title: Production of polygalacturonases by Aspergillus oryzae in stirred tank and internal- and external-loop airlift reactors.
abstract: The production of endo- and exo-polygalacturonase (PG) by Aspergillus oryzae was assessed in stirred tank reactors (STRs), internal-loop airlift reactors (ILARs) and external-loop airlift reactors (ELARs). For STR production, we compared culture media formulated with either pectin (WBE) or partially hydrolyzed pectin. The highest enzyme activities were obtained in medium that contained 50% pectin in hydrolyzed form (WBE5). PG production in the three reactor types was compared for WBE5 and low salt WBE medium, with additional salts added at 48, 60 and 72h (WBES). The ELARs performed better than the ILARs in WBES medium where the exo-PG was the same concentration as for STRs and the endo-PG was 20% lower. These results indicate that PG production is higher under experimental conditions that result in higher cell growth with minimum pH values less than 3.0.
authors.affiliation: Instituto de Biotecnologia, Universidade de Caxias do Sul, Caixa Postal 1352, CEP 95001-970, Caxias do Sul, RS, Brazil. rcfontan@ucs.br
authors.forename: Roselei Claudete
authors.initials: RC
authors.lastname: Fontana
authors.forename: Maurício Moura
authors.initials: MM
authors.lastname: da Silveira
mesh_terms: D001236:Aspergillus oryzae / Q000201:enzymology* / Q000254:growth & development; D019149:Bioreactors / Q000382:microbiology*; D001709:Biotechnology / Q000295:instrumentation* / Q000379:methods*; D002241:Carbohydrates / Q000032:analysis; D003470:Culture Media; D006863:Hydrogen-Ion Concentration; D006868:Hydrolysis; D010100:Oxygen / Q000032:analysis; D010368:Pectins / Q000378:metabolism; D011096:Polygalacturonase / Q000096:biosynthesis*
chemical_list: D002241:Carbohydrates; D003470:Culture Media; D010368:Pectins; D011096:Polygalacturonase; D010100:Oxygen