| Congresso Brasileiro de Microbiologia 2023 | Resumo: 99-2 | ||||
Resumo:Polyurethanes (PUs) are the world's sixth most produced synthetic polymer, making it an environmental problem. PU residues accumulate in the environment and pollute the whole ecosystem. Sustainable methods, using microorganisms or microbial consortium, may be the solution to mitigate pollution by this recalcitrant polymer. Therefore, this study aimed to form a microbial consortium with Serratia liquefaciens L135 and Staphylococcus warneri UFV_01.21 for the biodegradation of PUs. S. liquefaciens was previously recognized for secreting a lipase identified as polyurethanase, and S. warneri was isolated on Luria Bertani (LB) agar supplemented with 1% Impranil® PU, aiming to form the microbial consortium. The growth ability of the two isolates in co-culture was evaluated during 48 h by colonies counting on agar plates. S. liquefaciens was counted on MacConkey agar, while S. warneri was counted on Mannitol Salt agar. The biodegradation test of PUs was verified using Impranil® disks and commercial PU films of poly[4,4′-methylenebis(phenyl isocyanate)-alt-1,4-butanediol/di(propylene glycol)/polycaprolactone] (PCLMDI). The Impranil® disks were transferred to Petri plates containing LB agar inoculated with the microbial consortium and incubated at 30°C for six days. Changes in the morphology of the Impranil® surface were visually evaluated by photographs and microscopically analyzed in a scanning electron microscope (SEM). Enumerating viable cells evaluated adhesion and biofilm formation on Impranil® disks. PCLMDI films measuring 1 cm 2 were placed in Erlenmeyer flasks containing 50 mL of LB broth inoculated with a microbial consortium. After 60 days of incubation, PCLMDI films were analyzed by SEM and for biofilm formation. The negative control consisted of Impranil® disks or PCLMDI films without inoculum. No inhibition was verified when the studied bacteria were co-cultivated. The non-inoculated Impranil® disks did not show macro and microscopically visible alterations in the physical structure after six days of incubation. However, disks inoculated with consortium showed alterations such as ruptures and forming several fragments. Micrographs obtained by SEM confirmed that, over six days, the cracks increased and became more profound, causing the disks to rupture. During the biodegradation of the Impranil® disks, the number of sessile cells ranged from 1.5 x 10 9 to 4.9 x 10 9 CFU / Impranil® disk, with no statistical difference in six days of incubation (p < 0.05). After 60 days of incubation of the PCLMDI films, it was verified, by SEM, that the negative control (without inoculum) did not present imperfections, keeping the surface smooth and intact. However, cracks, roughness, and pores in the PCLMDI films were formed in the consortium's presence. The physical changes observed in the PUs films are evidence of microbial biodegradation. They can be explained by the formation of biofilms on the surface of the films, which reached a population density of 8.3 x 10 6 CFU/cm 2. This is the first work exploring the biodegradation potential of PU by a microbial consortium formed by S. liquefaciens and S. warneri . The results suggest that the consortium, under optimized conditions, can be promising for the biodegradation of other PUs. Palavras-chave: biodegradation, biofilm, microbial consortium Agência de fomento:CNPq, CAPES, FAPEMIG | |||||