Others factors that are important to tannase production
are the supplementation of the culture medium with an
adequate concentration of carbon, nitrogen and mineral
source (besides cultivation in an ideal pH), temperature
and incubation time. Aspergillus sp. GM4 tannase production
was increased with low MgSO4 supplementation.
Many enzymes require metal ion activators to achieve
full catalytic activity. At low concentrations, metal ions
act as enzymatic cofactors, thereby increasing the catalytic activity of the enzyme, whereas at high concentrations,
metal ions can reduce catalytic activity [25]. Mg2+
is a well-known enzyme cofactor. The supplementation
of the culture medium with salts containing magnesium
is important for adequate action of magnesium-dependent
enzymes, which are present in the general metabolic
pathways and in synthesis of nucleic acids.