title: Xylanase production by Bacillus circulans D1 using maltose as carbon source.
abstract: Bacillus circulans D1 is a good producer of extracellular thermostable xylanase. Xylanase production in different carbon sources was evaluated and the enzyme synthesis was induced by various carbon sources. It was found that D-maltose is the best inducer of the enzyme synthesis (7.05 U/mg dry biomass at 48 h), while D-glucose and D-arabinose lead to the production of basal levels of xylanase. The crude enzyme solution is free of cellulases, even when the microorganism was cultivated in a medium with D-cellobiose. When oat spelt xylan was supplemented with D-glucose, the repressive effect of this sugar on xylanase production was observed at 24 h, only when used at 5.0 g/L, leading to a reduction of 60% on the enzyme production. On the other hand, when the xylan medium was supplemented with D-xylose (3.0 or 5.0 g/L), this effect was more evident (80 and 90% of reduction on the enzyme production, respectively). Unlike that observed in the xylan medium, glucose repressed xylanase production in the maltose medium, leading to a reduction of 55% on the enzyme production at 24 h of cultivation. Xylose, at 1.0 g/L, induced xylanase production on the maltose medium. On this medium, the repressive effect of xylose, at 3.0 or 5.0 g/L, was less expressive when compared to its effect on the xylan medium.
authors.affiliation: Laboratório de Bioquímica e Microbiologia Aplicada, IBILCE-Instituto de Biociências Letras e Ciências Exatas, UNESP-Universidade Estadual Paulista, São José do Rio Preto, São Paulo, Brazil.
authors.forename: D A
authors.initials: DA
authors.lastname: Bocchini
authors.forename: E
authors.initials: E
authors.lastname: Gomes
authors.forename: R
authors.initials: R
authors.lastname: Da Silva
mesh_terms: D001407:Bacillus / Q000145:classification* / Q000201:enzymology*; D019149:Bioreactors / Q000382:microbiology*; D002244:Carbon / Q000378:metabolism; D018929:Cell Culture Techniques / Q000379:methods*; D043364:Endo-1,4-beta Xylanases / Q000378:metabolism*; D008320:Maltose / Q000378:metabolism*; D013045:Species Specificity
chemical_list: D008320:Maltose; D002244:Carbon; D043364:Endo-1,4-beta Xylanases