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Pectinase production by Aspergillus niger LB-02-SF is influenced by the culture medium composition and the addition of the enzyme inducer after biomass growth

Reginatto, Caroline, Rossi, Caroline, Miglioranza, Betina Gamba, Santos, Marielem dos, Meneghel, Lenara, Silveira, Mauricio Moura da, Malvessi, Eloane
Process biochemistry 2017 v.58 pp. 1-8
Aspergillus niger, Citrus, biomass, culture media, developmental stages, glucose, microbial growth, mixing, oxygen, pH, pectins, polygalacturonase
The production of pectinase by Aspergillus niger LB-02-SF was focused on a submerged cultivation, before it was evaluated in a solid-state process. This study involved the creation of a defined culture medium and an evaluation of the effects of the addition of the enzyme inducer, citrus pectin, to the medium after the intense biomass growth phase. A culture medium formulated without glucose allowed a reduction of biomass growth and greater pectinase production, facilitated by the control of process parameters such as mixing, pH and oxygen supply. The addition of pectin when a minimum pH of 2.7 was reached at 22h of cultivation did not affect fungal growth. The maximum biomass concentration was 11.0g/L at 48h, a value similar to that observed for the control, in which pectin was included in the medium at the beginning of the process (11.5g/L, at 41h). However, this condition favored the production of 14U/mL pectinase, which was approximately 40% higher than the value observed for the control. These results show that pectinase production by A. niger in a submerged cultivation is strongly affected by the medium composition as well as the delayed addition of pectin to the fermentation broth.