| Congresso Brasileiro de Microbiologia 2023 | Resumo: 35-1 | ||||
Resumo:In 2021, about 390 million tons of plastic were produced around the world, and polyethylene (PE) is the most consumed (30%) for its durability and versatility. Moreover, PE is resistant to several chemical agents and biodegradation. Plastic waste management methods currently applied are not able to effectively reduce the accumulation of plastic waste on aquatic and terrestrial life. Given this negative impact, there is a great need for sustainable alternative methods. Interestingly, the larvae Galleria mellonella insect have been reported as capable of biodegrading PE. This animal belongs to Lepidoptera order and feeds on beeswax in their natural habitat (beehives). Studies investigating the role played by larval microbiota of G. mellonella in this process are mostly focused on bacterial activity. Although fungi are well-recognized for polymer biodegradation, so far, there are only two reports in literature on the PE biodegradation by fungal species obtained from the G. mellonella gut: Aspergillus flavus and Cladosporium halotolerans. The aim of this work is to isolate cultivable fungi from the gut and salivary glands of G. mellonella larvae individually submitted to four different nutritional conditions, for 5 days: (i) starvation, (ii) laboratory diet, (iii) beeswax, and (iv) PE, to be then tested for PE biodegradation. The larvae were dissected and one pool of twenty salivary glands or ten guts were added separately to 500 µL of sterile saline solution (NaCl 0.9%), to form a microbial inoculum. Then, each inoculum was added to flasks containing 100 mL of potato-dextrose (PD) broth (KASVI, Spain) with 0.05 % chloramphenicol (Sigma-Aldrich, Brazil), and were incubated at 28oC without agitation, until turbidity of the broth. Afterward, 50 µL of the broth were transferred to agar plates of PD and Sabouraud-dextrose (HIMEDIA, India), both with 0.05 % chloramphenicol, and incubated at 28oC. Once fungal growth was observed, a small portion of agar containing each colony was transferred to the center of a new agar plate, until each fungus was completely isolated. Fungal microscopical structure was characterized by microculture technique and some genera were identified using guides of identification keys. Until this moment, six isolates were obtained from G. mellonella salivary glands: three from the beeswax group (GSC1, GSC2 and GSC3); two from the starvation group (GSJ1 and GSJ2); and one from the laboratory diet group (GSR1). The colony morphology and microscopical structures of GSC1 and GSR1 indicated that they belong to the Aspergillus genus. However, it was not possible to isolate any fungi from the larval guts, which points to the salivary glands as an important niche for bioprospection of fungi involved in biodegradation processes. The genus has been reported in the literature as capable of biodegrading PE. The identification of the other isolates (GSC2, GSC3, GSJ1 and GSJ2) was not possible by these cultural techniques, and all isolates will be identified by ITS region sequencing. To the best of our knowledge, this is a pioneer study considering fungal bioprospection from salivary glands of G. mellonella larvae. Screening tests to select PE-biodegrading fungi will be performed using a carbon-free basal medium with PE as sole carbon source. Our findings might aid the development of sustainable and alternative plastic waste management technologies based on the microorganisms from G. mellonella larvae. Palavras-chave: Biodegradation, Fungi, Galleria mellonella, Polyethylene Agência de fomento:FAPERGS (21/2551-0002320-1), CNPq (405355/2022 and 308617/2021-5) and UFCSPA. | |||||