Licuri (Syagrus coronata) Oil Cake as a Substrate for Collagenolytic Protease Production by Submerged Fermentation Using a Novel Strain of Penicillium citrinum Isolated from the Brazilian Caatinga

Purpose This work aimed to produce, purify, and characterize a collagenase from a new strain of Penicillium citrinum isolated from Caatinga, introducing the residue from licuri (Syagrus coronata) oil extraction as a substrate. Methods Collagenase production through 72-h submerged fermentation was optimized by response surface methodology, varying the substrate concentration, temperature, initial pH of the medium, and orbital agitation, following a 24-factorial design. The enzymatic purification used low and high-resolution processes, and the enzyme was characterized by their physicochemical properties. Results Our results showed that the maximum collagenolytic activity, obtained under optimized conditions, was 295.56 U/mL. Collagenase was stable at a wide range of pH (6-10) and temperature (25-40 degrees C), with optimal activity at 37 degrees C and pH 9. Enzyme activity was completely inhibited by phenylmethylsulfonyl fluoride (PMSF) and Zn+, while it was promoted by Na+ (by 43%), Ca2+ (by 8%), and beta-mercaptoethanol (by 39%). Conclusions By introducing a natural residue as a promising substrate in addition to a new collagenase-producing strain, these results highlight the potential of resources from the Caatinga biome to produce new industrially useful enzymes.