Levan Produced by the Halophilic Bacterium Bacillus licheniformis BK1 as a Nanoparticle for Protein Immobilization

This study examined the potential of levan from the halophilic bacterium Bacillus licheniformis BK1 as a nanoparticle system for protein immobilization. Levan produced by B. licheniformis BK1 was obtained by incubating the bacterium in the optimized Belghith medium, containing 15% (w/v) sucrose, 7.5% (w/v) NaCl and pH 8, in a rotary shaker at 150 rpm for 16 h, at 40 °C. The structure of the levan produced was verified by FTIR and NMR. It appeared that the levan had the same structure as that from Erwinia herbicola. The obtained levan was then used as a nanoparticle system to immobilize BSA and lysozyme proteins. The BSA-nanoparticle had a non-spherical shape with a surface charge of about -4.72 mV and a size distribution in the range of 83–298 nm. In contrast, the lysozyme-nanoparticle exhibited more spherical shapes with a surface charge of -2.57 mV and 206–285 nm size distribution. The efficiency of immobilization was about 74.26% and 81.77% for BSA and lysozyme, respectively. The study thus shows that levan produced by B. licheniformis BK1 can be used as a nanoparticle system for protein immobilization.

Identification of enterobacteria in free-living nonhuman primates in an urban park in the northern Region of the State of Paraná, Brazil

Populations of nonhuman primates are often considered to be a link in the chain of emerging infectious diseases, as they are reservoirs for different zoonotic pathogens. The objective of this study was to identify the presence of bacteria from the family Enterobacteriaceae in free-living nonhuman primates. The research was carried out in an urban park located in a city in the northern region of the State of Paraná, Brazil. The animals were captured in Tomahawk-type traps and chemically restrained, being oral and rectal samples collected with sterile swabs. For bacterial isolation, the samples were seeded on MacConkey agar plates and grown under anaerobic conditions. The subsequent identification was conducted using a commercial biochemical kit. Sixteen primates identified as black-capuchin-monkeys (Sapajus nigritus) were captured. Seven different enterobacterial species were identified from the oral cavity swabs: six Escherichia coli (42.9%), three Kluyvera species (21.40%), one Serratia rubidaea (7.14%), one Enterobacter aerogenes (7.14%), one Enterobacter cloacae (7.14%), one Hafnia alvei (7.14%), and one Erwinia herbicola (7.14%). Seven different species were identified from the rectal swabs: six Escherichia coli (40%), three Kluyvera species (20%), two Enterobacter aerogenes (13.32%), one Erwinia herbicola (6.67%), one Serratia rubidaea (6.67%), one Pragia fontium (6.67%), and one Edwardsiella tarda (6.67%). The results indicate that the isolated bacteria belong mainly to the human microbiota and had crossed the interspecific barrier, contaminating the nonhuman primates.