Stabilization of carboxymethyl cellulase from the fungus Aspergillus niger produced by solid-state fermentation in fruit residues using chemical preservatives.

Abstract The residues of fruticulture of fruits such as acerola, guava, passion fruit, and mango can be efficiently used to produce enzymes by solid-state fermentation. In this work, we used these residues and the filamentous fungus Aspergillus niger ATCC 1004 to obtain carboxymethyl cellulase (CMCase). The preservation of enzyme activity is fundamental for providing commercial enzymes with a good price and high enzyme activity. Three substances (sodium chloride, sodium benzoate, and monosodium phosphate) were tested as enzyme activity preservatives; a simplex-centroid mixture design was applied to obtain the best concentrations of these substances. The effect of preservatives on the activity of the CMCase enzyme was tested for 72 hours by incubating the enzyme with the salts of sodium chloride, monosodium phosphate, and sodium benzoate at various concentrations, in citrate-phosphate buffer pH 5.0 at 50 mM, at a temperature of 50°C. The results showed that the mixture that produced the optimum response was composed of 42% sodium chloride, 38% sodium benzoate, and 20% monosodium phosphate. Then, the substances studied shows that are good option to preserve the CMCase enzyme produced by the fungus Aspergillus niger ATCC 1004.