Produção, caracterização e aplicação de enzimas proteolíticas de Bacillus licheniformis CCMA 1674

Abstract

Proteases are enzymes that hydrolyze protein peptide bonds into peptides and amino acids. Although there are several sources for obtaining enzymes, microbial sources have dominated the industrial sectors, due to the easy availability and rapid growth of microorganisms. The bacterial genus, Bacillus, has stood out in laboratory use and in the commercial production of proteases, as they are capable of developing in extreme conditions of temperature and pH. Every year, a huge amount of waste is generated by agroindustries. Enzymatic technology seeks to use these cheap and renewable agro-industrial residues as a substrate for the production of enzymes through fermentation processes in order to meet the growing world need. Solid waste generated in the fishing and aquaculture production chain corresponds to 20% of the volume produced, with a high crude protein content. The use of these, as a source of carbon, energy and nutrients, has ensured good enzymatic production and reduced costs of industrial processes and also helps to reduce the environmental impacts caused by improper disposal. In this context, the present work aimed to evaluate the potential of protease production by Bacillus licheniformis CCMA 1674, in cultures containing flour from fish processing waste. Throughout the entire fermentation process, when incubated at a temperature of 37 °C at 150 rpm, the maximum protease activity (779,27 U/mL) was found in a medium containing 0.5% fish residue meal, pH 7, for 72 hours. The experiments showed that the optimum temperature for enzyme action was 70°C, pH 8.5, Mg2+ as a stimulator ion and EDTA and 1-10 phenanthroline as inhibitors. When under optimized conditions at 96 hours, varying the concentration of fish residue meal and initial pH, the test with 1.05% of fish residue and initial pH of 7.5 obtained the best results in the protease activity (821,01 U/mL). In the study for the application of protease, using casein and fish residue as substrate, and testing two temperatures (70°C and room temperature), greater activity of the enzyme was observed when the fish residue was used at room temperature.