Metabolic profiling of antimicrobial secondary metabolites produced by Penicillium bilaiae EWB-3 isolated from electronic wastes in Algeria

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

In Vitro and Ex Situ Biodegradation of Low-Density Polyethylene by a Rhizopus sp. Strain Isolated from a Local Dumpsite in North-East Algeria

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

In Vitro Removal of Electronic and Electrical Wastes by Fungi Isolated from Soil at Annaba Area in Northeast of Algeria

Electronic 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