Produção de protease por Bacillus sp. CL18 em cultivos submersos e bioatividades de hidrolisados proteicos obtidos por conversão microbiana e catálise enzimática

Abstract

In this study, the effect of different organic substrates/co-substrates to increase the production of extracellular proteases by Bacillus sp. CL18 in submerged cultures was evaluated, as well as the in vitro bioactivities of supernatants recovered from cultures with the best substrate/co-substrate combination, and the application of the obtained protease to produce antioxidant hydrolysates from soy protein isolate (PIS). Ground fish scales (FS) resulted in the highest protease production at a concentration of 30 g/L (FS30). The addition of milled chicken feathers (MF) caused an increase in the protease yield, particularly at the concentration of 5 g/L (FS5), with the production peak observed after 4 days of cultivation. An increase in antioxidant, antidiabetic and antihypertensive potentials was observed during cultivations with the CL18 strain in the optimized medium (FS30+MF5), which suggests the release of bioactive molecules from fish scales and feathers. The protease recovered from cultivations in optimized medium was able to hydrolyze PIS, with increased antioxidant capacity in the obtained hydrolysates, which was demonstrated by radical scavenging, reduction of Fe3+ and chelation of Fe2+. In summary, it was possible to obtain proteases and bioactive hydrolysates from the bioconversion of wastes (FS and MF) by Bacillus sp. CL18. The produced protease showed potential for the hydrolysis of a food protein (PIS), with the consequent generation of hydrolysates with antioxidant capabilities. Subsequent studies can assess the protease's ability to hydrolyze other proteins (food or non-food), as well as advance towards the identification of bioactive molecules obtained through microbial bioconversion and enzymatic catalysis.