indigenous to e-waste-con- taminated soils. Bacterial cultures were isolated using a chemically defined medium containing PCBs pieces as the sole carbon source. Phenotypic characterization and partial 16S rRNA gene sequencing of isolates HB3 and HB4 supported their identification as Pseudomonas aeruginosa and Achromobacter sp., respectively. At pH 7, the P. aeruginosa strain caused stronger PCBs degradation (weight loss almost 8%) than Achromobacter sp., while at pH 11 Achromobacter sp. was dominant leading to a 42% weight loss. Surface modifications of the treated PCBs were demonstrated by scanning electron microscopy images showing cracks and fissures. Energy-dispersive X-ray analysis indicated the presence of magnesium, aluminum, silica, calcium, titanium and copper as additional elements on the surface of the treated PCBs. Further, fourier transform infrared spectroscopy analysis suggested the presence of the O–H band (3678.1 cm –1 ), benzene rings (1601.07 cm –1 ) and C–H bonds (883 cm –1 ) in bacterial-treated PCBs. This study highlights the ability of indigenous soil bacteria to degrade PCBs without pre-treatment steps.

Résumé: Biodegradation poses a challenge for environmentalists and scientific community, offering a potential solution to the plastic waste problem. This study aims to investigate the biological degradation of low-density polyethylene (LDPE) bags by a fungus in both batch and continuous cultures, with the goal of identifying an eco-friendly and cost-effective waste management strategy. The fungal strain Rhizopus arrhizus SLNEA1, isolated from a landfill located in northeastern Algeria, was tested for its capability to degrade LDPE films and utilize them as a sole carbon source in batch (α-LDPE) and continuous (γ-LDPE) cultures. The results indicated a higher rate of weight loss for γ-LDPE (29.74%) compared to α-LDPE (23.77%). The biodegradation effect was examined using scanning electron microscopy (SEM), Energy Disper- sive X-ray Spectroscopy (EDS) and Attenuated Total Reflectance-Fourier Transform Infrared (ATR-FTIR) to evaluate morphological and chemical changes in LDPE samples, highlighting alterations of LDPE films through cracks, veins and holes under SEM and chemical transformation and appearance of new functional groups in the FTIR data. Rhizopus arrhizus SLNEA1 demonstrated the ability to break down and utilize LDPE films as a carbon source. This isolate shows promise for LDPE biodegradation applications, which may be leveraged for the development of future plastic degradation systems involving fungi.

Résumé: Penicillium species research has progressed far beyond their ability to produce secondary metabolites with potential biological applications, particularly as antimicrobial agents. In this work, Penicillium bilaiae EWB-3 was isolated from electronic waste and identified using morphological and molecular (ITS and β-tubulin regions) methods. For 15 days, Penicillium bilaiae EWB-3 was grown into Czapek Yeast Broth using an orbital shaker. Finally, the secondary metabolites in this strain’s filtrates were extracted using ethyl acetate. The agar well diffusion method tested this crude extract for antimicrobial activity. The Penicillium bilaiae EWB-3 extract exhibited strong antimicrobial potential against all tested microorganisms, including Pseudomonas aeruginosa, Bacillus cereus, Enterococcus faecalis, Escherichia coli, Salmonella typhimurium, Staphylococcus aureus, Methicillin-resistant Staphylococcus aureus, Klebsiella pneumoniae, Candida albicans and Aspergillus niger. With diameters of 31, 26, and 25 mm, the largest inhibition zones were observed against C. albicans, S. aureus, and E. faecalis, respectively. The presence of 24 active compounds was revealed by gas chromatography-mass spectrometry (GC-MS) analysis of the crude extract of Penicillium bilaiae EWB-3. The findings suggest that the secondary metabolite extract of Penicillium bilaiae EWB-3 could be a promising active pharmaceutical component.

Résumé: The aim of this study is to establish the taxonomic position of the halotolerant bacterium ESM2-25 GTF strain isolated from the extreme environment of El-Mellah lagoon water, which is situated in the city of El-Kala in the northeast of Algeria and to study its phenotypic characteristics, antibacterial activity against several pathogenic bacteria, and hydrolytic enzymes production. The novel bacterium ESM2-25 GTF strain was isolated from water samples by the dilution agar plating method using the starch-casein medium, screened in vitro for its hydrolytic enzymes production and antibacterial activity. The phenotypic and molecular characteristics show that the strain ESM2-25 GTF belongs to the genus Streptomyces. However, the comparison of the morphological and physiological characteristics of the strain ESM2-25 GTF with those of the nearest species showed significant differences. This strain showed an antibacterial activity against Bacillus subtilis subsp. spizizenii CIP 106094, Escherichia coli ATCC 29522, Enterococcus faecalis ATCC 29212, Staphylococcus aureus ATCC 29213 and S. aureus MRSA ATCC 43300, while it is not active against Pseudomonas aeruginosa ATCC 27853. Furthermore, the strain ECM2-25 GTF was able to produce different hydrolytic enzymes such as lipase, protease, amylase, catalase, and gelatinase, which have applications in the field of food and industry. The interesting antibacterial activity of the strain ESM2-25 GTF against pathogenic bacteria and hydrolytic enzymes production indicate the importance of the exploitation of marine actinomycetes for biotechnological applications and the discovery of new antibacterial molecules and could encourage further research on the bioactive molecules secreted by this strain.

Résumé: Low density polyethylene (LDPE) is the most abundant non-degradable plastic waste. Widely used in packaging material, it represents a serious threat to all ecosystems. In the present study, a Rhizopus sp. fungal strain was isolated from soil of a landfill located in north-east Algeria and cultured on potato dextrose agar. The in vitro biodegradability of pieces of the same plastic bag (0.2, 0.4, and 0.6 g) was estimated in minimal liquid medium and on minimal solid medium. Furthermore, biodegradation of plastic bag pieces was examined in seawater, tap water and soil. The isolated Rhizopus sp. strain could degrade the plastic bag waste. The highest in vitro rate occurred in the minimal liquid medium for both the 0.4-g and 0.6-g pieces (a 20% decrease in weight). In natural media, the highest weight decrease was different depending on the substrate: 5% in seawater for the 0.2-g piece, 10% in tap water for the 0.4-g piece and 8% in soil for the 0.4-g piece. This strain could also form a biofilm in Malt Extract Broth (MEB). These results revealed that the isolated Rhizopus sp. strain has considerable biodegradative ability based on different measures.

Résumé: lectronic and electrical wastes (EEW) have increased exponentially in recent years due to technological progress. The uncontrolled incineration of these wastes causes pollution of air, soil, and water that has dangerous effects on health of human beings and other living organisms. This work isolated fungi that are capable of degrading some of these electronic wastes. In this study, fungi isolated from soil polluted by EEW were grown on potatoes dextrose agar (PDA) medium. The estimation of the biodegradation was achieved by inoculation of both rechargeable batteries and printed circuit boards on a minimum solid and liquid medium with selected fungal strains. During the process of biodegradation on solid medium, microscopic observation was done, and on liquid medium the production of keratinolytic enzymes was evaluated using a colorimetric method after incubation with keratine powder. After 30 days, the obtained results showed that Geotrichum candidum is capable of degrading battery and circuit boards with rates of 23% and 71%, respectively, while Rhizopus stolonifer reduced battery weight by 7% and printed circuit boards by 60%. Microscopic observations showed no morphological modification in Geotrichum candidum, while there was sporocyst formation in Rhizopus stolonifer. The detection of enzymatic production indicated that there is a relation between the biodegradation process of electronic wastes and keratinolytic enzymes in Geotrichum candidum.

Résumé: The Metal pollution is one of the major risks in the world nowadays. Iron is an essential metal for growth and proliferation of a vast majority of organisms, but it can be toxic to human health and other living beings in the environment at high concentrations due to its increased industrial activity. Fungi have a remarkable capacity to uptake and detoxify iron metal using different mechanisms such as bioaccumulation. Thus, the aim of this work is to study the ability of iron uptake by the fungal strains isolated from Arcelor Mittal-Annaba-in Algeria