Degradation of amoxicillin applying photo-Fenton and acid hydrolysis processes with toxicity evaluation via antimicrobial susceptibility tests.

ABSTARCTThe antibiotic amoxicillin (AMX) is a semisynthetic aminopenicillin, classified as an ß-lactam antibiotic. This work aims to evaluate the AMX degradation (190 mg L-1), in aqueous medium, applying photo-Fenton ([TOC]0 = 100 mgC L-1; FH2O2 = 3.27 mmol min-1; [Fe2+] = 0.27 mmol L-1; pH = 3.0; T = 40°C) and acid hydrolysis processes. Along the experiments, samples were withdrawn and analyzed by a total organic carbon (TOC) analyzer and a liquid chromatography system coupled to diode array (HPLC-DAD) and mass spectrometry (HPLC-MS) detectors. The hydrolysis process proved to be less efficient, because AMX removals greater than 80% were observed only after 24 hours of reaction (pH 2). Conversely, the photo-Fenton process removed completely AMX in just 20 minutes, reaching 85% of TOC removal in 2 hours. Finally, the AMX aqueous solutions treated by the studied processes was also evaluated in respect of its toxicity to some microorganisms, applying two antimicrobial susceptibility tests: disk-diffusion and broth microdilution methods. It was observed that the AMX aqueous solutions, pretreated by the photo-Fenton process, for just 7.5 min of reaction time, did not inhibit the microorganisms growth. The obtained results show that the photo-Fenton process was able to degrade AMX, in a relatively short time, and that the generated degradation products did not inhibit the microorganisms growth, when compared to acid hydrolysis process. Thus, it was verified the potential application of the photo-Fenton system as a pretreatment step to conventional biological oxidation processes for the treatment of industrial wastewaters.

Evaluation of bacterial diversity recovered from petroleum samples using different physical matrices

ABSTRACT Unraveling the microbial diversity and its complexity in petroleum reservoir environments has been a challenge throughout the years. Despite the techniques developed in order to improve methodologies involving DNA extraction from crude oil, microbial enrichments using different culture conditions can be applied as a way to increase the recovery of DNA from environments with low cellular density for further microbiological analyses. This work aimed at the evaluation of different matrices (arenite, shale and polyurethane foam) as support materials for microbial growth and biofilm formation in enrichments using a biodegraded petroleum sample as inoculum in sulfate reducing condition. Subsequent microbial diversity characterization was carried out using Scanning Electronic Microscopy (SEM), Denaturing Gradient Gel Electrophoresis (DGGE) and 16S rRNA gene libraries in order to compare the microbial biomass yield, DNA recovery efficiency and diversity among the enrichments. The DNA from microbial communities in petroleum enrichments was purified according to a protocol established in this work and used for 16S rRNA amplification with bacterial generic primers. The PCR products were cloned, and positive clones were screened by Amplified Ribosomal DNA Restriction Analysis (ARDRA). Sequencing and phylogenetic analyses revealed that the bacterial community was mostly represented by members of the genera Petrotoga, Bacillus, Pseudomonas, Geobacillus and Rahnella. The use of different support materials in the enrichments yielded an increase in microbial biomass and biofilm formation, indicating that these materials may be employed for efficient biomass recovery from petroleum reservoir samples. Nonetheless, the most diverse microbiota were recovered from the biodegraded petroleum sample using polyurethane foam cubes as support material.

Evaluation of bacterial diversity recovered from petroleum samples using different physical matrices.

Unraveling the microbial diversity and its complexity in petroleum reservoir environments has been a challenge throughout the years. Despite the techniques developed in order to improve methodologies involving DNA extraction from crude oil, microbial enrichments using different culture conditions can be applied as a way to increase the recovery of DNA from environments with low cellular density for further microbiological analyses. This work aimed at the evaluation of different matrices (arenite, shale and polyurethane foam) as support materials for microbial growth and biofilm formation in enrichments using a biodegraded petroleum sample as inoculum in sulfate reducing condition. Subsequent microbial diversity characterization was carried out using Scanning Electronic Microscopy (SEM), Denaturing Gradient Gel Electrophoresis (DGGE) and 16S rRNA gene libraries in order to compare the microbial biomass yield, DNA recovery efficiency and diversity among the enrichments. The DNA from microbial communities in petroleum enrichments was purified according to a protocol established in this work and used for 16S rRNA amplification with bacterial generic primers. The PCR products were cloned, and positive clones were screened by Amplified Ribosomal DNA Restriction Analysis (ARDRA). Sequencing and phylogenetic analyses revealed that the bacterial community was mostly represented by members of the genera Petrotoga, Bacillus, Pseudomonas, Geobacillus and Rahnella. The use of different support materials in the enrichments yielded an increase in microbial biomass and biofilm formation, indicating that these materials may be employed for efficient biomass recovery from petroleum reservoir samples. Nonetheless, the most diverse microbiota were recovered from the biodegraded petroleum sample using polyurethane foam cubes as support material.

Halotolerant bacteria in the São Paulo Zoo composting process and their hydrolases and bioproducts

Halophilic microorganisms are able to grow in the presence of salt and are also excellent source of enzymes and biotechnological products, such as exopolysaccharides (EPSs) and polyhydroxyalkanoates (PHAs). Salt-tolerant bacteria were screened in the Organic Composting Production Unit (OCPU) of São Paulo Zoological Park Foundation, which processes 4 ton/day of organic residues including plant matter from the Atlantic Rain Forest, animal manure and carcasses and mud from water treatment. Among the screened microorganisms, eight halotolerant bacteria grew at NaCl concentrations up to 4 M. These cultures were classified based on phylogenetic characteristics and comparative partial 16S rRNA gene sequence analysis as belonging to the genera Staphylococcus, Bacillus and Brevibacterium. The results of this study describe the ability of these halotolerant bacteria to produce some classes of hydrolases, namely, lipases, proteases, amylases and cellulases, and biopolymers. The strain characterized as of Brevibacterium avium presented cellulase and amylase activities up to 4 M NaCl and also produced EPSs and PHAs. These results indicate the biotechnological potential of certain microorganisms recovered from the composting process, including halotolerant species, which have the ability to produce enzymes and biopolymers, offering new perspectives for environmental and industrial applications.