Biotechnological Potential of Biodigester-Derived Bacteria

Aim: To isolate and characterize bacterial strains derived from a bovine biodigester sludge with potential for biotechnological application. Study Design: We used six bacterial isolates from genera Brucella, Microbacterium, and Brevibacillus previously isolated from swine and bovine sludge samples collected from an up-flow anaerobic sludge blanket reactor fed with bovine manure in western Paraná, Brazil. Place and Duration of Study: The research was conducted at the Laboratory of Biochemistry and Genetics, UFPR/Sector Palotina, between June 2023 and July 2024. Methodology: The microbiological composition of the sludge was established by 16sRNA genetic characterization, phosphate and potassium solubilization capacity, catalase and oxidase, fungal antagonism, and enzymatic (protease, caseinolytic, lipolytic, amylolytic, and cellulolytic) capacities. Results: Microbacterium mangrovi and M. arabinogalactanolyticum showed the highest values for the defined enzyme index. Three isolates showed potassium solubilization but none showed phosphate-solubilizing capacity. Partial antifungal activity was detected exclusively against M. arabinogalactanolyticum. Biofilm formation was strain-, carbon source-, and incubation time-dependent. Further, several isolates consistently showed low biofilm production, which is advantageous for industrial application. Conclusions: Our findings highlight the untapped microbial potential of biodigester sludge and strongly support the idea of testing it as a source of promising bacteria for biotechnological applications and sustainable agriculture.