Polycarbonate biodegradation by newly isolated Bacillus strains

As polycarbonate is frequently used in many products, its accumulation in landfills is absolutely harmful to the environment. The aims of this study were the screening and isolation of polycarbonate-degrading bacteria (PDB) and the assessment of their ability in the degradation of polycarbonate (PC) polymers. Nine-month buried- -PC films were used for PDB isolation and identification. The biodegradation ability of the isolates was determined by growth curve, clear zone formation, lipase and amylase production, AFM and FTIR. Bacillus cereus and Bacillus megaterium were identified and considered as PDB. The degradation ability of B. megaterium was significantly higher than that of B. cereus. Both were lipase and amylase positive. AFM and FTIR results showed the initiation of bacterial attachment. The PC biodegradation ability of isolates can be very efficient. Finding such efficient isolates (which was less studied before) will promise a decrease in plastic contamination in the future

Identification of Mucorales isolates from soil using morphological and molecular methods

Background and Purpose: Soil is the main habitat of saprophytic and pathogenic fungi. Mucormycetes are one of the most parts of soil fungi and certain members are among opportunistic fungi and can cause systemic fungal infections in immunocompromised patients. The majority of human and animal infections are caused by members of the genera Rhizopus, Mucor, Rhizomucor, Lichtheimia (Absidia), Cunninghamella and Mortierella. The objective of this research was to isolate and identify the main genera of Zygomycetes, using molecular assay and morphological features. Materials and Methods: A total of 340 soil samples were collected from different sites of seven public parks and 14 municipality districts in Isfahan. All samples were cultured on appropriate media and incubated at 27° C for 2 to 4 days, and then examined daily for visible fungal growth. PCR-RFLP method and macroscopic, microscopic and physiological characteristics were applied to identify fungal colonies. Results: Four hundred pure colonies belonging to six genera of Zygomycetes including Lichtheimia, Rhizopus, Rhizomucor, Mucor, Cunninghamella and Mortierella were identified. The genus Rhizopus (35.5%) was the most frequent isolate, followed by Mucor (32.25%) and Rhizomucor (27.5%). Conclusion: These finding may help us to understand about the importance of opportunistic fungi in public areas and the risk of exposure with immunocompromised persons

Isolation of Cryptococcus neoformans and other opportunistic fungi from pigeon droppings

Background: Invasive fungal infections cause considerable morbidity and mortality in immunocompromised hosts. Pigeon droppings could especially be a potential carrier in the spread of pathogenic yeasts and mold fungi into the environment. The objective of this study was to isolation of Cryptococcus neoformans and other opportunistic fungi from pigeon droppings. Materials and Methods: One hundred twenty samples of pigeon droppings were suspended 1:10 in saline solution and then cultured. Identification of C. neoformans was performed on bird seed agar, presence of a capsule on India ink preparation, urease production on urea agar medium and RapID yeast plus system. The identification of candida species was based on micro-morphological analysis on corn meal-Tween 80 agar, RapID yeast plus system and growth in CHROMagar candida. The identification of other fungi was based on macromorphologic, microscopic, biochemical and physiological characteristics. Results: The highest frequency of yeasts and mold fungi were observed in Candida albicans 6.6% and Penicillium spp. 25%. The frequency rate of C. neoformans isolation was 2.5%. Conclusion: Several types of fungi are present in pigeon droppings that can spread in environment and transmit to children and elderly as well as immunocompromised patients who are at increased risk of contracting opportunistic diseases