Composting operation systems are valuable sources of microorganisms and enzymes. This work reports the assessment of proteolytic enzymes from cultivable bacteria isolated from a composting facility of the Sao Paulo Zoo Park (SPZPF), Sao Paulo, Brazil. Three hundred bacterial isolates were obtained and identified based on 16S rRNA gene as belonging to 13 different genera. The most common genus among the isolates was Bacillus (67%); some of which show high proteolytic activity in their culture media. Biochemical assays of hydrolytic activities using FRET peptides as substrates allowed the characterization of a repertoire of serine proteases and metalloproteases with different molecular weights secreted by Bacillus strains isolated from composting. Furthermore, thermostable serine and metalloproteases were detected in the composting leachate, which might be of interest for industrial applications.
Cellulolytic and proteolytic ability of bacteria isolated from gastrointestinal tract and composting of a hippopotamus
The bioprospection for cellulase and protease producers is a promise strategy for the discovery of potential biocatalysts for use in hydrolysis of lignocellulosic materials as well as proteic residues. These enzymes can increment and turn viable the production of second generation ethanol from different and alternative sources. In this context, the goal of this study was the investigation of cellulolytic and proteolytic abilities of bacteria isolated from the gastrointestinal tract of a hippopotamus as well as from its composting process. It is important to highlight that hippopotamus gastrointestinal samples were a non-typical sources of efficient hydrolytic bacteria with potential for application in biotechnological industries, like biofuel production. Looking for this, a total of 159 bacteria were isolated, which were submitted to qualitative and quantitative enzymatic assays. Proteolytic analyzes were conducted through the evaluation of fluorescent probes. Qualitative assays for cellulolytic abilities revealed 70 positive hits. After quantitative analyzes, 44 % of these positive hits were selected, but five (5) strains showed cellulolytic activity up to 11,8 FPU/ mL. Regarding to proteolytic activities, six (6) strains showed activity above 10 %, which overpassed results described in the literature. Molecular analyzes based on the identification of 16S rDNA, revealed that all the selected bacterial isolates were affiliated to Bacillus genus. In summary, these results strongly indicate that the isolated bacteria from a hippopotamus can be a potential source of interesting biocatalysts with cellulolytic and proteolytic activities, with relevance for industrial applications.
Application of Conventional Heating and Microwave Irradiation for the Biocatalytic Reduction of Fluoroacetophenones by Thermophilic Bacteria
This paper describes the bioreduction of four fluoroacetophenones with thermophilic bacteria (Bacillus sp. FPZSP005, B. subtilis FPZSP088, B. licheniformis FPZSP055 and BC-FPZSP051). The reduction reactions were performed under microwave irradiation and the thermophilic bacteria of the Bacillus genus provided moderate conversions to fluoroalcohols with yields in the 26-42% ranges and 5-62% e.e. When the reactions were carried out under conventional heating, they showed high conversions and selectivities (up to > 99% e.e.). This is the first study in the literature on the use of microwave irradiation with thermophilic bacteria applied on biocatalysis.