Production of Pectin Lyase by Aspergillus niveus under Submerged and Solid State Fermentations Using Agro-Industrial Residues as Carbon Sources

Agricultural wastes are rich in sugars and other nutrients that can support the growth of microorganisms which may in turn produce a variety of technologically valuable enzymes, such as pectin lyase (PL). This work reports the production of PL A. niveus grown under Submerged (SbmF) and Solid State Fermentations (SSF), with agroindustrial wastes or citrus pectin as substrate. A. niveus produced high levels of PL under SbmF using Czapeck medium supplemented with citrus pectin, after 4 days at 40 oC, without agitation. Besides citrus pectin, 16 other carbon sources were also tested. Apple peel provided the highest PL levels, followed by orange peel and passion fruit peel. Other agricultural residues were used for SSF, among them wheat bran which showed to be the best PL inducer, followed by apple peel. PL had maximum activity at 55 oC, was stable at 50 oC with the addition of 1% PEG and maintained 50% activity at 70 oC adding 1% sorbitol, during 30 min. These results suggested that the production of PL by A. niveus can be obtained at low cost using inexpensive residues resulting from agroindustrial activities. Furthermore, the thermal stability of this enzyme is promissory for eventual exploration in industrial processes.